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المستخلص
Abbreviations:
AIR-PAMI: a randomized trial of transfer for primary angioplasty versus on-site thrombolysis in patients with high-risk myocardial infarction
AMI: acute myocardial infarction
ARTSII: the Arterialization Therapies Study part II
CABG: coronary artery bypass graft
CAPTIM: the Comparison of Angioplasty and Prehospital Thrombolysis in Acute Myocardial Infarction study
%DS: diameter stenosis
MACE: major adverse cardiac events
MLD: minimal luminal diameter
PCI: percutaneous coronary intervention
PRESTO: the Prevention of Restenosis with Tranilast and its Outcome trial
QCA: quantitative coronary assessment
RVD: reference vessel diameter
Stent-PAMI: the Stent Primary Angioplasty for Myocardial Infarction trial
STOPAMI: the Stent versus Thrombolysis for Occluded coronary arteries in Patients with Acute Myocardial Infarction trial
TIMI: the Thrombolysis in Myocardial Infarction study
TLR: target lesion revascularization
TVR: target vessel revascularizat
Introduction
from the anatomical point of view the coronary arteries are like a tree with multiple bifurcations. Bifurcation lesions account for about 15% to 20% of coronary artery stenoses managed by percutaneous coronary intervention (PCI). This realtively high frequency is underestimated for many reasons especially because of “false” bifurcation lesions (lesion of the main branch without significant lesion of the side branch) that become “true” in the majority of cases after stenting the main branch because of axial plaque redistribution. Another reason is what is called “hidden” bifurcation lesions. This phenomenon is caused by poor visualisation of the side branch ostium due to inadequate views or non identification of the side branch involvement in acute MI (1).
The best strategy for treating bifurcation lesions remains controversial. Factors that influence treatment decisions include target vessel size, nature and angle of the side branch, whether the ostium is involved, plaque volume, and likelihood of plaque shifting (2-5). Although PCI techniques have improved substantially with the introduction of new stent designs, side-branch protection, kissing balloon inflation, and debulking, bifurcation lesions raise technical challenges (6,7). First generation stents (Palmz-Schatz and cook stents) were not satisfactory either, with many sacrificed small side branches and laborious angioplasty through the struts of the stent. Although coronary stenting has become a routine technique with highly predictable results in the majority of cases, lower angiographic success rates and higher restenosis and thrombosis rates were noted after PCI for bifurcation lesions especially when multiple stents were used (8-10,22). It has been suggested that the risk of side branch occlusion does not represent a real problem since bifurcation lesions usually involve side branch <2.5 mm in diameter . Indeed , side branch compromise is often associated with non-Q-wave MI, consequentely an attempt to acheive patency of the side branch as much as possible is the objective in most of the cases of bifurcation lesion stenting. The learning curve in bifurcation lesions involves the stratgy more than the technique .Understanding the cruicial role of appropriate strategies using optimal stent designs, the predictable plaque shifting phenomenon especially in false bifurcation lesions, and the benficial effect of final kissing balloon inflation in order to optimise the results and correct the secondary stent deformation are the key points that improve the immediate and long- term outcomes (22, 23). Using dedicated technical strategy adapted to the angiographic morphology of the lesion, along with the tips and tricks that we learned during the training phase , the angiographic sucess rate become high with low in- hospital and one- month complication rates. The risk of major adverse cardiac events at 7 months follow-up (especially the risk of target vessel revascularisation ) was influenced by the strategy, the use of tubular stents for the main branch and final kissing ballon inflation (16). The recent introduction of drug eluting stents has resulted in lower events rate and reduction of main branch restenosis however, side branch ostial restenosis remains a problem (25).
Approach to bifurcation lesions may be time-consuming and costely during the learning phase . However , adequate training, indexed mangement of the lesions and use of low profile balloons may decrease the first difficulties.
Although there are many points of reseache in bifurcation lesions, little is known about the impact of bifurcation lesions on procedural success rates and long-term outcomes after primary PCI in patients with acute myocardial infarction (AMI). We evaluated immediate and mid-term outcomes of PCI used to treat bifurcation lesions compared to non-bifurcation lesions in patients referred for AMI.
Aime of The work
The primary objective of this study was to evaluate the impact of bifurcation lesion on the clinical outcome and prognosis of primary PCI for patients with acute myocardial infarction.
METHODS
Patients and study design. We examined data of 646 consecutive patients who were reffered to the catheterization laboratory of Henri Mondor Hospital (University Paris XII Hospital, Creteil, France). The patients were admitted within 12 hours after AMI, were eligible for primary PCI, and were free of cardiogenic shock at presentation.We retrospectively analyzed the data-base comparing patients with and without bifurcation on the treated culprit vessel. AMI was diagnosed according to American College of Cardiology/American Heart Association criteria which includes : typical chest pain, ST segment elevation by more than 2 mm in one or more leads of a 12-lead electrocardiogram, new left bundle branch block, and or elevation of biochemical markers for myocardial damage (CPK MB and/or cardiac troponins) (11).
To evaluate the impact of bifurcation lesions on clinical outcomes of primary PCI for AMI, we compared the rate of major adverse cardiac events (MACE) during the hospital stay and during the first post-procedure year in patients with and without bifurcation lesions. MACE encompasses death, recurrent myocardial infarction, and target lesion revascularization (TLR). TLR was defined as a repeated revascularization procedure (PCI or CABG) driven by symptoms or laboratory test results combined with control angiographic evidence of at least 50% stenosis within the treated lesion.
Angioplasty Procedures. Primary PCI was performed in almost all study patients using 6F material. Percutaneous access was via the femoral or radial approach. Diagnostic and angioplasty materials (e.g., catheters, guide wires, balloons, and stents) were selected according to the target vessel, lesion type, and lesion morphology. Aspirin in a dosage of 250 mg to 325 mg was given before the procedure, either before arrival to the hospital or in the catheterization laboratory, together with a 300-mg loading dose of clopidogrel or an equivalent dose of ticlopidine unless the patient was on antiplatelet therapy before the AMI. Intravenous heparin was given to maintain an activated clotting time greater than 300 seconds during the procedure, and glycoprotein IIb/IIIa inhibitors were used when indicated. Intracoronary vasodilators were injected before balloon inflation to allow accurate lesion assessment. In the bifurcation-lesion group, the treatment strategy was determined according to the type of the bifurcation lesion, size and accessibility of the side branch, and likelihood of plaque shifting. Lesions were pre-dilated if needed, and final kissing balloon inflation was performed to optimize the results. After the procedure, aspirin was continued indefinitely, and clopidogrel 75 mg/day or ticlopidine 250 mg twice daily was used for a variable period according to the clinical status and concomitant medications. Procedural success was defined as less than 30% residual stenosis in the treated vessel without acute complications during the hospital stay.
Follow-up. Follow-up data were obtained by telephone interview or during an outpatient clinic visit 1 year after the procedure. Patients who reported symptoms or signs of recurrent ischemia underwent a full physical examination, a 12-lead electrocardiogram, biochemical assays, and tests to evaluate myocardial ischemia and viability. Selective coronary angiography with angioplasty or CABG was performed in patients who had evidence of recurrent ischemia.
Quantitative Coronary Assessment. Quantitative coronary assessment (QCA) was performed in the bifurcation-lesion group. Minimal luminal diameter (MLD), reference vessel diameter (RVD), and diameter stenosis (%DS) of the target lesion were measured for both the main vessel and the side branch on similar angiographic views before and after PCI, using dedicated software (CAASII, Pie Medical Imaging, The Netherlands). For control angiography during follow-up, in-stent restenosis was defined as (%DS) 50% within the stented segment.
Bifurcation lesions were categorized using the “ICPS” classification scheme (12) figure (8 ), in which type 1 lesions (true bifurcation lesions) involve the main branch proximal and distal to the bifurcation and the ostium of the side branch, type 2 lesions the main branch at the bifurcation site but not the ostium of the side branch, type 3 lesions the main branch proximal to the bifurcation, type 4a lesions the main branch distal to the side-branch ostium, and type 4b lesions the side branch distal to the side-branch ostium.
Statistical Analysis
Continuous variables were expressed as means±SD and compared using Student’s t tests. Chi-square tests were used to compare categorical variables. P values <0.05 were considered statistically significant. (Stateview programe was used for statistical analysis of the data).
Coronary Bifurcational Lesions
Defention and Anatomical considerations:
A true bifurcation lesion is defined as the presence of stenosis > 50% involving both parent vesseles and the ostium of the side branch (Fig 5).Vessel bifurcation are predisposed to atherosclerosis from turbulent flow and increased shear stress (8). Recent advances in percutaneous coronary intervention and lately the introduction of drug eluting- stents have led to dramatic changes in number of patients treated percutaneously . Bifurcated lesions are one of the complex lesion subsets that are now being confronted more frequentely. Bifurcation interventions when compared with non-bifurcation interventions, have a lower rate of procedurale success and a higher rate of restenosis (1-4). Paradoxically although stenting of individual lesion has been showen to be superior to balloon angioplasty , stenting of both branches seems to offer no advantage over stenting of main branch alone. Despite refinements and improvements in the techniques, especially using the ”kissing balloon” and different types of stents, puplished studies have showen unsatisfactory results when PCI is the primary mean used for treating bifurcations (5-9) , which can be du to :
Relatively low success rates (75-85%)
High complication rates (8-22%)
Unacceptable restenosis rates(40-65%)
While the best strategy and approach to treat bifurcated lesions is still controversial ( each case is different according to size of the target vessel , relevant side branch , presence of ostial stenosis, degree of angulation of the side branch , plaque volume , potentioal plaque shifting , and the presence of calcification) there is an increased interset by physician in stenting the bifurcation lesions. (2-5)
The immediate angiographic result is often cosmetically specular, superior to that obtained by balloon angioplasty (PTCA). However restenosis rates following bifurcation stent implantation is still high (25-40% ) in all reported puplications for each of the involved branches using the stents avaliable commercially nowadays.(9,27)
Lesion clacification:
Bifurcation Lesion clacifications take into account the angulation between the main branch and the side branch and the precise location of plaque burden. Axial redistribution of the plaque is an underestimated phenomenon in PTCA. This was clearly demonestrated by Gary Mintez using IVUS (28): because the plaque is not compressible, after balloon PTCA the lumen is enlarged not only due to vessel stretching and dissection but also to plaque elongation.This phenomenon is the key to understanding what occure (plaque shifting or snow plough effect) during the treatment of different types of bifurcational lesions (2,6, 29)
Angulation between both branches of the bifurcation is a very important issue in terms of access to the side branch , plaque shiftining and treatment strategy. According to angulation bifurcation lesions can be divided into:
Y- shape lesion : when the angulation between side and main branch is less than 70°, access to side branch is usually easy but plaque shifting is also more pronounced.
T-shape lesions: when the angulation between side and main branch is more than 70°, access to side branch is usually more difficult and plaque shifting less important. Its very important to note that this angulation is usually favorably modified after wiring both branches of the bifurcation. (2,6) , Fig (6)
Location of the plaque burden is also a very important issue . According to position of the plaque there have been 5 attempts to classify bifurcation lesion which chronologically are Duke (Fig7A) (56), the Sanborn (Fig7B) (57) ,the Safian (Fig7C) (58) , lévefre (Fig7D,8) (12), and Medina (Fig 9) the above recommendations are very commendable but suffer the limitations of coronary angiography (different palque distribution and extention of the lesions when evaluated by intravascular ultrasound), and they do not take into account what happens to the side branch on dilatation of the main branch. Therefore, each lesion must be approached therapeutically in the context of its owen anatomy. (22,23)
Approach to bifurcation lesions :
1- Need for side branch protection : The likelihood of significant side branch narrowing or closure depends on wheather the side branch originates from the primary lesion and the degree to which its ostium is narrowed (Table A). Branch vessel which dose not originate from the parent vessels are at low risk for side branch occlusion even if they are transientely occluded during balloon inflation ( 6 ).
For side branches that originate from the parent lesion, the risk of occlusion is lowest if the side branch contains an ostial stenosis < 50%, intermediate if the side branch contains a non-ostial stenosis >50% and highest if the side branch contains an ostial stenosis >50%. In one study , the riske of progressive narrowing was 12% if the branch ostial stenosis ≤50% vs. 41% if the branch ostial stenosis was > 50% (30) .When primary atheroma obstructs both the parent vessel and the sidebranch ostium by >50%, there is a high incidence of branch occlusion “14-34%” ( 6,31 ) or narrowing “27-41%” (29, 30) unless the branch is protected by guidewire. (table B shows the need for side branch protection)
Table (A) .Parent vessel- side branch relationships ( 6,,29,30,31,32)
Anatomy Risk of Sidebranch Technical Difficulty Protection
Occlusion Wiring Occluded Branch Recommended
Branch not involved by parent
Vessel lesion but in jeoparady low<1% Low No
Due to transient occlusion during
Balloon inflation
Branch originates from diseased Moderate (1-10%) Low to moderate Probably yes
Parent vessel segment ; branch is depends on vessel size
Normal and distribution
Ostium of branch vessel High (14-35%) High Yes
> 50 % stenosis
Table (B) ( Need for Side Branch Protection ) (2,29)
Side branch Protection Recommended:
1- Any side branch > 2mm in diameter that has an ostial stenosis > 50% and
originates from the parent vessel lesion “ True bifurcation lesions” are associated
with a high incidence of side branch occlusion and a low salvage rate when left
unprotectd
2- Any side branch > 2mm in diameter (without ostial stenosis) that originates
from the parent vessel lesion. Although it is usually possible to retrieve these
occluded side branch , their large caliber justifies protection.
Side branch Protection Probabely not necessary:
1- The side branch is normal and dose not originate from the parent vessel lesion
2- The side branch is < 1.5 mm in diameter and would not receive a bypass
graft during CABG
3- The side branch supplies a small amount of viable myocardium
4- Isolated stenosis of the origin of the side banch usually dose not require
protection of the parent vessel
Equebments, set-up and preparation of the operating room:
The angioplasty sets including catheters, inflator, angioplasty guidwires, balloons and one or two stents, tourquers with different colors may be used but its extremely important to have an experienced assistant who is able to keep the guid.
Procedure Performance:
Access site may be femoral or radial depending on the operator performance and experience (33)
Primary Angiograpgy:
Device selection: selection of the guiding catheters: the selection of the size (6F, 7F, 8F) of the guiding catheter occurs after deciding to stent or not the side branche.Treatment of bifurcation lesions frequentely requires simultaneous insertion of 2 balloons, or 2 stents ( sometimes 3 in case of trifurcation) ; therefore some specific considerations are important regarding the selection of an appropriate guiding catheter.
Large- lumen (> 0.67 inch) 6-F catheter are used in about 95% of cases because kissing balloon inflation can be performed with up to two 3.5mm Viva ballloon. If two stents are needed some limitations should be understood. The two stents can only be inserted one after the other, not simulatenously in 6-F guiding catheter.
The standard crush and V technique ( kissing stents) technique can not be performed unless a guiding catheter of at least 7-F with internal diameter of 0.081 inch (2.06mm) for the Taxus stent (Boston scientific) or 8-F with an internal diameter of 0.088 inches (2.2mm) for Cypher ( Cordis, Jonson and Jonson, Warren, New Jersey) is used. A 6- F guiding catheter can be used if the operator performes a provitional T-stenting technique. Techniques like T- technique, reversed crush, step crush can all be performed using 6-F guiding catheter.
The modified T- technique requires at least 7-F guiding catheter, and Cullots, Y, and skirit technique require at least 8-F guiding catheter.
Seven French catheters can be used in 4% of cases when rotablator is planned for very calcified lesions. Eight-French catheters are used cases of simultaneous inflation of ballons for some trifurcation lesions . New large lumen 5-French catheters are not compatible with kissing balloons.
Good back-up is necessary as in any stent implantation procedure. Using the femoral or left radial approach the first choice is Extra back-up XP 4 for the left coronary artery especially for LAD-diagonal bifurcation. Amplatz left (AL2) guides are used somtimes for bifurcation of the circumflex artery depending on the operator’s performance. The first choice for the right coronary artery is JR4 and somtimes AL, Amplatz right or multipurpose guide. using the right radial approach , the first choice, for LAD is XB4 guide and for circumflex artery XB4 or AL2 or AL3. For the right coronary artery we can use JR4 or AL2 in the majority of cases. After kissing balloon inflation , its very important to check the guiding ctheter position when pulling back both balloons because deep intubation may occure. Its also very important to open the Y connector in order to avoid creation of bubles in the guide by Venturi effect. (1,2, 4)
Imaging Views:
Choosing imaging views is also very important issue, especially to visulaize ostial take off of the side branch and for good positioning of the stent in the side branch. For the LAD - diagonal bifurcation we can use RAO 10°, Cranial 40° as a reference, but the positioning of the side- branch stent at the ostium level is always checked at least in other views (LAO 45°, Cranial 25° and somtimes the spider view). For the Circumflex- marginal bifurcation , the working incidence is usually the RAO 15° Caudal 25° and the side branch ostium is checked using the spider view or modified spider view ( more or less LAO). For distal right coronary artery , the working incidence is AP, Cranial 20° and LAO 45°. ( 1,2 )
Primary Lesion Crossing
Device Choice: Guidewire selection is based on experience. Having a good tourqability and steerability of guid wire during the whole procedure is essential. In most of the cases with monorail balloon , we can use 182 or 190 cm 0.014 inch guidewires.The BMW wire manufactured by ACS Guidant considered one of the best choices because it is well balanced between supporte, tourquability and steerability. Guidewires with increased radiopacity are not useful in some cases (tourtuosity, calcification, difficult access to side branch) a hyDROPhilic guidwire such as PT graphix (Boston Scientific) may be useful. This guidwires may also be helpful when crossing the struts of the stent proves difficult.
The J tip is shaped usually depending on the angulation of the side branch and the length of tip depending on the diameter of the main branch. In some cases a 90° angulation is necessary for entering the side branch. In the ”extreme” lesions, it is usually impossible to enter the side branch directely. In these cases recommendation is crossing the main branch firstely and then pulling back the wire that ”jump” in the side branch ostium, gentel tourque manouvere helps to feel the lesion and cross it progresssively. In cases of faliure to enter the side branch , infilating a small balloon in the main branch ( with 2 guidewires in the main branch) may be useful to facilitate guidewire manibulation to enter the side branch, using either a BMW or a hyDROPhlic wire.
To avoid guidewire crossing, the recommendation is that the most difficult branch, which is usually the side branch, should be wired firstly.The second guidewire should then be used to cross the main branch lesion with gentel tourqing (no more than a rest rotation).The two guidewires should be positioned separately on the table, according to their location on the screen and the position kept during the whole procedure.
The jailed guidwire: the guidewire in the side branch may be voulantarily ”jailed” (left outside the stent of the main branch). The advantage of this technique is that it modifies favourably the angulation between both branches. Access to the side branch after main branch stenting is, therfore, facilitated . After stenting the main branch , we can use the ”exchange technique”. The guide wire in the main branch ( secured by the stent) is pulled back and ideally the most distant cell of the stent is crossed and the wire is pushed in the distality of the side branch. Then the ”jailed” wire is withdrawn from the side branch and pushed into the main branch ( causations is recommended in order to avoid deep intubation of the guiding catheter). (Fig 12 ) (62)
Dilatation Process
Double guidewire, sequetial PCA: This approach involves placing guidewires in both parent and side branh before balloon inflation .The main advantage of this technique is that it maintains continuous access to both limbs of the bifurcation if acut closure occurs or balloon exchage is needed, better contrast opacification and less expensive if the same balloon can be used for both branches, it dose not , however prevent plaque- shifting or side branh narrowing (40). Monorail balloon, over-the wire balloons, fixed wire balloons or any combination of the above may be used . Once both guide wires are in place , the parent vessel and side branche are dilated in sequential fashion ; the same balloon can be used if the bifuration limbs are the same in diameter. Fixed wire-balloon sytstem can be used, but the side branch cannot be protected if balloon upsizing become necessary. When a fixed- wire system is used to dilate the parent or the side branch, it is best to advance the balloon byoned the lesion to assess the agioraphic results before moving the system. This technique has the disadvantages of increased riske of wire entaglment , single balloon may not match the diameter of the parent vessel proximal and distal to the branch, and it dose not eliminate the plaque shifing .
The “Plaque Shifting” Phenomenon:
The main difference between in vitro models and real patients is the presence of atheromatous plaque that can be calcified or not, concentric or eccentric, thick or thin, with a varying degress of arterial wall remodeling and plaque volume. It has been clearly showen that subsequent to balloon inflation , atheromatous plaque may shift proximally or distally and even along the arterial circomflex (axial plaque redistribution is not only longitudinal but also circumferential) (fig 10 ) ( 28) . This phenomenon is accentuated by stent placement (fig 11) (60) . Thus dilatation or stenting of a lesion proximal or distal to a bifurcation often results in plaque shifting towards the side branch, which requires dilatation or even stenting of the ostium and , sometimes, even placement of a third stent in proximal or distal segment of the main branch in order to address the plaque shifting from the side branch. The same phenomenon occurs during dilatation of a main branch lesion located opposite a side branch; side branch occlusion is reported in 4.5-26% of cases and predectors are: side branch originating from main branch lesion, presence of an ostial lesion in the side branch , small side branch reference diameter, stent/artery ratio in the main branch, unstable coronary syndrome. The type of stent use dose not impact the risk of side branch occlusion. Side branch occlusion is usually considered of littel consequence (temporary chest pain, moderate CPK elevation) and patency of most of these occluded side branch is spontaneously restored; However in the recent NIRVANA study the use of NIR stent was associated with 4.7% risk of side branch occlusion and 27% risk of stenosis. The rate of Q wave myocardial infarction was 7% when side branch occlusion occured (CPK elevation was >8 times the normal value in 20% of cases, >5 times in 33% of cases). Overall the rate of Q or non-Q wave MI ( CPK >5 times the normal value) in 40% in the side branch occlusion group. Consequentely, because of the risk of side branch occlusion, tight lesions located in the main branch next to a bifurcation lesion must be considered a bifurcation lesion. (61)
Endoprosthesis implantation
One or two stents:
Is the side branch is large enough with a sufficient territory of distribution to justify stent implantation? This initial question must be answered before going into further detail. There are also rare circumstances in which the side branch is important and can not be wired . In this situation the operator must considere alternative solutions, such as bypass surgery if the bifurcation in question is the left main or the left anterior descending vessel and a larg diagonal vessel. In general we try not to stent the side branch but if needed , we plane an effective strategy for stenting both branches . the decsion to use one or two stents , or sometimes even three (in case of trifurcation) , should be mad as early as possible .
An appropriate and timely taken decision will affect the results , save time, lower costs, and lower the risk of complications. If we decided to use one stent (at the main branch) there is almost always the possibility of placing a second stent on the side branch in case the result is not optimale or adaquate , this condition defined as (provitional stenting.) Fig (13) (62)
One stent by intention to treat:
The most commen approach to treat bifurcation lesions is stenting only the main branch. The first step is to decide whether a wire is needed in the SB. We propose that a wire is needed in the following circumstances: 1) the operator is undecided regarding whether or not to place wire, 2) the side branch has a narrowing at its ostium 3) the main branch has sever stenosis with large plaque burden and side branch originate with an angle of ≤ 45°) or 4) the ostium of the side branch deteriorates after pre-dilatation whether pre-dilatation of the main branch and or side branch is required.
The second step is to decide whether pre-dilation of the main branch and/or the side branch is required. The third step is to place a stent in the main branch. The stent should be deployed at low pressure (8 atm) so as not to damage the trapped wire in the side branch or to deteriorate the ostium of a side branch without a wire across the stent struts of the main branch. The fourth step is to place a wire into the SB; this procedure can be performed with the wire trapped behind the stent serving as a marker. Regarding the wire of choice for re-entering the SB, we prefer first to use a floppy wire such as the Balance Universal (Guidant, Temecula, Califor¬nia); or Balanced Middel Weight (BMW , ACS Guidant), if not successful, we would then try an intermediate wire or a Rinato wire (Asahi Intecc [Thailand] Co. Ltd., Pathumthani, Thailand), and in rare cases we may use a hyDROPhilic wire such as the Pilot 50 or 150 (Guidant).
The fifth step, after having rewired the side branch, is to post-dilate the MB stent at high pressure. We may use the same balloon for stent delivery, or if we are concerned about distal or proximal dissections, we will use a short balloon, usually noncompliant. If we think that the stent may be under-deployed, especially in its proximal part, it is important to perform sequential step inflations with the short balloon. In the sixth step, the results are evaluated. At the level of the MB, the results should be optimal, or higher-pressure dilatation should be performed. If the result at the level of the side branch is satisfactory, the procedure is considered complete.
The seventh step is performed only if the operator considers the result at the side branch not satisfactory. In this case, dilatation of the SB and kissing balloon inflation (usually at 8 atm) between the main and the side branch is performed. If the result is acceptable after kissing balloon inflation, the procedure is considered complete. The eighth step occurs only if the result at the SB is unsatisfactory. At this point the operator can still decide to stop because the side branch is not ideal for stenting because of difficulty in positioning a stent, size, distal run off, complex¬ity of the procedure, and so on. If the operator thinks that the result at the level of the side branch needs to be improved, then stenting is performed.
Main Branch stenting
Experimental data show well-preserved flow into non-diseased side branch after stent placement. Nevertheless, stents should be used cautiously in patients with stenosis involving significant sidebranches; even though side branches may be accessible by PTCA, added technical expertise is required for successeful salvage. When a parent lesion requires intervention but has a side branch , the decision to implant stent is based on the need for immediate revascularization , the size of the side branch, and the amount of viable myocardium served by that branch. The choice of stent design for the main branch of bifurcation lesion is a compromise between sid branch access and plaque scafolding (36). When using the tubular stents there is some degree of coverage of the side branch ostium with the main branch stent following inflation of the balloon in the side branch.This cause secondery stent deformation in the main branch results in the non-apposition of the stent to the vessele wall opposite to the entery of the side branch , which is restored by kissing balloon inflation. In some studies , the optimal side branch access and stent coverage was first obtained with the bestent. More recentely , new generation tubular stents became avaliable and BX Velocity and Biocompatible stents proved comparable to the Bestent in terms of side branch access and scafolding. The Duet or Tristar stent can also be used but side branch access is more difficult and not achieved in all cases (especially when the main branch is <3.5 mm in diameter).The AVE microstent or the AVE II which is a multicellular stent, gives a good access to the side branch but a less optimal coverage of the carina and there are some cases of plaque prolapse.The Cross Flex which is a coil stent gives also a good access to the side branch but less optimal plaque scafolding. Fig ( 14 ) ( 37 ).
Side branch stenting
Side branch stenting is not necessary in all cases especially when the side branch lesion is short.The main reason is that when using tubular stents , the ostium of the side branch is partely ”stented”by the deformation of the main branch stent in the majority of cases. Initial profile of the stent (crossability through the main branch stent windows) and visibility to achieve ideal stent positioning (good stent radiopacity or visible markers) are the other two important criteria in stent choice strategy for the side branch. Bestent, AVE S540 or S670, biocompatible stent, BX Velocity are acceptable in this respect, with the use of AVE microstent some cases of sten displacement after kissing balloon inflation have been observed despite an intial good positioning at side branch ostium.(38)
Classification of tratment: in order to classify different types of treatment used for bifurcation lesions, we can defined 4 groups Fig ( 15,16 )
Type “A” Treatment: consists in positioning two stents in a T-shape configuration at the coronary bifurcation, the side branch being stented first . The technique is now rarely used (only when side branch access seems difficult after guidwire positioning or predilatation. The main limitation is that correct positioning of the side branch stent may be difficult and even if the stent is perfectly positioned , plaque shifting in the side branch may occur after stenting the main branch and this can not be corrected by kissing ballon inflation (12,38,39).
Type “B” Treatment: ( provitional T stenting which was described in detalies earlier) consists in the placement of 1 stent in the main branch followed by provitional stenting of the side branch in a T-shape configuration through the main branch stent, the “jalied wire” technique is almost always used: one wire is positioned in each branch of the bifurcation, starting with the most difficult branch. The main branch stent is implanted first whereas the side branch wire is left (jailed) outside the stent. The main branch wire is pulled back and pushed across the strut of the stent in the side branch. The jailed wire is then pulled back and positioned in the main branch. Then the strut of the main branch is dilated separately or directly by using kissing ballon inflation. When there is a distal lesion in the side branch, its very important to dilate first the strut of the stent because when distal dilatation is performed without opening the strut of the stent it may be impossible to pull back the deflated ballon through the non opend cell.(12)
Advantage: the main advantage of this technique is that stenting of the side branch is optional (if there is a plaque shifting or ostial stenosis), in such way that we can stent both branches with one stent (it is the prefered technique in the vast majority of cases of bifurcation lesions).
Disadvantage: in some cases its difficult to wire the side branch through the struts of the stent of the main branch, and restenosis can occur as a result of gape between the two stents.
Type “C” Treatment : “Cluotte” technique involves placement of stent into the side branch with extension into the proximal aspect of the parent vessel. A wire is then passed through the side of this stent and into the distal vessel through side of the first stent , so that the proximal ends of the first and second stents overlap in the proximal vessel. Idealy, this and other bifurcation stent approaches should be finished by “kissing balloon” inflations to optimize both lumens.
Advantages: This technique is suitable for all angles of bifurcations and provides near-perfect coverage of the SB ostium.
Disadvantages: it leads to a high concentration of metal with a double-stent layer at the carina and in the proximal part of the bifurcation. The main disadvantage of the technique is that rewiring both branches through the stent struts can be difficult and time consuming. (40)
Type “D” Treatment : ( Kissing Stents) whereby stents are simultaneously deployed in the parent vessel and side branch, allowing the operator to shift the “Carina” or bifurcation more proximally in the vessel.
Other types of treatment include Y stent technique which is a complex variant of type D treatment. The V technique , which is also a variant of type D treatment ( 2 stents side by side).(41,42,43)
The Y and Skirit Technique
The Y technique has a particular historical value because it was one of the first bifurcation stenting techniques demon¬strated in a live case course . This technique involves an initial pre-dilatation, followed by stent deployment in each branch (40) . If the results are not adequate, a third stent may also be deployed in the main branch . To effectively try to approximate the proximal stent to the already-deployed stents, it is necessary to modify the stent delivery device by placing one stent over two balloons. With this technique, wire access to both branches is not lost.
Advantages. This technique is a last resort for treating very demanding bifurcations in which there is a need to maintain wire access to both branches.
Disadvantages. The major limitation of this approach is the need to modify the delivery system of the proximal stent and to manually crimp the stent on two balloons. When using a drug eluting stents , this approach may lead to alteration of the polymer. In addition to this issue, it is not always feasible to closely approximate the proximal stent to the two more distal one.
For these reasons, when there is a need to perform the Y technique, a more practical approach is to remove the wire from the side branch and advance and deploy a proximal stent in the MB, trying to approximate this stent as close as possible to the already-deployed stents at the newly formed carina, If necessary, a distal stent can be implanted in the main branch
slightly overlapping the proximal stent. (41)
The V Technique
The V technique consists of the delivery and implantation of two stents together. One stent is advanced in the side branch , the other in the main branch , and the two stents touch each other, forming a proximal carina (63). When the carina extends a considerable length (usually 5 mm or more) into the main vessel, this technique is called simultaneous kissing stents (as described earlier). The type of lesion we consider most suitable for this technique is a very proximal lesion such as a bifurcation lesion located at the left main stem with a left main artery that is short or free of disease. Ideally the angle between the two branches should be less than 90°. The V technique is also suitable for other bifurcations provided the portion of the vessel proximal to the bifurcation is free of disease and there is no need to deploy a stent more proximally.
Advantages. The main advantage of these techniques is that the access to either of the two branches is never lost addition, when a final kissing inflation is performed, there is no need to re-cross any stent.
Disadvantages. It is intuitive how problematic may be the need to position a stent proximal to the double barrel. There is an inevitable bias toward one of the two branches and the high likelihood of leaving a gap. If there is a need to place a stent at the proximal segment of a vessel treated with V stenting, there are two options: 1) a stent is placed proximally, leaving a small gap between the kissing stents and the proximal stent, and 2) the kissing stent technique is con¬verted into a crush technique, with the stent in the main branch compressing the other stent (one arm of the V) in the side branch . A wire will then cross the struts into the side branch , and a balloon will be inflated toward the side branch . After wire removal from the side branch , the proximal stent will be advanced toward the main branch . In this case we are left with a short segment of the main branch proximal to the bifurcation, which has four layers of struts. Because of the complexity of this maneuver, it is clear how important it is to select lesions for the V technique in which there is a very low risk of performing proximal stenting. (64)
Recently proposed approaches with conventional stents and balloons:
In order to avoid the “ potential difficulties” associated with the problem of crossing the main branch stent strut with the guide wire, many authors have proposed new approaches.
Modified T-stent technique was proposed by antonio colombo in 2001, it consists in positioning the proximal part of the side branch stent in the mide part of the main branch. The side branch stent is deployed when the main branch stent is in place. Then the side branch ballon and guide wire are removed and the main branch stent is deployed. Final kissing balloon is recommended . This technique may be usful in a few cases and the only advantage is that osteal stenting of the side branch is obtained in all cases.
The “ Crush technique” was recentely proposed by Antonio Colombo using drug eluting stents. It is an extreme “variant” of the modified T-stenting strategy which consists in positioning the proximal part of the side branch stent at least 5 mm in the main branch lumen, whilst the main branch stent is ready for deplyoment . The side branch stent is deployed, balloon and side branch wire are removed The stent subsequently deployed in the main branch flattens the protruding cells of the stent in the side branch, ie the proximale part of the side branch stent is crushed while deploying the main branch stent ( Hence the name Crush). Wire re-crossing and dilatation of the SB with a balloon of a diameter at least equal to that of the stent , and then final kissing balloon inflation, is recommende. The implementation of final kissing balloon infla¬tion was done to allow better strut contact against the ostium of the SB and therefore better drug delivery . The crush technique therefore became a sort of simplified culottes technique . The positive aspect is that whenever restenosis occurs, this narrowing is very focal (<5 mm in length) and most of the time is not associated with symp¬toms or ischemia. An important element to keep in mind when planning to perform the crush technique is that the two available DES will reach different maximal openings of their cells . The maximal cell diameter will be 3.0 mm for the Cypher stent and 3.7 mm for the Taxus stent. This information should be kept in mind when the side branch has a diameter >3.0 mm.
The main advantage of of this technique is that it is simple ( if final kissing balloon is not performed) . The immediate patency of both branches is assured. This is important when the SB is functionally important or difficult to be wired. In addition, this technique provides excellent coverage of the ostium of the SB
However , several drawbacks have to be underlined .The risk of SAT seems to be high as well as the risk of restenosis of the side branch which is surprisigly as high as 20-25%. The recent bench study performed by John Ormiston have shown that final kissing should be performed to correct stent deformation and obtain optimal stent apposition, which is crucial with DES. Therfore this apparently simple technique has become more complex (2 layers of stent to cross in order to end with Kissing) ( 65).
The reversed Crush
The main indication for performing the reverse crush is to allow an opportunity for provisional side branch stenting. A stent is deployed in the main branch, and balloon dilatation with final kissing inflation toward the side branch is performed. It is assumed that the result at the ostium or at the proximal segment of the side branch is suboptimal for deploying a stent at this site. A second stent is advanced into the side branch and left in position without being deployed. Then a balloon sized according to the diameter of the main branch is positioned at the level of the bifurcation, making sure to stay inside the stent previously deployed in the MB. The stent in the SB is retracted about 2 to 3 mm into the MB and deployed, the deploying balloon is removed, and an angiogram is obtained to verify that a good result is present at the side branch (no further distal stent in the side branch is needed).
If this is the case, the wire from the SB is removed and the balloon in the main branch is inflated at high pressure (12 atm or more). The other steps are similar to the ones described for the crush technique and involve re-crossing into the side branch, performing side branch dilatation, and final kissing balloon inflation.
Advantages. The main advantages of the reverse crush technique are that the immediate patency of both branches is assured and that the technique can be performed using a 6-F guiding catheter.
Disadvantages. This technique has the same disadvantages as the standard crush and is even more laborious.
The step Crush Technique
The only difference from the standard crush technique is that each stent is advanced and deployed separately. First, a stent is advanced in the side branch protruding into the main branch a few millimeters. A balloon is then advanced in the main branch over the bifurcation. Then the stent in the side branch is deployed, the balloon is removed, and an angiogram is performed: if the result is adequate, the wire is also removed. The main branch balloon is then inflated to crush the protruding side branch stent and is removed. Subsequently, a stent is advanced in the main branch and is deployed (usually at 12 atm or more).The next steps are similar to those of the crush technique and involve re-crossing into the SB, performing SB stent dilatation, and final kissing balloon dilatation.
Advantages. The main reason to use this technique is to perform the crush technique with a 6-F guiding catheter. Operators who perform the radial approach may be partic¬ularly interested in this technique.
Disadvantages. This technique has the same disadvantages as the standard crush technique.
All of these techniques are technically difficult and may result in significant difficulty in accessing the parent vessel or side branch because of overlaping metalic elements
Optimization of the final results
The kissing balloon inflation is the necessary “final touch” recommended at the end of the procedure in all cases after opening the main branch stent strut toward the side branch .The most important benefit of this technique is to optimize the final results in order to correct stent deformations after balloon inflation in the other branch. Position and length of each balloon is adapted to the anatomy of the lesion and the risk of proximal or distal dissection. Balloon size is selected according to the distal reference of each branch. Inflation pressure for each branch depends on the fluroscopic apperance of the balloon (no residual waist, balloon/artery ratio 1 to 1:1). Short balloon are now avaliable that help to reduce the risk of geographic miss.
Kissinng Balloon Technique:
Using larg-lumen (>0.067 inch) 6 -french guiding catheter , kissing balloon inflation can be performed with up to two 3 mm (Viva balloon , Boston Scientific).we can use monorail balloons because of increased maneuverability of the bare guidewire in the guiding catheter. With other monorail balloons, 7-Fr guides are necessary to be able to perform kissing balloon inflation.
Kissing balloon inflation: is defined as the simultaneous inflation of both balloons positioned in each branch of the bifurcation, we can use the same balloons for hand crimped stents and final kissing ballooon inflation as for predilatation. (34, 35).
Results Justiification
In the stenting era, the treatment of bifurcation lesion is considered successful when QCA shows < 30% residual stenosis in the main branch and <50% in the side branch along with TIMI 3 flow.QCA analysis of bifurcation lesions is chalenging , in fact there is only one proximal reference for both branches and some disparity between the proximal reference and the distal reference. Defention of the reference diameter for the main branch is difficult: should we use an interpolated analysis or a reference defintion depending on the lesion location ( lesion proximal or distal to the bifurcation). What is the reference for the side branch? (there is no proximal reference , interpolation is not correct despite the flagging technique, only distal reference is mesurable). The current defintion for main branch reference is the interpolated reference and for the side branch is the largest distal reference. This will be improved by Can algorithm (Medis, General Electric) didicated to bifurcation lesions. (2,4,5)
Special cases :
Faliure to wire the side branch: in some instances, because of very eccentric plaque or tourtous vesseles, wiring the side branch is impossible. Sometimes it may be necessary to predilate or stent the main branch , further high-pressure dilatation of the stent at the MB may better open the stent struts and facilitate the access toward the SB. Although rare, after attempting different types of wires with all types of curves and techniques, it may still be impossible to advance a wire in the SB. At this point few options are available: 1) stop the procedure because the risk of losing the SB will be too high, considering also the size and distribution of the branch .
At this point , CABG has to be discussed , because a larg side branch may be lost. It has been proposed to use rotative atherectomy to solve this problem by debulking the main branch lesion, without compromising side branch access.
Passing through the main branch stent : access to the side branch through the strut of the stent is usually possible through 2 or 3 different cells ( proximal , mid and distal). The cell choice influences stent deformation and the best approach is to open the most distal cell. Therefor we can try to cross the most distal cell of the stent during guidwire side branch access. We generally try to pull back the wire from the main branch and find access to the side branch as distally as possibl.
Faliure to cross the stent windows: When using type B treatment , after stent implantation in the side branch , it is pereferable to start with one guidwire in each branch. Indeed when using one guidwire, if after stent implatantation in the side branch the guidwire is pulled back and pushed in the main branch, it may slip through the proximal struts of the stent which may results in faliure to cross with the balloon or deformation of the stent in case of balloon crossing.
Direct stenting
Direct stenting is now used in high proportion of patients , especially in acute coronary syndromes were the soft plaque is associated with a higher risk of distal embolisation . Consequentely, now we can use direct stenting for bifurcation lesions in acute coronary syndromes with the technique previousely described (45).
Matching lesions to treatment:
False bifurcation lesions “Types 2, 3, 4 a lesions selon ICPS classification”
Are the easiest to treat . The lesion is located on the main branch , proximal, distal or at the level of the bifurcation with no significant lesion of the side branch ostium. “The wrong” approach in type 3 and 4a lesion is to try to deploy the stent at the level of the lesion (proximal or distal to the bifurcation) in order to make it simple. Unfortunately in many cases plaque shifting proximal or distal to the stent requires additional stent implantation. Therefore , the approach in this case can be type B treatment (provitional T stenting) in nearlly all cases.
Type 4 lesions are rare (< 10% of cases) , because there is no lesion proximal to the bifurcation, type D treatment can be applied in some cases . The procedure should be performed throgh 7 F guiding catheter. Both branches are wired , predilatation is performed using a kissing ballon in order to ensure that there is no proximal plaque shifting . In cases of proximal plaque shifting , its preferrable to convert type D treatment into classic type B treatment. If not , 2 well visible stents are developed simultaneously at the level of each ostium.
True Bifurcation lesion (type 1 lesion) , are more difficult to treat because the plaque involves the whole bifurcation and side branch access may be difficult. We always wire both branches , starting by the the most chalenging branch to access. Predilatation is performed when required. The strategy is then selected after carful angiographic analysis:
a) for treatment of bifurcation lesions with a short ostial lesion in an easily accessible side branch after wiring , without any evidences of dissection , we use the same approach as for “false bifurcation lesion” (type B treatment) . Because, the side branch lesion is puerly ostial in 50% of cases , side branch stenting is performed only if the results is not optimal after kissing balloon. The “jailed wire” technique maintains facilities side branch patency and side branch access through the main branch stent strut thanks to angle modifications.
b) When access to the side branch remains apparently difficult despite wiring of both branches (long side branch, sever angulation not cover by the “jailed wire technique” , side branch dissection after predilatation), cross-over to type A treatment is preferable . visulaization of the origin of the side branch ostium may be challenging and its importante to check ostial stent positioning before stent deplyoment . When in doubt, the side branch stent may be deplyoed whilst an undeplyed balloon is positioned in the main branch. Therfore , the balloon can be inflated during or immediately after side branch stent deplyoment in order to avoid side branch stent protrusion in the main branch. This specific approach requires 7F catheters or 6F when using TAXUS or LIBERITE stents.
Type 4b lesions, (branch ostial lesions) are very challenging because :
1) perfect osteal stent position is difficult ; 2) there is a high risk of snow –plough effect (especially in Y shape lesions) in the main branch leading to ballon angioplasty and sometimes stenting of the previously healthy main branch. For this reason the strategies such as debulking or cutting should be considered. Medical treatment and CABAG should also be disscussed.
Specific sittings
Left main bifurcation
Until recently, unprotected left main (LM) lesions were considered a relative contra-indication to coronary stenting . Now, because we are confident in the stratigic and technical approach to bifurcation lesions, the indications to distal LM has been extended.In one french registry , stenting for unprotected LM stenosis was associated with good in –hospital outcome compared to cardiac surgery (the rate of MACE was 2.1% for stenting and 13.4% for surgery). Angiographic sucess including distal LM was obtained in 100% of caese. At one year follow –up, the rate of TLR was higher in patients treated with PCI (13.4%) compared to surgery (3.7%). Despite a non significant higher rate of TLR in patients treated for distal LM, the strategy of distal left main stenting was considered a valid and safe strategy.
The use of coated stents was proposed in order to decrease the rate of re-intervention. Both sirolimus and paclitaxel eluting stents were used in the treatment of LM bifurcation. (46)
Trifurcation lesions
Trifurcation may be defined as bifurcation lesions involving two side branches, the strategy and guide wire mangement are especially important in these complex lesions.The strategy will be agin “provitional T stenting of the side branch” but with 2 side branches. Therfore , each branch of the “trifurcation” is wired , then the main branch is stented with two”jailed wires”. After guidewire exchange there are two options:
If the reference diameter of the main branch proximal to the bifurcation is < 140% larger than the distal reference (the most frequent case) .Two consecutive kissing balloon inflations are performed.
If the reference diameter of the main branch proximal to the bifurcation is >140% larger than the distal reference , a “trissing” balloon inflation is performed. (12)
Outcome results
The learning curve in the treatment of bifurcation lesions is the most important point Nevetheless, it involves the strategy more than the technique. The acute results were influenced by the gradually increasing rate of kissing balloon inflation and use of tubular stents such as Bestent and more recentely the BX Velocity and Biocomptible stents.This optimized approach was also correlated with a progressive decrease in Total Vascular Resistance (TVR) at 7 month follow up. Now when we look carefully at the lesion before PTCA and after wiring, we know what to expect and what to do. In NHLBI dynamic Registry conducted on 2436 patients MACE at 1- year follow up was 25% higher in bifurcation than in non bifurcation group ( 32.1% versus 25.7%) (23).
Procedural results:
1- PTCA : Although successful dilatation can be achieved in 87-100% of parent vessel lesions, successful side branch revascularization occurs less often (76-89%). (43,44)
In addition to the usual risks of PTCA, bifurcation angioplasty is associated with the additional risks of side branch occlusion , incomplete dilation due to the snow-plough effect , and retrograde propagation of dissection from side branch to parent vessel .Branch occlusion may be silent, or may present with chest pain, haemodynamic instability, or malignant arrhythmias depending upon the vessel caliber, presence and adequacy of collaterals, other coronary disease, and left ventricular function, causes of side branch occlusion include snow-plough injury, dissection, spasm, and thrombosis.( 3, 5, 23, 35)
2- Debulking Technique.
Plaque removal before stent implantation, using directional atherectomy in noncalcified lesions and rotational atherec¬tomy in calcified lesions, has been attractive. However, the encouraging results of many single-center experiences (35) have not been reproduced in the context of randomized studies Several studies suggest that debulking ( followed by PTCA) is an alternative to PTCA alone for bifurcation lesions; Direct Coronary Atherectomy (DCA), Rotablator, and other devices have been used. (47)
A- Direct Coronary Atherectomy Technique: Bifurcation DCA can be performed using sequential or kissing guidwires. Sequential intervention is recommended, using either DCA of the parent vessel and PTCA of the side branch , or DCA of both vessels. Nitinol wires are resistant to damage during DCA and should be used for kissing wire technique; (when this tecnique is used , the Atherocath should be rotated < 180º) to prevent wire entanglement. Predilatation of side branches with ostial disease is somtimes recommended to reduce the risk of side branch occlusion during DCA of the parent vessel. Low balloon inflation pressures should be used to reduce the risk of side branch occlusion during DCA of the parent vesel. Low balloon inflation pressure should be used to reduce risk of shifting plaque (33,34,47,48)
Results of Direct Coronary Atherectomy: observational studies reported that side branch occlusion occures in 0.7-7.7% of un-selected lesions and in up to 37% of bifurcation treated by DCA. Fortunately, most side branch closures can be salvaged by PTCA. Much like PTCA, bas-line narrowing of the side branch origin increases the risk of side branch occlusion during DCA.(49,50,51)
In highly selected bifurcation lesions, high procedural success (91-100%) and low major complications rates (0-3%) have been reported. In one study of transient sidebranch occlusion after DCA, salvage by PTCA or DCA resulted in final diameter stenosis of 6-12% in parent vessel and 0-17% in the side branch. In CAVETA-1 trial , DCA led to higher success (88% vs. 74%, p<0.001) and less restenosis (50% vs 61% p<0.001) compared to PTCA but more ischemic complications (9.5% vs 3.7 %, p< 0.001). This result was obtained with an increased risk of side branch occlusion, with an increase in small non-Q wave myocardial infarc¬tion, and with no difference in the six-month rate of restenosis (66). In the time of the Stenting after Optimal Lesion Debulking (SOLD) registry (67), bifurcational le¬sions were included with very encouraging results, leading to the launch of the Atherectomy and MULTILINK Stenting Improves Gain and Outcome trial (AMIGO) (68). How¬ever, this study failed to support the original findings and hypothesis, even in the subgroup of lesions involving a bifurcation. The main problem of directional atherectomy is that the technique is very operator-dependent and the amount of tissue removal varies depending on the commit¬ment of the operator to performing extensive debulking. In addition, except for the very recent introduction of the Silverhawk device (Fox Hollow Technologies, Redwood City, California), no further developments in the devices available were made for a long time period.
In spite of these concerns and the lack of scientific evidence supporting the advantage of plaque debulking in bifurcation lesions, our experience in this setting has been favorable and we still occasionally combine atherectomy and DES when the anatomical setting is appropriate, such as a left main stenosis with a large plaque burden shown by intravascular ultrasound and plaque characteristics suitable for removal with current directional atherectomy devices. study, debulking with DCA resulted in less target lesion revascularization. (48,49, 50, 51).
B- Rotablator: initially considered a contraindication, rotablator is now often used to debulk bifurcation lesions prior to PTCA or stenting. As opposed to directional coronary atherectomy, which can be considered an optional procedure, the use of rotational atherectomy could be, in some lesions, the only procedure to permit lesion dilatation and hence stent delivery. The incidence of side branch occlusion with rotablator depends on the degree of branch ostial stenosis: 42% for ostial stenosis > 50% and 16% for ostial stenosis <50%.
Protection of a side branch is not feasible during rotablator of bifurcation lesions.If both limbs of bifurcation excced 2.5 mm in diameter , the vessel that is more difficult to wire should be treated first. Some operators recommend gentel predilatation of the side branch befor rotablator of parent vessel to minimize side branch occlusion. If the branch origin is angulated, conservative burr strategey is recommended using a final burr-to artery ratio ≤ 0.6. kissing balloons are commenly employed after Rotablator. (66)
In most catheterization laboratories, the use of this procedure is <5% of all interventions. Early reports stated an advantage in facilitating stent delivery and expansion, with a suggestion for clinical benefit when used in lesions that demanded the use of this technology (41). The Stent¬ing Post Rotational Atherectomy (SPORT) randomized study, using rotational atherectomy and stenting, failed to support any advantage of this technology over standard stenting (37). Our interpretation is that a niche technology cannot show its advantage when used outside the specific area of very calcified lesions, which were excluded from the SPORT trial. Most of the time, rotablation is performed only on the MB, but occasionally (very rarely) also or only on the SB. We think that especially with the use of DES, lesion preparation with compliance change for a very calci¬fied lesion can substantially facilitate stent delivery and symmetrical stent expansion with more homogeneous drug delivery (69).
Role of cutting balloon
A number of single-center studies reported the beneficial combination of stenting preceded by cutting balloon dilatation. In bifurcation le¬sions, in which there is a large fibrotic plaque at the ostium of the SB, the use of the cutting balloon as a pre-dilatation strategy before stenting seems reasonable. The Restenosis reduction by Cutting balloon Evaluation trial (REDUCE III) evaluated the role of cutting balloon pre-dilatation before stenting versus standard balloon pre-dilatation in a variety of lesions. This trial reported a lower restenosis rate when lesions were pre-dilated with the cutting balloon.
Currently, we suggest the use of the cutting balloon in moderately calcific and fibrotic lesions, especially ones that involve the origin of the side branch. In heavily calcified lesions, instead of using a larger burr, the cutting balloon could be used after small-burr rotablation with the goal of minimiz¬ing any distal embolization. Symmetric stent expansion, avoidance of side branch recoil, and stent compression are all attractive hypotheses that need proper evaluation (70-71).
3- Stents
Stents should be used causiously in lesions with side branches. Early studies with the Gianturco- Roubin and Palmaz-Schatz stents suggested acceptable success and complication rates, with sidebranch occlusion in 6-19%. Predictors of sid branch occlusion included osteal stenosis > 50% and parent vessel disease spanning the bifurcation . In the randomiszed STARS trial, side branch occlusion occured in 5% after palmaz-schatz stenting and was associated with great need for CABG and TLR. In contemporary stent practice, access to occluded sid branches has been facilitated by ability of flexible , low-profile modified coil and tubular mesh designs. Despite several stent techniques for bifurcation lesions, non has clearly emerged as the treatment of choice and all are techniqally demanding. In most cases, the simpler technique of “stent-and-retrive” has been associated with fewer complictions and better late outcome than more complex double –stent techniques .Acute side branch occlusion after stenting may be successfuly salavaged by PTCA in 84% of patients, and the development of osteal sidebranch stenosis later after prior stent placement “stent-jail” may be treated by PTCA or Rotablator. (2,4, 14, 52,53)
Drug eluting stents
A promising way of reducing the rates of re-intervention after PCI of bifurcation lesions is the use of drug-eluting stents. Although the provitional T stenting strategy with final kissing ballon was showen to significantly reduce the rate of re-intervention , the real question was “will drug eluting stents make all these techniques obsolete?”. A few data are now avaliable regarding the treatment of bifurcation lesions using drug eluting stents . The sirolimus bifurcation study published in february 2004 was a multicenter randomized trial that aimed to asses the efficacy of the sirolimus-coated BX velocity stent (Cypher) in preventing restenosis after bifurcation lesion stenting (86 patients) and to compare the strategy of systemic stenting of the side branch to that of provitional side stenting. Because of a very high rate of cross-over (51%) observed in the group of patients randomized to one stent , the issue of using 1 or 2 cypher stents still remained unresolved. However , the study showed a low rate of main branch restenosis and a quite acceptable rate of side branch restenosis particularly in the group treated bye provitional T stenting strategy.So fare, there has been no clear explanation for the relative high late loss observed in the side branch treated with cypher stent. The potential impact of the technical approach needs to be confirmed since higher rate of restenosis were specifically observed in patients treated with 2 stents (type A or modified T stenting ). (25)
In one study by lever et al, using sirolimus eluting stent in treating bifurcation lesions resulted in high procedural success rates and low clinical event rates at 6 months follow- up in a high risk population of patients including diabetics (44%) presenting with acute coronary syndrome (42%) and multivessel disease (77%) .The provitional T technic strategy was used in the vast majority of caese (94%) and the side branch was stented in 25% of them. Angiographic success rate was 100% for the main branch and 98% for the side branch.
Repeat angiography was performed at 6 months follow-up in patients with spontaneous or induced ischemia and the rate of TVR accounted for 4% of the whole population (48 patients) Based on this experience , our belief is that the provitional T stenting approach remains the best approach even with DES. In subgroup of ARTSII trial there was no difference between bifurcation and bifurcation groups as regards angiographic success and one- year outcome (26)
Thrombotic issues after drug eluting stents
Pathological studies have suggested that arterial branch points are foci of low shear and low flow velocity and are sites predispose to developement of atherosclerotic plaque, thrombus and inflamation . The two or even three layers of stuts (with crush) of DES opposed to the vessel wal initially raised concerns about possible increases thrombogenicity . Furthermore , delayed endotheliazation associated with drug eluting stents may extend the risk of thrombosis beyond 30 days . In the SES bifurcation study, the rate of stent thrombosis was 3.5% . Rcentely a prospective observational cohort study showed a rate of 3.6% of cumulative stent thrombosis at nine-months follow- up after DES implantation in bifurcations (71)
Complications
Using this indexed approach with tubular stents which give a good access to side branch and final kissing balloon inflation, the rate of faliure and complication is low. The main problem in true bifurcation lesion is to access both branches with the 2 wires.When both wires are well positioned and not crossed, the rate of angiographic success for both branches is > 95%. Proximal dissection is rare occurrence and requires additional stenting in less than 5% of cases.The risk of acute or subacute closure is 1 to 1.5% at one month.(3, 4)
Post Procedural Care
After completion of the procedures, the introducer is withdrawn immediately using compression dressing for radial approach or closing device for the femoral approach.
Associated Phrmacological treatment:
When performing bifurcational stenting, we do not usually change our protocol of peri-procedural heparin administra¬tion (100 U/kg without and 70 U/kg with concomitant elective glycoprotein Ilb/IIIa inhibitors). Use of glycopro¬tein Ilb/IIIa inhibitors is reserved to thrombus-containing lesions, patients with unstable angina, acute myocardial infarction, and when long stents are implanted on both branches. These agents are sometimes administered when the final result at the SB seems suboptimal and for when various clinical or anatomical reasons the operator thinks it is not necessary to implant another stent.
We carefully consider peri-procedural preparation with thienopyridines, and when in doubt we administer a 600- mg loading dose of clopidogrel in the catheterization laboratory.
The duration of combined thienopyridine and aspirin treatment after stent implantation varies according to the length of the stent implanted, the type of stent used, and the clinical conditions of the patient (acute coronary syndrome at the time of stenting or diabetes mellitus).
Limitations of the technique, Future directions.
For the operators experienced in PTCA and stenting, the technique of bifurcation stenting is not an issue .The strategy is more crucial therefore an indexed mangment of bifurcation lesions is very important and may help to simplify the approach to an apparentely complex lesion.
New stent for bifurcation lesions
from a technical point of view, it seems difficult to create a bifurcated stent providing good flexibility between both branches, optimal scaffolding of the carena and capacity of rotation of the device in order to perfectely fit the coronary anatomy in 3 dimensions. All bifurcated stents have a reduced trackability and crossability. The DBS Cordis was evaluated after animal testing in a prospective pilot study of 40 patients with a “promissing”angiographic success of 94% and an acceptable restenosis rate of 33%. The current technological limitation of this kind of stent lies in its profile (only 8 french compatible) and its relatively limited rotation ability to be positioned in phase with bifurcation. However , the results look promising especially for distal LM lesions and profile of the device (designed in 1998) could be siginificantly improved. (43)
Bifurcated stents
These types of stents are based on concepts that we tried to develop with work-horse stents; stenting the main branch and the ostium of side branch with one stent. The Frontier stent from Guidant is a satinless steel 18 mm stent premounted on a 7F compatible delivery system. The dual guide wire design allows for a rapid exchang lumen for the main branch and an over-the-wire lumen for the side branch balloon. The side branch distal tip is joined to the main shaft by a mandrel to avoid wire crossing whilst the device is being advanced. The stent is applied against the carina and deployed in the main branch while the simultaneous inflation opens portal to the side branch , avoiding the deformation of the stent structure in the main branch. This system allows fitting of the 3-D bifurcation anatomy whilst providing optimal side branch ostium coverage. A pilot study that aimed to assess the feasibility and safety of the frontier stent (guidant) in bifurcation lesions was conducted in 11 center in 2002. Technical success with the device was obtained in 92% of the 10 patients included. The rate of death /MI/TVR was 2.9% at 30 days and 17.1% at 6 months follow-up with a very acceptable TLR rate of 13.4% in a study with systemic angiographic follow-up. IVUS confirmed optimal placement on the carina of the vast majority of patients and showed limited neointimal hyperplasia. Long and calcified plaques were associated with higher rates of sub-optimal apposition of device against the carina.(54)
A new stent developed by AST, Kala, has recentely obtained but few clinical data are avaliable. The stent is now 6 french compatible and is deployed on one main branch balloon with 2 wires in place . A new design has been evaluated recentely , the Tulip stent. A didicated provitional T-stenting solution for bifurcation lesions has also been developed by
Invatec (Italy). It consists of a stent platform which combiens a closed-cell and a “variable geometry” design resulting into a uniform scaffolding in the proximal and distal of the main vessel as well as in the typically enlarged main vessel area around the carena. The next step will be the era of drug eluting stents with stent dedicated for bifurcation lesions which will make bifurcation lesion stenting easy for everybod (Fig 18, 19) (62).
RESULTS
Patients and lesions characteristics
Bifurcation lesions were detected in 150 (23%) of the 646 patients. The baseline characteristics of the patients are reported in Table 1. No statistically significant differences were found between the bifurcation and non-bifurcation groups regarding age, gender distribution, diabetes, smoking, hypertension, dyslipidemia, left ventricular function, history of myocardial infarction, history of CABG, need for GPIIb/IIIa inhibitors, or time from chest-pain onset to PCI. The distribution of bifurcation lesions according to the previously described classification (12) was as follows: type 1, 68%; type 2, 16.7%; type 3, 8%; and type 4, 7.3% (type 4a, 5%; and type 4b, 2.3%) ( Fig2 ). In the bifurcation group, the lesion involved the left anterior descending/diagonal arteries in 65.4% of cases, left circumflex/marginal arteries in 16.5%, right coronary artery/crux in 15.5%, and left main bifurcation in 2.6%. Characteristics of the bifurcation lesions are shown in table 2, Fig 1.
Procedural data
The procedural success rate was 92% in the bifurcation group and 93% in the non-bifurcation group (P=0.65). All procedural failures were characterized by 30% or greater residual stenosis with a TIMI flow grade less than 3 at the end of the procedure. In the bifurcation group, provisional T-stenting was performed in 89.3% of cases, with stenting of the main branch only in 82% of cases and of both branches in 7.3% of cases. In the remaining 10.7% of cases, revascularization was performed by balloon angioplasty without stenting. Double guidewire protection was used in 54.6% of cases and final kissing balloon inflation in 33% of cases. Mean stent diameter was 3.17±0.3 mm for the main branch and 2.64±0.2 mm for the side branch; mean stent length was 16.2±4.6 mm for the main branch and 11.5±4.1 mm for the side branch (Table 3).
Quantitative coronary angiography in the group with bifurcation lesions
Quantitative angiographic measurements for the main branch and side branch are reported in Table 4. Mean RVD for the main branch was 2.81±0.41 mm before PCI and 3.13±0.57 mm after PCI; corresponding values for the side branch were 2.32±0.52 mm and 2.42±0.61 mm, respectively. MLD for the main branch was 0.42±0.21 mm before PCI and 2.76±0.65 mm after PCI; corresponding values for the side branch were 0.57±0.28 mm and 2.05±0.46 mm, respectively. The %DS before PCI was higher in the main branch than the side branch (86% versus 75%), whereas the %DS after PCI was higher in the side branch than in the main branch (15% versus 11%) (P0.05 for all comparisons).
Clinical follow-up
Data were obtained at least 1 year after PCI for 96% of the patients, in whom mean follow-up was 1.2 year; 26 patients were lost to follow-up (8 patients in bifurcation group, 18
patients in non-bifurcation group). The in-hospital MACE rate was 13.3% in the bifurcation group and 11.4% in the non-bifurcation group (P=0.72). Corresponding rates were 3.3% vs. 2% for in-hospital mortality (P=0.35), 4% vs. 4.4% for recurrent myocardial infarction (P=0.81), and 6% vs. 5% for target lesion revascularization (TLR) , respectively (P=0.94). After 1 year, mortality was 4.6% in the bifurcation group versus 3% in the non-bifurcation group (P=0.15); corresponding rates were 6.6% vs. 6% for recurrent myocardial infarction (P=0.91), 11.3% vs. 10.5% for TLR (P=0.74), and 22.6% vs. 19.5% for MACE (P=0.56) after 1 year, respectively (Table 5), Fig (3,4).
Bifurcation
(n=150) Non-bifurcation
(n=496) P value
Age, years 59±14 59±13 0.41
Male, % (n) 86 (129) 82.25 (408) 0.29
Diabetes mellitus, % (n) 24 (36) 22.1 (110) 0.46
Hypertension, % (n) 32.7 (49) 30.2 (150) 0.46
Current smoking, % (n) 38.7 (58) 36.3 (180) 0.24
Hypercholesterolemia, % (n) 35.3 (53) 33.1 (164) 0.39
Previous MI, % (n) 13 (20) 12 (60) 0.47
Previous revascularization 8 (12) 6.1 (30) 0.42
Use of glycoprotein IIb/IIIa inhibitor, % (n) 30 (45) 26 (129) 0.28
LVEF, % 53±12 56±10 0.35
Time from pain onset to PCI, min 180±25 195±30 0.52
MI: myocardial infarction; LVEF: left ventricular ejection fraction; PCI: percutaneous Coronary intervention
Table 1. Characteristics of the study patients
Infarct-related arteries
LM 2.6%
LAD/Diag 65.4%
LCX/Mg 16.5%
RCA/PDA-RVB 15.5%
Types of bifurcation lesions
Type 1 68%
Type 2 16.7%
Type 3 8%
Type 4 7.3%
4a 5%
4b 2.3%
LM: left main; LAD: left anterior descending; Diag: diagonal; LCX: left circumflex; Mg: marginal; RCA: right coronary artery; PDA: posterior descending branch; RVG: retro ventricular branch
Table 2. Characteristics of the bifurcation lesions
Double guidewires, % (n) 54.6 (82)
Stenting of both branches, % (n) 7.3 (11)
Stenting only in main branch, % (n) 82 (123)
Provisional (T) stenting, % (n) 89.3 (134)
Balloon dilatation only, % (n) 10.7 (16)
Stent diameter, main branch (mm) 3.170.3
Stent length, main branch (mm) 16.24.6
Stent diameter, side branch(mm) 2.640.2
Stent length, side branch (mm) 11.54.1
Kissing balloon inflation, % (n) 33 (49)
Angiographic success, main branch, % (n) 92 (138)
Angiographic success, both branches, % (n) 87 (130)
Table 3. Procedural characteristics in the patients with bifurcation lesions
RVD
(mm) MLD
(mm) DS
(%)
Main branch
Pre PCI 2.810.41 0.420.21 86.19.1
Post PCI 3.130.57 2.760.65 11.87.3
Side branch
Pre PCI 2.320.52 0.570.28 75.412.4
Post PCI 2.420.61 2.050.46 15.37.8
RVD: reference vessel diameter; MLD: minimal luminal diameter; DS: diameter stenosis; PCI: percutaneous intervention
P<0.05 for all comparisons between pre and post PCI
Table 4. Quantitative coronary angiography measurements for
bifurcation lesions
Endpoints Bifurcation
(n= 150) Non-bifurcation
(n= 496) P value
Angiographic success %(n) 92% (138) 93% (462) 0.65
In-hospital, % (n)
Death 3,3 (5) 2 (10) 0.35
AMI 4 (6) 4.4 (22) 0.81
Revascularization 6 (9) 5 (25) 0.96
CABG 3.3 (5) 2.2 (11) 0.95
PCI 2.7 (4) 2.8(14) 0.88
MACE 13.3(20) 11.4 (57) 0.72
1-year outcomes % (n)
Death 4.6 (7) 3 (15) 0.15
AMI 6.6 (10) 6 (30) 0.91
Revascularization 11.3 (17) 10.5 (52) 0.74
CABG 4 (6) 3.8 (19) 0.81
PCI 7.3 (11) 6.7 (33) 0.76
MACE 22.6 (34) 19.5 (97) 0.56
Table 5. Immediate and mid-term outcomes
Figure (1)
Types of Bifurcation
Figure (2)
In-Hospital MACE
Figure (3)
1 Year MACE
Figure (4)
Disscussion
Angioplasty of bifurcation lesions remains challenging. In most studies, long-term outcomes were less favorable compared to non-bifurcation lesions. To our knowledge, no previous studies specifically assessed the impact of bifurcation lesions on the immediate and mid-term outcomes of PCI used to treat AMI. Patients with bifurcation lesions were excluded from most of the randomized studies of AMI. In our study, the prevalence of bifurcation lesions was 23% among 646 consecutive patients referred for AMI. Lower prevalences, usually less than 20%, were found in studies of PCI in the absence of acute coronary syndrome; for example, bifurcation lesions were found in only 12.3% of patients in the large cohort studied by Garot et al. (13). Rheologic considerations are consistent with a higher prevalence of bifurcation lesions in patients with acute arterial occlusion. In our study, the bifurcation and non-bifurcation groups were similar regarding the history of myocardial infarction and CABG, left ventricular function, diabetes, and other risk factors. The procedural success rate was not significantly different between the two groups, i.e., 92% for the bifurcation main artery and 93% for the non-bifurcation lesions. Failure rates in bifurcation lesions ranged from 3% to 13% in the previous studies (14, 15), being higher than for non-bifurcation lesions. The absence of a significant difference in our study may be ascribed to the techniques used to treat bifurcation lesions and to the comparable times from pain onset to PCI in the two groups. In previous studies, provisional T-stenting, the technique used for most of the lesions in our patients, yielded higher feasibility rates and lower complication rates than other techniques. Furthermore, provisional T-stenting may predict a favorable outcome, according to a study done by Lever et al. (16) on a large single-center registry of 1149 bifurcation lesions seen over 7 years.
The in-hospital MACE rate was not significantly different between the bifurcation and non-bifurcation groups (13.3% versus 11.4%, P=0.72). Lower rates were found in the previous studies of PCI for AMI. The 30-day MACE rates after PCI were 8.4% in the AIR-PAMI trial (17) and 6.2% in CAPTIM (18). The higher MACE rate in our study may be ascribed to the absence of patient selection. MACE rates after 1 year in our study were not significantly different in the two groups (22.6% in the bifurcation group and 19.5% in the non-bifurcation group, P=0.56). The 6-month MACE rates in Stent-PAMI (19) were 12.6% with stenting and 20.1% with balloon dilatation alone. In STOPAMI (20), 6-month MACE rates were 8.5% after stenting and 23.2% after thrombolysis. Our results also swing between bifurcation lesions and adverse 1-year outcomes after AMI. In patients treated at a distance from AMI, Lever et al. (16) recorded 7-month MACE rates of 13.7% with provisional T-stenting followed by implantation of a single stent, 18% with provisional T-stenting followed by implantation of two stents, 24.5% with primary implantation of two stents, 42.8% with the culotte technique, and 33..8% with kissing stents; they concluded that provisional T-stenting significantly reduced the MACE rate and the need for repeat TVR within the first 7 months. Similarly, in a prospective two-center study using the Bestent™ (21), provisional T-stenting was associated with a low 6-month MACE rate of 14.3%, including a 9.4% TVR rate. Several other studies found better outcomes with one stent than with two stents in patients who had bifurcation lesions (22-24). In the PRESTO trial (13), angioplasty of bifurcation lesions was associated with an increased 9-month MACE rate (18% versus 15% for non-bifurcation lesions). This difference was mainly ascribable to a higher TVR rate in bifurcation lesions (17% versus 14%), whereas death (1%) and AMI (1%) were not different between the two groups. The increased need for TVR in patients with bifurcation lesions in PRESTO was due in part to the “oculostenotic reflex” and in the other part to lesion and procedural factors (larger numbers of treated lesions, ostial lesions, lower stent use, and different techniques). The low TLR rate in our study may be ascribed to technical factors and the higher MACE rate to the prognostic impact of AMI.
Whether drug-eluting stents will overcome the technical challenges raised by bifurcation lesions remains debated. In the sirolimus bifurcation study by Colombo et al. (25), results were improved compared to bare-metal stents, with a 25.7% restenosis rate and an 8.1% TLR. However, routine side-branch stenting was associated with a higher rate of restenosis compared to provisional side-branch stenting (28 % vs. 18.7%) (25). In the recent Nordic Bifurcation study, a sirolimus-eluting stent in only the main branch produced similar clinical and angiographic results to routine stenting of both branchs. These findings indicate that technical factors exert a major influence on outcomes even when drug-eluting stents are used, as confirmed by the recent analysis of the bifurcation subgroup of the ARTSII trial (26).
In our study, location of the culprit lesion on a bifurcation had no impact on immediate or mid-term outcomes, most notably death, AMI and need for repeat revascularization. The prognostic impact of bifurcation lesions is probably small compared to that of other factors (e.g., size of the infarction and time to revascularization). A well-standardized technique designed to ensure complete revascularization by preserving the side branches produces immediate and mid-term outcomes similar to those of non-bifurcation lesions.
Summmary
Primary PCI is a well-established treatment for acute myocardial infarction (AMI) but faces
specific challenges when a bifurcation is involved. The primary objective of this study was to determine the impact of bifurcation lesions on the outcome and prognosis of primary PCI for the patient prsented with acute myocardial infarction.
Mthods: We retrospectively reviewed a single-center database of 646 patients admitted to the catheterization laboratory of Henri Mondor Hospital, paris, France for primary angioplasty within 12 hours after AMI. We compared baseline characteristics and outcomes between bifurcation and non-bifurcation lesions.
Results: Bifurcation lesions were found in 23% of patients. They predominantly involved the left anterior descending artery. Provisional T-stenting was used in 89.3% of patients (with stenting of the main branch in 82% and of both branches in 7.3%), side-branch protection in 54.6%, and final kissing balloon inflation in 33%. The procedural success rate was 92% for the main branch of bifurcation lesions compared with 93% for non-bifurcation lesions (p=0.65). Major adverse cardiac event (MACE) rates were comparable in the two groups: in-hospital MACE was 12.5% in the bifurcation group versus 11.3% in the non-bifurcation group (p=0.72), and the 1-year total MACE rate was 21.7% in the bifurcation group versus 19.5% in the non-bifurcation group (p = 0.56).
Study Limitations
We tried as much as possible to explore the impact of bifurcation lesions on the outcome of primary PCI in patient presented with AMI. This study has certain limitations:
1- Lack of randomisation and multi-centricy which can give much more validity and credibility to the study results.
2- We did not study the effect of other types of treatment of bifurcation lesions and we used only the fastest and safest technique to open the occluded artery taking into account the emergency nature of the cases.
3- Abscence of angiographic follow-up, which can give a more valiable information.
Conclusion
This study of a single-center database showed that angioplasty of bifurcation lesions for AMI produced good immediate and mid-term outcomes when a well-standardized provisional T-stenting technique was used. In the specific setting of AMI, involvement of a bifurcation by the culprit lesion dose not impact the prognosis.
Recommendations
1- Bifurcations Lesion is a prevelant subset of coronary artery disease so we have to be alert to this important subset of coronary artery diseases.
2- Inspite of the refinement of techniques , bifurcation lesions are still considered technically difficult lesions.
3- the startegy of treatment should be conducted according to type, morphology of the lesion, and the possibility of side branch occlusion.
4- Provisional –T stenting still the most effective option of treatment in most of the cases.
5- One stent is better than two stents even when we use a drug eluting stents.
6- Technique of dilatation is an important factor in the angiographic and clincal outcomes.
7- Optimization of the final results should be acheived using kissing balloon technique.
8- Further studies are required for further exploration of the dark points of the intervention in bifurcation lesions.
Fig (5) Bifurcation lesion LAD/Dg, LAD= Left Anteriour Descending Artery Dg= Diagonal Branch
( A ) ( B )
Fig ( 6 ) Classification of Bifurcation lesions according to the angle
(A) T- Shape angle , (B) Y-shape angle
Fig ( 7) different Classification Of the Bifurcation Lesions according to The plaque burden.
Fig (8 ) ICPS Classification of bifurcation lesions
Fig ( 9 ) Medina Classifications for bifurcation lesions
Fig (10 ) plque shifting effect after stenting
Fig ( 11 ) Mechanism of Lumen enlargemengt During Intervention
Pre -Intervention
post - Intervention
(Fig 12 ) (Gailed Guide Wire Technique)
(A) (B) (C)
(D) (F) (G)
After Stenting of the main branch , the wire is pulled back to enter the side branch . Then the jailed wire is pulled-back and pushed in the main branch . Stent deformation during strut opening. Stent Implantation in the side branch is provitiona . Final Kissing balloon.
Fig ( 13 )
Provitional “ T” Stenting ; from left to right , stent implantation in the main branch of the Circomflex artery with “jailed wire” then “snow plough effect” in the marginal branch. Guide wire exchang. Kissing Ballon inflation . Final results
Bestent Biocompatible BX Velocity Carbostent Penta R stent
Fig (14) Aspect of Different tubular stents compatible with bifurcation lesion in bench after kissing balloon inflation .
Fig (15) Classification og Treatment Of Bifurcation lesions
Type “A” Type “B” Type “C” Type “D”
Fig (16) Classification of treatment in Bifurcation lesions
Fig (17) A case of Type 2 , Y shaape bifurcation lesion in the Left Circomflex Artery of a patient presented with Acute Myocardial Infarction. Type “B” treatment with a “gailed wire” technique using a direct stenting. from left to right, deplyoment of 18mm BX velocity stent in the Cx, plaque shifting effect in the marginal branch, wire exchang, kissing balloon, and final results.
Frontier Nile
Fig ( 18) Bifurcated Stent ( Frontier to the left, Nile to the right)
Invatec AST Kala AST Tulip
Fig (19) Bifurcated Stents from left to right Invatec, AST Kala, AST Tulip
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الملخص العربي
تهدف هذه الدراسة لتحديد تأثير النوع المتشعب لأمراض الشرايين التاجية علي المردود الإكلينيكي للتوسيع الشرياني التاجي عبر الجلد في حالات جلطة القلب الحادة .
- وقد تمت هذه الدراسة علي 446 مريض أدخلوا إلي وحدة قسطرة القلب بمستشفي هزي موندور ” مستشفي جامعة باريس 12 ” خلال 12 ساعة من بدء جلطة القلب الحادة . وقد تمت دراسة مقارنة بين النوع المتشعب والنوع الغير متشعب من أمراض الشرايين التاجية لتحديد أثر الأخير علي التدخل بالتوسيع الشرياني التاجي .
النتائج : بلغت نسبة حالات النوع المتشعب 23 % من حالات الدراسة . وكانت الطريقة الغالبة للعلاج هي التوسيع باستخدام دعامة واحدة في 89.3 % من الحالات مقابل 7.3 % من الحالات ثم فيها التوسيع باستخدام دعامتين . في الشريان الرئيسي والفرعي . وقد بلغت نسبة نجاح التوسيع 92 % للنوع المتشعب ، 93 % للنوع الغير متشعب حيث لم تكن هناك دلالة إحصائية واضحة للفرق بينهما وبالنسبة للمضاعفات القلبية الهامة ( الجلطة الحادة – إعادة التوسيع الشرياني – الوفاة ) كانت النسبة أثناء فترة الحجز بالمستشفي 12.5 % للنوع المتشعب مقابل 11.3 % للنوع الغير متشعب والمضاعفات بعد عام من الدراسة بلغت 21.7 % للنوع المتشعب مقابل 19.5 % للنوع الغير متشعب حيث لم تكن هناك أيضا دلالة إحصائية للفرق بينهما .
الخلاصة النهائية
النوع المتشعب من أمراض الشرايين التاجية يمثل نسبة لا بأس بها من الحالات الواردة للتوسيع أثناء جلطة القلب الحادة .
ليس هناك فرق في المردود الإكلينيكي للتوسيع الشرياني التاجي بين حالات النوع المتشعب والنوع الغير متشعب .