الفهرس 
Anatomy of the coronary arteriesOnly 14 pages are availabe for public view
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Abstract
Coronary artery disease (CAD) is the leading cause of death in the United States. Coronary artery bypass grafting (CABG) is an established revascularizing treatment for (CAD) and can increase life quality and expectancy as well as reduce ischemic complications.
The coronary arteries are conductive vessels running through the epicardial surface of the heart, embedded in adipose tissue, and showing short segments of mild penetration into the myocardial tissue. Coronary arteries emerge from the aorta through the coronary ostia, located at the right (or anterior) and the left (or left posterior) sinuses of Valsalva.
Resting coronary blood flow is slightly less than 1 mL/g of heart muscle per minute. This blood flow is delivered to the heart through large epicardial conductance vessels and then into the myocardium by penetrating arteries leading to a plexus of capillaries. The bulk of the resistance to coronary flow is in the penetrating arterioles (20 to 120 μm in size).
Ischemic heart disease evolves from a disease in the coronary arteries, most commonly atherosclerosis. In advanced atherosclerosis, the coronary artery can be partly blocked by an atherosclerotic plaque, which decreases the blood pressure distal to the sclerotic zone. To compensate for this reduced blood pressure, coronary arteries will dilate to maintain normal resting blood flow. Thus, most patients with coronary atherosclerosis do not have symptoms of ischemia at rest, depending of course on the extent of the stenosis of the coronary artery.
Several advantages to arterial grafting have been demonstrated relative to CABG without arterial grafts. Most notably, the LIMA-LAD graft has been shown to be an independent predictor of survival after CABG when compared with patients not receiving LIMA-LAD. In addition, using more than one IMA graft reduces the need for subsequent reintervention and prolongs survival relative to patients receiving only one arterial grafts.
Intraoperative graft related problems are one of the important causes for mortality after coronary artery bypass grafting (CABG). Transit time flow measurements (TTFM) have been shown to detect occluded grafts intra-operatively. The test is noninvasive and can be easily performed on the operation table. It may help detection and subsequent correction of graft related problems on table and may therefore reduce mortality and morbidity associated with CABG.
In our study 50 patients underwent coronary artery bypass grafting (CABG) using total arterial revascularization technique for left coronary system. The total number of distal anastomoses were 140. The average number of distal anastomoses were 2.80 ± 0.80. Distal anastomoses performed were LIMA to LAD 50(35.7%),RIMA to OM 43(30.7%), Left radial to OM 18(12.9%), RIMA to D 16(11.4%),RIMA to RAMUS 3(2.1%), Left radial to D 10(7.2%) which LIMA with RIMA used in 38(76%) patients, LIMA with left radial used in 10(20%)patients and LIMA with RIMA and left radial used in 2(4%)patients.This study provides evidence that the LIMA limb of a composite Y or T-graft has intraoperative statistically significance increasing in mean flow comparable to that of the independent LIMA graft with p-value <0.001. Mean flow in LIMA graft was 41.72 ± 15.59 during clamping of the Y or T- graft and mean flow in LIMA graft was 78.60 ± 29.58 during patent Y or T-graft.
Regarding to pulsility index there was statistically significance decreasing in PI with p-value <0.001. PI in LIMA graft was 2.39 ± 0.82 during clamping of the Y or T- graft and PI in LIMA graft was 1.89 ± 0.65 during patent Y or T-graft.