الفهرس 
Anatomy of Mitral Valve
Epidemiology and Classification of CIMROnly 14 pages are availabe for public view
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Abstract
The MV is a complex structure with dynamic physiology that relies on interplay of its individual components to achieve timely and efficient valve closure, This process requires well- coordination of the left ventricle, papillary muscles, mitral annulus, and left atrium to achieve competent valve closure. Failure of any one of these components, can lead to MR.
Ischemic mitral regurgitation is one of the common complication of CAD and may develop in the acute or chronic phase ,however the term IMR is usually understood to relate to CIMR.
The acute IMR is secondary to PMs infarction and rupture, and patients usually present in cardiogenic shock due to acute volume overload. Acute mitral regurgitation is a surgical emergency that requires appropriate diagnosis and rapid intervention for optimal outcomes.
Strict definition of CIMR by Carpentier’s triad defined as MR occurring more than 2 week after MI with the following: (1) one or more left ventricular segmental wall motion abnormalities. (2) significant coronary disease in the territory supplying the wall motion abnormality. (3) structurally normal MV leaflets and chordae tendinae. This third criterion is particularly important as it excludes patients with organic MR and associated CAD.
The prevalence of CIMR varies according to the technique used for its detection. Between 17% and 55% of patients with echocardiographic evidence of IMR early after acute MI .In patients undergoing cardiac catheterization within 6 h of the onset of their AMI, 18% have ventriculographic evidence of IMR.
Chronic ischemic mitral regurgitation is a complex and multifactorial disease, which starts primarily in the LV wall and leads to secondary valvular changes. The main underlying mechanism is left ventricular remodeling leading not only to annular dilatation, but particularly to displacement of the papillary muscles, and there by to augmented tethering of the mitral leaflets. This restricts appropriate mitral leaflet closure and regular coaptation. Two-dimensional trans-thoracic echocardiography is the preferred diagnostic imaging tools which Provide accurate information about LV dimensions and function, regional wall motion abnormalities, MR aetiology, MR severity and mitral valve geometry, including annular dilatation and mitral valve tenting. Semi-supine bicycle exercise echocardiography can provide additional useful information about the dynamic component of CIMR. Patients with CAD and CIMR have a worse prognosis even if mild than patients with CAD and no CIMR. And 1-year mortality for severe CIMR was 40%, for moderate CIMR 17%, for mild CIMR 10%
Medical treatment may lead to a reduction in MR severity. Several studies suggest that angiotensin-converting enzyme inhibitors (ACEi), nitrates and diuretics can lead to a partial reduction in MR severity. Treatment with CRT resulted in a modest reduction in the severity of IMR.However, approximately 25 % of patients treated with CRT do not respond to treatment .Independent predictors of lack of response to CRT are ischaemic heart disease, severe MR and LV end-diastolic dimension _75 mm. The indications for surgery in CIMR are not strictly defined. The general consensus is that patients who have an indication for CABG with moderate-to-severe or severe CIMR (grade 3+or 4+) should also undergo concomitant mitral valve surgery.
Restrictive MVA combined with CABG is the most frequently used technique in the surgical treatment of severe CIMR. Although restrictive MVA is currently the preferred treatment option in some selected cases. Restrictive MVA and CABG can provide good results in selected patients with minimal LV dilatation and minimal tenting. However, in general the persistence and recurrence rate for restrictive MVA remains high. This lead to appearance of many new technique in treatment of CIMR.