Ischemic mitral regurgitation (MR) is a complication of coronary heart disease; it primarily occurs in patients with a prior myocardial infarction (MI). MR may also occur with acute ischemia, a setting in which the MR typically resolves after the ischemia resolves. Following an MI, the MR is usually due to infarction with permanent damage to the papillary muscle or adjacent myocardium; in such patients, MR may become more severe with adverse remodeling or subsequent ischemia. Thus, a better term for this condition might be “post-infarction” mitral regurgitation. (See "Mechanical complications of acute myocardial infarction".)
The optimal treatment of ischemic MR is a matter of controversy and there is wide variation in practice among cardiovascular surgeons. Much of this controversy stems from a lack of good data addressing this issue. There have been no randomized trials comparing mitral valve repair and replacement, and many of the early surgical studies included patients with different types of mitral valve disease, including patients who had mitral valve prolapse in association with coronary heart disease.
Better definitions of ischemic MR have evolved as echocardiographic techniques have allowed appropriate classification of these patients. This has allowed the performance of higher quality studies, although the lack of randomized trials still limits the ability to make strong recommendations for management.
An overview of the presentation and management of patients with ischemic MR is presented here. The special case of papillary muscle rupture in the setting of acute MI is discussed briefly, but a more extensive review is found separately. (See "Mechanical complications of acute myocardial infarction".)
Most studies of ischemic MR have focused on chronic post-infarction MR, rather than reversible MR caused by acute ischemia. Ischemic MR can be classified by the mechanism of the valve dysfunction [1,2]: