3、Ischemic Mitral Regurgitation-Repair vs Replacement
IMR is a result of adverse LV remodeling after myocardial injury, including enlargement of the LV chamber and mitral annulus, apical and lateral displacement of the papillary muscles, leaflet tethering and decreased closing forces. These processes can lead to malcoaptation of the leaflets and varying degrees of MR , which can fluctuate dynamically with heart rhythm, volume status, afterload, and residual ischemia[57]. The leaflets are normal, and the pathological changes appear in the myocardium rather than in the valve itself. Therefore, the treatment of functional IMR is quite different from that of primary degenerative MR[58]. Practice guidelines recommend that for patients with severe IMR who experience restrictive symptoms despite the best available medical treatment and possibly cardiac resynchronization, MV repair or chordal-sparing replacement should be considered[59,60]. However, these guidelines do not specify whether to do the MV repair or replacement, because there is no clear evidence on which of these intervention is better. Clinical studies have shown that MV repair is associated with lower perioperative mortality[61-63], but replacement provides better long-term correction and lower risk of recurrence (an important consideration is that recurrence of mitral regurgitation may lead to atrial fibrillation, heart failure and readmission) (Table 1 )[64-68]. But some studies suggest the early mortality of the repair group is higher than that of the replacement group[69,70]. And some other studies have demonstrated that survival after combined surgery is mainly affected by factors related to the patient’s condition during the operation, but not by the MV repair or replacement (Table 1 )[71,72]. This perceived trade off between reduced operative morbidity and mortality with repair and better long term IMR correction with replacement has produced significant variation in surgical practice for this high-prevalence condition[58].