Role of mitral valve surgery for secondary mitral regurgitation in heart failure.

n nonischemic and ischemic cardiomyopathies, geometric perturations in the left ventricle (LV) result in dysfunction of the mitral alve and secondary (functional) mitral regurgitation (MR). An ncrease in interpapillary muscle distance, annular dilation, and nhanced leaflet tethering contribute to secondary MR. Because he MR in these patients is primarily a function of distorted LV eometry rather than a primary valve problem, “the advantages of orrection of secondary MR are less clear,” as discussed by arabello (1). This prevailing concept is buttressed by the lack of survival benefit in a retrospective analysis of 419 patients (2). owever, this study did not report changes in patient symptoms. arabello (1) notes that “some have questioned whether surgery in schemic MR improves survival and/or long-term quality of life.” hat being the case, several studies actually suggest an improveent in functional status after mitral valve repair of secondary MR n heart failure patients. Over 200 patients with cardiomyopathy nd severe MR who underwent mitral valve repair were prospecively studied over a 10-year period (3). In addition to low overall ortality and improvements in quantitative echocardiographic ndexes of cardiac function at 2 years, the New York Heart ssociation (NYHA) functional class for all patients improved rom a pre-operative mean of 3.2 0.2 to 1.8 0.4 postperatively. Another study of patients with severe LV dysfunction nd MR also demonstrated improvement in NYHA functional lass from 2.8 0.8 to 1.2 0.5 (p 0.0001) and freedom from eadmission for heart failure of 88%, 82%, and 72% at 1, 2, and 5 ears, respectively (4). These patients were also able to tolerate igher doses of medications after repair (4). When functional utcomes after mitral valve repair of secondary MR were assessed n yet another study of patients with severe dilated cardiomyopahy, it was noted that, in addition to a low hospital mortality, YHA functional class improved from 3.4 0.4 to 1.4 0.6 p 0.0001) (5). The authors of that study concluded that, “in atients with end-stage dilated cardiomyopathy, mitral valve repair s feasible with low hospital mortality and important symptomatic mprovement.” These positive findings on functional status have een reported in a number of other studies (6–10). In patients with YHA functional class III to IV symptoms and severe MR on aseline maximal drug therapy, operation led to improved NYHA unctional class from 3.9 0.3 to 2.0 0.6 (6). Similar findings ere noted in a prospective study of 125 patients with 4 MR, evere LV dysfunction (mean ejection fraction of 14%) and NYHA unctional class III or IV symptoms wherein NYHA functional lass improved for all the patients from a preoperative mean of .2 0.2 to 1.8 0.4 post-operatively (8). In patients with a ean LV ejection fraction of 30%, NYHA functional class also mproved significantly (3.2 to 1.6; p 0.0001) at follow-up (10). inally, a prospective, randomized, multicenter trial of 193 paients with NYHA functional class II to IV heart failure, all with ntensive background medical therapy, demonstrated the safety nd efficacy of mitral valve surgery after a median follow-up of 23 onths (11). Notably, there were significant improvements in uality of life at 3, 6, 12, and 18 months as assessed with the innesota Living with Heart Failure and the Short-Form 36 uestionnaires and improved 6-min walk tests (11). Taken toether, although surgical correction of secondary MR is controersial, in part because the prognosis is thought to be related rimarily to the underlying cardiomyopathy, physicians should onsider offering mitral valve surgery to medically optimized yet ymptomatic patients with severe MR and end-stage heart failure.