Insights on left ventricular and valvular mechanisms of recurrent ischemic mitral regurgitation after restrictive annuloplasty and coronary artery bypass grafting

Abstract

We investigated leaflet and subvalvular configurations to identify mechanisms leading to recurrent mitral regurgitation after combined undersized mitral annuloplasty and coronary artery bypass and to preoperatively recognize patients who are unlikely to benefit from this approach. Among 261 subjects with chronic ischemic mitral regurgitation undergoing undersized annuloplasty and coronary bypass surgery at one institution between September 2001 and September 2007, 31 were excluded: 4 had intraoperative annuloplasty failure, 12 showed residual regurgitation, and 15 had incomplete echocardiograms available. The study population consisted of 230 patients who were divided into 2 groups: patients without (group 1, n = 176) or with (group 2, n = 54) late recurrent mitral regurgitation. Fifty healthy subjects were used as control subjects. Serial echocardiographic analysis was performed preoperatively, at discharge, and at follow-up appointments (early: median, 6 months [interquartile range, 5-6 months; late: median, 33 months [interquartile range, 17-51 months]). Subjects with late regurgitation had preoperatively more symmetric tethering (P < .001), more accentuated anterior mitral leaflet tethering (P < .001), and more restricted anterior leaflet excursion (P = .003) than patients in group 1. Postoperatively, tethering of the posterior leaflet increased (P < .001) and was predominant in both groups, whereas tethering of the anterior leaflet was reduced at discharge (P = .01 and P = .03, respectively), remaining constant afterward. Multivariable analysis showed an anterior tethering angle of 39.5 degrees or greater (P < .001), an anterior/posterior tethering angle ratio of 0.76 or greater (P < .001), an anterior leaflet excursion angle of 35 degrees or less (P = .001), and a coaptation height of 11 mm or greater (P = .04) to be predictors of recurrent mitral regurgitation. Preoperative symmetric tethering with anterior mitral leaflet predominance was strongly associated with recurrence of mitral regurgitation. Measures of leaflet tethering resulted in fundamental findings to identify ischemic patients who can really benefit from restrictive annuloplasty. Further larger studies are necessary to confirm our results.