Determinants of functional capacity after mitral valve annuloplasty or replacement for ischemic mitral regurgitation

Objective: To identify the exercise echocardiographic determinants of long-term functional capacity, in patients with chronic ischemic mitral regurgitation, after restrictive mitral valve annuloplasty (RMA) or mitral valve replacement (MVR). Methods: We retrospectively analyzed 121 patients with significant chronic ischemic mitral regurgitation, who underwent RMA (n = 62) or MVR (n = 59), between 2005 and 2011. Preoperatively, all patients underwent a resting echocardiographic examination, and a 6-minute walking test (6-MWT) to measure distance. Resting and exercise stress echocardiography, and the 6-MWT were repeated at 41 +/- 16.5 months. Results: After surgery, the 6-MWT distance significantly improved in the MVR group, and decreased in the RMA group (+37 +/- 39 m vs -24 +/- 49 m, respectively; P < .0001). Exercise indexed effective orifice area was significantly higher in the MVR, versus the RMA, group (MVR: change from 1.3 +/- 0.2 cm(2)/m(2) to 1.5 +/- 0.3 cm(2)/m(2); RMA: change from 1.1 +/- 0.3 cm(2)/m(2) to 1.2 +/- 0.3 cm(2)/m(2); P = .001). The mean mitral gradients significantly increased from rest to exercise, in both groups, but to a greater extent in the RMA group (change from 4.4 +/- 1.4 to 11 +/- 3.6 mm Hg; MVR: change from 4.3 +/- 1.8 to 9 +/- 3.5 mm Hg; P = .006). On multivariate analysis, MVR and exercise indexed effective orifice area were the main independent determinants of postoperative 6-MWT. In the RMA group, 25 patients experienced late mitral regurgitation recurrence, severe in 9 (14%) of them. The rate of postoperative cardiovascular events was significantly higher in the RMA group (21% vs MVR: 8%; P = .03). Follow-up survival was 83% in the RMA group and 88% in the MVR group (P = .54). Conclusions: For chronic ischemic mitral regurgitation, MVR versus RMA was associated with better postoperative exercise hemodynamic performance and long-term functional capacity.