Mitral gradients and frequency of recurrence of mitral regurgitation after ring annuloplasty for ischemic mitral regurgitation

Abstract

Background: Undersized ring annuloplasty and surgical revascularization are commonly used to correct ischemic mitral regurgitation (MR), but published series have failed to demonstrate a benefit compared with revascularization alone. We hypothesized that surgical revascularization and annuloplasty lead to a durable repair, but may also lead to increased mitral gradients that could limit the benefit of the repair technique.

Methods: Data were collected for 222 consecutive patients who underwent combined revascularization and repair for ischemic MR between 1999 and 2006. The most recent transthoracic echocardiogram available for each patient (namely, the study that occurred at the latest date after surgery) was reviewed to define the fate of ischemic MR. When present, the mean gradient across the mitral valve was measured. Cox regression modeling was then performed to determine whether increasing gradients were associated with decreased long-term survival or increased hospitalization for heart failure.

Results: For the group of 222 patients, echocardiographic follow-up was available for 68% (149 patients). At follow-up, 1.3% had severe MR and 9.4% had moderate MR; 54% of patients (66 of 123) were found to have gradients of 5 mm or greater across the mitral valve, with 11% demonstrating gradients of 8 mm or more. Cox proportional hazards models failed to show adverse effects of increasing mitral gradient on outcomes analyzed: survival hazard ratio = 0.95 (95% confidence interval: 0.82 to 1.11, p = 0.527) and survival/heart failure hospitalization hazard ratio = 1.04 (95% confidence interval: 0.93 to 1.17, p = 0.488).

Conclusions: Undersized ring annuloplasty and revascularization can provide a durable correction of ischemic mitral regurgitation. This technique frequently increases the gradient across the mitral valve, but increasing mitral gradient does not appear to adversely impact survival or heart failure hospitalization.