Repairing or Replacing Mitral Valve After Ischemic MR

Dallas—Many practice guidelines—including the American Heart Association/American College of Cardiology and the European Society of Cardiology guidelines—recommend repairing or replacing the mitral-valve following a severe ischemic mitral regurgitation (MR); however, little research has compared the 2 interventions.

A recent study sought to determine which of the 2 interventions yielded better outcomes. Michael Acker, MD, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, presented the results of this study at the AHA Scientific Sessions in a session titled Medical and Surgical Approaches to Improving Heart Failure Outcomes. The results of this study were also recently published online in the New England Journal of Medicine [doi:10.1056/NEJMoa1312808].

This severe MR randomized trial was designed to evaluate the safety and effectiveness of mitral-valve repair versus replacement in patients with severe ischemic MR. A total of 251 patients were included in the study—126 were randomized to undergo mitral-valve repair and 125 were randomized to undergo chordal-sparing replacement.

Primary study end points included the degree of left ventricular reverse remodeling, which was assessed by LV end systolic volume index (LVESVI) using transthoracic echocardiography at 12 months and group differences based on the Wilcoxon Rank-Sum test with deaths categorized as lowest LVESI rank. End points were measured at 30 days, and subsequently at 6, 12, and 24 months. The 24-month follow-up is still ongoing. 

The rate of death was 14.3% in the repair group and 17.6% in the replacement group (hazard ratio, 0.79; 95% confidence interval, 0.42-1.47; P=.45). The results showed no difference in the degree of reverse remodeling and mortality between the 2 therapy groups. The 30-day mortality rate for the repair group was 1.6%, while the replacement group was 4%. The 1-year mortality rate for the repair group was 14.3%, while the replacement group was 17.6%.

There was significantly more recurrent MR at 1 year in the repair group compared with the replacement group (32.6% vs 2.3%; P<.001). The mean LVESVI at 12-months among surviving patients was 54.6±25 mL/m² of body-surface area in the repair group and 60.7±31.5 mL/m² in the replacement group.

The researchers noted that the treatment of severe ischemic MR remains controversial. They are hopeful that these results will help delineate the appropriate therapeutic approach for this condition.