Early Surgery Versus Conventional Treatment for Asymptomatic Severe Mitral Regurgitation: A Propensity Analysis

Study Questions:

What are the long-term outcomes of asymptomatic patients with severe mitral regurgitation (MR) who undergo early surgery compared with a conventional treatment strategy?

Methods:

From 1996 to 2009, 610 consecutive asymptomatic patients (364 men, ages 50 ± 14 years) with severe degenerative MR and preserved left ventricular function were prospectively evaluated. Early surgery was performed in 235 patients and a conventional treatment strategy was pursued in 375 patients. A propensity-score matched cohort of 207 pairs was derived. Overall mortality, cardiac mortality, and cardiac events (operative mortality, cardiac mortality, repeat surgery, and urgent admission due to heart failure) were compared between the two treatment strategies in the propensity-matched cohort.

Results:

For the 207 propensity-score matched pairs, early surgery had a lower risk of cardiac mortality (hazard ratio [HR], 0.109; 95% confidence interval [CI], 0.014-0.836; p = 0.03) and cardiac events (HR, 0.216; 95% CI, 0.08-0.558; p = 0.002) than did conventional treatment. On Cox proportional hazard model analysis, the risk of cardiac events was significantly lower in the early surgery group than in the conventional treatment group in patients ages ≥50 years (HR, 0.221; 95% CI, 0.086-0.567; p = 0.002), but not significantly different in those ages <50 years (p = 0.20).

Conclusions:

Compared with conservative management, early surgery is associated with significant long-term reductions of cardiac mortality and cardiac events in asymptomatic severe MR patients ages ≥50 years.

Perspective:

The optimal timing of surgery in asymptomatic patients with severe degenerative MR remains controversial. This large study, performed at two centers in the Republic of Korea, provides data that further reinforce a growing, but unproven belief that early surgery is superior to ‘watchful waiting’ for asymptomatic patients with severe degenerative MR, as long as intervention is very likely to be mitral valve repair (as opposed to replacement). The study is a post-hoc analysis of prospectively collected data, using propensity-score matching in an attempt to minimize differences between groups. As is pointed out in the accompanying editorial, a multicenter randomized controlled trial would be appropriate and welcomed to help resolve the question of whether, and in whom, ‘prophylactic’ surgery for severe degenerative MR is superior to a strategy of watchful waiting.

Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Valvular Heart Disease, Cardiac Surgery and Heart Failure, Cardiac Surgery and VHD, Acute Heart Failure, Interventions and Structural Heart Disease, Mitral Regurgitation

Keywords: Republic of Korea, Propensity Score, Reoperation, Proportional Hazards Models, Ventricular Function, Left, Mitral Valve Insufficiency, Cardiology, Heart Failure, Confidence Intervals, Cardiac Surgical Procedures, ACC Annual Scientific Session


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