Asymptomatic Mitral Regurgitation: When Is Surgery Indicated?

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Asymptomatic Mitral Regurgitation: When Is Surgery Indicated?

Patients with regurgitant orifices $≥$ 40 mm² should be considered for prompt surgery.

Asymptomatic mitral regurgitation (MR) presents a dilemma: We'd like to avoid surgery in asymptomatic patients, but outcomes might be worse if we wait for heart failure to occur. This prospective observational study from Mayo Clinic provides some guidance.

Researchers followed 456 patients (mean age, 63) with initially asymptomatic primary MR due to diseased valve leaflets (as opposed to MR secondary to dilated cardiomyopathy or ischemia); 80% had mitral valve prolapse. Effective regurgitant orifice (determined by echocardiography) was the best predictor of adverse outcomes. Even with medical management, patients with orifices of $≥$ 40 mm² and those with orifices of 20 mm² to 39 mm² had significantly reduced 5-year survival compared with expected U.S. survival rates (58% and 66% vs. 78%). Patients with orifices of <20 mm² had normal survival rates.

During follow-up, 230 patients underwent surgery for symptoms or progressive echocardiographic abnormalities (209 had valve repair, and 21 had valve replacement). Statistical analyses suggested that surgery normalized life expectancy, although 2 patients died from postoperative complications.

Comment: Although these patients were not randomized to surgery or no surgery, we can infer that patients with regurgitant orifices of $≥$ 40 mm² should be considered for prompt surgery; those with orifices of 20 mm² to 39 mm² should be followed closely. As editorialists note, surgery becomes more attractive when valve repair is feasible, because repair avoids some of the complications associated with valve replacement.

— Allan S. Brett, MD

Published in Journal Watch General Medicine March 15, 2005