Should patients with severe degenerative mitral regurgitation delay surgery until symptoms develop?

Abstract

Background: The American College of Cardiology/American Heart Association practice guidelines recommending surgery for asymptomatic patients with severe mitral regurgitation caused by degenerative disease remain controversial. This study examined whether delaying surgery until symptoms occur causes adverse cardiac changes and jeopardizes outcome.

Methods: From January 1985 to January 2008, 4,586 patients had primary isolated mitral valve surgery for degenerative mitral regurgitation; 4,253 (93%) underwent repair. Preoperatively, 30% were in New York Heart Association (NYHA) class I (asymptomatic), 56% in class II, 13% in class III, and 2% in class IV. Multivariable analysis and propensity matching were used to assess association of symptoms (NYHA class) with cardiac structure and function and postoperative outcomes.

Results: Increasing NYHA class was associated with progressive reduction in left ventricular function, left atrial enlargement, and development of atrial fibrillation and tricuspid regurgitation. These findings were evident even in class II patients (mild symptoms). Repair was accomplished in 96% of asymptomatic patients, and in progressively fewer as NYHA class increased (93%, 86%, and 85% in classes II to IV, respectively; p < 0.0001). Hospital mortality was 0.37%, but was particularly high in class IV (0.29%, 0.20%, 0.67%, and 5.1% for classes I to IV, respectively; p = 0.004). Although long-term survival progressively diminished with increasing NHYA class, these differences were largely related to differences in left ventricular function and increased comorbidity.

Conclusions: In patients with severe degenerative mitral regurgitation, the development of even mild symptoms by the time of surgical referral is associated with deleterious changes in cardiac structure and function. Therefore, particularly because successful repair is highly likely, early surgery is justified in asymptomatic patients with degenerative disease and severe mitral regurgitation.