Impact of untreated mild-to-moderate mitral regurgitation at the time of isolated aortic valve replacement on late adverse outcomes.

OBJECTIVE

The impact of untreated mild-to-moderate mitral regurgitation (MR) on patients undergoing isolated aortic valve replacement (AVR) is uncertain. The aim of this study is to investigate its long-term effects on outcomes.

METHOD

We retrospectively reviewed 193 consecutive patients undergoing isolated AVR between 1993 and 2007. The mean age of the study group was 64+/-12 years, 59% were male and the mean preoperative ejection fraction was 59+/-12%. The pathologic aetiology and degree of MR was determined on preoperative echocardiogram. Patients were stratified into preoperative no/trivial MR (group I; n=134) versus mild-to-moderate MR (group II; n=59). The aetiology of MR in group II was either organic (n=35, 60%) or functional (n=24, 41%). Survival and functional outcome were compared between the two groups and analyses for predictors of adverse events were performed by the Cox proportional hazard model.

RESULTS

Operative mortality was 2.6% (n=5). In group II, mean degree of MR significantly decreased from 2.1+/-0.3 to 1.6+/-0.8 during the late period (p=0.003). The improvement in MR grade was more obvious in patients with functional aetiology. Although the actuarial survival was not significantly different between groups, freedom from re-admission for heart failure at 10 years was significantly lower in group II than in group I (23% vs 83%; p=0.002). Multivariate analysis demonstrated that independent predictors of heart failure were presence of mild-to-moderate MR (p=0.012, odds ratio (OR) 3.8) and left ventricular ejection fraction (p=0.004, OR 0.95).

CONCLUSION

Despite the significant reduction after isolated AVR, preoperative mild-to-moderate MR is an independent risk factor impacting long-term functional outcome. Our results suggested that the concomitant mitral valve surgery for mild-to-moderate MR is warranted, especially in patients with reduced left ventricular function.