Management and outcomes in patients with moderate or severe functional mitral regurgitation and severe left ventricular dysfunction.

Abstract

The management and outcomes of patients with functional moderate/severe mitral regurgitation and severe left ventricular (LV) systolic dysfunction are not well defined. We sought to determine the characteristics, management strategies, and outcomes of patients with moderate or severe mitral regurgitation (MR) and LV systolic dysfunction. For the period 1995-2010, the Duke Echocardiography Laboratory and Duke Databank for Cardiovascular Diseases databases were merged to identify patients with moderate or severe functional MR and severe LV dysfunction (defined as LV ejection fraction ≤ 30% or LV end-systolic diameter > 55 mm). We examined treatment effects in two ways. (i) A multivariable Cox proportional hazards model was used to assess the independent relationship of different treatment strategies and long-term event (death, LV assist device, or transplant)-free survival among those with and without coronary artery disease (CAD). (ii) To examine the association of mitral valve (MV) surgery with outcomes, we divided the entire cohort into two groups, those who underwent MV surgery and those who did not; we used inverse probability weighted (IPW) propensity adjustment to account for non-random treatment assignment. Among 1441 patients with moderate (70%) or severe (30%) MR, a significant history of hypertension (59%), diabetes (28%), symptomatic heart failure (83%), and CAD (52%) was observed. Past revascularization in 26% was noted. At 1 year, 1094 (75%) patients were treated medically. Percutaneous coronary intervention was performed in 114 patients, coronary artery bypass graft (CABG) surgery in 82, CABG and MV surgery in 96, and MV surgery alone in 55 patients. Among patients with CAD, compared with medical therapy alone, the treatment strategies of CABG surgery [hazard ratio (HR) 0.56, 95% confidence interval (CI) 0.42-0.76] and CABG with MV surgery (HR 0.58, 95% CI 0.44-0.78) were associated with long-term, event-free survival benefit. Percutaneous intervention treatment produced a borderline result (HR 0.78, 95% CI 0.61-1.00). However, the relationship with isolated MV surgery did not achieve statistical significance (HR 0.64, 95% CI 0.33-1.27, P = 0.202). Among those with CAD, following IPW adjustment, MV surgery was associated with a significant event-free survival benefit compared with patients without MV surgery (HR 0.71, 95% CI 0.52-0.95). In the entire cohort, following IPW adjustment, the use of MV surgery was associated with higher event-free survival (HR 0.69, 95% CI 0.53-0.88). In patients with moderate or severe MR and severe LV dysfunction, mortality was substantial, and among those selected for surgery, MV surgery, though performed in a small number of patients, was independently associated with higher event-free survival.