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Moderate or Severe Functional MR and Severe LV Dysfunction
Study Questions:
What are the characteristics, management strategies, and outcomes of patients with moderate or severe mitral regurgitation (MR) and severe left ventricular (LV) systolic dysfunction?
Methods:
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). Treatment effect was examined in two ways: 1) A multivariable Cox proportional hazards model was used to assess the independent relationship of different treatment strategies and long-term event-free survival (death, LV assist device, or transplant) among those with and without coronary artery disease (CAD). 2) To examine the association of mitral valve (MV) surgery with outcomes, the entire cohort was divided into two groups: those who underwent MV surgery and those who did not; inverse probability weighted (IPW) propensity adjustment was used to account for nonrandom treatment assignment.
Results:
Among 1,441 patients with moderate (70%) or severe (30%) MR, a significant history of hypertension (59%), diabetes (28%), symptomatic heart failure (83%), and coronary artery disease (CAD) (52%) was observed. Past revascularization was noted in 26%. At 1 year, 1,094 (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 interventional treatment produced a borderline result (HR, 0.78; 95% CI, 0.61-1.00). However, among patients with CAD, isolated MV surgery did not have a statistically significant effect on outcomes (HR, 0.64; 95% CI, 0.33-1.27; p = 0.20). Among patients 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). Among 466 patients without significant CAD included in the adjusted models, 43 underwent MV surgery; compared with medical therapy alone, MV surgery did not have a statistically significant effect on event-free survival (HR, 0.73; 95% CI, 0.45-1.19; p = 0.21). In the entire cohort (with and without CAD), following IPW adjustment, the use of MV surgery was associated with higher event-free survival (HR, 0.69; 95% CI, 0.53-0.88).
Conclusions:
In patients with moderate or severe MR and severe LV dysfunction, mortality was substantial. The authors concluded that, among those selected for surgery, MV surgery, although performed in a small number of patients, was independently associated with higher event-free survival.
Perspective:
In the absence of a powerful, prospective, randomized trial addressing the impact of MV surgery for functional MR among patients with or without CAD, and with or without revascularization, uncertainty will remain as to whether isolated MV intervention affects survival outcomes. This sophisticated retrospective analysis of a large set of prospectively collected data suggests that MV intervention improves survival. However, the effect was demonstrable among patients with CAD who underwent concomitant revascularization (and for the whole cohort), but not for either patients with CAD who underwent isolated MV surgery or for patients without CAD who underwent MV surgery. Without compelling data in those subsets of patients, the survival benefit of isolated MV surgery for functional MR will remain open to debate.
Keywords: Cardiac Surgical Procedures, Coronary Artery Bypass, Coronary Artery Disease, Diabetes Mellitus, Echocardiography, Heart Failure, Heart Valve Diseases, Hypertension, Mitral Valve Insufficiency, Percutaneous Coronary Intervention, Ventricular Dysfunction, Left
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