Contractile reserve induced with dobutamine echocardiography predicts outcome in patients with left ventricular dysfunction and mitral regurgitation

The appropriate management of patients with mitral regurgitation (MR) and left ventricular dysfunction (LVD) is controversial. The study aim was to determine whether the presence of contractile reserve (CR) assessed by dobutamine stress echocardiography (DSE) was associated with improved outcomes.Death and heart transplantation were analyzed as the primary outcomes associated with the presence of CR. A total of 125 consecutive patients (96 males, 29 females; mean age 60 +/- 12 years) with left ventricular ejection fraction (LVEF)or = 35% and hemodynamically significant MR underwent DSE between 1999 and 2005. CR was defined as an increase in LVEF ofor = 10% during dobutamine infusion.Among 125 patients, 55 (43.0%) showed evidence of CR. Within five years after DSE, 24 patients (34.3%) in the CR- group and seven (12.7%) in the CR+ group had died or required heart transplantation (p0.01, log rank). After adjusting for age, baseline LVEF, NYHA class and moderate/severe tricuspid regurgitation (TR), CR remained an independent predictor of time to death or heart transplantation (HR 0.34; 95% CI: 0.15-0.76, p0.01). Improvement in the degree of MR was present at one year in 85.0% of CR+ patients, and in 62.5% of CR- patients (p = 0.03). An improvement of 5% in LVEF was noted in the CR+ group, compared to 0% in the CR- group (p = 0.04).In patients with advanced LVD and severe MR, CR detected by DSE was associated with significant reductions in the risk of death and heart transplantation.