Abstract 3174: The Use of Dobutamine Stress Echocardiography to Predict Clinical Outcomes in Patients with Cardiomyopathy and Mitral Regurgitation
Background- Management of patients with mitral regurgitation (MR) and far-advanced left ventricular dysfunction (LVD) is a common clinical dilemma. To date, there are no reliable predictors for their prognosis after treatment, either medically or surgically. Dobutamine stress echocardiography (DSE) was proposed as a part of a work-up to identify patients most likely to improve with treatment.
Methods and Results- Between May 1999 and November 2005, 126 consecutive patients underwent DSE for assessment of contractile reserve (CR) in the setting of advanced LVD and MR (LVEF of ≤35% and MR grade moderate or higher). Of these, 56 (44.4%) patients had evidence of CR (positive DSE defined by LVEF improvement ≥10% with protocol dobutamine infusion). In the entire cohort, 29 (23%) patients underwent mitral valve surgery (MVS) and 97 (77%) were treated medically. There were 11 (8.7%) deaths and 20 (15.9%) deaths or heart transplantation during a median follow up of 642 days. Contractile reserve was associated with lower risk of death or heart transplantation (log rank, p= 0.04) (Figure 1⇓). Contractile reserve was an independent predictor of death or transplantation after adjusting for age, MVS, and base-line functional class (RR 0.31, p = 0.046). Risk of death in patients who had CR was 5.9% with MVS, 7.7 % with medical therapy alone, as compared to 11.4% in patients with no CR.
Conclusion-Among patients with advanced MR and LVD, evidence of CR, as detected by DSE is associated with better clinical outcomes, regardless of treatment. Improved left ventricular function with inotropic stimulus in this setting may reflect a myocardium that is not irreversibly fibrosed and has potential of recovery.