Absence of exercise capacity improvement after exercise training program: a strong prognostic factor in patients with chronic heart failure.

BACKGROUND: Exercise training is established as adjuvant therapy for chronic heart failure, but the prognostic value of improvement in exercise capacity after exercise training has never been evaluated. METHODS AND
RESULTS: In this prospective bicentric study, all chronic heart failure patients with left ventricular ejection fraction <45% who underwent an exercise training program in a cardiac rehabilitation center between January 2004 and September 2006 were consecutively included. Improvement in exercise capacity was assessed by change in peak oxygen consumption (deltaPVo(2)) and in PVo(2) expressed as a percentage of predicted PVo(2) (delta%PPVo(2)) measured before and after the training program. We included 155 patients (54+/-12 years old, male 81%, left ventricular ejection fraction=29.5+/-7.1%). Patients underwent 20 (10-30) training sessions. PVo(2) and %PPVo(2) were significantly increased after the training program (14% and 13%, respectively, P<0.001 for both). After 16+/-6 months follow-up, 27 patients had a cardiac event (death [n=12], cardiac transplantation [n=5], hospitalization for acute heart failure [n=10]). Univariate analysis revealed that among 17 significant predictors of cardiac events, the 2 more powerful ones were level of B-type natriuretic peptide at baseline (P<0.0001) and improvement in exercise capacity as assessed by deltaPVo(2) and delta%PPVo(2) (P<0.0001). Multivariate analysis revealed B-type natriuretic peptide level and delta%PPVo(2) as only independent predictive factors of outcome (P=0.01). The risk ratio of cardiac events for nonresponse versus response to the training program (defined as median delta%PPVo(2)<6%) was 8.2 (P=0.0006).
CONCLUSIONS: Among patients with chronic heart failure, the lack of improvement in exercise capacity after an exercise training program has strong prognostic value for adverse cardiac events independent of classical predictive factors such as left ventricular ejection fraction, New York Heart Association class, and B-type natriuretic peptide level.