Prognostic Value of Percent Achieved of Predicted Peak Oxygen Consumption for Patient with Chronic Heart Failure

Peak oyxgen consumption (VO2) during cardiopulmonary exercise testing (CPX) is a powerful independent prognostic marker to risk stratify patients with heart failure. Recently, percent predicted peak VO2 was found to be a more useful predictor of one-year outcome than peak VO2 alone. In this study, we aimed to evaluate the prognostic value of percent achieved of predicted peak VO2 for patients with chronic heart failure.
METHODS
One hundred-two patients with chronic heart failure (NYHA II-III) were studied. All patients performed CPX, and their peak VO2 values were measured. Predicted peak VO2 values were also estimated according to Wasserman's formula. Finally, percent achieved of predicted peak VO2 (measured/predicted peak ) VO2 values of each patient were calculated. Patients were divided into two groups, according to their percent achieved of predicted peak VO2 value, patients with a percent achieved of predicted peak VO2 > 50% (group 1), and patients with a percent achieved of predicted peak 50% (group 2). During a mean follow-up period of 13.6±6.2 months, mortality in each group were noted, and findings were evaluated with Kaplan-Meier survival analysis.
RESULTS
Eighty-six patients (84%) were men, and 16 (16%) were women with mean age of 60.7±9. Among them 68 (67%) had ischemic, and 34 (33%) had nonischemic dilated cardiomyopathy. One-year survival rate was 76% for the group 2, and 94% for the group 1 (p=0.02). Whereas, one-year survival rates were 70% for patients with peak VO2 14 ml/kg/min, and 98% for patients with peak VO2 > 4 ml/kg/min (p=0.001). We conclude that. percent achieved of predicted peak VO2 can be used as a useful prognostic marker for patients with chronic heart failure, but it is not superior to peak VO2 >14 ml/kg/min for one-year survival estimation.