Comparison of peak exercise oxygen consumption and the Heart Failure Survival Score for predicting prognosis in women versus men

The Heart Failure Survival Score (HFSS) and peak exercise oxygen consumption (VO2) predict survival in ambulatory patients with heart failure and are used for selection for cardiac transplantation. However, the populations tested have predominately been men. To investigate if peak VO2 and the HFSS predict prognosis in women, we derived HFSS and measured peak VO2 in 274 women referred for cardiac transplantation and in 278 men matched by referral year. Seven HFSS parameters were obtained, including presence of coronary artery disease, left ventricular ejection fraction, heart rate, mean arterial blood pressure, peak VO2, presence of intraventricular conduction defects, and serum sodium. Subjects were divided into high-, medium-, and low-risk strata for HFSS and VO2 based on previous cutpoints. Survival curves were derived using Kaplan-Meier analysis and compared by log-rank analysis. Follow-up averaged 929 days. For women, 1-year event-free survival in the low- (> 14), medium- (10.1 to 14), and high-risk (< 10 ml/kg/min) VO2 strata was 93%, 84%, and 80%, respectively. For the HFSS, 1-year event-free survival in the low( >= 8.10), medium- (7.20 to 8.09), and high-risk (<= 7.19) strata was 90%, 87%, and 67%, respectively. Survival curves for VO2 (p < 0.01) and HFSS (p < 0.001) demonstrated significant differences. In both genders, the low-risk groups for HFSS and VO2 can safely have transplantation deferred. Women had better survival than men for a given peak VO2. The HFSS was consistent between genders. In conclusion, peak VO2 and the HFSS are excellent parameters to predict survival in women with congestive heart failure. The HFSS is more consistent than the peak VO2 between the genders. (c) 2007 Elsevier Inc. All rights reserved.