The Heart Failure Survival Score outperforms the peak oxygen consumption for heart transplantation selection in the era of device therapy

Abstract

Background: The peak oxygen consumption (VO(2)) and the Heart Failure Survival Score (HFSS) risk stratify patients with chronic heart failure (CHF) referred for heart transplantation. However, these tools were developed before widespread use of implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy (CRT). The prognostic accuracy of these tools in patients with ICD and/or CRT is unknown.

Methods: Cardiopulmonary exercise testing with measurement of peak VO(2) and calculation of the HFSS was done in 715 CHF patients (54 ± 12 years; ICD, 244; CRT, 30; CRT-D, 108; none, 333) referred for heart transplantation.

Results: During an average follow-up of 962 ± 912 days, 354 patients died or received urgent heart transplant or left ventricular assist device. By Cox hazard analysis, both peak VO(2) and HFSS were powerful independent prognostic markers. By Kaplan-Meier analysis, the HFSS was effective in discriminating patients into low-, medium-, and high-risk groups in all device groups. In contrast, the peak VO(2) did not discriminate between low (>14 ml/min/kg) and medium (10.1 to 14 ml/min/kg) risk in device patients. By area under the receiver operating characteristic curve, the HFSS performed better than the peak VO(2) (1-year in total cohort; 0.72 vs. 0.65; p < 0.001; 1-year in device patients; 0.69 vs. 0.65; p < 0.001).

Conclusion: The HFSS outperforms the peak VO(2) in risk stratification for CHF in the presence of an ICD and/or CRT. Furthermore, a peak VO(2) ≤ 10 ml/kg/min rather than the traditional cutoff value ≤ 14 ml/min/kg may be more useful for risk stratification in the device era.