Peak Oxygen Consumption as a Predictor of Death in Patients With Heart Failure Receiving β-Blockers

Abstract

Background— Peak oxygen uptake (peak V̇ o 2 ) is a strong predictor of mortality and is commonly used in the evaluation of patients for cardiac transplantation. β-Blockers reduce mortality in patients with heart failure, without influencing peak V̇ o 2 , raising the possibility that peak V̇ o 2 is no longer suitable as an indicator of prognosis in these patients. Methods and Results— We analyzed prospectively gathered data on 2105 patients referred for cardiopulmonary testing for all-cause mortality and for occurrence of death or transplantation. Patients receiving β-blockers were younger, more likely to have coronary disease, and had a greater mean ejection fraction but had a similar peak V̇ o 2 . There were 555 deaths (26%) and 194 (9%) transplants during a median follow-up of 3.5 years. Peak V̇ o 2 was a predictor of mortality irrespective of β-blocker use; a decrease of 1 mL · kg −1 · min −1 resulted in an adjusted hazard ratio (HR) of 1.13 (95% CI 1.09 to 1.17, P <0.0001) in patients not receiving β-blockers and 1.27 (95% CI 1.18 to 1.36, P <0.0001) in patients receiving β-blockers. Similar findings were noted when considering death or transplantation as an end point. β-Blocker use was associated with better outcomes until peak V̇ o 2 values became very low (≈10 mL · kg −1 · min −1 ), at which level survival rates were equally poor. Conclusion— Peak V̇ o 2 is a determinant of survival in patients in heart failure even in the setting of β-blockade. Because of improved survival in patients treated with β-blockers, the cut point value of 14 mg · kg −1 · min −1 for referral for cardiac transplantation in these patients requires reevaluation, and a lower cut point may be more appropriate.