Relation of Pretransplant Peak Oxygen Consumption to Outcomes After Heart Transplantation

Peak exercise oxygen consumption (pVO₂) is an important predictor of prognosis in patients with heart failure (HF). The association between pretransplant pVO₂ and post-transplantation outcomes in HF patients has not been previously studied. We identified adult OHT recipients with available pVO₂ in the United Network for Organ Sharing registry (2000 to 2015). Patients were divided into 3 categories using Weber classification: class B (pVO₂ 16 to 20 ml/kg/min), class C (pVO₂ 10 to 16 ml/kg/min), and class D (pVO₂ <10 ml/kg/min). Postoperative outcomes (mortality, renal failure, rejection) were compared between the groups. A total of 9,623 patients were included in this analysis; the mean age was 54 ± 11 years, 74% were male, 75% were white and 59% had nonischemic etiology of HF. The mean pVO₂ was 11.7 ± 3.6 ml/kg/min: 1,202 (12.5%) in class B, 6,055 (62.9%) in class C, and 2,366 (24.6%) were in class D. At a median follow-up of 6.1 years, 2,730 (28.4%) died. Post-transplantation survival decreased with decreasing pVO₂; 1 and 5-year survival: B (92%, 80%), C (90%, 79%), and D (87%, 75%), p <0.001 by log-rank. After multiple adjustments, patients in class D had significantly higher post-transplantation mortality compared with class C (Hazard Ratio (HR) 1.21 [1.03 to 1.43], p = 0.02). When analyzed as a continuous variable, each 1 ml/kg/min increase in pVO₂ was associated with 2% decrease in mortality during follow-up (adjusted HR 0.98 [0.96 to 0.99], p <0.001). Patients in class D had significantly prolonged (>14 days) hospitalization (adjusted Odds Ratio (OR) 1.42 [1.20 to 1.68], p <0.001) and a trend toward increased need for dialysis (adjusted OR 1.36 [1.00 to 1.84], p = 0.05) compared with patients in class B. In this large cohort, lower pretransplant pVO₂ was associated with greater mortality and morbidity after OHT. These results suggest that earlier transplantation might improve post-transplantation outcomes in advanced HF patients.