Relation of Pretransplant Peak Oxygen Consumption to Outcomes After Heart Transplantation

Peak exercise oxygen consumption (pVO) is an important predictor of prognosis in patients with heart failure (HF). The association between pretransplant pVO and post-transplantation outcomes in HF patients has not been previously studied. We identified adult OHT recipients with available pVO in the United Network for Organ Sharing registry (2000 to 2015). Patients were divided into 3 categories using Weber classification: class B (pVO 16 to 20 ml/kg/min), class C (pVO 10 to 16 ml/kg/min), and class D (pVO <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 pVO 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 pVO; 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 pVO 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 pVO was associated with greater mortality and morbidity after OHT. These results suggest that earlier transplantation might improve post-transplantation outcomes in advanced HF patients.