Impaired Exercise Tolerance Early After Heart Transplantation Is Associated With Development of Cardiac Allograft Vasculopathy

Background. Exercise performance remains limited in some patients after heart transplantation (HTx). The goal of this study was to assess for association between cardiopulmonary exercise test performance at 1 year after HTx and future development of cardiac allograft vasculopathy (CAV). Methods. Overall 243 HTx recipients performed cardiopulmonary exercise testing at 1 year after HTx. During the median follow-up period of 31 (interquartile range 19;61) months, 76 (32%) patients were diagnosed with CAV (CAV group). Results. The CAV group patients had lower exercise capacity (5.2 +/- 1.9 versus 6.5 +/- 2.2 metabolic equivalents;P= 0.001) and duration (9.6 +/- 3.5 versus 11.4 +/- 4.8 min;P= 0.008), lower peak oxygen consumption (VO2) (18.4 +/- 5.4 versus 21.4 +/- 6.1 mL/kg/min;P= 0.0005), lower normalized peak VO2(63% +/- 18% versus 71% +/- 19%;P= 0.007), and higher minute ventilation (VE)/carbon dioxide production (VCO2) (34 +/- 5 versus 32 +/- 5,P= 0.04). On Cox proportional hazards regression analysis, normalized peak VO2 <= 60%, and VE/VCO2 >= 34 were associated with a high hazard for CAV (HR = 1.8 [95% CI 1.10-4.53,P= 0.03] and 2.5 [95% CI 1.01-8.81,P= 0.04], respectively). The subgroup of patients with both normalized peak VO2 <= 60% and VE/VCO2 >= 34 was at highest risk for development of CAV (HR = 5.2, 95% CI 2.27-15.17,P= 0.001). Conclusions. Normalized peak VO2 <= 60% and VE/VCO2 >= 34 at 1 year after HTx are associated with the development of CAV.