Exercise training attenuates progressive decline in brachial artery reactivity in heart transplant recipients

Background: Heart transplantation normalizes central hemodynamics, but endothelial dysfunction persists after transplantation. Methods: To investigate the effects of aerobic exercise on arterial function, oxidative stress, lipid profile, and symathetic nervous system activity, 20 heart transplant recipients (age, 54.3 +/- 9.1 years; 17 men, 3 women) were randomly assigned to 12 weeks of supervised treadmill exercise (Trained; n = 10) or standard medical care (Control; n = 10). Supervised exercise was initiated at 8 weeks after transplant. Brachial artery reactivity was assessed using flow-mediated dilation. Results: The VO2 peak increased 26% in the Trained patients (15.4 +/- 4.3 vs 19.4 +/- 5.5 ml/kg/min; p <= 0.05) but did not change in the Controls (16.2 +/- 5.2 vs 16.8 +/- 2.8 ml/kg/min; p >= 0.05). Brachial artery flow-mediated dilation (10.1% +/- 6.1% vs 9.6% +/- 6.2%) and,absolute brachial diameter (0.48 +/- 0.22 vs 0.42 +/- 0.24 mm) did not change in Trained patients, but brachial flow-mediated dilation (10.5% +/- 2.8% vs 7.9% +/- 5.1%) and the absolute change in brachial diameter (0.48 +/- 0.16 vs 0.36 +/- 0.24 mm) decreased significantly (p <= 0.05) in the Control patients. Resting norepinephrine decreased significantly (p <= 0.05) after training (0.32 +/- 0.19 vs 0.22 +/- 0.22 ng/ml), but there was a nonsignificant trend toward increased norepinephrine in the Controls (0.26 +/- 0.17 vs 0.53 +/- 0.41 ng/ml; p = 0.07). The lipid profile and marker of oxidative stress did not differ between the groups before or after the intervention. Conclusions: To our knowledge, this is the first prospective, randomized study to investigate the effects of heart transplantation and aerobic exercise on peripheral artery function in the same cohort of heart transplant recipients. Brachial artery flow-mediated dilation increased early in the post-operative period. Aerobic exercise preserved but did not improve brachial artery flow-mediated dilation. Heart transplant recipients who did not participate in supervised exercise showed a progressive decline in brachial, artery flow-mediated dilation.