Sequential assessment of exercise tolerance in heart transplantation compared with coronary artery bypass surgery after phase II cardiac rehabilitation

Abstract

To investigate the improvement in exercise capacity of transplant patients after an early postoperative (phase II) cardiac rehabilitation program during the first year after surgery, we analyzed retrospectively exercise capacity within 3 months (at the completion of phase II rehabilitation) and 1 year after surgery in 17 orthotopic heart transplantation patients (15 men and 2 women) and 17 age- and gender-matched coronary artery bypass graft (CABG) patients. All patients participated in a phase II cardiac rehabilitation exercise program followed by a home-based exercise program. At the completion of phase II cardiac rehabilitation, mean peak oxygen (VO2) adjusted for body weight in heart transplant patients was not significantly different from that in CABG patients (19.7 +/- 3.7 vs 21.9 +/- 4.1 ml/kg/min), and oxygen pulse at peak exercise did not differ between the 2 groups (11.5 +/- 2.5 vs 12.6 +/- 2.4 ml/beat). Between 3 months and 1 year after surgery, CABG patients had a marked increase in exercise time, increase in heart rate from rest to peak exercise (heart rate reserve), peak VO2, and oxygen pulse. In contrast, heart transplant patients had a significant but only modest increase in peak VO2, and were much more limited in exercise capacity at 1 year than were CABG patients (21.3 +/- 3.9 vs 27.4 +/- 4.7 ml/kg/min, p <0.0001). In our limited patient population, usual phase I rehabilitation with subsequent home-based exercise training was inadequate to improve the exercise capacity of heart transplant patients, and different rehabilitation protocols, such as long-term supervised exercise training, specific to this patient group may be indicated.