Late pulmonary haemodynamic changes in heart-lung transplantation

As survival improves following heart-lung transplantation (HLT) the importance of obliterative bronchiolitis (OB) as a cause of late death increases. Whilst coronary occlusive disease (COD) may be less common in heart-lung transplant recipients than in patients receiving heart transplants, COD associated with OB can be lethal. We have studied 22 long-term survivors of heart-lung transplantation at an average of 25 months following transplantation during rest and at 50 W supine exercise and with prostacyclin induced vasodilation. Cardiac index increased less with exercise as the physiological measurement of OB using forced expiratory volume in one second (FEV1) fell (P = 0.018). Although resting pulmonary vascular resistance increased with falling FEV1, this increase was still within the normal range. We conclude that a fall in cardiac reserve on exercise accompanies the fall in FEV1 which characterizes OB and may reflect cardiac vascular disease.