We present cardiac and pulmonary function data obtained at serial annual reviews in 21 heart-lung transplant (HLT) recipients followed for up to four years postoperatively, reflecting the entire Stanford experience as of June 1987. A total of 50 cardiac catheterisation procedures and endomyocardial biopsies yielded the following results: rejection on biopsy (0/50) (0% of patients), angiographic coronary artery disease (1/50) (5%), pulmonary hypertension (2/50) (10%), elevated pulmonary vascular resistance (PVR) (1/50) (5%), and low cardiac index (CI) (4/50) (14%). Systemic hypertension was common, with an elevated systemic vascular resistance (SVR) (26/44) (76%) and an elevated mean aortic pressure (MAP) (22/44) (67%). Pulmonary function testing frequently revealed abnormalities. Airflow limitation was manifested by a reduction in both FEV1/FVC ratio (17/50) (52%) and FEF25-75 (30/50) (71%), and was often associated with arterial hypoxaemia (13/50) (52%). Subsequently, five patients with these findings have died with obliterative bronchiolitis (OB), one underwent retransplantation for OB, six have stable OB, and one has progressive OB. Length of survival was highly correlated with the resting PaO2 at the first annual review (r = 0.99) (p less than 0.001), and, to a lesser degree, on the reduction in FEF25-75 (r = 0.73) (p less than 0.05) and FEV1/FVC ratio (r = 0.77) (p less than 0.05). Resting PaO2 was determined by ventilatory (r = 0.80) (p less than 0.001) rather than circulatory factors and all patients with airflow limitation who died had OB at post-mortem examination. These results support the continued study of HLT as a therapeutic modality for selected patients with irreversible pulmonary hypertension. They demonstrate that, in the absence of severe OB, haemodynamics, cardiac function, and coronary patency are preserved for several years after HLT. Whereas the value of regular pulmonary function testing has become evident, there does not appear to be a clinical need for annual surveillance with invasive cardiac procedures in long-term survivors of HLT.