Physiologic aspects of human heart-lung transplantation. Pulmonary function status of the post-transplanted lung

Pulmonary function measurements were performed before and after heart-lung transplantation in nine patients who had undergone surgery for end-stage pulmonary hypertension. In seven of them, sequential follow-up studies were performed at variable times postoperatively with the longest period 27 months. Pre-transplant studies showed a mild restrictive defect in 33 percent and obstructive disease in 50 percent of the patients, respectively. Arterial hypoxemia was present in all patients. The degree of mechanical changes found did not appear severe enough to account for the marked dyspnea and disability characterizing this group of patients with pulmonary hypertension. Following transplantation, all patients showed striking improvement of symptoms and general physical status. In the early post-transplant period, there was a marked decrease in most lung volumes resulting in a moderately severe restrictive ventilatory defect. Flow parameters that were reduced could be related to decreased volumes and not to intrinsic airway obstruction. Arterial O2 tensions improved dramatically and gas exchange was maintained at essentially normal levels. Lung function tended to improve progressively following transplantation with the passage of time. Heart-lung transplant is consistent with an adequate long-term pulmonary functional state which has the capacity to sustain the normal activities of daily living. From the standpoint of lung function, heart-lung transplantation appears to be acceptable as a form of therapy in selected patients.