Heart-lung transplantation: an overview

Heart-lung transplantation is in a state of evolution, but for selected patients with end-stage cardiopulmonary and pulmonary disease, it can offer long-term rehabilitation. In the 8 years since heart-lung transplantation was begun at Stanford, much experience has accrued and significant improvements have been made. Advances that have made heart-lung transplantation feasible include better immunosuppression, particularly the triple-drug protocol of cyclosporine, azathioprine, and corticosteroids which decreases the incidence of obliterative bronchiolitis. Techniques of improved lung preservation have made distal donor procurement a reality, and increasing numbers of lung and heart-lung transplantations are now being performed. More importantly, better recipient and donor selection has occurred such that the perioperative mortality has been reduced from 35 to 16 per cent. Currently, the major threat facing survivors of heart-lung transplantation is the insidious development of restrictive airway disease. Our impression is that the development of obliterative bronchiolitis results from repeated rejection episodes or possibly an injury mechanism following severe viral pneumonia. The common pathway seems to be repeated injury and repair mechanism, with the end-stage being obliterative bronchiolitis by scar formation. As suggested, the injury mechanism is probably that of repeated or chronic rejection. To further support the hypothesis of an immunerelated etiology, obliterative bronchiolitis has occurred in recipients of bone marrow transplants if they develop graft-versus-host disease. In an attempt to ameliorate the effects of rejection on airway function, we have increased our maintenance immunosuppression by adding azathioprine. Consequently, patients with early obliterative bronchiolitis on enhanced immunosuppression have had stabilization of the airway disease, and we have noted a significant reduction in the occurrence of obliterative bronchiolitis from 62 per cent in Group 1 patients to 20 per cent in Group 2 patients. Since obliterative bronchiolitis may be reversed by early recognition and treatment of rejection, we have aggressively used bronchoscopy with transbronchial lung biopsy and bronchoalveolar lavage for surveillance of both rejection and infection in our recent patients. Open lung biopsy has not been used since 1986 to diagnose rejection, and we are encouraged that bronchoscopic surveillance is sensitive and effective. The primary goal of the bronchoscopic evaluation protocol was to monitor the patients closely and to treat both rejection and infection early and effectively. Concurrently, we are also measuring pulmonary function parameters, which includes FEV1, FEF 25-75, PaO2, total lung capacities, and profusion gradients. The desired outcome was the maintenance of normal airway dynamics by reversing airway disease at a reversible stage.(ABSTRACT TRUNCATED AT 400 WORDS)