Bronchiolitis obliterans syndrome (BOS) following heart-lung transplantation.

With the increasing number of successfully performed lung transplants and a longer follow up of patients, there is an interest in the analysis of long-term complications and their impact on patient survival. Heart-lung transplantation was performed in 157 patients with 126 patients surviving at least 6 months. Early death was mainly caused by bacterial and viral infection. Long-term patient survival was decisively influenced by obliterative bronchiolitis. With the new international definition of bronchiolitis obliterans syndrome (BOS) based on an irreversible decline of FEV1 from baseline values, it became possible to analyse the incidence of BOS and the impact on patient mortality in long-term survivors. FEV1 reached a peak value of 102% predicted at a median of 219 days. In 106 of 126 patients (84%), FEV1 showed no decline within the first year. A total of 60 patients (47.6%) developed BOS grade 1 with progression to BOS grade 2 in 85% of these patients. The incidence of BOS was 12.6% at 1 year increasing to more than 50% 5 years after transplantation. Patient mortality due to obliterative bronchiolitis increased from 1% at 1 year to 18% more than 5 years after transplantation. Almost all deaths (86%; 32/37) more than 1 year after HLT were associated with bronchiolitis obliterans. In summary, bronchiolitis obliterans decisively contributes to long-term patient morbidity and mortality after heart-lung transplantation. Clinical and research efforts should be directed towards avoiding this important complication.