Bronchiolar airflow impairment after lung transplantation:An early and common manifestation

Background: Bronchiolitis obliterans syndrome (BOS) is the major limitation to long-term survival after lung, transplantation (LT). In this study we investigate the extent and frequency of airflow limitation after LT and its value for the diagnosis of BOS.Methods: Flow-volume measurements were analyzed retrospectively in 36 recipients of a bilateral LT, with a median follow-up of 32.9 months. The prevalence and onset of a decline of FEV1, FEF25, FEF50, FEF75 and MMEF75/25 were evaluated and subsequently related to the occurrence of Grade 1 BOS.Results: Grade I BOS was diagnosed in 16 recipients at a median of 218 (range 88 to 1007) days after LT. A persistent and significant decrease in FEV1, FEF25, FEF50, FEF75 and MMEF75/25 was observed in 23, 24, 30, 32 and 29 patients, respectively. In those patients developing BOS during follow-up this decrease was determined at 147 (55 to 657), 130,(78 to 932), 110 (21 to 573), 103 (32 to 657) and 121 (32 to 657) days after LT (p <0.0005), respectively. The respective predictive values of these parameters for the occurrence of Grade 1 BOS (within 120 days) were 88%, 60%, 50%, 35% and 41%.Conclusion: Bronchiolar dysfunction is a common and early finding after LT. The decrease of FEV1 in BOS is often preceded by a decrease of bronchial airflow. Airflow markers may be used as an early warning sign for the development of BOS, although their predictive values are moderate.