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

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.

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 FEV(1), FEF(25), FEF(50), FEF(75) and MMEF(75/25) were evaluated and subsequently related to the occurrence of Grade 1 BOS.

Grade 1 BOS was diagnosed in 16 recipients at a median of 218 (range 88 to 1,007) days after LT. A persistent and significant decrease in FEV(1), FEF(25), FEF(50), FEF(75) and MMEF(75/25) 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%.

Bronchiolar dysfunction is a common and early finding after LT. The decrease of FEV(1) 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.