Abnormal spirometry 1 year after lung transplantation may identify patients at risk for chronic lung allograft...

Baseline lung allograft dysfunction (BLAD) is the failure to achieve predicted pulmonary function after lung transplantation. BLAD, as defined by abnormal spirometry at 12 months post-transplant (Spiro12M), has been associated with increased mortality and chronic lung allograft dysfunction (CLAD) in a single-center study. We sought to validate Spiro12M in a prospective multicenter study that included bilateral (BLTx) and single (SLTx) lung recipients.

The cohort included first lung recipients from 5 North American transplant centers participating in the Clinical Trials in Organ Transplantation-20 study. Abnormal Spiro12M was defined as a percent predicted forced expiratory volume in 1 second (FEV1) or forced vital capacity (FVC) at 12 months post-transplant <80% predicted based on recipient demographics, or FEV1/FVC <0.7. A modified Spiro12M definition was separately analyzed whereby recipients met at least 2 criteria. Cox regression models assessed the primary endpoints of time to probable CLAD, probable CLAD composite (including CLAD-related death/retransplantation), obstructive CLAD, or graft loss (death/retransplantation).

517 patients met inclusion criteria, with 229 (60.4%) BLTx and 109 (79.0%) SLTx recipients having abnormal Spiro12M. Among BLTx, abnormal Spiro12M was associated with an increased risk of probable CLAD composite (HR, 1.58; 95% CI, 1.09, 2.29; p = 0.015), while modified Spiro12M was associated with probable CLAD (HR, 1.70; 95% CI, 1.15, 2.52; p = 0.008), probable CLAD composite (HR, 1.82; 95% CI, 1.25, 2.65; p = 0.002), and graft loss (HR, 1.68; 95% CI, 1.14, 2.48; p = 0.009).

Spiro12M and modified Spiro12M are reproducible, clinically relevant definitions that can prospectively identify BLTx at risk for CLAD.