Baseline Allograft Dysfunction in Single-lung Transplant Recipients: More Questions Than Answers?

Résumé fourni par la source

We read with interest the article by Gerckens et al.1 This article defines baseline lung allograft dysfunction (BLAD) in a population of single-lung transplant recipients (SLTRs) and characterizes its risk factors. The findings reported are of particular interest. The authors provide an innovative definition of BLAD in SLTRs, as the inability to achieve a forced expiratory volume in 1 s (FEV1) and a forced vital capacity (FVC) of >60% of their theoretical values on 2 consecutive tests at a minimal time lag of 3 wk. This definition, adapted from the criteria used in double-lung transplant recipients (DLTRs)2 and based on the respiratory function findings of SLTRs compared with DLTRs,3 is also reflected in clinical observations and outcomes. Indeed, the incidence of BLAD in SLTRs and DLTRs was close in 2 distant cohorts,1,2 validating the definition proposed by Gerckens et al. Despite these indisputable strengths, this article deserves further discussion. The authors report a significantly higher median age in SLTRs without BLAD. In our opinion, this finding is expected. Similar to our centers, Gerckens et al also used Global Lung Function Initiative equations4 to estimate the theoretical FEV1 and FVC. These predicted physiological measures are affected by age: the higher the age, the lower the expected FEV1. This definition allows elderly participants to reach predicted values above their theoretical baseline FEV1, particularly with younger donors’ organs. Conversely, achieving a baseline lung function close to the predicted is more difficult at a younger age, especially if an older donor is used. As total lung capacity (TLC) is independent of age, one could wonder whether results would have been similar if BLAD diagnosis had been based on a TLC measured after LT of <60% of predicted TLC, precisely in SLTRs, as older candidates are more prone to receive SLTRs compared with DLTRs. Likewise, it would be valuable to analyze donor-to-recipient mismatch according to predicted donor FVC and FEV1 and actual preLT measured physiological parameters. An additional issue may arise from the inclusion of patients with early posttransplant death. Can the authors provide a minimum survival time in included patients to judge whether some patients included in the BLAD group had died too early to have had a chance to achieve optimal lung function? A final concern arises from the absence of reporting of bronchial complications in this cohort. Among bronchial issues, stenosis and bronchomalacia may significantly impair lung function,5 thus precluding the patient from achieving a satisfactory FEV1. To which extent were bronchial complications responsible for BLAD in this cohort? The first point is particularly relevant for SLTRs, the 2 latter can be equally applied to BLAD in both SLTRs and DLTRs. This landmark article provides strong data on BLAD in SLTRs. Single-lung transplantation is known to be a satisfactory option to improve the quality of life of patients with terminal lung disease.3 Whether BLAD significantly impacts the quality of life of SLTRs remains to be determined. BLAD should remain an important research subject to improve LTR outcomes.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.