Adaptive Chest Cavity Expansion Following Lung Allograft Oversizing in Idiopathic Pulmonary Fibrosis

Due to parenchymal fibrosis and chest wall contraction in idiopathic pulmonary fibrosis (IPF), donor lung allografts are generally undersized to accommodate smaller diseased chest cavities. We hypothesized that transplanting oversized allografts (OAs) in recipients with IPF would be associated with thoracic cavity expansion.

A single center retrospective study of IPF patients who underwent lung transplant between 2014 and 2022 was conducted. Size matching was determined by comparing donor and recipient lung height on chest radiographs, measured from lung apex to middiaphragm on donor and recipient inspiratory anterior to posterior chest radiographs. Allografts that were ≥10% larger on chest radiograph compared to corresponding recipient lungs were deemed OAs, or not oversized allografts. Allograft lung height and pulmonary function tests were collected at 1, 6, and 12 mo and a comparative analysis was performed.

The OA group had a significant increase in change of height in the left lung at 1 mo and both lungs at 6 mo (P < 0.05). There were no significant differences in change of forced expiratory volume in 1 s at 1, 6, 12 mo between the two groups. The change in forced vital capacity was significantly increased in the OA group at 6 mo (P < 0.05). The degree of donor to recipient allograft size mismatch and resultant recipient pleural cavity expansion was significantly correlated at 1 and 6 mo (P < 0.05).

Transplanting larger allografts into IPF patients was associated with pleural cavity expansion, without an associated change in pulmonary function tests. Thus, larger allografts potentially can be used in IPF patients, thereby increasing donor availability for these patients.