Impact of Unilateral Diaphragmatic Dysfunction on Postoperative Outcome after Bilateral Lung Transplantation

Objectives: Diaphragmatic dysfunction after bilateral lung transplantation is often unrecognized and its impact on postoperative course has not been evaluated yet. The aim of this study was to evaluate the prevalence of diaphragmatic dysfunction after lung transplantation and its impact on postoperative course.

Methods: The records of patients transplanted at our institution between January 2010 and May 2019 were reviewed. Presence of posttransplant unilateral diaphragmatic dysfunction was retrospectively evaluated using two-projection chest X-rays performed at hospital discharge, and was defined, according to our radiologists, by a > 40 mm difference between right and left diaphragmatic height, measured in an anterior–posterior projection while patients were standing upright and spontaneously breathing. Patients without a chest X-ray while spontaneously breathing and patients undergoing single-lung transplantation were excluded from the study. Posttransplant outcomes were compared between included patients with and without diaphragmatic dysfunction.

Results: During the study period, among the 1,154 lung-transplanted patients at our institution, 1,102 (95%) patients were included. Of these, 99 (9%) patients showed a > 40 mm difference between right and left diaphragmatic height (median, 47.5 mm) and the remaining 1,003 (91%) patients did not (median, 15.3 mm), at the chest X-ray performed at a median of 21 days after lung transplantation. Patients with diaphragmatic dysfunction were transplanted more often for pulmonary fibrosis (41 vs. 29%, p = 0.010) and less often for cystic fibrosis (13 vs. 22%, p = 0.041). Postoperatively, patients with diaphragmatic dysfunction required longer invasive ventilation (median, 24 vs. 13 hours, p = 0.001), ICU (median, 3 vs. 2 days, p < 0.001), and hospital stay times (24 vs. 23 days, p = 0.012). Prevalence of primary graft dysfunction (PGD) grade 3 at 72 hours did not differ between groups (7 vs. 4%, p = 0.092). At the last available chest X-ray (median time, 31 months), diaphragmatic dysfunction was persistent in 48 (48%) patients. At 1-year follow-up, forced expiratory volume in 1 second (FEV1, %predicted) was lower in patients with than without diaphragmatic dysfunction (75 vs. 87%, p = 0.002). At 5-year follow-up, graft survival did not differ between groups (69 vs. 72%, p = 0.29).

Conclusion: Unilateral diaphragmatic dysfunction prolonged the early postoperative course after lung transplantation, but did not impair long-term graft survival.