Graft Side-mismatching for Single-lung Transplantation Does Not Affect Outcomes: Role of the Pre-operative Quantitative Lung Perfusion Scan

Background: There are concerns about which lung to explant during single-lung transplantation (SLT). Traditionally, a quantitative lung perfusion scan (QLPS) is performed, and the better-perfused lung is retained. Occasionally, there is transplantation with graft "side-mismatching," where the less-well-perfused lung is retained. We performed a retrospective study of patients undergoing SLT at our institution to evaluate the effects of side-mismatching (according to the QLPS) on graft performance and outcome. Methods: We defined graft side-mismatching with a prospectively designed formula using baseline QLPS, and defined patients as either side-matched or side-mismatched. Data on mortality, requirement for cardiopulmonary bypass, relative graft perfusion, lung function and exercise capacity were obtained from institutional databases and patients' files. Results: In a cohort of 114 patients, we defined 97 as having received a side-matched SLT and 17 as having received a side-mismatched graft. After lung transplantation, forced expiratory volume in 1 second (FEV₁) and exercise capacity improved in both groups (p < 0.001). Patients with mismatched lungs had significantly higher relative graft perfusion post-operatively (p = 0.0012). There was no significant difference between the two groups (matched vs mismatched) in mortality, physiologic parameters and need for cardiopulmonary bypass. Conclusions: There is no apparent risk to the patient when a side-mismatched lung graft is transplanted. We conclude that side-mismatched lung transplantation appears to be feasible when required.