Acute kidney injury after lung transplantation, incidence, risk factors, and effects: A Swedish nationwide study.

Background: Acute kidney injury (AKI) is a serious complication after lung transplantation, but the reported incidence varies in the literature. No data on AKI have been published from the Swedish lung transplantation program.

Methods: The aim of our study was to investigate the incidence, perioperative risk factors, and effects of early postoperative acute kidney injury (Kidney Disease Improving Global Outcomes [KDIGO] criteria) after lung transplantation. A retrospective, nationwide study of 568 lung-transplanted patients in Sweden between 2011 and 2020 was performed.

Results: The incidence of AKI (any grade) was 42%. Renal replacement therapy was used in 5% of the patients. Preoperative factors independently associated with increased incidence of AKI were higher body mass index (odds ratio [OR]: 1.07, 95% CI: 1.02, 1.12) longer time on transplantation waiting list (OR: 1.05 [1.01, 1.09]), re-transplantation (OR: 2.24 [1.05, 4.80]) and moderate to severe tricuspid regurgitation (OR: 2.61 [1.36, 5.03]). Intraoperative factors independently associated with increased incidence of AKI were use of cardiopulmonary bypass (OR: 2.70 [1.57, 4.63]), increasing number of transfused red blood cell units, and use of immunosuppressive therapy other than routine (OR: 2,56 [1.47, 4.46]). A higher diuresis (OR: 0.70, 95% CI: 0.58-0.85) was associated with less incidence of acute kidney injury. Development of AKI was associated with increased time to extubation (median 30 h, IQR [9, 118] vs. 6 [3, 16]), length of stay in the intensive care unit (9 days [4, 25] vs. 3 [2, 5]) and increased rate of primary graft dysfunction (OR 2.33 [1.66, 3.29]) and 30-day mortality (OR: 10.8 [3.0, 69]).

Conclusions: Acute kidney injury is common after lung transplantation and affects clinical outcomes negatively. Preoperative factors may be used for risk assessment. The use of cardiopulmonary bypass is a potentially modifiable intraoperative risk factor.

Editorial comment: Acute kidney injury is a common complication after lung transplantation that severely influences patient outcomes. This large study of more than 500 patients treated over a decade identified potentially modifiable factors associated with the development of acute kidney injury.