Perioperative Acute Kidney Injury after Sequential Bilateral Lung Transplant: Comparing Intraoperative Elective VA ECMO to an "Off Pump" Strategy

Abstract

<h3>Purpose</h3> Perioperative acute kidney injury (AKI) is associated with worsened outcomes after bilateral orthotopic lung transplantation (BOLT). While elective veno-arterial (VA ECMO) strategies are increasingly common, the incidence of perioperative AKI in the context of various surgical strategies is unclear. In this retrospective observational study of BOLT patients, we propose that AKI rates differ between elective VA ECMO and off-pump (OP) strategies. <h3>Methods</h3> Adult patients undergoing BOLT from 1/1/17 to 9/6/2020 were included. As of Feb 2020, all BOLTs were performed on elective VA ECMO. Patients requiring preoperative or urgent conversion to ECMO, cardiopulmonary bypass, concomitant cardiac surgery, re-transplantation, severe pulmonary hypertension (mean PA pressures >40 mmHg), or missing creatinine (Cr) data were excluded. Patients were stratified into OP and VA ECMO cohorts. VA ECMO patients were matched 1:1 to OP patients based on transplant indication, baseline Cr and transfusion requirements. The primary outcome compared was AKI rates (KDIGO criteria). Secondary outcomes included the ratio of maximum postoperative Cr to baseline, and peak Cr. <h3>Results</h3> 383 BOLT patients were identified. 188 met inclusion criteria, while 19 were missing creatinine data. Of those, 134 patients were available prior to Feb 2020 and 35 between Feb-Sep 2020. We identified 33 matched pairs for comparison. Minimal differences in donor, recipient, and procedural characteristics were seen between matched, paired groups. AKI was more common in the OP compared to the VA ECMO group (27/33 vs. 17/33, p=0.009). Both the ratio of peak relative to baseline Cr (1.6 vs 1.3 g/DL; p=0.022) and peak Cr (1.3 vs 1.0 g/dL; p=0.012) were higher in the OP compared to the VA-ECMO group (Table). <h3>Conclusion</h3> In this retrospective study using matched pairs of BOLT patients, we observed a lower incidence of AKI associated with elective intraoperative VA-ECMO when compared to an off-pump strategy.