Association of Intraoperative Hypotension With Delayed Graft Function Following Kidney Transplant: A Single Centre Retrospective Cohort Study

Background: Intraoperative hypotension is associated with acute kidney injury after surgery. However, the definition (duration and magnitude) of hypotension during kidney transplantation (KT) surgery on early graft function remains unclear. Methods: We conducted a retrospective cohort study of KT recipients from December 1, 2009, to December 31, 2019. Exposure to intraoperative hypotension was characterized as the duration (minutes) of mean arterial pressure (MAP) <55, <65, <75, and <85 mmHg. Our co-primary outcomes were DGF-creatinine reduction ratio (DGF-CRR, <30% creatinine reduction, postoperative days 1 and 2), and DGF-dialysis (DGF-D, required dialysis within the week of KT for deceased donor recipients). Logistic regression models were fitted to assess this relationship between MAP and DGF. Results: We included 1602 KT (939 deceased donors, 663 living donors) and 23 were excluded. DGF-CRR occurred in 33% of patients. DGF-CRR was associated with MAP < 65 (>5 min: OR 1.77, 95% confidence interval [CI]: 1.39–2.30; 6–10 min: OR 1.67, 95% CI: 0.97–2.86; 11–20 min: OR 2.18, 95% CI: 1.31–3.63) in unadjusted and <55 mmHg (5 min: OR 1.85, 95% CI: 1.47–2.32; 5–10 min: OR 2.41, 95% CI: 1.65–3.53; 11–20 min: OR 2.36, 95% CI: 1.60, 3.48) in adjusted models. There was also a signal for increased risk of DGF-CRR at MAP < 75 (>5 min: OR 1.69, 95% CI: 1.02–2.80). DGF-D (incidence 35%) in deceased donor KT was not associated with hypotension. Conclusions: We found an association between intraoperative hypotension and DGF-CRR at a threshold MAP of 55 mmHg, with a consistent signal toward increased risk at both 65 and 75 mmHg, as indicated by unadjusted models.