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.