Association of intraoperative hypotension and acute kidney injury in noncardiac surgery patients: a post hoc secondary analysis of the EU HYPROTECT registry

Purpose: Previous cohort studies suggest that intraoperative hypotension is associated with acute kidney injury (AKI) in noncardiac surgical patients. We sought to ascertain that intraoperative hypotension is independently associated with AKI within the first 3 days after surgery in a contemporary cohort of noncardiac surgery patients in whom clinicians strove to avoid profound intraoperative hypotension. Methods: This was a post hoc secondary analysis of the multicentre EU HYPROTECT registry, which includes patients undergoing major noncardiac surgery who underwent predictive blood pressure monitoring. The primary outcome of this secondary analysis was AKI within the first 3 days after surgery. To quantify the duration and severity of intraoperative hypotension we calculated the area under a mean arterial pressure (MAP) of 65 mmHg. We used logistic regression analysis to identify factors independently associated with AKI. Results: We analysed 697 patients. 62 of these 697 patients (9%) developed AKI within the first 3 days after surgery. In multivariable binary logistic regression analysis adjusted for confounding variables, the area under a MAP of 65 mmHg was independently associated with AKI within the first 3 days after surgery (OR 1.03 [95% CI 1.01–1.05] per 10 mmHg*min; P < 0.001). Conclusion: Our secondary analysis of the EU HYPROTECT registry shows that, in a contemporary population of noncardiac surgery patients in whom clinicians strove to avoid profound intraoperative hypotension, intraoperative hypotension is independently associated with AKI within the first 3 days after surgery.