Perioperative Renal Perfusion Pressure Deficits and Risk of Acute Kidney Injury in Cardiac Surgery: A Pilot Study Using Right Heart Catheterization (PRO-AKI)

Abstract

Objectives: To evaluate the association between postoperative renal perfusion pressure (RPP) deficit and acute kidney injury (AKI) after cardiac surgery.

Design: A retrospective case-control pilot study.

Setting: A single academic medical center.

Participants: Data were collected from 486 patients who underwent cardiac surgery requiring cardiopulmonary bypass from July 2018 to March 2024.

Interventions: None.

Measurements and main results: Preoperative hemodynamics, including (RPP = mean arterial pressure (MAP) - central venous pressure (CVP), which was obtained via right heart catheterization. Postoperative RPP, MAP, and CVP were tracked from postoperative days 0 to 4 and analyzed as percent deficits from preoperative baseline. The primary outcome was AKI progression using the Kidney Disease: Improving Global Outcomes score, and secondary outcomes included adverse events. Among 486 patients, 70 (14.4%) developed AKI. Compared with patients without AKI (416, 85.6%), patients with AKI had a higher percent deficit in RPP (23% v 16%, p < 0.001) and MAP (15% v 8%, p < 0.001). A 10% decrease in average RPP and MAP was associated with a 46% (odds ratio: 1.46, 95% confidence interval: 1.03-2.10, p < 0.036) and 42% (odds ratio: 1.42, 95% confidence interval: 1.16-1.75, p < 0.001) increase in odds of AKI, respectively, adjusted for preoperative hemodynamics and AKI risk factors.

Conclusions: Greater postoperative decreases in RPP and MAP from preoperative baseline were independently associated with increased AKI risk after cardiac surgery.

Keywords: acute kidney injury; cardiac surgery; central venous pressure; kidney; mean arterial pressure; renal perfusion.