Elevated Pulse Pressure, Intraoperative Hemodynamic Perturbations, and Acute Kidney Injury After Coronary Artery Bypass Grafting Surgery

Abstract

To explore whether baseline pulse pressure (PP) confers an increased risk for acute kidney injury (AKI) independent of intraoperative hypotension or hypertension in patients who undergo coronary artery bypass grafting (CABG) surgery. Retrospective study. Single academic center. 5,808 patients who underwent CABG surgery. Baseline arterial blood pressure was defined as the mean of the first 5 measurements recorded by the automated record keeping system before anesthesia was induced. Weighted duration of intraoperative hypotension and hypertension were defined as the area (min × mmHg) below a mean arterial pressure of 55 mmHg and above a mean arterial pressure of 100 mmHg. Multivariable logistic and proportional odds regression analyses were performed to determine whether baseline PP and weighted duration of intraoperative hypotension and hypertension were independently associated with postoperative AKI. Of the 5,808 patients, PP was <40 mmHg in 90 (1.6%), 40-to-80 mmHg in 2,463 (42.4 %), and >80 mmHg in 3,255 (56%) patients. The incidence of AKI was 57.7%, which included 7.4% (249 patients) and 2.8% (93 patients) who experienced stages 2 and 3 AKI, respectively. In the risk-adjusted analyses, baseline PP was associated with higher odds for postoperative AKI (odds ratio for every 20 mmHg increase in PP, 1.15; 95% confidence interval 1.10-1.21; p < 0.0001) and a higher severity of postoperative AKI (proportional odds ratio, 1.13; 95% confidence interval 1.03-1.24; p = 0.0098). There was no evidence that weighted duration of intraoperative hypotension or hypertension was associated with postoperative AKI or that either interacted with the association of baseline PP with AKI. Baseline PP was significantly associated with postoperative AKI after CABG surgery, independent of weighted duration of intraoperative hypotension or hypertension.