Impact of Renin-Angiotensin System Blockers on Mortality in Veterans Undergoing Cardiac Surgery

Abstract

Background Renin-angiotensin system blockers (RASBs) have well-validated benefit in patients with hypertension, coronary artery disease, and left ventricular systolic dysfunction. Their use in the perioperative period, however, has been controversial, including in patients undergoing cardiac surgery, who often have a strong indication for their use. In the current study, we explore the impact of RASB use with 30-day and 1-year mortality after cardiac surgery. Methods and Results The Veterans Affairs Surgical Quality Improvement Program and Corporate Data Warehouse were data sources for this retrospective cohort study. A total of 37 197 veterans undergoing elective coronary artery bypass grafting and or valve repair or replacement over a 10-year period met inclusion criteria and were stratified into 4 groups by preoperative exposure (preoperative exposure versus no preoperative exposure) and postoperative continuing exposure (current exposure versus no current exposure) to RASBs. After adjusting for all baseline covariates, the preoperative exposure/current exposure group had lower 30-day and 1-year mortality than the preoperative exposure/no current exposure (30-day hazard ratio [HR], 0.25; 95% CI, 0.19-0.33 [P<0.001] and 1-year HR, 0.40; 95% CI, 0.33-0.48 [P<0.001] or no preoperative exposure/no current exposure (30-day HR, 0.44; 95% CI, 0.32-0.60 [P<0.001] and 1-year HR, 0.72; 95% CI, 0.62-0.84 [P<0.001] groups. The no preoperative exposure/current exposure group had significantly lower 30-day (HR, 0.31; 95% CI, 0.14-0.71 [P=0.006]) and 1-year (HR, 0.64; 95% CI, 0.53-0.77 [P<0.001]) mortality than the no preoperative exposure/no current exposure group. Conclusions Continuation of preoperative RASBs and initiation before discharge is associated with decreased mortality in veterans undergoing cardiac surgery. Given these findings, continuation of preoperative RASBs or initiation in the early postoperative period should be considered in patients undergoing cardiac surgery.

Keywords: ACEI; ARB; cardiac surgery; mortality.

Figure 1. Study flow diagram.

AKI indicates acute kidney injury; CABG, coronary artery bypass grafting; CAD, coronary artery disease; eGFR, estimated glomerular filtration rate; HF, heart failure; HTN, hypertension; Pre‐op, preoperative; PVD, peripheral vascular disease; RRT, renal replacement therapy; and VAD, ventricular assist device.

Figure 2. Unadjusted mortality by study group.

CABG indicates coronary artery bypass grafting; Post‐op, postoperative; Pre‐op, preoperative; and RASB, renin‐angiotensin system blocker.

Figure 3. Cumulative incidence for all‐cause mortality.

A, Thirty‐day mortality; (B) 365‐day mortality. Predicted incidences are from the adjusted model for the average patient. CE indicates current exposure; NCE, no current exposure; NPE, no preoperative exposure; and PE, preoperative exposure.