Effects of continuing or withholding angiotensin axis blockers prior to elective surgery: The PAAB randomized clinical trial.

BACKGROUND: Current guidelines favour preoperative withholding of angiotensin-axis blockers (AABs) in patients without hypertension or systolic heart failure to decrease peri-operative cardiorenal risk, although evidence of such effects is lacking. OBJECTIVE: To assess rates of postoperative cardiovascular events with continuing or withholding AABs before elective, noncardiac surgery. METHODS: A single-center, single-blind randomized controlled trial was conducted in a tertiary adult hospital. Consecutive patients assessed at a preoperative admission clinic and receiving AABs at a stable dose for at least 28 days were enrolled and randomized in a 1:1 ratio to continue or withhold AABs for 24 h preoperatively. The primary outcome was a composite of major adverse cardiovascular events (MACE) at 5 days postoperatively. Secondary outcomes included intraoperative hypotension, acute kidney injury (AKI), and length of stay. RESULTS: Among 667 randomized patients with 29 postrandomization exclusions, 325 continuing AABs (control), and 313 having AABs withheld (intervention) were included in the final analysis. Mean age was 66 (SD+/-10) years; 64% were male. Primary outcome occurred in 9 of 325 (2.8%) control and 9 of 313 (2.9%) intervention patients (0.1% increase [95% confidence interval (CI): -2.5% to 2.8%]; p = 1.00); intraoperative hypotension occurred in 204 (63.5%) and 190 (60.7%) (2.8% decrease [95% CI: -5.5% to 9.6%]; p = 0.63) and AKI occurred in 24 (7.4%) and 15 (4.8%) (2.6% decrease [95% CI -1.1% to 6.3%]; p = 0.19). No significant between-group differences were seen for secondary outcomes or subgroup analyses. CONCLUSIONS: In this study of patients with low cardiac risk undergoing elective, noncardiac surgery, withholding AABs for 24 h preoperatively did not reduce MACE, intraoperative hypotension or AKI.