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.