Should renin-angiotensin system inhibitors be held prior to major surgery?

Many patients undergoing surgical procedures have a history of hypertension, diabetes mellitus, heart failure, or a combination. Often, these conditions involve the chronic use of a renin-angiotensin system inhibitor, including angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs). Observational studies have suggested that continuing ACEIs/ARBs before major noncardiac surgery can increase the risk of intraoperative hypotension, which might drive postoperative complications such as acute kidney injury, myocardial injury, or stroke. Strong recommendations on how to manage ACEIs/ARBs before surgery are, however, lacking owing to insufficient evidence, mostly limited to data from observational studies. Recently, the SPACE trial investigated the impact of preoperative management of ACEIs/ARBs on postoperative myocardial injury. Myocardial injury occurred in 48.3% patients randomised to discontinue and 41.3% patients randomised to continue ACEI/ARB (odds ratio for continuing: 0.77, 95% confidence interval 0.45-1.31). Patients randomised to the 'Stop' group experienced more postoperative hypertension. In a post hoc analysis, patients randomised to the 'Continue' group with low preoperative NT-proBNP concentrations (<100 pg ml^-1) experienced less myocardial injury after surgery than the 'Stop' group, whereas no significant difference was observed in patients with elevated preoperative NT-proBNP concentrations. The SPACE trial provides important and new reassuring data on the safety of continuing ACEIs/ARBs before major surgery, challenging previous beliefs.