Should We Withhold ACE Inhibitors Just Before Noncardiac Surgery?

Authors: Roshanov PS et al.

Anesthesiology 2017 Jan.

In an observational study, withholding angiotensin-converting–enzyme inhibitors was associated with fewer adverse events.

For patients who take angiotensin-converting–enzyme (ACE) inhibitors and undergo noncardiac surgery, some observational studies suggest that continuing the ACE inhibitors on the morning of surgery is associated with excess risk for intraoperative hypotension. However, the evidence is not decisive, and the 2014 American College of Cardiology/American Heart Association guideline on management of patients undergoing noncardiac surgery concludes that continuation of ACE inhibitors or angiotensin-receptor blockers (ARBs) perioperatively “is reasonable” (Circulation 2014;130:e278).

Now, researchers have addressed this issue using data from a prospective cohort study of patients (age, ≥45) who underwent noncardiac surgery and required overnight hospital admission. Among 4802 patients who used ACE inhibitors or ARBs routinely, 74% took the drug during the 24 hours before surgery; the drug was withheld in the remaining 26%. The following outcomes were noted:

• The primary composite outcome (death, stroke, or myocardial injury defined by perioperative rise in troponin level) occurred in 12.0% of patients whose ACE inhibitor or ARB was withheld and in 12.9% of those whose drug was continued; after adjustment for potentially confounding variables (including preoperative blood pressure and use of other antihypertensive drugs), the relative risk for this outcome was significantly lower in the drug-withheld group (RR, 0.82;P=0.01).
• Incidence of intraoperative hypotension was lower in the drug-withheld group than in the drug-continued group (23.3% vs. 28.6%); in adjusted analyses, relative risk was significantly lower in the drug-withheld group (RR, 0.80;P<0.001).
• Clinical and surgical factors were not associated substantially with continuing versus withholding ACE inhibitors or ARBs; thus, most decisions to withhold the drugs likely were arbitrary and based on clinician preference.

COMMENT

This analysis doesn’t carry the authority of a randomized trial, but the authors’ conclusion — that we should consider withholding ACE inhibitors and ARBs before noncardiac surgery — is reasonable. They note that anesthesia-related blunting of sympathetic vascular tone might increase reliance on the renin-angiotensin system to maintain blood pressure intraoperatively.