Prospective randomized evaluation of preoperative angiotensin-converting enzyme inhibition (PREOP-ACEI)

BACKGROUND: Intraoperative hypotension is associated with an increased risk of end organ damage and death. The transient preoperative interruption of angiotensin-converting enzyme inhibitor (ACEI) therapy prior to cardiac and vascular surgeries decreases the occurrence of intraoperative hypotension. OBJECTIVE: We sought to compare the effect of two protocols for preoperative ACEI management on the risk of intraoperative hypotension among patients undergoing noncardiac, nonvascular surgeries. DESIGN: Prospective, randomized study. SETTING: Midwestern urban 489-bed academic medical center. PATIENTS: Patients taking an ACEI for at least six weeks preoperatively were considered for inclusion. INTERVENTIONS: Randomization of the final preoperative ACEI dose to omission (n = 137) or continuation (n = 138). MEASUREMENTS: The primary outcome was intraoperative hypotension, which was defined as any systolic blood pressure (SBP) < 80 mm Hg. Postoperative hypotensive (SBP < 90 mm Hg) and hypertensive (SBP > 180 mm Hg) episodes were also recorded. Outcomes were compared using Fisher’s exact test. RESULTS: Intraoperative hypotension occurred less frequently in the omission group (76 of 137 [55%]) than in the continuation group (95 of 138 [69%]) (RR: 0.81, 95% CI: 0.67 to 0.97, P = .03, NNH 7.5). Postoperative hypotensive events were also less frequent in the ACEI omission group (RR: 0.49, 95% CI: 0.28 to 0.86, P = .02) than in the continuation group. However, postoperative hypertensive events were more frequent in the omission group than in the continuation group (RR: 1.95, 95%: CI: 1.14 to 3.34, P = .01). CONCLUSION: The transient preoperative interruption of ACEI therapy is associated with a decreased risk of intraoperative hypotension. REGISTRATION: ClinicalTrials.gov: NCT01669434.