Hemodynamic effects of angiotensin inhibitors in elderly hypertensives undergoing total knee arthroplasty under regional anesthesia

The aim was to investigate the association between continuing angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARB) with postinduction hypotension and vasoactive drug use in elderly orthopedic surgery patients under regional anesthesia. Retrospective design consisted of 114 patients (mean age 66) undergoing elective total knee arthroplasty, including 84 patients with chronic hypertension, and they were divided as group I (n = 37), ACEI/ARB continued; group II (n = 23), ACEI/ARB withdrawn; group III (n = 24), β-blocker/calcium channel blocker continued; and group IV (n = 30), without hypertension (control). Primary end points are systolic blood pressures (SBPs) and mean arterial blood pressures (MAPs) at 0, 30, 60, and 90 minutes postinduction, incidence of hypotension (SBP <85 mm Hg), and ephedrine requirements. Repeated measurements were analyzed using generalized estimating equations controlling for baseline characteristics and accounting for correlations. Logistic regression was used for remaining variables. Hypotension occurred more frequently (P = .02) in group I (30%) versus groups II–IV (9%, 13%, 3%). Ephedrine use was increased (P < .001) in group I (51%) compared with groups II–IV (26%, 17%, 7%). Group I had lower mean SBPs compared with group II (110 vs. 120; P = .0045) and group IV (110 vs. 119; P = .0013). Lower mean MAPs were found in group I versus group II (74 vs. 81, P = .001) and group IV (74 vs. 80; P = .001). Group I had an increased odds of receiving ephedrine versus group IV (odds ratio, 16.27; 95% confidence interval, 3.10–85.41; P = .001). No adverse clinical events were recorded. Day of surgery ACEI/ARB use is associated with a high incidence and severity of postinduction hypotension with associated high vasopressor requirements. Associated clinical outcomes merit further study.