Hemodynamic Effects of Anesthesia in Patients Receiving Angiotensin-Converting Enzyme Inhibitors

To the Editor: We were interested to read the work of Ryckwaert and Colson [1] on the hemodynamic effects of anesthesia in patients with ischemic heart failure treated chronically with angiotensin-converting enzyme inhibitors (ACEIs), but we were initially confused by the conclusion of the authors, which implied a minimal difference between the groups in their hemodynamic responses to anesthesia. They concluded that ACEI treatment in these patients does not increase the incidence of severe hypotension after the induction of anesthesia, but on closer reading of the paper, we note that they have demonstrated in their Table 3substantial and significant decreases from baseline in systolic blood pressure (-30.4%) and cardiac index (-27.3%) after induction, and that these changes are significantly different from those of patients not receiving ACEIs. Indeed, the changes that they have described are broadly similar in direction and magnitude to those described in their earlier paper, in which they studied patients receiving ACEIs undergoing coronary artery bypass surgery without a history of heart failure (mean arterial pressure -33.5%; cardiac index -23.9% with respect to baseline after the induction of general anesthesia using a similar technique) [2]. We have relied heavily on the work of Colson et al. [2] and Coriat et al. [3] in developing algorithms for the preoperative assessment of patients presenting for anesthesia who have hypertension treated with ACEIs, and have advised our surgical and medical colleagues to withhold ACEIs on the day of surgery to minimize the chances of profound hemodynamic disturbances on the induction of general anesthesia. Although we understand the fundamental weakness of comparing percent changes between studies, we are reluctant to alter our recommendations based on this latest work, and ask Ryckwaert and Colson to clarify their conclusion and to advise us as to the suitability of our recommendations. David G. Whalley, MB, ChB Walter G. Maurer, MD Division of Anesthesiology and Critical Care Medicine; The Cleveland Clinic Foundation; Cleveland, OH 44195