Perioperative Angiotensin Axis Blockade, to Continue or Discontinue, That Is the Question?

To the Editor In a recent editorial reflecting on whether angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ARBs) should be stopped preoperatively to avoid hypotension with induction and maintenance of anesthesia,1 Dr. Sear2 notes that the major issues are the described perioperative hypotension as well as impaired cardiovascular outcomes associated with continued angiotensin axis blockade (AAB) and the potential for perioperative hypertension associated with their withdrawal. Highlighting this uncertainty, he cites 3 large cohort studies assessing such outcomes. The first, in vascular surgery patients, showed increased mortality with continuation,3 a second, improvement in mortality when AAB is maintained,4 and still a third, no difference in mortality whether this therapy was maintained or stopped.5 We wish to add a further consideration to this question, namely, a concern for the enhanced potential for acute kidney injury (AKI) associated with use of AAB perioperatively. Ishikawa et al.6 recently demonstrated an increase in AKI associated with ARB therapy in thoracic surgical patients. Furthermore, in a retrospective review of patients presenting for major orthopedic surgery, we demonstrated an increase in AKI independent of the associated enhanced hypotension, in patients receiving AAB therapy preoperatively.7 The latter study has prompted us to discontinue preoperative AAB therapy in controlled hypertensive patients presenting for major orthopedic surgery in our institution. We were concerned, however, that discontinuing preoperative AAB might lead to another concern expressed by Dr. Sear: perioperative hypertension. We were thus pleased to read that the study by Twersky et al.8 demonstrated no difference in either pre- or postoperative hypertensive events in patients where AAB therapy had been discontinued when compared with those in whom it was continued. We would add, however, that discontinuing AAB therapy preoperatively, to avoid possible AKI, needs to be evaluated in a properly conducted randomized controlled trial. This is especially important because the required period of cessation of AAB preoperatively may vary considerably with different angiotensin-converting enzyme inhibitors and ARBs that have a prolonged systemic half-lives (>24 h), and the duration of ongoing tissue-based activity needs to be better defined.1,9 Berend Mets, MB, PhD, FRCA, FFASA Department Anesthesiology Penn State Hershey Medical Center Hershey, Pennsylvania [email protected]