Discontinuation of Beta Blockers Increases Risk of Postoperative Myocardial Infarction and Death
Clinical question: Does perioperative beta-blocker discontinuation affect postoperative myocardial infarction (MI) in low-risk patients undergoing joint arthroplasty?
Background: Recent trials show no benefit of perioperative beta blockers in reducing the incidence of perioperative myocardial infarctions (POMI) in low-risk patients. This retrospective study examined the impact of continuing or discontinuing beta blockers and the occurrence of POMI in patients undergoing elective joint arthroplasties.
Study design: Retrospective chart review.
Setting: Large academic center in Ottawa, Canada.
Synopsis: Medical records for 5,178 patients undergoing elective hip or knee arthroplasty from January 2002 to June 2006 were included in the review. The primary outcome was POMI, defined as an increased troponin level. Patients were divided into three groups: beta blocker prescribed on post-operative day (POD) zero and continued for one week or until discharge; beta blocker prescribed on POD zero and discontinued at any time in the first week; and no beta blocker on POD 0.
Beta blockers were continued in 992 patients and discontinued in 252 patients. The rate of POMI and death increased in the beta-blocker discontinuation group (odds ratio 2.0 [1.1-3.9] and 2.0 [1.1-3.9], respectively). This association persisted after adjustment for cardiac risk using a validated risk score.
The study was limited by the fact that the control group did not include patients who were on a beta blocker at home, thus potentially increasing the number of events in this group. The discontinuation beta blocker group had an increased baseline risk for POMI. The reason for discontinuing the beta blocker was not known, and cessation of beta blocker could have been due to an acute event.
Bottom line: This study adds support to the American College of Cardiology and American Heart Association (ACC/AHA) guidelines, which recommend continuation of beta-blocker therapy in the perioperative period.
Citation: Van Klei WA, Bryson GL, Yang H, Forster AJ. Effect of beta-blocker prescription on the incidence of postoperative myocardial infarction after hip and knee arthroplasty. Anesthesiology. 2009;111(4):717-724.
