ABSTRACT
BACKGROUND: Attempts to reduce serious cardiac events during major noncardiac surgery have traditionally relied on preoperative assessments of risk. In the highest risk patients, cardiac revascularization is often considered to reduce postoperative cardiac events, without much evidence to support its use. Researchers have begun to examine whether β-blockade during the perioperative period could be used in lieu of revascularization to reduce these events. This systematic review summarized what is known about this intervention.
POPULATION STUDIED: The researchers identified 6 publications of 5 randomized, controlled trials, completed after 1980, through a MEDLINE search. Reference lists from relevant articles were reviewed to identify additional studies. These studies evaluated patients who were undergoing elective noncardiac major surgery and who either had known ischemic heart disease or risk factors for ischemic disease. Studies were inconsistent in inclusion or exclusion of patients on long-term β-blocker therapy.
STUDY DESIGN AND VALIDITY: In this systematic review, the authors identified prospective randomized trials but did not evaluate the quality of the trials. The 5 trials used a variety of β-blocker drugs, doses, and dosing schedules. All but 1 study titrated β-blocker therapy before or with the induction of anesthesia to a target heart rate of 70 beats per minute or slower. The β-blocker therapy was continued through the operative period and for a varied time after surgery. No information was presented in the article regarding randomization method or intention-to-treat analysis in the trials.
OUTCOMES MEASURED: All trials reported 1 or more of the following outcomes: myocardial ischemia, myocardial infarction, cardiac death, and all-cause mortality.
RESULTS: Two trials found statistically significant reduction in ischemia with β-blocker therapy, with 1 ischemic event prevented in 2.5 to 6.7 patients treated with a β-blocker (33% vs 73%, P < .05, number needed to treat [NNT] = 2.5; 24% vs 39%, P = .03, NNT = 6.7). A third trial found a decrease in ischemia that did not reach statistical significance. The control group in the third trial had a low incidence of ischemia.
Using β-blocker therapy perioperatively reduces myocardial ischemia, infarction, and mortality. Family physicians should recommend and prescribe perioperative β-blocker therapy in patients who meet criteria that put them at higher risk for coronary artery disease. The algorithm and the eligibility criteria described in the article provide specific guidance in implementing the evidence in day-to-day practice.