Clinical question: Does peri-operative clonidine prevent myocardial infarction (MI)?
Background: A meta-analysis showed that peri-operative clonidine decreased death and MI compared to placebo in patients undergoing vascular surgery. It also showed that rates of death and MI were the same for patients taking clonidine vs. placebo undergoing nonvascular surgery without significant effects on hemodynamics.
Study design: Randomized controlled trial.
Setting: One hundred thirty-five centers across 23 countries.
Synopsis: The POISE-II [PeriOperative Ischemic Evaluation-II] study randomized 10,010 patients in a 1:1:1:1 fashion to analyze peri-operative clonidine and aspirin against placebo. This paper specifically examined the effects of peri-operative clonidine vs. placebo. The average age of the population was 69 years old. The most common comorbidities were diabetes (38%) and coronary artery disease (23%).
The outcomes showed that clonidine vs. placebo yielded insignificant results with respect to the primary endpoints (death, MI, or stroke: 7.6% vs. 7.0%; P=0.30); however, there were significantly higher rates of clinically significant hypotension (47.6% vs. 37.1%; P<0.001), bradycardia (12.0% vs. 8.1%; P<0.001), and nonfatal cardiac arrest (0.3% vs. 0.1%; P=0.02) in the clonidine group.
These results differ from previous, smaller studies, which suggested that there were no significant hemodynamic changes when patients received peri-operative clonidine.
Bottom line: Peri-operative clonidine does not affect the rate of MI but increases clinically significant hypotension, bradycardia, and nonfatal cardiac arrest.
Citation: Devereaux PJ, Sessler DI, Leslie K, et al. Clonidine in patients undergoing noncardiac surgery. N Engl J Med. 2014;370(16):1504-1513.