Patient Care

Peri-Operative Clonidine Increases Hypotension, Bradycardia, Nonfatal Cardiac Arrest


Clinical question: In patients at risk for vascular complications undergoing noncardiac surgery, do the benefits of aspirin outweigh the risks?

Background: Aspirin has been shown to reduce the rate of myocardial infarction (MI) and major vascular events in patients not undergoing surgery. The benefits of initiating or continuing aspirin in patients undergoing surgery, balanced by the potential increase in bleeding risk, have not been widely studied.

Study design: International randomized placebo-controlled trial with a 2-by-2 factorial design.

Setting: One hundred thirty-five hospitals in 23 countries, from 2010-2013.

Synopsis: The study enrolled 10,010 patients, with a mean age of 68.6 years. Inclusion criteria were age >45 years old and risk for vascular complications, defined as a history of coronary artery disease, peripheral vascular disease, or cerebrovascular accident; major vascular surgery; or at least three of the following: age >70, congestive heart failure, transient ischemic attack, hypertension, diabetes mellitus type 2, creatinine >2 mg/dL, recent smoking, undergoing major surgery, or urgent/emergent surgery.

Groups were stratified by current use of aspirin and then assigned to aspirin or placebo; patients on aspirin held it a median of seven days before surgery. Those in the active group received 200 mg of aspirin pre-operatively. Patients not previously on aspirin then continued aspirin at 100 mg/day for 30 days; those on aspirin previously received 100 mg/day for seven days and then resumed their prior dose.

No difference was found in the primary outcome of death or non-fatal MI at 30 days, but aspirin was noted to increase the risk of major bleeding (4.6% vs. 3.8%, P=0.04), most commonly occurring at the surgical site (78.3%) and the GI tract (9.3%). Because major bleeding can be associated with peri-operative MI, this may have counteracted the cardiovascular benefits of aspirin.

Bottom line: Peri-operative administration of aspirin to patients at risk for vascular complications undergoing noncardiac surgery does not decrease the risk of peri-operative death or MI and may increase the risk of post-operative bleeding.

Citation: Devereaux PJ, Mrkobrada M, Sessler DI, et al. POISE-2 Investigators. Aspirin in patients undergoing noncardiac surgery. N Engl J Med. 2014;370(16):1494-1503.

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