ABSTRACT & COMMENTARY
Perioperative Use of Aspirin in Patients Undergoing Noncardiac Surgery
By Harold L. Karpman, MD, FACC, FACP
Clinical Professor of Medicine, UCLA School of Medicine
Dr. Karpman reports no financial relationships relevant to this field of study.
SYNOPSIS: Administration of aspirin before surgery and throughout the early postsurgical period had no significant effect on the rate of composite of death or nonfatal myocardial infarction but did increase the risk of major bleeding.
SOURCE: Devereaux PJ, et al. Aspirin in patients undergoing noncardiac surgery. N Eng J Med 2014;370:1494-1503.
Since an acute myocardial infarction (MI) is the most common major vascular complication that occurs after noncardiac surgery1-4 and acute coronary artery thrombosis is the likely mechanism of most perioperative MIs,5,6 the perioperative use of aspirin, which inhibits platelet aggregation,7 may decrease the frequency of major vascular complications by preventing thrombus formation.8 There is substantial variability in the perioperative administration of aspirin to patients undergoing cardiac surgery both for those patients who already are on an aspirin regimen and among those who are not. Uncertainty regarding the risks and benefits of aspirin administered perioperatively9,10 underscored the need for a large perioperative trial.
Devereaux and his colleagues conducted the Perioperative Ischemic Evaluation 2 (POISE-2) trial to evaluate the effect of low-dose aspirin as compared with placebo on the 30-day risk of a composite of death or nonfatal MI among patients who were undergoing noncardiac surgery. The 4382 patients who were on an aspirin regimen prior to enrolling in the study discontinued aspirin intake 3 days prior to the surgery. A second group of 5628 patients who had not been on aspirin therapy preoperatively was also enrolled in the study. The total of 10,010 patients were randomly assigned to receive aspirin (200 mg daily) or placebo starting just before surgery. Aspirin was continued at a dose of 100 mg daily for 30 days after surgery or, if patients had been on aspirin preoperatively, they resumed their usual aspirin regimen 7 days after surgery. The primary outcome was a composite of death or nonfatal MI at 30 days. The primary outcome occurred in 351 patients (7%) in the aspirin group and in 355 patients (7.1%) in the placebo group. The authors concluded that administration of aspirin before surgery and throughout the early postsurgical period had no significant effect on the rate of a composite of death or nonfatal MI but did increase the risk of major bleeding.
Devereaux and colleagues conducted this major trial because of the uncertainties surrounding the risks and benefits of aspirin therapy in patients undergoing noncardiac surgery.11 They concluded that aspirin therapy did not increase the risk of death or nonfatal MI, but did increase the risk of postoperative hemorrhage, which appears to be decreased significantly if aspirin therapy was stopped ≥ 3 days prior to the surgical procedure. If clinicians plan to use an anticoagulant agent for perioperative prevention of venous thromboembolism, the results of this study suggest that aspirin provides no additional benefit but increases the risk of major bleeding. It should be carefully noted that this study did not address the relative merits of aspirin vs other anticoagulant agents for perioperative thromboprophylaxis.12 The authors suggested that aspirin should be discontinued ≥ 3 days prior to surgery and not be restarted until 8-10 days after surgery at which time the bleeding risks will have diminished considerably.
In summary, it would appear that aspirin should not be continued or started in patients undergoing noncardiac surgery because it did not decrease the rate of thrombotic events and the risk of major bleeding was increased. If aspirin therapy is needed on a continuing basis in a patient, it should be discontinued prior to surgery and resumed postoperatively; other anticoagulants with a lesser bleeding risk such as Lovenox may be used to "bridge" the time period when aspirin therapy has to be discontinued.
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