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POISE-2 ASA

"Aspirin in Patients Undergoing Noncardiac Surgery". The New England Journal of Medicine. 2014. ClinicalTrials.gov number, NCT01082874.

Clinical Question

Does the perioperative administration of aspirin to patients undergoing noncardiac surgery at risk for vascular complications affect the rate of death or nonfatal myocardial infarction without increasing the risk of major bleeding?

Bottom Line

The perioperative administration of low-dose aspirin compared with placebo did not reduce the rate of death or nonfatal myocardial infarction but increased the risk of major bleeding in patients undergoing noncardiac surgery.

Major Points

There is variability in the use of perioperative aspirin among patients undergoing noncardiac surgery. The POISE-2 trial evaluated whether low-dose aspirin could reduce the rate of vascular complications without significantly increasing the risk of major bleeding. The trial found that perioperative aspirin did not reduce the primary outcome of death or nonfatal myocardial infarction but did increase the risk of major bleeding.

Guidelines

Current guidelines do not provide recommendations on the use of perioperative aspirin for patients undergoing noncardiac surgery.

Design

- Multicenter, double-blind, parallel group, randomized, placebo-controlled trial (part of 2-by-2 factorial design, with aspirin and clonidine interventions reported separately)
- N=10,010 patients undergoing noncardiac surgery who were at risk for vascular complications
- Interventions: aspirin (200 mg pre-surgery and 100 mg daily post-surgery for 30 days or 7 days) vs. placebo
- Stratified by aspirin initiation stratum (n=5,628, not previously on aspirin) and continuation stratum (n=4,382, already on aspirin regimen)
- Primary outcome: composite of death or nonfatal myocardial infarction at 30 days
- Analysis: intention-to-treat
- Mean follow-up: 30 days

Population

- Inclusion Criteria: patients undergoing noncardiac surgery, at risk for vascular complications, some on long-term aspirin therapy
- Exclusion Criteria: patients who received a bare-metal coronary stent <6 weeks or drug-eluting stent <1 year before surgery
- Baseline Characteristics: mean age 68.6 years, 52.8% male, 32.7% with history of vascular disease, 4.3% with previous coronary stenting

Interventions

- Aspirin: Administered pre-surgery and continued post-surgery for 30 days in the initiation stratum and 7 days in the continuation stratum
- Placebo: Administered following the same schedule as aspirin

Outcomes

- Primary Outcome: Occurred in 351 of 4,998 patients (7.0%) in the aspirin group and in 355 of 5,012 patients (7.1%) in the placebo group (HR 0.99; 95% CI, 0.86 to 1.15; P=0.92)
- Major bleeding: More common in the aspirin group (230 [4.6%] vs. placebo 188 [3.8%]; HR 1.23; 95% CI, 1.01 to 1.49; P=0.04)

Criticisms

- Did not resolve the issue of the relative merits of aspirin versus other anticoagulant agents for perioperative thromboprophylaxis.

Funding

- Funded by the Canadian Institutes of Health Research and others; aspirin supplied by Bayer Pharma; clonidine and some funding supplied by Boehringer Ingelheim.