Perioperative aspirin may improve outcomes after noncardiac surgery in patients with prior PCI

Patients taking aspirin had a significantly lower risk of myocardial infarction, leading editorialists to conclude that benefits would exceed risks for those with a prior percutaneous coronary intervention (PCI) except in procedures with very high bleeding risk.

Compared to placebo, perioperative aspirin during noncardiac surgery may improve 30-day outcomes in patients with prior percutaneous coronary intervention (PCI), a recent study found.

Researchers conducted a post hoc subgroup analysis of 470 patients with prior PCI who were enrolled in POISE-2, a previous multicenter factorial trial that randomized 10,010 patients having noncardiac surgery to receive aspirin and clonidine, placebo and clonidine, aspirin and placebo, or placebo for both drugs. The subgroup analysis compared 30-day events among patients with previous PCI who received either aspirin or placebo (200 mg within four hours before surgery).

Participants in the PCI subgroup were ages 45 years and older and were recruited from 82 centers in 21 countries. The 30-day primary outcome was a composite of death or nonfatal myocardial infarction (MI). Results were published online on Nov. 13 by Annals of Internal Medicine.

Of the 470 patients with prior PCI, 234 received aspirin and 236 received placebo. Fewer patients experienced the primary outcome with aspirin than placebo (14 patients [6.0%] vs. 27 patients [11.5%]; absolute risk reduction, 5.5% [95% CI, 0.4% to 10.5%]; hazard ratio, 0.50 [95% CI, 0.26 to 0.95]). In trial participants without prior PCI, the primary outcome did not significantly differ between those who received aspirin and those who received placebo.

The beneficial effect of aspirin in the PCI cohort was driven by a reduction in MI incidence compared to placebo (12 patients [5.1%] vs. 26 patients [11.0%]; absolute risk reduction, 5.9% [95% CI, 1.0% to 10.8%]; hazard ratio, 0.44 [95% CI, 0.22 to 0.87]; P=0.021 for interaction).

In terms of major and life-threatening bleeding, a composite secondary outcome, the estimated risk in patients with prior PCI was uncertain (absolute risk increase, 1.3% [95% CI, −2.6% to 5.2%]; hazard ratio, 5.08 [95% CI, 0.59 to 43.56]). In the overall trial population, aspirin increased the risk of major bleeding compared to placebo (230 patients [4.6%] vs. 189 patients [3.8%]; absolute risk increase, 0.8% [95% CI, 0.1% to 1.6%]; hazard ratio, 1.22 [95% CI, 1.01 to 1.48]). There was no significant interaction for major bleeding in the prior-PCI versus no-prior-PCI subgroups.

The authors noted limitations to the subanalysis, such as the small number of events that occurred in the cohort of patients with prior PCI and resulting imprecision in the effect estimates. In addition, patients with recent stent implantation were excluded, and no formal threshold was set for cardiac biomarkers, which could have affected adjudication and incidence of MI, an accompanying editorial noted.

“On the basis of this study's findings, 17 patients with prior PCI (95% CI, 9 to 100 patients) would need to be treated with aspirin to prevent 1 myocardial infarction during the perioperative period,” the editorialists wrote. “If we consider the 22% higher relative risk for major or life-threatening bleeding events associated with aspirin, only surgical procedures with a very high baseline bleeding risk (≥26%) would neutralize aspirin's ischemic benefit.”