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Patients with prior PCI benefit from aspirin during noncardiac surgery
ANAHEIM, Calif. — Among patients with prior PCI undergoing noncardiac surgery, aspirin conferred better outcomes compared with placebo, according to new data from the POISE-2 study.
The results in the PCI subgroup differed from the overall results, which showed no benefit of initiating or continuing aspirin before and during noncardiac surgery in patients at high CV risk.
“Providers commonly encounter patients with previous PCI undergoing surgery, and they have increased risk of major perioperative complications,” Michelle M. Graham, MD, from the University of Alberta and Mazankowski Alberta Heart Institute, Edmonton, said during a presentation at the American Heart Association Scientific Sessions. “Uncertainty remains regarding effects of aspirin in patients with prior PCI who are undergoing noncardiac surgery.”
As Cardiology Today’s Intervention previously reported, in the main POISE-2 study, 10,010 patients at high CV risk undergoing noncardiac surgery were randomly assigned to receive aspirin (initiated or continued) or placebo (patients previously taking aspirin stopped before surgery).
Patients implanted with a bare-metal stent within 6 weeks before surgery or with a drug-eluting stent within 1 year before surgery were excluded. The researchers did not expect to enroll anyone with prior PCI in the trial, but 470 patients with prior PCI (mean age, 68 years; 22% women) were ultimately enrolled, Graham said.
Among the PCI cohort, 54.3% had a BMS, 25.3% had a DES, 11.7% had an unknown type of stent and 8.7% had no stent. In 0.4%, it was uncertain whether a stent was used. The median duration from PCI to noncardiac surgery was 64 months.
The primary outcome was death or nonfatal MI at 30 days. In the PCI cohort, death or nonfatal MI occurred in 11.4% of those assigned placebo vs. 6% assigned aspirin (HR = 0.5; 95% CI, 0.26-0.95). Graham reported no difference between aspirin and placebo in the overall cohort or the non-PCI cohort (P for interaction = .036).
The results were driven by MI at 30 days. In the PCI cohort, MI at 30 days occurred in 11% of the placebo group vs. 5.1% of the aspirin group (HR = 0.44; 95% CI, 0.22-0.87). Again, Graham said, the results differed greatly from the overall cohort and the non-PCI cohort (P for interaction = .021).
There was no subgroup interaction for death at 30 days, according to the researchers. In addition, there was no interaction for bleeding outcomes between the PCI cohort and the non-PCI and overall cohorts, according to Graham.
To determine whether the results were a function of CAD history instead of PCI, Graham and colleagues conducted the same analysis in patients with vs. without a history of CAD, but found no subgroup effect, she said during the presentation.
The researchers calculated that for every 1,000 patients with prior PCI, administration of perioperative aspirin will prevent 59 MIs, but cause eight major bleeds.
“Among those with prior PCI undergoing noncardiac surgery, perioperative aspirin may be more likely to benefit than harm patients,” she said.
During a discussant presentation, Bernard J. Gersh, MB, ChB, DPhil, professor of medicine at Mayo Clinic, Rochester, Minnesota, and Cardiology Today Editorial Board Member, said “the magnitude of this [MI] benefit [of aspirin] is surprising” in the PCI cohort, but pointed out the wide confidence intervals. “The differences we are seeing are due to prior history of PCI and stenting, as opposed to coronary disease, per se. I’m not going to stop aspirin for noncardiac surgery unless it’s absolutely essential.” – by Erik Swain
Reference:
Graham MM, et al. LBS.05 – New Insights into the Risks, Benefits and Costs of Antithrombotic Therapy. Presented at: American Heart Association Scientific Sessions; Nov. 11-15, 2017; Anaheim, California.
Disclosures: Graham reports no relevant financial disclosures. Gersh reports he has financial ties with Boston Scientific, Janssen and Medtronic.
Perspective
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The researchers were trying to see whether there would be increased bleeding events on aspirin or increased CV events in those assigned placebo among patients with prior PCI undergoing noncardiac surgery. In this cohort, there was a slight increase in bleeding in the aspirin group, but the reduction in death and MI far outweighed the bleeding risk of initiating aspirin before noncardiac surgery or continuing patients on it. For every 1,000 patients, administering aspirin will prevent nearly 60 MIs, but cause eight major bleeds. Simple math tells us that overall, unless a patient [has] known high bleeding risk, patients fitting this profile will do better with aspirin. The risk is higher to stop aspirin than to continue it.
This may help change practice somewhat. Some doctors are very worried about bleeding and want to stop aspirin in this scenario. These findings give strong credence to the idea that stopping aspirin is harmful in this population. This solidifies the guidelines and gives doctors taking care of a patient with prior PCI the ammunition to tell the surgeon that if at all possible, aspirin should be continued.