Perioperative aspirin reduces risk of death, MI versus placebo

After noncardiac surgery, low-dose aspirin therapy reduced the risk of death and nonfatal myocardial infarction in patients with prior percutaneous coronary intervention compared with placebo, according to findings published in Annals of Internal Medicine.

Perspective from Grant Reed, MD

“Noncardiac surgery is common, with more than 200 million annual procedures worldwide,” Michelle M. Graham, MD, from the University of Alberta and Mazankowski Alberta Heart Institute, and colleagues wrote. “Despite the benefits of noncardiac surgery, major perioperative cardiovascular complications occur and are associated with mortality, prolonged hospitalization, and costs.”

“Uncertainty remains about the effects of aspirin in patients with prior percutaneous coronary intervention (PCI) having noncardiac surgery,” they added.

Graham and colleagues conducted a substudy of POISE-2 to determine how perioperative aspirin benefits and/or harms patients with prior PCI. The subgroup included 470 adults aged 45 years or older who had or were at risk for atherosclerotic disease and were undergoing noncardiac surgery at one of 135 centers in 23 countries. Patients who received a bare-metal stent within 6 weeks, a drug-eluting stent within 1 year or a nonstudy aspirin within 72 hours prior to surgery were excluded.

A total of 234 patients received 200 mg of aspirin and 236 patients received an identical-appearing placebo within 4 hours before surgery and continued to receive a dosage of 100 mg per day for 30 days in the initiation period and 7 days in the continuation period.

Data indicated that the risk for death or nonfatal MI (absolute risk reduction = 5.5%; 95% CI, 0.4-10.5%; HR = 0.50; 95% CI, 0.26-0.95]; P for interaction = 0.036) and MI (absolute risk reduction = 5.9%; 95% CI, 1.0-10.8%; HR = 0.44; 95% CI, 0.22-0.87; P for interaction = 0.021) within 30 days was reduced with aspirin treatment in patients with prior PCI.

The researchers could not determine how aspirin impacted the composite of major and life-threatening bleeding in patients with prior PCI (absolute risk increase = 1.3%; 95% CI, –2.6 to 5.2%). Overall, the risk for major bleeding increased with aspirin treatment (absolute risk increase = 0.8%; 95% CI, 0.1-1.6%; HR = 1.22; 95% CI, 1.01-1.48]; P for interaction = 0.50).

“Among patients with prior PCI, perioperative aspirin may be more likely to benefit rather than harm those undergoing noncardiac surgery,” Graham and colleagues concluded. “The risk–benefit tradeoff will likely shift on the basis of the risk for bleeding and myocardial infarction associated with the type of noncardiac surgery a patient has.”

In a related editorial, Raffaele Piccolo, MD, PhD, and Stephan Windecker, MD, both from the department of cardiology at Bern University Hospital, Switzerland, wrote that the research by Graham and colleagues offers important insight to managing patients who require non-cardiac surgery.

“In the absence of a very high bleeding risk, low-dose aspirin should be continued or resumed during the perioperative period among patients with previous coronary stents, whereas it remains dispensable in patients at increased risk of vascular events but without coronary stents,” they concluded. – by Alaina Tedesco

Disclosure: Graham and Piccolo report no relevant financial disclosures. Windecker reports receiving grants from Bracco, Boston Scientific and Terumo. Please see study for all other authors’ relevant financial disclosures.

Perspective

Grant Reed, MD

Previously published, the main results from the POISE-2 trial were that among patients undergoing non-cardiac surgery, perioperative administration of low-dose aspirin did not prevent death or non-fatal myocardial infarction (MI), but did increase major bleeding. The current analysis evaluated patients from POISE-2 who had established coronary artery disease and prior stent placement (bare metal stent at least 6 weeks ago, or drug eluting stent at least 1 year ago).

Ths results from the current study suggest that for every 1,000 patients with prior PCI undergoing non-cardiac surgery, perioperative aspirin would prevent 59 MIs and cause eight major bleeding events.

The current study is important as it helps to better understand the perioperative risks of death and MI in patients undergoing non-cardiac surgery. That said, there are certain caveats with the study; principally, this was a post-hoc analysis stratified by whether patients had prior PCI, and thus could be subject to bias from unbalanced patient characteristics between groups.

In addition, while POISE-2 was a large trial, the current study had only 470 patients total. As the authors acknowledge, effect size can be overestimated with a small sample. This study is the highest quality data we have to guide care of such patients and suggests that aspirin should indeed be continued perioperatively in patients with prior PCI undergoing non-cardiac surgery.

Samir Kapadia, MD
Professor of Medicine
Section Head, Interventional Cardiology
Director, Cardiac Catheterization Laboratory
Cleveland Clinic

Grant Reed, MD

Fellow, Interventional Cardiology

Cleveland Clinic

Disclosures: Kapadia and Reed report no relevant financial disclosures.

Sources/Disclosures

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Source:

Graham MM, et al. Ann Intern Med. 2017;doi:10.7326/M17-2341.
Piccolo R, Windecker S. Ann Intern Med. 2017;doi:10.7326/M17-2954.