Antiplatelets for Coronary Stent Patients Undergoing Noncardiac Surgery

April 9th, 2025

Study Overview: ASSURE-DES Trial

The ASSURE-DES (Aspirin in Patients with DES Undergoing Noncardiac Surgery) trial addressed a key clinical question: Should aspirin monotherapy be continued in stable patients with second- or third-generation drug-eluting stents (DES) undergoing elective noncardiac surgery more than one year after stent implantation?

Conducted across 30 sites in Korea, India, and Turkey, this open-label, randomized controlled trial included 926 patients with a median of five years post-DES placement. The study compared two groups: patients who continued aspirin (100 mg) monotherapy and those who received no antiplatelet therapy starting five days prior to surgery. Aspirin or other antiplatelet therapy was resumed within 48 hours post-surgery unless significant bleeding occurred.

Key exclusion criteria included recent acute coronary syndrome (within one month), ejection fraction < 30%, valvular disease, need for oral anticoagulants, emergency surgeries, or high bleeding risk surgeries (e.g., brain, eye, spine).

Primary and Safety Outcomes

The primary composite endpoint — all-cause mortality, myocardial infarction (MI), stroke, or stent thrombosis within 30 days post-surgery — occurred at low and statistically similar rates in both groups:

• Aspirin group: 0.6%

• No therapy group: 0.9%
  (P = not significant)

Rates of MI were identical in both groups (0.6%), although two of the MIs in the aspirin group were fatal. Importantly, no cases of stent thrombosis were reported.

In a subgroup of 283 patients with serial troponin monitoring, 23% in the aspirin group and 20% in the no-therapy group showed post-operative elevations (P = not significant).

Bleeding outcomes included:

• Major bleeding: 6.5% in aspirin group vs. 5.2% in no-therapy group (P = not significant)

• Minor bleeding: 15% in aspirin group vs. 10% in no-therapy group (P = 0.027)

The increase in minor bleeding in the aspirin group was statistically significant, although not associated with major clinical harm.

Clinical Implications and Guideline Context

Current guidelines (Class I-B) recommend continuing aspirin monotherapy in patients with DES placed more than one year prior to elective noncardiac surgery. However, this recommendation largely has been based on observational data and earlier-generation stent technology.

The findings of ASSURE-DES suggest that in stable patients undergoing low- to intermediate-risk elective noncardiac surgeries, withholding aspirin may not increase ischemic risk, but could reduce minor bleeding events. This is clinically relevant because minor bleeding may extend hospital stays and impact patient recovery.

Importantly, no increase in stent thrombosis or ischemic complications was observed in the aspirin withdrawal group, which supports the safety of selective aspirin discontinuation.

Study Limitations

Several limitations should be considered in interpreting the results:

• Low event rates: The observed adverse event rate was far below predicted levels, possibly underpowering the study to detect differences in rare outcomes.

• Demographic representation: The majority of patients were East Asian, a population who may have a different thrombotic risk profile.

• Surgical risk level: Most procedures were low to intermediate in risk, limiting generalizability to high-risk surgeries (e.g., vascular).

• DES duration: Few patients were within one to two years of DES implantation, a period associated with relatively higher thrombotic risk.

• Timing of antiplatelet withdrawal: Aspirin was stopped five days pre-surgery, whereas some guidelines recommend seven days. This might have disadvantaged the no-aspirin group in terms of washout period.

For a fuller look at the ASSURE-DES trial and its implications, click here.