Comparison of Biolimus Eluted From an Erodible Stent Coating With Bare Metal Stents in Acute ST-Elevation Myocardial Infarction - COMFORTABLE AMI

Contribution To Literature:

The COMFORTABLE AMI trial showed that a biolimus-eluting stent with biodegradable polymer during STEMI reduces adverse events.


The goal of the trial was to evaluate treatment with a biolimus-eluting stent with biodegradable polymer compared with a bare-metal stent among patients with ST-segment elevation myocardial infarction (STEMI).

Study Design

  • Randomized
  • Blinded
  • Parallel
  • Stratified

Patient Populations:

  • Patients at least 18 years of age with STEMI undergoing primary percutaneous coronary intervention

    Number of screened applicants: 2,575
    Number of enrollees: 1,157
    Duration of follow-up: 1 year, 5 years 
    Mean patient age: 61 years
    Percentage female: 21%
    Ejection fraction: 49%


  • Mechanical complication of MI
  • Allergy to study medication
  • Use of vitamin K antagonist
  • Planned surgery
  • Bleeding abnormality
  • Pregnancy
  • Participation in another clinical trial
  • Inability to provide informed consent
  • Life expectancy <1 year

Primary Endpoints:

  • Composite of cardiovascular death, target vessel reinfarction, or ischemia-driven target lesion revascularization

Secondary Endpoints:

  • Cardiovascular death, any MI, or any repeat revascularization

Drug/Procedures Used:

Patients with STEMI were randomized to a Biomatrix biolimus-eluting stent with biodegradable polylactic acid polymer (n = 575) versus a bare-metal stent (n = 582). Aspiration thrombectomy was recommended prior to stent implantation.

Concomitant Medications:

Dual antiplatelet therapy was recommended for 1 year (aspirin plus clopidogrel or prasugrel). At discharge, 43% of patients received prasugrel.

Principal Findings:

Overall, 1,175 patients were randomized. The mean age was 61 years, 21% were women, mean body mass index was 27 kg/m2, 15% had diabetes, median time from symptom onset to balloon inflation was 234 minutes, mean left ventricular ejection fraction was 49%, and mean SYNTAX score was 15. Thrombus aspiration was performed in 62%, and 47% received a glycoprotein IIb/IIIa inhibitor.

At 1 year, cardiovascular death, target vessel reinfarction, or ischemia-driven target lesion revascularization occurred in 4.3% of the biolimus-eluting stent group vs. 8.7% of the bare-metal stent group (p = 0.004).

  • Cardiovascular death: 2.9% for biolimus-eluting stent vs. 3.5% for bare-metal stent (p = 0.53)
  • Target vessel reinfarction: 0.5% for biolimus-eluting stent vs. 2.7% for bare-metal stent (p = 0.01)
  • Definite stent thrombosis: 0.9% for biolimus-eluting stent vs. 2.1% for bare-metal stent (p = 0.10)
  • Ischemia-driven target lesion revascularization: 1.6% for biolimus-eluting stent vs. 5.7% for bare-metal stent (p < 0.001)

Intravascular imaging at 13 months:

  • Malapposed stent struts: 0.08% for biolimus-eluting stent vs. 0.02% for bare-metal stent (p = 0.10)
  • Uncovered stent struts: 2.1% for biolimus-eluting stent vs. 0.15% for bare-metal stent (p < 0.001)

Five-year outcomes:

  • Major adverse cardiac events: 8.6% for biolimus-eluting stent vs. 14.9% for bare-metal stent (p = 0.001)
  • Cardiovascular death: 4.9% for biolimus-eluting stent vs. 5.5% for bare-metal stent (p = 0.61)
  • Target vessel reinfarction: 2.2% for biolimus-eluting stent vs. 5.0% for bare-metal stent (p = 0.018)
  • Ischemia-driven target lesion revascularization: 4.4% for biolimus-eluting stent vs. 10.4% for bare-metal stent (p < 0.001)
  • Definite or probable stent thrombosis: 4.1% for biolimus-eluting stent vs. 6.2% for bare-metal stent (p = 0.14) 


Among patients with STEMI, the use of a novel biolimus-eluting stent with biodegradable polymer was superior to a bare-metal stent. This device reduced target vessel reinfarction and ischemia-driven target lesion revascularization. Benefit was sustained to 5 years. There were more uncovered stent struts in the biolimus group; however, this did not appear to translate into safety concerns. There was a nonsignificant reduction in definite or probable stent thrombosis with the biolimus-eluting stent. This study expands upon the LEADERS trial, which documented the noninferiority of the biolimus-eluting stent with biodegradable polymer compared with a sirolimus-eluting stent among patients with stable angina and non-ST-elevation acute coronary syndromes.

Biolimus is a semi-synthetic analog of sirolimus with enhanced lipophilicity. In-vivo studies suggest that the polylactic acid polymer is fully converted to lactic acid within 6-9 months, leaving the bare-metal stent platform.


Räber L, Yamaji K, Kelbæk H, et al. Five-year clinical outcomes and intracoronary imaging findings of the COMFORTABLE AMI trial: randomized comparison of biodegradable polymer-based biolimus-eluting stents with bare-metal stents in patients with acute ST-segment elevation myocardial infarction. Eur Heart J 2019;40:1909-19.

Räber L, Kelbæk H, Ostoijc M, et al. Effect of biolimus-eluting stents with biodegradable polymer vs bare-metal stents on cardiovascular events among patients with acute myocardial infarction. The COMFORTABLE AMI randomized trial. JAMA 2012;308:777-87.

Keywords: Acute Coronary Syndrome, Myocardial Infarction, Angina, Stable, Sirolimus, Percutaneous Coronary Intervention, Stents, Metals, Thrombectomy, Thrombosis, Polymers, Stroke Volume, Lactic Acid, Diabetes Mellitus, Platelet Glycoprotein GPIIb-IIIa Complex

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