XienceV Stent vs Cypher Stent in Primary PCI for Acute Myocardial Infarction - XAMI

Description:

Although there have been a few head-to-head studies comparing so-called “second-generation” drug-eluting stents (DES) such as everolimus-eluting stents (EES) with “first-generation” DES such as sirolimus-eluting stents (SES), no randomized controlled trials have compared EES to SES in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). The XAMI trial sought to compare outcomes of EES and SES implantation in a real-world population of patients presenting with STEMI and undergoing PPCI.

Hypothesis:

EES would be noninferior to SES in reducing clinical outcomes in a real-world population of patients presenting with STEMI and undergoing PPCI.

Study Design

  • Randomized
  • Blinded
  • Parallel

Patient Populations:

  • STEMI requiring PPCI or non-STEMI with need for emergent PCI

    Number of enrollees: 625
    Duration of follow-up: 12 months
    Mean patient age: 61.5 years
    Percentage female: 26%

Exclusions:

  • Stent thrombosis of previous stent or chronic total occlusion as target lesion
  • Known allergy or intolerance to sirolimus, everolimus, aspirin, or clopidogrel
  • Intubated patient after extensive resuscitation or shock patients for whom no informed consent
    could be obtained
  • Estimated life expectancy <1 year
  • Stent size required to treat lesion >3.5 mm (maximum diameter of SES)

Primary Endpoints:

  • MACE (composite of cardiac death, MI, target vessel revascularization) at 12 months

Secondary Endpoints:

  • Stent thrombosis at 30 days; 1, 2, and 3 years
  • MACE at 30 days; 2 and 3 years
  • All-cause mortality at 1, 2, and 3 years

Drug/Procedures Used:

Patients were randomized in a 2:1 fashion to either EES (Xience V) or SES (Cypher).

Concomitant Medications:

Dual antiplatelet therapy (DAPT) was mandated for a minimum of 12 months in both arms, and 94% were on DAPT at the end of 12 months. Clopidogrel 600 mg loading (97%), glycoprotein IIb/IIIa inhibitors (76%), statins (90%).

Principal Findings:

A total of 625 patients were randomized, 404 to EES and 221 to SES. Baseline characteristics were fairly similar between the two arms. About 10% had diabetes, and 4% had undergone prior PCI. Although 96% presented with a true STEMI, about 4% of patients presented with a non-STEMI, but had an emergent indication for PCI. The mean ischemic time was about 170 minutes. The target vessel was the left anterior descending artery in 40%, right coronary artery in 39%, and the left main artery in 0.3% of the patients. Visible thrombus was noted in 86% of patients, with baseline TIMI 0 flow in 56%. About 13% had evidence of three-vessel disease. Thrombus aspiration was carried out in about 62% of patients. The mean number of stents per patient was 1.3.

Thirty-day outcomes were similar between the EES and SES arms, including mortality (1.0% vs. 2.7%, p = 0.18) and stent thrombosis (0.7% vs. 2.3%, p = 0.14). The primary endpoint of major adverse cardiac events (MACE) at 12 months met the predefined criteria for noninferiority for EES as compared with SES, and in fact, was superior (4.0% vs. 7.7%, p for superiority = 0.048). Other endpoints, including mortality (2.0% vs. 3.2%, p = 0.36), myocardial infarction (0.5% vs. 1.4%, p = 0.35), target vessel revascularization (2.5% vs. 4.1%, p = 0.27), and definite or probable stent thrombosis (1.2% vs. 2.7%, p = 0.21) were similar between the EES and SES arms.

Interpretation:

The results of the XAMI trial in a real-world population of patients with STEMI indicate that EES is superior to SES for MACE at 12 months. These results are similar to those noted in studies comparing EES to SES in other settings. Stent thrombosis rates were higher than those noted in prior studies comparing the two stents, in keeping with higher stent thrombosis rates in patients with acute MI. Further long-term follow-up data are awaited.

References:

Hofma SH, Brouwer J, Velders MA, et al. Second-generation everolimus-eluting stents versus first-generation sirolimus-eluting stents in acute myocardial infarction: 1-year results of the randomized XAMI (XienceV Stent vs. Cypher Stent in Primary PCI for Acute Myocardial Infarction) trial. J Am Coll Cardiol 2012;60:381-7.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention

Keywords: Myocardial Infarction, Follow-Up Studies, Thrombosis, Drug-Eluting Stents, Human Rights, Immunosuppressive Agents, Sirolimus, Coronary Vessels, Diabetes Mellitus, Stents, Percutaneous Coronary Intervention


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