Safety and Efficacy Study of MGuard Stent After a Heart Attack - MASTER (Mesh-Covered Stent)

Description:

The goal of the trial was to evaluate treatment of a thin-strut stent with micronet covering compared with a commercially available stent among patients with ST-segment elevation myocardial infarction (STEMI).

Hypothesis:

MGuard stent will prevent distal embolization, and thus improve myocardial reperfusion.

Study Design

  • Randomized
  • Parallel
  • Stratified

Patient Populations:

  • Patients ≥18 years of age with STEMI ≤12 hours in duration
  • De novo lesion <33 mm in length between 3 and 4 mm in diameter

    Number of enrollees: 433
    Duration of follow-up: 30 days
    Mean patient age: 60 years
    Percentage female: 25%

Exclusions:

  • Left bundle branch block, paced rhythm, or other electrocardiogram abnormality precluding assessment of ST-segments
  • PCI within the last 6 months
  • Prior coronary artery bypass grafting
  • Bleeding abnormality or use of warfarin
  • Contraindication to any study medication or device
  • Chronic kidney disease
  • Left ventricular ejection fraction ≤20%
  • Cardiogenic shock or cardiopulmonary resuscitation
  • Life expectancy <1 year
  • Left main stenosis ≥50%
  • Ostial or bifurcation lesion
  • Target vessel with excessive calcification, tortuosity, or angulation
  • >50% stenosis proximal or distal to the culprit lesion
  • Prior stent proximal to or 10 mm distal to target lesion

Primary Endpoints:

  • Rate of complete ST-resolution (≥70%) 60-90 minutes post-procedure

Secondary Endpoints:

  • TIMI 3 flow
  • Myocardial blush grade 2/3
  • Mortality at 30 days
  • Reinfarction and stent thrombosis at 30 days
  • Major adverse cardiac events at 30 days

Drug/Procedures Used:

Patients with STEMI were randomized to a thin-strut stent with micronet covering (MGuard; n = 217) versus a commercially available bare-metal or drug-eluting stent (n = 216).

Prior to percutaneous coronary intervention (PCI), patients received aspirin and a loading dose of an adenosine diphosphate receptor antagonist (clopidogrel, prasugrel, or ticagrelor). During PCI, patients received unfractionated heparin plus a glycoprotein IIb/IIIa inhibitor or bivalirudin monotherapy. Low molecular weight heparin, fondaparinux, or intracoronary glycoprotein IIb/IIIa inhibitor was not permitted.

Aspiration thrombectomy and/or pre-dilatation prior to stent implantation was left to operator discretion.

Principal Findings:

Overall, 433 patients were randomized. The mean age was 60 years, 25% were women, 12% had diabetes, mean body mass index was 27 kg/m2, aspiration thrombectomy was performed in 66%, and pre-dilatation was performed in 50%.

Device success was 96% in the MGuard group versus 99% in the control group (p = 0.03).

The primary outcome, complete ST-resolution 60-90 minutes post-procedure, occurred in 57.8% of the micronet-covered stent group versus 44.7% of the control group (p = 0.008).

The following individual outcomes were reported as MGuard versus control:
- TIMI 3 flow: 91.7% versus 82.9% (p = 0.006)
- Myocardial blush grade 2/3: 83.9% versus 84.7% (p = 0.81)
- Mortality at 30 days: 0 versus 1.9% (p = 0.06)
- Reinfarction and stent thrombosis at 30 days: 1.4% versus 0.9% (p = 1.0)
- Major adverse cardiac events at 30 days: 1.8% versus 2.3% (p = 0.75)

Interpretation:

Among patients with STEMI treated with aspiration thrombectomy, the use of the novel micronet-covered stent was feasible. This device improved one marker of myocardial reperfusion: complete ST-resolution (primary outcome); however, it did not improve myocardial blush grade 2/3 (secondary outcome). Although it was not necessarily designed to improve epicardial coronary flow post-PCI compared with a conventional stent, TIMI flow 3 was also improved in the micronet-covered stent group. Clinical outcomes appeared similar between the treatment groups. It is unknown how this device would have performed without the frequent use of aspiration thrombectomy.

References:

Stone GW, Abizaid A, Silber S, et al. Prospective, randomized, multicenter evaluation of a polyethylene terephthalate micronet mesh-covered stent (MGuard) in ST-segment elevation myocardial infarction: The MASTER trial. J Am Coll Cardiol 2012;Oct 24:[Epub ahead of print].

Presented by Dr. Gregg Stone at the Transcatheter Cardiovascular Therapeutics meeting (TCT 2012), Miami, FL, October 24, 2012.

Clinical Topics: Anticoagulation Management, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Aortic Surgery

Keywords: Myocardial Infarction, Follow-Up Studies, Drug-Eluting Stents, Heparin, Low-Molecular-Weight, Dilatation, Purinergic P2Y Receptor Antagonists, Percutaneous Coronary Intervention, Body Mass Index, Thrombectomy, Thrombosis, Diabetes Mellitus, Myocardial Reperfusion


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