Prospective, Randomized, Multicenter Evaluation of a Polyethylene Terephthalate Micronet Mesh–Covered Stent (MGuard) in ST-Segment Elevation Myocardial Infarction: The MASTER Trial

Study Questions:

What is the potential utility of a novel polyethylene terephthalate micronet mesh–covered stent (MGuard) in patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI)?

Methods:

A total of 433 patients with STEMI presenting within 12 hours of symptom onset undergoing PCI were randomized at 50 sites in nine countries to the MGuard (n = 217) or commercially available bare-metal or drug-eluting stents (n = 216). The primary endpoint was the rate of complete (70%) ST-segment resolution measured 60-90 minutes post-procedure.

Results:

Baseline characteristics were well matched between the groups. The primary endpoint of post-procedure complete ST-segment resolution was significantly improved in patients randomized to the MGuard stent compared with control patients (57.8% vs. 44.7%; difference: 13.2%; 95% confidence interval, 3.1-23.3%; p = 0.008). By core laboratory analysis, the MGuard stent compared with control stents also resulted in superior rates of Thrombolysis In Myocardial Infarction (TIMI) 3 flow (91.7% vs. 82.9%, p = 0.006) with comparable rates of myocardial blush grade 2 or 3 (83.9% vs. 84.7%, p = 0.81). Mortality (0% vs. 1.9%, p = 0.06) and major adverse cardiac events (1.8% vs. 2.3%, p = 0.75) at 30 days were not significantly different between patients randomized to the MGuard stent and control stent, respectively.

Conclusions:

The authors concluded that among patients with acute STEMI undergoing emergent PCI, the MGuard micronet mesh–covered stent compared with conventional metal stents resulted in superior rates of epicardial coronary flow and complete ST-segment resolution.

Perspective:

This pilot study reports that among patients with acute STEMI undergoing emergent PCI enrolled in the present multicenter, randomized, controlled trial, the MGuard micronet mesh–covered stent compared with conventional metal stents resulted in significantly higher rates of TIMI flow grade 3, acute angiographic success, and complete ST-segment resolution, the latter representing the powered primary endpoint of the study. Furthermore, the greater rate of complete ST-segment resolution achieved with the MGuard stent was consistent among numerous important subgroups, including infarct vessel, lesion length, reference vessel diameter, and use of aspiration. Larger randomized trials are needed to assess whether these benefits result in improved hard clinical endpoints.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Stable Ischemic Heart Disease, Chronic Angina

Keywords: Myocardial Infarction, Suction, Coronary Restenosis, Drug-Eluting Stents, Polyethylene Glycols, Microbial Sensitivity Tests, Angioplasty, Balloon, Coronary, Percutaneous Coronary Intervention, Stents, Cardiology, Polyethylene Terephthalates, Pregnancy


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