MASTER: Potential Mortality Advantage With Mesh-Covered Stent in STEMI Patients at 1 Year

In STEMI patients undergoing primary PCI, treatment with a polymer mesh-covered BMS instead of conventional stents could potentially reduce mortality at 1 year, according to a study published online January 20, 2015, ahead of print in Circulation: Cardiovascular Interventions. However, the novel device is associated with higher 1-year MACE risk, driven by more TLR.

Take Home: MASTER: Potential Mortality Advantage With Mesh-Covered Stent in STEMI Patients at 1 Year

MGuard (InspireMD; Tel Aviv, Israel), a bare-metal device covered with a thin, flexible sleeve of polyethylene terephthalate mesh, is designed to reduce the risk of distal embolization in thrombus-containing lesions. Thirty-day results of the MASTER trial, presented at the Transcatheter Cardiovascular Therapeutics meeting in October 2012 and simultaneously published in the Journal of the American College of Cardiology, showed higher rates of complete ST-segment resolution with MGuard compared with conventional BMS and DES in 433 randomized STEMI patients.

For the current analysis, Dariusz Dudek, MD, PhD, of Jagiellonian University Medical College (Krakow, Poland), and colleagues followed 204 MGuard patients and 206 controls out to 1 year. There were no differences between the groups in the frequency of aspirin or P2Y12 inhibitor use.

Kaplan-Meier estimates of all-cause and cardiac mortality were lower in study patients vs controls at 30 days (P = .04 for both), but only trends persisted at 1 year. Risk of MACE (cardiac death, MI, or ischemia-driven TLR) was higher in the MGuard group at 1 year (9.1% vs 3.3%; P = .02), driven by an increased rate of ischemia-driven TLR (8.6% vs 0.9%; P = .0003; table 1).

Table 1. Risk of Clinical Events at 1 Year: MGuard Patients vs Controls

A trend toward an increase in definite stent thrombosis was observed in MGuard patients vs controls at 1 year (2.3% vs 0.5%; P = .10), but no differences were seen in definite/probable stent thrombosis or reinfarction.

When the MGuard results were compared with DES or BMS separately in a post hoc nonrandomized analysis, the findings were largely similar.

Also, in 38 MGuard patients who received angiography at 13 months, late lumen loss was 0.99 ± 0.80 mm and binary restenosis was 31.6%.

In addition, propensity-matched analysis of 191 MGuard patients and 443 BMS-treated patients from HORIZONS-AMI showed no differences in the rates of MACE or ischemia-driven TLR and TVR between the groups at 30 days and 1 year.

Updated Device Could Improve Outcomes Further

Although the trend toward improved survival seen with MGuard at 1 year is promising, the authors say, they caution that the study was not powered for mortality and “endpoints other than ST-segment resolution should be considered exploratory and hypothesis generating.”

Nonetheless, they suggest, “effective epicardial and microcirculatory reperfusion, which was more frequently observed in patients treated with the MGuard than with a standard metallic stent, may improve long-term survival.” However, this idea must be tested in larger randomized trials, the researchers add.

Dr. Dudek and colleagues also note that more angiographic follow-up will be required to examine low-frequency safety events like stent thrombosis. Meanwhile, the first-generation MGuard device used in MASTER is now being replaced by the MGuard Prime stent (also InspireMD), which has even thinner struts, they report, proposing that the new system might reduce the rate of restenosis compared with its predecessor.

They say that 2 ongoing studies—MASTER-II and GUARDIAN—“should afford a balanced assessment of the competing benefits (potentially improved myocardial reperfusion, reduced infarct size, and greater survival) and risks (potentially greater restenosis) of the MGuard in comparison with conventional metallic stents.”

Note: Several study coauthors are faculty members of the Cardiovascular Research Foundation, which owns and operates TCTMD.


Source:
Dudek D, Dziewierz A, Brener SJ, et al. Mesh-covered embolic protection stent implantation in ST-segment–elevation myocardial infarction: final 1-year clinical and angiographic results from the MGUARD for Acute ST Elevation Reperfusion trial. Circ Cardiovasc Interv. 2015;Epub ahead of print.

Disclosures:

  • The MASTER trial was sponsored by InspireMD.
  • Dr. Dudek reports receiving research grants from and serving as a consultant to InspireMD.

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