Mesh-Covered Stent Safe in STEMI Patients but Risk of TLR, TVR Higher vs BMS

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Compared with a bare-metal stent (BMS), use of a mesh-covered metallic stent in patients with ST-segment elevation myocardial infarction (STEMI) results in no apparent differences in overall mortality or major adverse cardiac events (MACE), according to a study published online June 17, 2014, ahead of print in Catheterization and Cardiovascular Interventions. However, the novel stent was associated with increased risk of target vessel revascularization (TVR) and target lesion revascularization (TLR). 

 

Methods

For the retrospective REWARD-MI study, Agustín Fernández-Cisnal, MD, of University Hospital Virgen del Rocío (Seville, Spain), and colleagues evaluated safety and efficacy in a real-world setting of STEMI patients who underwent PCI with the MGuard Prime stent (InspireMD; Tel Aviv, Israel; n = 92) or conventional BMS (n = 170) at a single center between July 2011 and January 2013. Propensity-matched analysis included 79 patients from each group.

MGuard Prime is a balloon-expandable, metallic stent coated with a polyethylene terephthalate micromesh designed to trap the thrombus against the wall of the artery, with the aim of preventing distal embolization.  
Baseline patient characteristics were similar between groups, although patients in the study arm were younger and more often smokers. The radial approach was used in 94.3% of the total cohort. The use of thrombectomy devices was more common in the MGuard group (85.9% vs 75.9%; P = .05), as was the use of glycoprotein IIb/IIIa inhibitors (52.2% vs 35.3%; P< .01).


Safety Confirmed, but Higher TLR, TVR Seen

After a mean 321 days of follow-up, rates of mortality, MACE (defined as all-cause death, MI, ischemia-driven TLR, TVR, and rehospitalization for cardiac causes), and other events were similar among patients who received the MGuard compared with BMS. However, TLR and TVR were higher with MGuard (table 1). 

Table 1. Long-term Outcomes with MGuard vs BMS in Propensity-Matched Patients

MGuard Prime

(n = 79) 

BMS

(n = 79) 

P Value

Mortality

7.6% 

7.6% 

NS 

MACE

20.3% 

12.7% 

NS 

CV-Mortality and Nonfatal MI

6.3% 

6.3% 

NS 

TVR

11.4% 

1.3% 

< .01 

TLR

11.4% 

1.3% 

< .01 

 

Three cases of definite stent thrombosis (2 in the mesh stent group, 1 in the BMS group) occurred, with none resulting in death. There were no differences between the groups in infarct size.

Interventionalists Must Balance Pros and Cons

The MGuard is specifically designed f or thrombus-containing lesions. Previously, the MASTER trial, presented at Transcatheter Cardiovascular Therapeutics in October 2012 and simultaneously published in the Journal of the American College of Cardiology, demonstrated an increased rate of complete ST-segment resolution with MGuard compared with conventional BMS and DES.  

In an email with TCTMD, Dr. Fernández-Cisnal noted that while the stent has been reported to be a useful device for reducing distal microembolization in STEMI patients, as measured by myocardial blush grade and ST-segment resolution, no differences have been observed in clinical endpoints. “Higher, but nonsignificant, rates of TLR and TVR were observed in some studies [that compared the MGuard] with BMS and DES,” he said, adding that no real-world data comparing MGuard exclusively to BMS existed previously. 

“Thrombus distal microembolization during the revascularization of STEMI remains an unsolved problem, and we thought perhaps the MGuard could be a partial solution, but with the present data, clinicians and interventional cardiologists should balance the potential benefit of decreasing microembolization with the risk of in-stent restenosis based on angiographic and clinical features of each patient,” he continued. “In some patients with high thrombus burden after thrombectomy and with low restenosis risk lesions, the MGuard could be a good option, but… more data are needed to recommend this stent.” 

Dr. Fernández-Cisnal said the ongoing MASTER-II trial, which is comparing BMS and the MGuard with a clinical endpoint, is expected to provide additional answers on the type of patients most likely to benefit from the mesh-covered stent. 

 


Source:
Fernández-Cisnal A, Cid-Álvarez B, Álvarez- Álvarez B, et al. Real world comparison of the MGuard stent versus the bare metal stent for ST elevation myocardial infarction (the REWARD-MI study). Catheter Cardiovasc Interv. 2014;Epub ahead of print. 

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Disclosures
  • Dr. Fernández-Cisnal reports no relevant conflicts of interest.

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