MUltidevice Thrombectomy in Acute ST-Segment Elevation Acute Myocardial Infarction - MUSTELA

Dec 13, 2012
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Author/Summarized by Author:
Anthony A. Bavry, MD, MPH, FACC
Summary Reviewer:
Deepak L. Bhatt, MD, MPH, MBA, FACC
Trial Sponsor:
Medrad
Date Presented:
01/01/2011
Date Published:
01/01/2012
Date Updated:
12/13/2012
Original Posted Date:
12/13/2012
References

Description:

The goal of the trial was to evaluate treatment with thrombectomy prior to percutaneous coronary intervention (PCI) compared with standard PCI alone among patients with ST-segment elevation myocardial infarction (STEMI) and large thrombus burden.

Hypothesis:

Thrombectomy prior to PCI will reduce infarct size and microvascular obstruction.

Study Design

  • Randomized
  • Parallel
  • Stratified

Patient Populations:

  • Patients ≥18 years of age with STEMI with onset of symptoms <12 hours and high thrombus burden (TIMI thrombus grade >3)
  • Reference vessel diameter ≥3.0 mm

    Number of enrollees: 208
    Duration of follow-up: 12 months
    Mean patient age: 62 years
    Percentage female: 12%

Exclusions:

  • Prior infarct in the same territory
  • Cardiogenic shock
  • Severe liver/renal failure
  • Contraindication to abciximab
  • Contraindication to MRI

Primary Endpoints:

  • Infarct size at 3 months
  • >70% ST-segment resolution 60 minutes after PCI

Secondary Endpoints:

  • Microvascular obstruction detected by magnetic resonance imaging (MRI)
  • Infarct transmurality by MRI
  • Dyshomogeneous necrosis
  • Postprocedural TIMI flow grade
  • Postprocedural TIMI myocardial perfusion grade
  • MACE-free survival at 1 year

Drug/Procedures Used:

Patients with STEMI were randomized to thrombectomy prior to PCI (n = 104) versus PCI alone (n = 104). Thrombectomy was alternated between rheolytic thrombectomy (RT AngioJet Ultra) versus aspiration thrombectomy (Export catheter).

All patients received aspirin and clopidogrel 600 mg at the time of STEMI diagnosis. During PCI, patients received unfractionated heparin and abciximab.

Principal Findings:

Overall, 208 patients were randomized. The mean age was 62 years, 88% were men, 19% had diabetes, 48% were current smokers, 47% had an anterior STEMI, mean left ventricular ejection fraction (LVEF) was 45%, and the radial approach was used in 95%. Direct stenting was used in 75% of the thrombectomy group versus 48% of the PCI alone group (p < 0.0001), final TIMI flow 3 was 90% versus 82% (p = 0.07), and final myocardial blush grade 3 was 68% versus 53% (p = 0.03), respectively. Among the thrombectomy group, thrombotic debris was retrieved in 82%.

>70% ST-segment resolution occurred in 57% of the thrombectomy group versus 37% of the standard PCI group (p = 0.004).

Infarct size was similar between the two groups: 20% versus 19%, respectively, for thrombectomy versus PCI alone (p = 0.54). LVEF was 56% versus 59% (p = 0.10), respectively. Microvascular obstruction was observed in 11% versus 27% (p = 0.02), respectively.

Freedom from major adverse cardiac events (MACE) was 91% versus 90% (p = 0.97), respectively.

Complete thrombus removal was higher with rheolytic thrombectomy (94%) versus aspiration thrombectomy (78%; p = 0.02).

Interpretation:

Among STEMI patients, the use of thrombectomy failed to reduce infarct size at 3 months; however, a larger proportion of these patients achieved a high degree of ST-segment resolution and good myocardial blush grade. Microvascular obstruction was observed less frequently with thrombectomy. Larger trials and meta-analyses have documented the benefit of aspiration thrombectomy during STEMI on important clinical outcomes. If thrombectomy is indeed confirmed to be associated with a reduction in adverse clinical events, this benefit would appear to be from a mechanism independent of infarct size. The more complete removal of thrombus with rheolytic thrombectomy is intriguing, and should stimulate head-to-head comparison of these devices.

References:

De Carlo M, Aquaro GD, Palmieri C, et al. A Prospective Randomized Trial of Thrombectomy Versus No Thrombectomy in Patients With ST-Segment Elevation Myocardial Infarction and Thrombus-Rich Lesions: MUSTELA (MUltidevice Thrombectomy in Acute ST-Segment Elevation Acute Myocardial Infarction) Trial. JACC Cardiovasc Interv 2012;5:1223-30.

Presented by Dr. Anna Petronio at the Transcatheter Cardiovascular Therapeutics Meeting (TCT 2011), San Francisco, CA, November 10, 2011.

Keywords: Myocardial Infarction, Follow-Up Studies, Heparin, Ticlopidine, Immunoglobulin Fab Fragments, Cost of Illness, Percutaneous Coronary Intervention, Thrombectomy, Thrombosis, Stroke Volume, Diabetes Mellitus


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