Thrombus Aspiration in ST-Elevation Myocardial Infarction in Scandinavia - TASTE

Description:

Current guidelines list thrombus aspiration as a Class IIa indication in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary PCI (PPCI). The current trial sought to investigate whether aspiration thrombectomy as an adjunct to primary PCI resulted in superior outcomes as compared with primary PCI alone in patients presenting with STEMI.

Hypothesis:

Aspiration thrombectomy + PPCI would be associated with a significant reduction in mortality in patients with STEMI as compared with PPCI alone.

Study Design

  • Randomized
  • Parallel

Patient Populations:

  • STEMI and ability to provide oral consent
  • <24 hours of symptoms
  • Correspondence between ECG and angio findings

    Number screened: 7,259
    Number of enrollees: 7,244
    Duration of follow-up: 1 month, 1 year 
    Mean patient age: 66 years
    Percentage female: 25%

Exclusions:

  • Need for emergency coronary artery bypass grafting
  • Age <18 years
  • Previous randomization in TASTE

Primary Endpoints:

  • All-cause mortality at 30 days

Secondary Endpoints:

  • Time to rehospitalization with reinfarction at 30 days
  • Time to stent thrombosis at 30 days

Drug/Procedures Used:

In a registry-randomized controlled trial format, patients enrolled in the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) (itself nested in the web-based SWEDEHEART registry) were randomized in an open-label fashion to either aspiration thrombectomy along with primary PCI or primary PCI alone. Aspiration thrombectomy was performed with an aspiration catheter such as Export®, Pronto®, or Eliminate®.

Concomitant Medications:

Aspirin (97.9%), clopidogrel/ticlopidine (66%), ticagrelor (28.5%), prasugrel (15%), bivalirudin (79%), and glycoprotein IIb/IIIa inhibitors (16.4%; higher use in conventional PCI arm)

Principal Findings:

A total of 7,244 patients were randomized at 31 Scandinavian centers: 3,621 to aspiration thrombectomy + PPCI and 3,623 to PPCI alone. Baseline characteristics were fairly similar between the two arms. Approximately 12.5% had diabetes mellitus, 12% had prior MI, and 10% had undergone prior PCI. The median ischemic time was 184 minutes, with a diagnostic electrocardiogram (ECG) to PCI (similar to door-to-balloon time) of 66 minutes. Radial access was utilized in 66% of patients. Less than 2% of patients had received prior thrombolytics, and approximately 78% had TIMI 0/1 flow prior to PCI. Direct stenting was more frequent in the aspiration thrombectomy arm (38.3% vs. 23.3%, p < 0.001). Total stent length was also lower (27.7 mm vs. 28.5 mm, p = 0.05).

The primary endpoint of all-cause mortality at 30 days was similar between the thrombectomy + PPCI vs. PPCI arms (2.8% vs. 3.0%, hazard ratio [HR] 0.94, 95% confidence interval [CI] 0.72-1.22, p = 0.63). Numerical reductions were noted in hospitalization for reinfarction (0.5% vs. 0.9%, p = 0.09), target lesion revascularization (TLR) (1.2% vs. 1.6%, p = 0.16), and stent thrombosis (0.2% vs. 0.5%, p = 0.06). Periprocedural stroke was similar (0.5% vs. 0.5%, p = 0.87).

One-year results: All-cause mortality was still similar between the thrombectomy + PPCI vs. PPCI arms (5.6% vs. 5.3%, HR 0.94, 95% CI 0.78-1.15, p = 0.57). Similarly, MI (2.7% vs. 2.7, p = 0.81), stent thrombosis (0.9% vs. 0.7%, p = 0.51), TLR (3.5% vs. 3.2%, p = 0.47), and the composite major adverse cardiac event (MACE) endpoint (8.5% vs. 8.0%, p = 0.48) were similar between the two arms.

Interpretation:

The results of the TASTE trial indicate that aspiration thrombectomy as an adjunct to PPCI is not superior to PPCI alone in reducing mortality at 30 days in patients with STEMI. Although numerical reductions were noted in MI, TLR, and stent thrombosis, these were not significant statistically. This is the largest randomized clinical trial (RCT) on this topic to date.

Following the results of the TAPAS trial and subsequent meta-analyses, aspiration thrombectomy (but not mechanical thrombectomy) is recommended as a Class IIa indication in the current guidelines. The results of this trial are thus at odds with current evidence. Several points are important here. First, the mortality reduction in the earlier studies was noted only at 6-12 months of follow-up, not acutely. However, in the current trial, results were identical at 1 year.

Second, this trial had a unique design: registry-RCT; i.e., the RCT was nested within the larger SCAAR registry. Thus, although randomization was appropriate, the study was not blinded. There was no adjudication of events. Even for the 30-day results, changes to the outcome numbers were subsequently necessary due to availability of more information. There was also no quantitative coronary angiography. Angiographic data were reported by each site into the database by the performing interventionalist. These elements could have introduced bias into the findings. Another large trial, TOTAL, also powered for clinical endpoints, is ongoing and will provide further evidence for or against aspiration thrombectomy in the future.

References:

Lagerqvist B, Frobert O, Olivecrona GK, et al. Outcomes 1 Year after Thrombus Aspiration for Myocardial Infarction. N Engl J Med 2014;Sep 1:[Epub ahead of print].

Presented by Dr. Bo Lagerqvist at the European Society of Cardiology Congress, Barcelona, Spain, September 1, 2014.

Fröbert O, Lagerqvist B, Olivecrona GK, et al. Thrombus aspiration during ST-segment elevation myocardial infarction. N Engl J Med 2013;Sep 1:[Epub ahead of print].

Presented by Dr. Ole Fröbert at the European Society of Cardiology Congress, Amsterdam, Holland, September 1, 2013.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Aortic Surgery, Interventions and Imaging, Angiography, Nuclear Imaging

Keywords: Stroke, Myocardial Infarction, Follow-Up Studies, Electrocardiography, Angioplasty, Balloon, Coronary, Stents, Registries, Coronary Angiography, Thrombectomy, Thrombosis, Confidence Intervals, Taste, Diabetes Mellitus, ESC Congress


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