AMSTERDAM, The Netherlands—Manual thrombus aspiration provides no additional mortality reduction at 30 days compared with percutaneous coronary intervention (PCI) alone in patients with ST-segment elevation myocardial infarction (STEMI), according to results of the randomized TASTE (Thrombus Aspiration in ST-Elevation myocardial infarction in Scandinavia) trial, presented September 1, 2013, at the European Society of Cardiology (ESC) Congress and published online in the New England Journal of Medicine.

“There is little role for manual thrombus aspiration as a routine adjunct to PCI in STEMI,” despite some nonsignificant trends favoring thrombus aspiration, concluded study author Ole Fröbert, MD, PhD, of Orebro University Hospital (Orebro, Sweden

Reperfusion failure following primary PCI is associated with unfavorable outcomes, Dr. Frobert noted in an ESC Hot Line presentation. Aspirating intracoronary thrombus, he said, may reduce distal embolization and increase reperfusion. No prior randomized trials of thrombus aspiration, however, have been powered for hard endpoints.

While in the TAPAS trial all-cause mortality was reduced with thrombus aspiration as compared with conventional PCI alone (P = 0.040), a Swedish registry (Fröbert O, et al. Int J Cardiol. 2010;145:572-573)including about 20,000 patients found that thrombus aspiration plus PCI increased all-cause mortality (HR 1.21). TASTE enrolled far more patients (sevenfold) than TAPAS.

Some Positive Trends, But Missed Primary Endpoint

The current analysis, by far the largest to date, included 29 Swedish centers, 1 Icelandic center, and 1 Danish PCI center. All enrolled patients had STEMI and appeared at the centers less than 24 hours from symptom onset.

None of the patients enrolled in TASTE (3,621 assigned to thrombus aspiration and 3,623 assigned to PCI alone) were lost to follow-up. The primary endpoint of 30-day all-cause mortality was similar between groups (HR 0.94; 95% CI 0.72-1.22 for PCI plus thrombus aspiration vs. PCI only; P = 0.63). A strong trend favored PCI plus thrombus aspiration for reinfarction at 30 days (0.5% vs. 0.9%; HR 0.61 95% CI 0.34-1.07; P = 0.09).

A reduction in stent thrombosis in the thrombus aspiration group just missed significance (0.2% vs. 0.5%; HR 0.47; 95% CI 0.20-1.02; P=0.06). Strokes, heart failure, and left ventricular function were similar between groups.

Subgroup analyses looking at gender, age, smoking, prior MI, prior PCI, time from symptoms to PCI and from ECG to PCI, artery location, thrombus grade, and TIMI flow grade before PCI all showed slight but nonsignificant trends favoring thrombus aspiration (except diabetes, which was equivalent between groups).

The Case is Weak

Beyond the missed primary endpoint, Dr. Fröbert said that given the lack of significant reductions in hospitalizations for MI, stent thrombosis at 30 days, and other important clinical endpoints during hospitalization, the case for routine adjunct manual thrombus aspiration is weak. “Recommendations for its general use in international guidelines should probably be downgraded,” he added.

“These results,” commented session Moderator Keith A. A. Fox, MD, of the University of Edinburgh (Edinburgh, United Kingdom), “are going to generate significant interest.”

The Question Still Burns

“The question is burning,” agreed discussant Raffaele De Caterina, MD, PhD, of d'Annunzio University (Chieti, Italy). “Although the findings allow little room for manual thrombus aspiration as a routine adjunct to PCI in STEMI, probably the door for thrombus aspiration is not yet fully closed. Will the trends toward less reinfarction and stent thrombosis at 30 days translate into later survival benefits? This needs to be addressed.”

He added that the “concept of thrombus aspiration is still logical and feasible, relatively easy—and will continue to be attractive for many. Maybe the use of other methods of thrombus removal. . . . may lead to better outcomes.” 

Study Details

All centers used endorsed aspiration catheters Eliminate (Terumo), Export (Medtronic), or Pronto (Vascular Solutions), and they administered anticoagulation and platelet inhibition in accordance with current guideline recommendations.

Mean age was approximately 66 years and three-quarters were male. Access was via the radial artery in two-thirds of cases. Thrombus scores were G3 to G5 in approximately 54% of randomized patients. GP IIb/IIIa inhibitors were administered in 17.4% of PCI-only patients and in 15.4% of thrombus aspiration patients (P = 0.02).

Median procedural X-ray time was longer in the thrombus aspiration group (625 seconds vs. 540 seconds, P < 0.001), and the median number of stents placed was slightly higher in the PCI only group (1.39 vs. 1.35, P = 0.02). Direct stenting was used more often in the thrombus aspiration group (P < 0.001), and mean total stent length was greater in the PCI only group (28.5 mm vs. 27.7 mm, P = 0.05).

Sources:

1. Fröbert O, Lagerqvist B, Olivecrona GK, et al. Thrombus aspiration during ST-segment elevation myocardial infarction. N Engl J Med. 2013;Epub ahead of print.
2. Byrne RA, Kastrati A. Unmet aspriations—where to now for catheter thrombectomy [editorial]? N Engl J Med.

Disclosures

• Dr. Frobert reports consulting, receiving royalties, and serving as an owner/stockholder of a health care company.

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