Manual thrombus aspiration before percutaneous coronary intervention provided no significant benefit to early mortality over PCI alone in patients with ST-segment elevation myocardial infarction in the registry-based, randomized TASTE trial.
Among 7,244 patients with STEMI, the primary endpoint of all-cause mortality at 30 days was 2.8% with thrombus aspiration plus PCI and 3.0% with PCI alone, a nonsignificant difference. The per-protocol analysis was also similar, at 2.6% and 2.9%, respectively.
Dr. Ole Fröbert
Further, there was no significant effect of thrombus aspiration on any of the prespecified secondary outcomes, according to results presented at the annual congress of the European Society of Cardiology by Dr. Ole Fröbert and simultaneously published online (N. Engl. J. Med. 2013 [doi:10.1056/NEJMoa1308789]).
The multicenter TASTE (Thrombus Aspiration in ST-Elevation Myocardial Infarction in Scandinavia) trial provides intriguing results, but is unlikely to settle the debate over the benefits of using manual thrombus aspiration in this setting.
Based on the current TASTE results, the mortality benefit observed with thrombus aspiration in earlier clinical trials "may have been a chance finding," interventional cardiologists Dr. Robert A. Byrne and Dr. Adnan Kastrati, with the German heart center, Technical University of Munich, wrote in an accompanying editorial (N. Engl. J. Med. 2013 [doi:10.1056/NEJMe1310361]).
However, "many interventional cardiologists will continue to perform thrombus aspiration for now, contending that the results of the TASTE trial do not entirely exclude the possibility of a potential benefit of the procedure."
The editorialists, as well as Dr. Fröbert, pointed to the need for an updated analysis of outcomes at 12 months since it wasn’t until 12 months of follow-up that a significant mortality benefit emerged in the single-center Thrombus Aspiration during Percutaneous Coronary Intervention in Acute Myocardial Infarction Study (TAPAS).
In addition, the reinfarction rate in TASTE was 40% lower with thrombus aspiration, and this magnitude of effect was significant at 1 year in TAPAS, said Dr. Fröbert of the department of cardiology, Örebro (Sweden) University Hospital.
The TASTE investigators enrolled 7,244 participants with STEMI or left bundle branch block from the online national Swedish Coronary Angiography and Angioplasty Registry (SCAAR), and randomized them 1:1 to manual thrombus aspiration followed by PCI or PCI alone. The use of platelet inhibitors or anticoagulants was at physician discretion.
SCAAR is part of the SWEDEHEART (Swedish Web System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies) registry of consecutive patients from all 29 Swedish coronary intervention centers and 1 Icelandic center. An additional center in Denmark was also included in the trial.
At 30 days, the aspiration-plus-PCI and PCI-only groups had similar rates of stent thrombosis (0.2% vs. 0.5%), target lesion revascularization (1.2% vs. 1.6%), and target vessel revascularization (1.8% vs. 2.2%), Dr. Fröbert reported.
Although a recent meta-analysis of 21 randomized trials identified a trend toward a higher risk of stroke with thrombectomy in STEMI patients undergoing primary angioplasty (Int. J. Cardiol. 2013;166:606-12), stroke and neurologic complications at discharge were identical at 0.5% (19 events vs. 18 events; odds ratio,1.06; P = .87).
In subgroup analyses, the results for 30-day mortality were consistent across all prespecified subgroups, including high-risk patients such as those with a TIMI (Thrombolysis in Myocardial Infarction) flow grade 0 or 1, thrombus grade 4 or 5 on a 5-point scale, and smokers, Dr. Fröbert reported.
The current results contrast with those of other studies, however, including a 2010 report by Dr. Fröbert showing higher mortality, after adjustment, with thrombus aspiration than PCI alone among a Swedish population (Int. J. Cardiol. 2010;145:572-3).
The inconsistent findings may be attributable to differences in follow-up, duration of symptoms, number of participating centers, and the finding that mechanical thrombectomy devices may be inferior to manual aspiration catheters, he noted in the article. Clot-busting drugs may also be more effective, as suggested by the INFUSE-AMI trial.
Further insights are expected from another larger manual thrombectomy trial, TOTAL, with a composite end point of cardiovascular death, recurrent myocardial infarction, cardiogenic shock, or new or worsening heart failure at 180 days.
Still, the TASTE trial is being heralded for its design and low-cost approach as a breakthrough in research that "can potentially release us from the circular (and expensive) trap of the randomized-versus-registry debate," wrote Dr. Michael S. Lauer, director, division of cardiovascular sciences, National Heart, Lung, and Blood Institute and Ralph D’Agostino Sr., Ph.D., professor of mathematics/Statistics, biostatistics, and epidemiology, Boston University, in a second editorial accompanying the study (N. Engl. J. Med. 2013 [doi:10.1056/NEJMe1310102]).
They acknowledged that a variety of hurdles must be overcome, including undertaking randomized registry trials in places where health care and clinical data are fragmented and of lower quality, but also that society can no longer afford to undertake randomized effectiveness trials that cost tens or hundreds of millions of dollars at a time when registries and other powerful digital platforms are available.