Diego Fernández-Rodríguez (Cardiology Department, University Hospital Clinic, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain) and others write in Circulation: Cardiovascular Interventions that patients who undergo manual thrombus aspiration prior to primary percutaneous coronary intervention (PCI) have a significantly higher rate of direct stenting and a significantly lower rate of postdilation compared with patients who do not undergo the procedure prior to primary PCI. However, manual thrombus aspiration is not associated with an improvement in long-term outcomes.
Fernández-Rodríguez et al report that there is conflicting data for the benefits of manual thrombus aspiration prior to primary PCI, with one study suggesting it confers a benefit (TAPAS) while a more recent study (TASTE) suggesting that it does not. They add: “There is scarcity of data about the impact between manual thrombus aspiration and stent complications as restenosis or stent thrombosis. However, a recent study reported that successful manual thrombus aspiration reduces restenosis in primary PCI involving bare metal stents.” The aim, therefore, of the current study was to review the effect of thrombus aspiration on immediate angiographic results and clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary PCI as part of the EXAMINATION study. The EXAMINATION study was the first trial to evaluate the use of second-generation everolimus-eluting stents in primary PCI.
Of the 1,498 patients enrolled in the EXAMINATION trial, 976 received manual thrombus aspiration (which the study protocol allowed) and 522 did not. Patients (as a result of EXAMINATION’s original randomisation process) received either a bare metal stent (Multilink Vision, Abbott Vascular) or an everolimus-eluting stent (Xience, Abbott Vascular). Fernández-Rodríguez et al note that the patients who did receive thrombus aspiration had, on admission, higher Killip class and higher peak of myocardial necrosis biomarkers than the patients who did not receive thrombus aspiration.
The thrombus aspiration group was associated with a higher use of IIb/IIIa inhibitors (59% vs. 40%; p<0.001), a higher rate of direct stenting (69.2% vs. 43.3%; p<0.001), and a lower rate of postdilatation (13% vs. 18%; p<0.009) compared with the no thrombus aspiration group. Furthermore, the investigators comment, fewer and larger stents were used in the thrombus aspiration group—1.35±0.62 vs. 1.45±0.71 (p=0.005) and maximal stent diameter 3.25±0.44mm vs. 3.11±0.46mm (p<0.001)—than in the no thrombus aspiration group. They state: “We can hypothesise that the observed reduction in the number of implanted stents and the lower number of angioplasty balloons for predilatation and postdilatation may reduce costs in primary PCI. Therefore, further studies about the cost-effectiveness implications of the use of manual thrombus aspiration in primary PCI are warranted.”
However, there was not a significant difference in the patient-oriented primary endpoint—a combination of all-cause death, any myocardial infarction, and any revascularisation—between the groups at two years: 14.8% for thrombus aspiration vs. 17.8% for no thrombus aspiration (p=0.122). Fernández-Rodríguez et al add: “The lack of difference persists after multivariate adjustment (p=0.862). No difference was also found in the device-oriented secondary end point [a combination of cardiac death, target vessel myocardial infarction, and clinically driven target vessel revascularisation]—8.7% vs. 10.7%, respectively (p=0.202) between groups.”
Study author Manel Sabaté (University Hospital Clinic, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain) told Cardiovascular News: “Based on our results, manual thrombectomy may improve initial outcomes and optimise the procedural technique in the context of primary PCI.”