Faster full strut coverage with self-apposing stent

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At EuroPCR (20–23 May, Paris, France), Robert-Jan van Geuns (Thoraxcenter, Erasmus MC, Rotterdam, The Netherlands) reported that the results of the APPOSITION IV study indicate that a self-apposing sirolimus-eluting stent (Stentys) is associated with significantly faster full strut coverage and better apposition at four months than a balloon-expandable zotarolimus-eluting stent.

Van Geuns commented that vasodilation, under sizing, and thrombus dissolution are acute and subacute stent thrombosis. He added: “Self-apposing stents have resolved the issue of early malapposition (0 to three days) as compared with balloon-expandable stents when implanted in anacute setting.”


Van Geuns explained that first-generation self-apposing stent was a bare metal stent, but the company behind it (Stentys) decided to add a limus drug to the stent because “it can be hypothesised that self-apposing sirolimus-eluting stents could also reduce late malapposition with a minimum of neointima hyperplasia”. Therefore, the aim of the current study (APPOSITION IV) was to compare strut coverage and apposition, under optical coherence tomography (OCT) with the new self-apposing sirolimus-eluting stent with that of balloon-expandable zotarolimus-eluting stent.


In the study, 152 patients with ST-segment elevation myocardial infarction (STEMI) were randomly assigned (on a 3:2 basis) to receive the self-apposing sirolimus-eluting stent (90) or a balloon-expandable zotarolimus-eluting stent (62). Patients underwent OCT and quantitative coronary analysis (QCA) at four months and at nine months. The endpoints, van Geuns said, were the percentage of malapposed struts as seen on OCT at the follow-up time points.


At four months, the percentage of malapposed and uncovered struts was 0.07±0.26 in the self-apposing stent arm and 1.16±1.59 in the balloon-expandable stent arm (p=0.002). Furthermore, the percentage of stents with all struts covered was significantly higher in the self-apposing arm (33.3% vs. 3.8% in the balloon-expandable arm; p=0.02). However at nine months, there were no significant differences between groups in either the percentage of malapposed struts (0.43 for the self-apposing stent vs. 0.28 for the balloon-expandable stent; p=0.55) or in the percentage of stents with total strut coverage (38.1 vs. 35, respectively; p=0.81).


There were no significant differences in clinical outcomes between the self-apposing arm and the balloon-expandable arm. The rate of acute stent thrombosis (≤24 hours) was 3.4% in the self-apposing arm and 0% in the balloon-expandable arm; there were no incidences of subacute stent thrombosis in either arm, but the incidence of late stent thrombosis was 1.8% in the balloon-expandable arm with no incidences in the self-apposing arm.  


Van Geuns concluded that the self-apposing sirolimus-eluting stents showed “faster full strut coverage than the balloon-expandable zotarolimus-eluting stent”, adding: “These findings support future randomised studies investigating the safety of early dual antiplatelet therapy termination for this stent when used in treatment for STEMI.”