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The bioresorbable vascular scaffold (BVS) has several theoretical advantages over existing metallic stents, including complete resorption and restoration of vasoreactivity. However, the mechanical properties of the BVS do not allow aggressive post–dilatation (PD), with consequent potential for strut malapposition depending on the interaction between the BVS and underlying tissue.
All patients undergoing elective BVS implantation at a single centre were included. Patients were suitable for BVS if angiography demonstrated no clear evidence of calcification. Optical coherence tomography (OCT) was performed both before and after intervention and all lesions adequately predilated before implantation. PD could be performed under the manufacturer's recommendation. An operator not involved in implantation adjudicated lesion type and degree of calcification. Two trained operators analysed all struts on each OCT frame and judged malapposition (defined as ≤50% contact of the abluminal strut surface with the endothelium) and underlying tissue.
10 patients (70% male; age 64.4±10.7years) underwent BVS implantation. The target lesion was LAD in 6 and RCA in 4, with 80% being ACC/AHA type B2/C lesions and 20% type A/B1. Calcification was absent (60%), mild (30%) and moderate (10%) on independent review. The median number of stents implanted was 1 with median size of 3.0 × 18 mm. 4 patients (40%) had PD performed. OCT–defined strut malapposition between observers was excellent (Kappa 0.93). In total, 9722 struts were visible with 372 (3.8%) of these being malapposed. The number of malapposed struts varied significantly between individuals, ranging from 0 to 146 (median 17). Tissue characterization under malapposed struts were, in decreasing frequency; calcium, fibrous, fibrocalcific and lipid (47.6%, 32.3%, 11.8% and 8.3% respectively; p = 0.049).
This study shows that the incidence of strut malapposition using BVS is low in an elective setting. Nevertheless intracoronary imaging may be useful to assess tissue characterization prior to implantation to ensure subtle calcification on angiography does not lead to unnecessary malapposition.
Poster Sessions, Expo North
Saturday, March 09, 2013, 10:00 a.m.–10:45 a.m.
Session Title: Coronary Stents
Abstract Category: 47. TCT@ACC–i2: Coronary Intervention, Devices
Presentation Number: 2101–232
- 2013 American College of Cardiology Foundation