Abstract 18645: Axial Integrity of Coronary Stents: Evaluation Using Intravascular Ultrasound

Abstract

Background: Longitudinal stent deformation (i.e. the axial shortening or lengthening of a stent after implantation) is increasingly reported. However, the axial integrity of stents has not been systematically studied using intravascular ultrasound (IVUS). Methods: Consecutive coronary artery disease patients who underwent IVUS analysis after drug-eluting stent implantation for de-novo lesions were evaluated. Stent length was studied using automatic pullback of an IVUS catheter (Boston Scientific Corp/SCIMED) and was further analyzed for change in length (IVUS - label) (mm), the absolute change in length [|IVUS - label|] (mm), and the absolute value of the relative change in length [|(IVUS -label)|/label] (%). Results: A total of 183 stents were included: 38.3% sirolimus-eluting stents (SES); 27.9% zotarolimus-eluting stents (ZES); 20.2% Co-Ch everolimus-eluting stents (Cc-EES); 7.1% Pl-Ch everolimus-eluting stents (Pc-EES) - the Element platform and 6.6% paclitaxel-eluting stents (PES). The change in stent length (mm) and the relative change in length (%) differed between groups: SES 0.3 ± 1.2; ZES 1.0 ± 1.3; Cc-EES 0.6 ± 1.0; Pc-EES 0.4 ± 1.1; PES -0.1 ± 1.4 (p=0.008) and SES 1.7 ± 6.0; ZES 5.7 ± 6.7; Cc-EES 3.5 ± 5.8; Pc-EES 2.3 ± 6.0; PES -2.2 ± 8.1 (p<0.001), respectively. The relative change in stent length was higher in the ZES group in comparison with SES and PES groups, (p<0.001 for both). There were no statistical differences between the Pc-EES (Element) and any other stent types. The absolute relative change in stent length (>5%) was lower in the SES group compared to the other groups: SES 34%; ZES 63%; Cc-EES 54%; Pc-EES 46%; and PES 67% (p=0.02). Significant (>15%) absolute value of the relative change in stent length was rare (3.8%) and did not differ between groups (p=0.54). Long stents (≥20 mm, n=62) had a higher absolute change in stent length when compared to other stent groups (18 mm, n=50 and ≤16 mm, n=71): 1.3 ± 1.0 vs. 1.0 ± 0.6 vs. 1.0 ± 0.6, respectively (p=0.02). Conclusion: IVUS analysis revealed that significant change in stent length after implantation was rare in all stent types. Stent axial integrity was influenced by stent length; longer stents displayed a higher absolute change in length than did shorter stents.