Serial angiographic and intravascular ultrasound evaluation to interrogate the presence of late "catch-up" phenomenon after Cypher® sirolimus-eluting stent implantation.

Despite the expressive reduction in the intimal hyperplasia (IH) formation after DES implantation at the mid-term, late restenosis has been recently noticed. Our objective was to determine, by means of serial angiography (QCA) and intravascular ultrasound (IVUS) at two different time points, whether the occurrence of the "late catch-up" phenomenon occurs after sirolimus-eluting stent (SES) implantation. Thirty-eight non-complex patients treated with a single 18-mm SES who had systematic serial QCA and IVUS analyses at mean 8 and 20 months were enrolled. Primary endpoint is to evaluate the temporal course of IH formation after SES implantation, by comparing QCA in-stent late loss and IVUS percent IH obstruction between the invasive follow-ups. Mean cohort age was 59.3 years and 31.6% were diabetics. Baseline reference vessel diameter was 2.8 ± 0.4 mm and lesion length was 11.5 ± 3.5 mm. Left anterior descending artery was the most frequent target vessel (55.3%). Between 8 and 20 months, a non-significant increase in in-stent late loss from 0.10 ± 0.18 to 0.15 ± 0.30 mm (P = 0.38) was observed. By IVUS, a slight increase in the percent IH obstruction (1.03 ± 2.13 to 1.76 ± 1.87%, P = 0.12) was detected between the two evaluations. Interestingly, all the neoformed tissue accrued from 8 to 20 months accumulated in the distal portion of the stent. In the non-complex scenario, SES implantation was associated with a minimal, non-significant increase in the IH volume between 8 and 20 months.