Extreme late-phase observation using coronary angioscopy until 7 years after sirolimus-eluting stent implantation

Little is known about the very late-phase morphological vessel characteristics within the sirolimus-eluting stent (SES).

We assessed a total of 12 patients with 15 SES implantations who underwent repeat angiographic and angioscopic procedures after 5 and 7 years. The degree of neointimal stent coverage (NSC) was classified as follows: grade 0, uncovered struts; grade 1, visible struts through a thin neointima; or grade 2, invisible struts with complete neointimal coverage. The maximum and minimum NSC grades were evaluated and the existence of in-stent thrombus was also recorded for all patients. The prevalence of a maximum NSC grade of 2 increased and that of a minimum NSC grade of 0 decreased, although there was no significant difference in prevalence between 5 and 7 years. One of four in-stent thrombus identified at 5 years had disappeared from 5 to 7 years and a new thrombus was found in another patient at 7 years. Thus, the incidence of in-stent thrombus did not change from 5 to 7 years. In one case, a thrombus was observed inside the angiographic aneurysmal change, but none of the thrombi were related to adverse events.

This angioscopic study reported gradual arterial repair and continuous delayed healing associated with subclinical thrombus formation 7 years after SES deployment.