Relationship between neointimal coverage of sirolimus-eluting stents and lesion characteristics: a study with serial coronary angioscopy.

Background: Delayed neointimal coverage after the implantation of a drug-eluting stent (DES) is thought to be related to their potential for developing late-stent thrombosis. However, few studies have shown which factor affects the neointimal coverage after DES implantation. We hypothesized that the extent of neointimal coverage after DES implantation is affected by the underlying lesion characteristics because arterial wall components are reported to determine the transport and distribution of the drugs.

Methods: Thirty-seven coronary artery lesions treated with a single sirolimus-eluting stent (SES) were evaluated in 37 patients with stable coronary artery disease. Angioscopy was performed before, immediately after, and 6 months after stenting to examine the existence of yellow plaque, thrombus, complex plaque, and intramural hemorrhage and the degree of neointimal coverage at 6-month follow-up. This was classified either as a noncoverage group (stent struts were predominantly exposed or visible through a thin neointima) or as a coverage group (stent struts were predominantly covered by neointimal hyperplasia and thus invisible).

Results: Twenty-one lesions were classified into the noncoverage group, and 16 lesions the coverage group. The frequency of preexistent yellow plaques was significantly higher in the noncoverage group than that in the coverage group (67% vs 19%, P = .007). A multivariate logistic regression analysis showed the preexistence of yellow plaque was the only independent factor behind less neointimal coverage at 6 months after SES implantation (odds ratio 19.5, 95% confidence interval 1.58-240.50, P = .020).

Conclusions: The preexistence of yellow plaque may be associated with decreased neointimal coverage of SES.