Impact of preinterventional plaque composition and eccentricity on late-acquired incomplete stent apposition after sirolimus-eluting stent implantation

Abstract

The present study aimed to investigate differences in plaque morphology and components in between the target coronary artery lesion with and without late-acquired incomplete stent apposition (LISA) using radiofrequency analysis (virtual histology) of intravascular ultrasound data. Incomplete stent apposition is frequently observed in patients with very late stent thrombosis after sirolimus-eluting stent implantation. The study group consisted of 70 coronary artery lesions in 43 patients who underwent elective coronary stenting for stable angina pectoris. Virtual histology intravascular ultrasound was performed at the implantation of stent and 12-month follow-up. LISA was defined as a separation of stent struts from the intimal surface of the arterial wall that had not been present at the time of stent implantation. The plaque eccentricity index (EI) was calculated as (lumen radius+maximal plaque thickness)/(lumen radius+minimal plaque thickness). At 12-month follow-up, LISA occurred in 15 plaques (LISA group). Compared with the non-LISA group, the LISA group had significantly longer stents, a higher EI, smaller amount of fibro-fatty component (7.7±4.2 vs. 12.5±7.0%, P=0.01) and larger amount of necrotic core component (16.6±9.8 vs. 11.1±6.4%, P=0.06). Multivariate logistic regression analysis revealed that amount of necrotic core and plaque EI were independent positive predictors for LISA (odds ratio=1.4, 95% confidence interval=1.1-1.6, P=0.04 and 11.2, 1.9-64.9, P<0.01, respectively). Plaques with increased amounts of necrotic core and higher eccentricity are associated with subsequent LISA after sirolimus-eluting stent implantation.