Abstract 12534: Changes in Neointimal Tissue Characteristics Inside Sirolimus-Eluting Stent Over Time: OCT Quantitative Tissue Property Analysis
Objective To study the changes in neointimal tissue properties inside sirolimus-eluting stent (SES) by optical coherence tomography (OCT) over time.
Methods 133 SES in 96 patients were divided into 2 groups depending on the follow-up time: Group 1, < 24 months (98 stents in 71 patients); Group 2, > 24 months (35 stents in 25 patients). The neointimal characteristics were studied using a new “OCT quantitative tissue property analysis system” which measures attenuation, backscatter and signal intensity in the region of interest (Figure A). Using these parameters, a multivariable logistic regression model was constructed to divide neointima into homogenous or heterogeneous.
Results The number of OCT cross-sections(CS) evaluated were 2501(1857 in Group 1 and 644 in Group 2). CS with neointimal thickness <100µm were excluded. The final number of CS included was 687(37.0%) in Group 1 and 277 (43.0%) in Group 2. Neoinitmal thickness (0.13±0.11mm vs. 0.16±0.14mm, P<0.01) and area (1.13±0.93mm2 vs. 1.25±1.13 mm2, P<0.01) were increased over time. Neointimal microvessels was more frequent in Group 2 than that in Group 1(P<0.001). Overall, 0.8% cross-sectional neointima in Group 2 had lipid plaque which was not detected in Group1. The formula ‘Logit P= 0.772atten-0.141min×mean/var + 7.366’ was used to quantitatively differentiate the homogeneous and heterogeneous neointima with a 0.811 Nagelkerke R2 value of the fitness of the model. The incidence of heterogeneous neointima was higher in Group 2 (18.4% vs. 11.9%, P<0.01). Heterogeneous neointima was associated with higher incidence of microvessels and lipid plaque (Figure B,C).
Conclusions The neoinitmal tissue properties inside SES change over time. The incidence of heterogeneous pattern, microvessels, and lipid plaque was higher in longer follow-up group. Neointimal heterogeneity may be an important finding for late neointima vulnerability following SES implantation.
- © 2011 by American Heart Association, Inc.