Abstract 4535: Progressive Neointimal Heterogeneous Property and Persistent Thrombogenicity After Paclitaxel-Eluting Stent Implantation: Comparison Between 6 and 18 Months Angioscopic Evaluation
Background: Several angioscopic studies have reported grade of neointimal coverage and the incidence of mural thrombi after drug-eluting stent implantation. However, long term follow-up data after paclitaxel-eluting stent (PES) implantation has not been examined yet. In this study, we compared neointimal coverage pattern and thrombogenicity between 6 and 18 months after PES implantation using coronary angioscopy.
Methods: Thirty-eight successive patients who received PES implantation underwent 6-month (35 patients, 40 stents) and/or 18 months (20 patients, 23 stents) follow-up coronary angioscopy. Among these study patients, 17 patients and 19 stents are absolute serial follow-up. We evaluated the minimum and maximum neointimal coverage grade within one stent using coronary angioscopy with the following neointimal coverage grade: 0: no neointimal coverage of stent struts, 1: very thin coverage, 2: between 1 and 3, and 3: invisible stent struts with full neointimal coverage. Heterogeneity score of neointimal coverage was defined by subtracting minimum grade from maximum grade. We evaluated and compared these angioscopic parameters and incidence of angioscopic red mural thrombus between the two groups.
Results: As shown in the table⇓, heterogeneity score of PES at 18 months become higher than that at 6 months follow-up (1.78±0.80 vs 1.27±0.75, p=0.014) while maximum grade was not significantly different. It is suggested that this phenomenon was provoked mainly by regressing the minimum neointimal grade. Besides, high incidence of angioscopic red mural thrombi at 6 months was maintained even at 18 months follow-up evaluation (50% at 6 months vs 70% at 18 months, p=0.187) although these thrombi were subclinical.
Conclusion: Serial angioscopic follow-up after PES implantation demonstrated the progressive neointimal heterogeneous property and persistent subclinical thrombogenicity of PES.