BACKGROUND: Bare metal stents (BMS) and drug-eluting stents (DES) are used to treat unstable plaques and may stabilize thin cap fibroatheromas (TCFA). This study was designed to evaluate stabilizing effects of bare compared to Everolimus (EES) and Beta-Estradiol (BES) eluting stents in a chronic atherosclerotic experimental animal model of TCFA. METHODS: Sixteen New Zealand hypercholesterolemic rabbits followed for 4 years were studied. Six animals received BMS, 5 EES and 5 BES (Guidant - Santa Clara, CA, USA). One polymer stent per animal was also implanted. Histologic analysis at 28 days of de-novo vs. BMS, EES, and BES stented TCFA were performed. RESULTS: BMS, EES, and BES stented TCFA showed reductions in lipid area by 62%, 67%, and 61%, and increases in cap thickness by 188%, 98%, and 140% respectively (p < 0.0001 for all). Strut-induced ruptured TCFA was found in 63% of stented sections and was associated with increased neointima in BMS (p = 0.03) but not in EES or BES (p = ns). CONCLUSIONS: Stenting thin cap fibroatheroma with BMS, EES and BES reduces lipid accumulation and increases cap thickness. Strut-induced fibrous cap rupture was frequently found and associated with increased neointima in BMS but not in EES and BES.
Atherosclerosis; Stents; Coronary restenosis; Recurrence; Models, animal; Rabbits
