984-27 Arterial Remodeling Contributes to Restenosis After Angioplasty, but is Prevented by Stenting in the Atherosclerotic Micropig

Abstract

We previously showed that 50% of angiographic late lumen loss (LL) following balloon dilation (PTA) was due to remodeling (REM) of the artery. By scaffolding the artery, the stent is likely to prevent remodeling. To test this hypothesis, we compared PTA and stenting of peripheral arteries of Yucatan micropigs in a combined denudation and diet-induced atherosclerosis model. Angiograms were taken before, during and after angioplasty and at termination (42 days after intervention). Acute gain (AG) and LL were quantitatively measured with digital calipers. Intravascular ultrasound (IVUS) was performed in 5 stented arteries. The peripheral arterial tree was pressure perfusion fixed. processed for histology and morphometrically analyzed with a computer-based system. Intimal Hyperplasia (IH) and Media (M) were expressed as mean Thickness (IHT, MT) for comparison with angiography. Empty CellnAG(mm)LL(mm)2×lHT(mm)MT(mm)REM%control12–0.14 ± 0.110.07 ± 0.020.14 ± 0.020PTA120.35 ± 0.060.27 ± 0.080.14 ± 0.030.15 ± 0.0448 ± 12*stent10.42 ± 0.100.51 ± 0.070.47 ± 0.08†0.14 ± 0.026 ± 12mean ± sem*p < 0.05 compared to zero†p < 0.01 stent versus PTA mean ± sem p < 0.05 compared to zero p < 0.01 stent versus PTA In 5 stented arteries, IH measured with IVUS and histology was 4.93 ± 0.91 and 4.41 ± 1.25 mm2, respectively. The correlation coefficient was 0.89, p = 0.045. We conclude that after the stent prevents remodeling, i.e. shrinkage after angioplasty. In stented arteries, restenosis is entirely due to intimal hyperplasia which is significantly larger than after balloon dilation alone. Stented arteries may therefore preferentially benefit from antiproliferative agents, whereas adjunctive therapy with balloon angioplasty should also be aimed at reducing remodeling.