# Comparison of vascular remodeling between a bioresorbable poly-L-lactic acid scaffold and a bare metal stent: a 6-month angiography and intravascular ultrasound analysis in porcine iliac arteries

## TL;DR

A bioresorbable stent caused less artery damage and inflammation than a metal stent in pigs over six months.

## Contribution

This study provides the first 6-month comparison of a bioresorbable scaffold and a metal stent in porcine iliac arteries.

## Key findings

- The bioresorbable stent showed significantly less neointimal hyperplasia at 12 and 24 weeks.
- The bioresorbable stent caused lower percent area stenosis and volume obstruction compared to the metal stent.
- The bioresorbable stent resulted in reduced tissue injury and inflammation scores.

## Abstract

Animal experimental studies involving the Igaki-Tamai stent (ITS), a bioresorbable poly-l-lactic acid scaffold, in peripheral arteries are limited, and existing studies evaluated only short-term (3-month) outcomes. This study compared arterial responses associated with the ITS and bare metal stent (BMS) over 6 months using intravascular ultrasound (IVUS) analysis and evaluated feasibility in porcine iliac arteries. Four miniature pigs underwent stent implantation with the ITS in the right iliac artery and the BMS in the left iliac artery. Follow-up evaluations at 6, 12, and 24 weeks included angiographic and IVUS analyses to assess neointimal hyperplasia, percent area stenosis (%AS), and percent in-stent volume obstruction (%VO). Histological analysis was performed to evaluate tissue injury and inflammation scores. At 6 weeks, the neointimal area did not differ significantly between the ITS and BMS groups (8.49 ± 2.10 mm² vs 13.47 ± 6.67 mm², P = .205). However, the ITS group exhibited a significantly smaller neointimal area at 12 weeks (6.87 ± 1.15 mm² vs 20.65 ± 10.99 mm², P = .050) and 24 weeks (5.20 ± 0.85 mm² vs 22.32 ± 12.03 mm², P = .042). %AS and %VO were significantly lower in the ITS group at all follow-ups. The ITS group showed reduced tissue damage (injury score: 0.80 ± 0.430 vs 1.74 ± 0.908, P < .001) and inflammation (inflammation score: 1.25 ± 0.516 vs 1.67 ± 0.832, P < .001) compared with the BMS group. The ITS was associated with reduced vessel injury, lower inflammatory response, and favorable luminal remodeling over 6 months in healthy porcine iliac arteries.