# Preclinical evaluation of the functionality of a polymer-coated sirolimuseluting stent in pigs

## TL;DR

This study evaluated how well different types of stents promote endothelial coverage in pigs after 28 days.

## Contribution

The study introduces a preclinical comparison of polymer-coated and drug-eluting stents in promoting endothelial coverage in porcine arteries.

## Key findings

- Complete endothelial coverage was observed for all stent types after 28 days.
- No exposed stent struts were found, indicating good integration with the arterial wall.
- Intimal hyperplasia was present but did not affect endothelial coverage.

## Abstract

To compare the endothelial coverage of different stents in porcine carotid arteries. Research problem: How effective are polyurethane stents (PU) and PU + rapamycin (PU + RAPA) compared to bare-metal stents on endothelial coverage by neointima in pigs after 28 days?

The methodology had two phases for an interventional, experimental, prospective study, with three Moura pigs, 12 weeks old and weighing between 19 and 22.5 kg. In phase I, eight stents were implanted in carotid arteries; three stents coated with PU, three coated with PU + RAPA, and two without coating. After 28 days, phase II was carried out, consisting of euthanasia, removal of the stents, to evaluate the exposed area of the stent struts, and the percentage of endothelialization through optical microscopy and scanning electron microscopy.

The eight stents implanted with ultrasound sizing and post-dilation with a larger diameter balloon were analyzed by Doppler ultrasound, intravascular ultrasound, and angiography after 28 days.

This study showed complete endothelial coverage by the endoluminal neointima of the stent struts, good integration and coverage with the arterial wall, with no exposed struts showing the presence of intimal hyperplasia (whitish tissue).