Iliac arteries: plain and heparin-coated Dacron-covered stent-grafts compared with noncovered metal stents--an experimental study.

Abstract

To compare lumen patency, neointimal thickening, and local inflammatory reaction with noncovered metal stents and plain and heparin-coated Dacron-covered stent-grafts. In each of 16 sheep, four prostheses were placed in the iliac arteries: a plain and a heparin-coated Dacron-covered Cragg stent-graft, a noncovered Cragg stent, and a noncovered Memotherm nitinol stent. Two prostheses were inserted in the iliac artery on each side. Patency was monitored with angiography and intravascular ultrasound (US). Eight animals were killed at 1-month follow-up, and the other eight at 6 month follow-up. Neointimal thickening and inflammatory foreign-body reaction to the prostheses were determined macroscopically and with light microscopy. More than 50% stenosis developed in 10 heparin-coated and three plain Dacron-covered stent-grafts but not in the noncovered stents. Two heparin-coated and one plain Dacron-covered stent-graft occluded completely. Neointimal thickening and inflammatory reaction were severe with the heparin-coated Dacron-covered stent-grafts, were less with the plain Dacron-covered stent-grafts, and were least with the noncovered stents. Neointimal thickening and inflammatory reaction significantly increased with covered compared with noncovered prostheses in the iliac arteries in sheep and were worst with heparin-coated Dacron-covered stent-grafts. If possible, use of noncovered stents should thus be preferred to use of Dacron-covered stent-grafts.