PURPOSE: To compare lumen patency, neointimal thickening, and local inflammatory reaction with noncovered metal stents and plain and heparin-coated Dacron-covered stent-grafts. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.
PURPOSE: To compare lumen patency, neointimal thickening, and local inflammatory reaction with noncovered metal stents and plain and heparin-coated Dacron-covered stent-grafts. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.