A new balloon-expandable tantalum coil stent: angiographic patency and histologic findings in an atherogenic swine model

Abstract

The angiographic patency and histologic characteristics of a new balloon-expandable tantalum stent were studied after implantation intervals ranging from 1 to 32 weeks in atherogenic miniature swine peripheral and coronary arteries. Stents were placed in 34 arteries (10 coronary and 24 iliac arteries) in a total of 13 swine. Two swine died within 24 h of stent implantation. Follow-up angiography was performed before death was induced in 11 swine (8 coronary and 19 iliac arteries) and revealed 100% patency without evidence of lumen stenosis, thrombosis or migration of the stents. The neointimal thickening was maximal at 4 weeks after stent implantation and was at its minimum at 32 weeks after implantation with reendothelialization of the stents generally complete at that time. An advantage of this balloon-expandable device is its inherent longitudinal flexibility. The coil configuration allowed the nondeployed stent to negotiate acute bends in coronary arteries to reach the site of implantation and also allowed the deployed stent to conform to the natural contour of tortuous coronary arteries. The tantalum device was remarkable for its radiographic visibility, which greatly aided its placement under fluoroscopic guidance. This study demonstrates this stent's ease of implantation, excellent patency rate and absence of restenosis due to neointimal proliferation for up to 8 months in this atherogenic swine model.