Intra-arterial stenting in the atherosclerotic rabbit.

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Abstract
The major problem associated with percutaneous transluminal coronary angioplasty is recurrence of the stenotic lesion. Balloon catheter-mounted intracoronary stent devices may reduce restenosis by improving luminal morphology and flow characteristics. This study assessed the effects of a stainless steel wire, interdigitating coil stent on restenosis in the atherosclerotic rabbit model. Fifteen cholesterol-fed rabbits with preexisting iliac arterial lesions induced by balloon deendothelialization were instrumented in one iliac artery with a 2.0-mm diameter stent after balloon dilatation; the contralateral iliac lesion was treated by dilatation only to serve as a control. The animals were given heparin with aspirin (60 mg) and aspirin every 3rd day until death. Arteriography was repeated 4 weeks after stenting, just before death. Tissue sections from stented and control arterial segments were analyzed morphometrically. Stented arteries had a significantly larger luminal diameter at restudy, whether measured by arteriography (1.38 +/- 0.19 vs. 0.94 +/- 0.35 mm, p less than 0.01) or from tissue sections (1.26 +/- 0.18 vs. 0.81 +/- 0.30 mm, p = 0.0001). Wall thickness of the stented segment was slightly, but significantly, less than the control segment (436 +/- 143 vs. 532 +/- 221 microns, p less than 0.05). Scanning electron microscopy of five stented atherosclerotic rabbit aortas revealed regeneration of a nonthrombogenic, confluent, flow-directed endothelium by 4 weeks after placement. Intra-arterial stenting may be of benefit in the prevention of restenosis by the preservation of a larger functional lumen and by a decrease in the neointimal hyperplastic response to arterial injury.