Although the materials selected for construction of endovascular grafts appears judicious, the assembly of these biomaterials into various interrelated structures within the device requires further improvement.
This short-term in vivo study of a nitinol-polyester self-expanding endograft demonstrated the effective exclusion of thoracic aneurysms with a satisfactory healing response and no excessive tissue or inflammatory reactions.
The intraluminal elastase perfusion model has been proved to be potentially effective in producing abdominal aortic aneurysm in rodents, but it produced unpredictable results in larger animals. The purpose of this study was to explore the potential ability of such a model to produce experimental aneurysm consistently in the Yucatán miniature swine. Six Yucatán miniature swine received infusion with porcine elastase into an isolated segment of the infrarenal aorta. The excised arterial segments were examined macroscopically to assess the luminal surface characteristics and histologically to describe the different pathologic injuries induced by the elastase treatment on the intima, media, and adventitia of the arterial wall. Histologic examination revealed that the elastic network of the media was destroyed. In the first week after perfusion, altered smooth muscle cells were located in the intima and innermost layer of the media in juxtaposition with the occlusive thrombus. Infiltration of inflammatory cells was observed in these regions of elastic network and smooth muscle cell alterations. In the arterial segments of swine sustained for 3 weeks, a reduction of smooth muscle cells was noted in some areas. An important number of necrotic lesions was observed, and they were associated with the development of calcium deposits. Significant intimal hyperplasic reaction was identified at day 19 and again at day 21. However, no aneurysmal development was observed. This study constituted the first experiment with infusion of porcine elastase in the Yucatán miniature swine infrarenal aorta. The present experimental protocol induced important elastic network and smooth muscle cell alterations leading to severe necrotic lesions associated with calcium deposition, but it produced no aneurysmal dilatation. This model requires further testing to obtain a more complete degradation of the elastic network in both the media and adventitia and more significant collagenolysis without early thrombotic events.
The impact of routine intraoperative carotid angiography was evaluated by comparing 206 procedures without such angiograms with our last consecutive 100 endarterectomies with completion angiography. No significant age or sex differences were observed between the two groups. Exploratory surgery was repeated in five cases for a stenosis greater than 40% or for an intimal flap. This protocol reduced operative mortality (2.9% to 1%), the permanent stroke rate (1.9% to 1%), and the temporary stroke rate (6.3% to 1%). Furthermore, a second angiogram was performed in these 100 cases (at a mean interval of 19.2 months later) and the incidence and evolution of both residual and recurrent carotid lesions were analyzed. Five internal carotid artery lesions that had been immediately repaired because of intraoperative angiographic defects remained normal. Of 58 normal internal carotid arteries at the completion of surgery, two became stenotic during the next year. In addition, three spastic internal carotid arteries became normal. Of 20 internal carotid arteries with modest irregularities, 16 became normal and four were stenosed. Of three internal carotid arteries with intimal flaps, two became normal and one was stenosed. Among 13 internal carotid arteries with modest stenosis (40%), eight became normal, two became severely stenotic, and three became thrombosed. Among 21 instances of a proximal common carotid artery "shelf," 17 resolved and four progressed to less than 50% stenosis. Of 67 normal external carotid arteries, late stenosis was seen in one case. Of 33 external carotid arteries with residual stenosis, 17 became normal, 14 remained unchanged, and two were thrombosed.(ABSTRACT TRUNCATED AT 250 WORDS)
While rupture of the EIA during angioplasty usually demands open surgical correction, an endovascular procedure can provide a fast, efficient, and less aggressive method of treating this serious complication.
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