| 1. |
- Lindh, Mats, et al.
(författare)
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Endovascular stent-anchored aortic grafts: a comparison between self-expanding and balloon-expandable stents in minipigs
- 1996
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Ingår i: Journal of Endovascular Surgery. - 1074-6218. ; 3:3, s. 284-289
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To study endovascular graft attachment with self-expanding Gianturco Z-stents and balloon-expanded Palmaz stents and the effect of these devices on the renal ostia. METHODS: Ten stent-grafts were constructed, 5 with Gianturco Z-stents and 5 with Palmaz stents. The endografts were implanted under fluoroscopic guidance into the abdominal aorta of 10 pigs so that the uncovered portion of the proximal stent extended over the renal artery orifices. Distal aortic blood pressure and flow were measured before and after graft placement and 1 hour postprocedure. The aorta was then exposed surgically, and the central portion of the stent-graft was inspected through an aortotomy to assess perigraft leakage. RESULTS: Stent-graft implantation was accurate and hemostatic in all cases, despite longitudinal folding of the graft due to oversizing. However, transverse folds produced pressure gradients (> 15 mmHg) between the ends of the graft in two cases. In another case, a pressure gradient resulted from partial thrombosis of the graft. In two cases, renal artery occlusion and thrombosis occurred due to coverage by the graft material. In two other animals, one of the renal arteries was entirely uncovered by a stent. The remaining 16 renal arteries were covered by the proximal stent but not the graft, as intended. One (6.25%) of these arteries thrombosed, but the remainder were grossly patent when the animals were sacrificed at 1 hour. CONCLUSIONS: Both Palmaz and Gianturco Z-stents produced hemostatic endovascular graft attachment, even in the presence of moderate graft oversizing. The risk of acute renal artery occlusion from juxtarenal stenting does not appear to be prohibitive, but longer term observations are needed.
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| 2. |
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| 3. |
- Hansen, F, et al.
(författare)
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Accuracy of duplex sonography before carotid endarterectomy--a comparison with angiography
- 1996
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Ingår i: European Journal of Vascular and Endovascular Surgery. - 1532-2165. ; 12:3, s. 331-336
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The aim of this prospective study was to contribute to the evaluation of the reliability of Duplex sonography (DS) before carotid endarterectomy (CEA). DESIGN: The study was performed prospectively in a university hospital setting. METHODS: Eighty-one consecutive patients aged 49-83 years were examined with DS and carotid angiography (CAG) before CEA. The results of the DS were judged as either confident, or CAG was assessed to be necessary preoperatively. The results from the DS and the CAG were then compared. RESULTS: DS was judged as confident in 148 of the 162 arteries examined. In none of these 148 arteries did CAG change patient management in any way, and the agreement between DS and CAG was good. In the remaining 14 arteries CAG was judged necessary, in 11 arteries because DS assessed the internal carotid artery (ICA) as occluded, which was confirmed by CAG in 10 arteries. In three arteries the reason was poor quality of the DS, however these three arteries were correctly assessed as severely diseased. CONCLUSIONS: This study confirms that DS alone is sufficient in the preoperative evaluation before CEA, provided that CAG is performed whenever DS shows occlusion of the ICA, or when the quality of the DS is poor.
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| 4. |
- Jensen, Norman, et al.
(författare)
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Early attachment of platelets, leukocytes, and fibrinogen in endothelial cell seeded Dacron grafts
- 1996
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Ingår i: Annals of Vascular Surgery. - 1615-5947. ; 10:6, s. 530-536
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Tidskriftsartikel (refereegranskat)abstract
- Endothelial cell seeding has been advocated as a method for reducing the thrombogenicity of prosthetic grafts. Principally two different techniques for endothelial cell seeding can be used: immediate seeding of grafts followed by implantation or initial growth and establishment of an endothelial cell-covered surface before subsequent late implantation. This study was designed to determine whether the immediate seeding technique altered thrombogenicity directly after graft implantation. Carotid arteries from 19 sheep were replaced with Dacron interposition grafts; one side was seeded with endothelial cells and the other side was left unseeded. The dynamics of thrombus formation involving radiolabeled platelets, leukocytes, and fibrinogen were studied for 4 hours with flow reduced to 35 ml/min. No difference in platelet uptake (approximately 6-fold increase compared to baseline values) was found between endothelial cell seeded and unseeded grafts. Likewise, there were no differences in leukocyte uptake (approximately 4-fold increase) or fibrinogen uptake (approximately 10- to 15-fold increase) between the two groups. No differences were demonstrated with regard to patency or thrombus weight. In this experimental investigation we were unable to verify any change in the uptake of platelets, white blood cells, or fibrinogen between endothelial cell seeded and unseeded Dacron grafts during the first 4 hours after graft placement. Immediate seeding does not affect the initial thrombogenicity of grafts.
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| 5. |
- Jensen, N, et al.
(författare)
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Recovery of endothelial cells and prostanoid production in endothelial cell-seeded grafts
- 1996
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Ingår i: European Journal of Vascular and Endovascular Surgery. - 1532-2165. ; 12:1, s. 54-59
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To investigate the function and morphology of endothelial cell (EC) seeded grafts. DESIGN: Experimental, open study. CHIEF OUTCOME MEASURES: Endoluminal release of prostacyclin (6-Keto-PGF1 alpha) and thromboxane B2 (TxB2), patency, EC coverage and cell identity. MATERIALS: In 12 sheep, segments of both carotid arteries were excised. On one side a seeded and on the other an unseeded dacron graft were inserted. After 3 months the grafts were excised. In grafts and arteries, the endoluminal release of 6-keto-PGF1 alpha and TxB2 was determined in a perfusion system. Scanning electron microscopy (SEM) and light microscopy were used to determine the EC coverage and cell identity. RESULTS: Eight animals survived. Three seeded and two unseeded grafts were occluded. Prostacyclin release did not differ significantly between seeded and unseeded grafts and arteries, when the arteries were looked upon as one group. When the graft was compared with its corresponding artery, i.e. the artery it replaced, a significantly lower release was found in the unseeded group. Thromboxane release was undetectable in arteries but significantly higher in both graft groups. SEM revealed a cellular coverage of 75% in the seeded grafts and 50% in the unseeded (not significant). Light microscopy showed a patchy staining for Factor VIII-related antigen in some grafts in both groups. CONCLUSION: Prostacyclin release in unseeded and seeded dacron grafts did not differ 3 months after implantation in sheep, except when the graft was compared with its corresponding artery. The significance of this remains to be settled. Seeded grafts did not have a higher proportion of endothelial coverage than unseeded grafts.
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