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- Mangell, Peter, et al.
(författare)
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Are self-expanding stents superior to balloon-expanded in dilating aortas? An experimental study in pigs
- 1996
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Ingår i: European Journal of Vascular and Endovascular Surgery. - 1532-2165. ; 12:3, s. 287-294
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To study the stent/vessel interaction and distensibility following the natural increase in vascular diameter using self-expanding and balloon-expanded stents. DESIGN: Open experimental study. SETTING: Animal laboratory, university hospital. MATERIALS AND METHODS: Eight Palmaz (P) and eight Gianturco (G) stents were transluminally placed in the infrarenal aortas of 16 pigs. Pulsatile diameter changes above, at and below the stents were non-invasively monitored with an ultrasound phase-locked echo-tracking system before and immediately after stenting and at 4 and 18 weeks. Blood pressure was registered intra-arterially and stiffness (beta) was calculated. Intravascular ultrasound (IVUS) was performed at 18 weeks. RESULTS: Median weight increased from 20 kg (19-26) to 93 kg (62-130). Diameter of the aorta increased 60%. In group P no pulsatile diameter change could be measured at the stent (beta = infinity). In group G stenting increased stiffness from beta 20.7 (9.2) to 43.2 (8.0) (p < 0.05). After 18 weeks stiffness returned to beta 20.1 (12.4). Expanded, median diameter of the P stents was 7.4 (0.8) mm, not increasing after 18 weeks. Initial diameter of the G stents was 7.8 (1.0) mm, increasing 56% to 12.2 (2.3) mm (p < 0.05). IVUS revealed the G stents to be well attached to the vascular wall, but five P stents were detached within half of the circumference. CONCLUSION: Self-expanding stents follow the pulsatile diameter change of the vessel wall, not adversely affecting distensibility after 18 weeks. They show good attachment despite 56% dilation. In contrast, the balloon-expanded stents do not show pulsatile movement and may detach during vessel diameter increase. This may be of importance when choosing stents for endovascular treatment of abdominal aortic aneurysms.
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| 4. |
- Vogt, K C, et al.
(författare)
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The use of intravascular ultrasound as control procedure for the deployment of endovascular stented grafts
- 1997
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Ingår i: European Journal of Vascular and Endovascular Surgery. - 1532-2165. ; 13:6, s. 592-596
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To assess whether intravascular ultrasound (IVUS), used systematically in a series of patients with abdominal aortic aneurysms (AAA), is a feasible control procedure to ensure correct transfemoral placement of endovascular stent grafts (TPEG). DESIGN: Descriptive study. MATERIALS AND METHODS: Fourteen patients with infrarenal aortic aneurysms were treated by the placement of one tube graft, 10 aorto-uni-iliac and three aorto-bi-iliac grafts. Arteriography and IVUS were performed before, during and after deployment of the graft to ensure correct placement in relation to side branches, and proper adaptation of the stents to the aortic wall. Postoperative CT-scan and arteriography served as control procedures. RESULTS: IVUS identified both renal arteries before graft deployment in eight of 13 (62%) patients. In the remaining patients only one renal artery was visualised due to interference from guidewires or the introducer system. Imaging during stent deployment was abandoned after IVUS catheter damage in two of three cases. Postprocedural IVUS was able to evaluate the expansion of the stents and the adaptation to the aortic wall in all instances. In four (29%) cases a leak was identified. Additional intervention included deployment of a further stent (n = 2) or redilation (n = 2). Covering of the renal arteries could only be indirectly determined by IVUS. CONCLUSION: IVUS can provide important decisive information before and after stented graft deployment, with the limitations that guidewires, introducer system and stents may cause interference. Contemporary IVUS designs are unsuitable for monitoring stent deployment.
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