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| 2. |
- Greenberg, R, et al.
(författare)
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Endovascular repair of descending thoracic aortic aneurysms: an early experience with intermediate-term follow-up
- 2000
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Ingår i: Journal of Vascular Surgery. - 1097-6809. ; 31:1 Pt 1, s. 147-156
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The purpose of this study was to report an initial experience with the endovascular repair of descending thoracic aortic aneurysm. Complications and intermediate-term morphologic changes were identified with the intent of altering patient selection and device design. METHODS: Endografts were placed into 25 patients at high-risk for conventional surgical repair over a 3(1/2)-year period. Devices were customized on the basis of preoperative imaging information. Follow-up computed tomography scans were obtained at 1, 3, 6, and 12 months and yearly thereafter. Additional interventions occurred in the setting of endoleaks, migration, and aneurysm growth. RESULTS: The overall 30-day mortality rate was 20% (12.5% for elective cases; 33% for emergent cases). There were 3 conversions to open repair. Neurologic deficits developed in 3 patients; 1 insult resulted in permanent paraplegia. Neurologic deficits were associated with longer endografts (P =.019). Three endoleaks required treatment, and 1 fatal rupture of the thoracic aneurysm treated occurred 6 months after the initial repair. Migrations were detected in 4 patients. The maximal aneurysm size decreased yearly by 9.15% (P =.01) or by 13.5% (P =.0005) if patients with endoleaks (n = 3 patients) were excluded. Both the proximal and distal neck dilated slightly over the course of follow-up (P =.019 and P =.001, respectively). The length of the proximal neck was a significant predictor of the risk for endoleakage (P =.02). CONCLUSION: The treatment of descending thoracic aortic aneurysms with an endovascular approach is feasible and may, in some patients, offer the best means of therapy. Early complications were primarily related to device design and patient selection. All aneurysms without endoleaks decreased in size after treatment. Late complications were associated with changing aneurysm morphologic features and device migration. The morphologic changes remain somewhat unpredictable; however, alterations in device design may result in improved fixation and more durable aneurysm exclusion.
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| 3. |
- 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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| 5. |
- 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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| 6. |
- Malina, Martin, et al.
(författare)
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Endovascular healing is inadequate for fixation of Dacron stent-grafts in human aortoiliac vessels
- 2000
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1532-2165 .- 1078-5884. ; 19:1, s. 5-11
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: migration and kinking of stent-grafts can occur late after endovascular aneurysm repair. It is unknown if endovascular grafts incorporate enough to be permanently anchored. In this report, healing of aortic stent-grafts was assessed in humans. PATIENTS AND METHODS: we retrieved 23 Dacron stent-grafts from patients treated for an aortic aneurysm since 1993. Twelve stent-grafts were explanted at late conversion to open repair and 11 at autopsy. The deaths were unrelated to graft fixation. The median age of the patients was 74 years (IQR 55-84 years) and the grafts were explanted 9 months (1-31 months) after insertion. Microscopic slides were prepared by conventional techniques or by cutting and grinding arterial specimens embedded in plastic with the stent-grafts in situ. RESULTS: the stent-grafts detached readily from the native arteries at surgery or autopsy, except when the stents had hooks or barbs which engaged the vessel wall. A space filled with poorly organised blood components persisted between the graft and the aortic wall 2.5 years after implantation. No firm incorporation of the grafts was observed proximally in the aneurysm neck or distally in the iliac segment. A friable neo-intimal layer covered parts of the luminal aspect of the grafts. CONCLUSIONS: endovascular healing provides poor fixation of Dacron stent-grafts in humans. At present, fixation relies on the mechanical properties of the stent-grafts.
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| 7. |
- Malina, Martin, et al.
(författare)
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Endovascular management of the juxtarenal aortic aneurysm: can uncovered stents safely cross the renal arteries?
- 1999
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Ingår i: Seminars in Vascular Surgery. - 0895-7967. ; 12:3, s. 182-192
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Tidskriftsartikel (refereegranskat)abstract
- A short or otherwise suboptimal neck precludes the use of endovascular repair in 30% to 50% of patients with abdominal aortic aneurysms. Stent-graft fixation in an unsuitable neck carries the risk of technical failure owing to development of a proximal endoleak or stent-graft migration. Furthermore, in some patients, the neck dilates postoperatively. Endovascular healing with tissue incorporation into the graft material seems in and of itself insufficient to fixate the stent-graft adequately or to prevent neck dilation. Therefore, neck dilation is often associated with detachment of the stent-graft from the aortic wall, which is followed by the development of a proximal endoleak or stent-graft migration. Fixation of stent-grafts can be improved by placing the proximal stent above one or both of the renal artery orifices. Current experimental and clinical data suggest that renal function is not impaired by suprarenal aortic stents during the first year; however, this finding may not apply to all types of stents. Fixation of stent-grafts also may be improved by using stents with barbs that pierce the aortic wall. Additionally, the force that is exerted on the anchoring device may well be reduced by fully stented grafts with an associated increase in column strength. In the future, the risk of neck dilation and stent-graft dislodgement might also be limited by novel techniques such as laparoscopic banding of the neck or endoluminal stapling devices.
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| 8. |
- Malina, Martin, et al.
(författare)
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Renal arteries covered by aortic stents: clinical experience from endovascular grafting of aortic aneurysms
- 1997
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Ingår i: European Journal of Vascular and Endovascular Surgery. - 1532-2165. ; 14:2, s. 109-113
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: During the endovascular repair of abdominal aortic aneurysms (AAAs), effective anchoring of the stent-graft is difficult in the presence of a short infrarenal aneurysm neck. The aim of this study was to investigate renal artery patency and renal function after deployment of graft anchoring stents across the renal arteries. DESIGN: Retrospective open study. PATIENTS: Twenty-five renal arteries, in 18 patients treated by endovascular exclusion of an AAA, were intentionally covered with the Gianturco Z-stent to ensure stent graft attachment. METHODS: Renal artery patency was assessed by repeated spiral computed tomography (CT) scans and angiography. Creatinine levels, blood pressure and antihypertensive medication were recorded. Follow-up was a median 6 months (2-9). RESULTS: All 25 stent-covered renal arteries remained patent. CT showed a small infarct in one kidney. Creatinine was 108 mumol/l (89-133) before intervention and 98 mumol/l (87-127) at follow-up. Blood pressure was 150/80 mmHg on both occasions. Antihypertensive therapy was intensified in one patient whose creatinine level remained stable and whose separate renin sampling was normal. CONCLUSIONS: Covering the renal arteries with the Gianturco Z-stent does not seem to affect renal function within 6 months. Further follow-up is needed before suprarenal stent deployment can be advocated.
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| 9. |
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| 10. |
- Resch, Tim, et al.
(författare)
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Distal migration of stent-grafts after endovascular repair of abdominal aortic aneurysms
- 1999
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Ingår i: Journal of Vascular and Interventional Radiology. - 1051-0443. ; 10:3, s. 257-264
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To analyze patients after endovascular repair of abdominal aortic aneurysm (AAA) with respect to distal migration of stent-grafts and its underlying causes. MATERIALS AND METHODS: Sixty-five patients underwent endovascular repair between January 1994 and February 1997. There were seven women and 58 men, with a mean age of 71 years (range, 51-84 years). Three patients died in the perioperative period (one of myocardial infarction and two of multiorgan failure) and two patients died within 4 months of the procedure of non-procedure-related causes. In addition, two patients were followed at another hospital. The remaining 58 patients were followed up with spiral computed tomography scans at 1, 3, and 6 months, and biannually thereafter. Angiography was performed at 1 month and 1 year after the procedure and additionally when deemed clinically necessary. Mean follow-up was 29 months (range, 1-49). Migration more than 5 mm was considered significant. RESULTS: Twenty-six patients (45%) showed distal migration of stent-grafts during follow-up. Mean follow-up time at detection of migration was 13 months (range, 1-36 months). Thirteen cases of migration were ascribed to dilatation of the proximal aneurysmal neck during follow-up. Ten cases of migration were ascribed to causes other than neck dilatation or poor patient selection. In three cases, no obvious cause for the migration was found. The migration was complete in eight cases, leading to late conversion to open surgical repair. On two of these occasions, complete migration lead to aneurysm rupture. In addition, four patients received additional stent-grafts as proximal extensions. CONCLUSIONS: Distal migration of stent-grafts after endovascular AAA repair occurred frequently in this series. Dilatation of the proximal aneurysmal neck is a major cause of distal migration of stent-grafts. Improved proximal fixation is needed to secure long-term durability.
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