| 1. |
- 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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| 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. |
- Resch, Tim, et al.
(författare)
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The impact of stent design on proximal stent-graft fixation in the abdominal aorta: an experimental study
- 2000
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1532-2165 .- 1078-5884. ; 20:2, s. 190-195
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: to study the proximal fixation of different aortic stent grafts in comparison to a hand-sewn anastomosis. DESIGN: experimental study. MATERIAL: the infrarenal aorta of 16 human cadavers were exposed, left in situ and transected 3 cm above the aortic bifurcation to mimic an infrarenal aortic neck. Stent grafts were deployed through a sheath 5 cm into the aorta. Ancure, Talent, Vanguard, Zenith and a Palmaz based stent graft were assessed. In addition a polyester graft was anastomosed to the aorta by running sutures. Distal force was applied to the grafts in increments of 0.5 Newton until the stent grafts were completely dislodged from the aorta. The displacement force (DF) was thereby determined. RESULTS: a force of 150 N (140-160) applied to the hand-sewn graft resulted in tearing of the aorta, without breakage of the sutures. The median displacement force was for Talent 4.5 N (1.3-5.5), Vanguard 9.0 N (3. 5-12), Ancure 12.5 N (12-14), Zenith 24 N (23-26.5) and Palmaz 25 N (17-25). Ballooning the stent after deployment improved fixation in some cases. CONCLUSIONS: a sutured anastomosis fixates a graft better than any stent design tested. Hooks and barbs improve the fixation of self-expandable stents. Balloon dilatation of the proximal stent after deployment might increase fixation further. Balloon expandable stents seem to provide good fixation without the use of hooks and barbs.
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| 4. |
- Resch, Tim, et al.
(författare)
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Midterm changes in aortic aneurysm morphology after endovascular repair
- 2000
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Ingår i: Journal of Endovascular Therapy. - 1545-1550. ; 7:4, s. 279-285
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To study midterm changes in aortic aneurysm morphology after endovascular aneurysm repair. METHODS: Of 94 patients with abdominal aortic aneurysms (AAAs) treated with endografts between November 1993 and August 1998, 84 were available for follow-up. Patients were evaluated preoperatively by spiral computed tomography (CT) and aortography; in follow-up, spiral CT scanning was performed at 1, 3, and 6 months and semiannually thereafter. Measurements of the aneurysm neck diameter, maximum aneurysm diameter, and the distance from the lowermost renal artery to the aortic bifurcation were made preoperatively and in follow-up. RESULTS: Mean follow-up was 17.5 +/- 1.1 months; 56 (67%) patients were followed for 1 year and 28 (33%) for > or = 2 years. There was a median 2-mm increase (interquartile range [IQR] 0 to 3) in neck diameter at 18 months. However, a > or = 3-mm increase was seen in 18 (46%) of 39 patients examined at 18 months (median 4 mm, IQR 3 to 4, p = 0.0001). The maximum AAA diameter decreased by 9 mm (IQR 4 to 16, p = 0.0003) at 24 months, but after 18 months, no further interval decrease was seen. Aneurysms with a persistent endoleak showed either increasing or unchanged AAA diameters. There was no change in the renal artery to bifurcation distance. CONCLUSIONS: The infrarenal aortic neck appears to dilate after AAA endografting, but only in a subset of patients. Shrinkage of aneurysms after successful stent-grafting seems to stop after 18 months, implying that the only indication of late failure in the absence of endoleak might be aneurysm enlargement. Graft-related endoleaks are often associated with an increase in aneurysm diameter.
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