| 1. |
- Chuter, Timothy A M, et al.
(författare)
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A telescopic stent-graft for aortoiliac implantation
- 1997
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Ingår i: European Journal of Vascular and Endovascular Surgery. - 1532-2165. ; 13:1, s. 79-84
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To test a new delivery system for a telescopic stent-graft. MATERIALS: Variable overlap between the components of this stent-graft combination allows length adjustment. This device differs from other multi-component stent-grafts in that both components are contained within a single delivery system. METHODS: The stent-graft was implanted in the distal thoracic to suprarenal aorta of five pigs (35-50 kg), where the arterial diameter falls by almost 50%. The proximal and distal components of the stent-graft were targeted to bony landmarks in the vertebral column. RESULTS: Inspection of completion angiograms showed both proximal and distal stent-grafts to be within 1 mm of their target locations in all five experiments. Overall combined stent-graft length varied from 13.5 cm to 16.1 cm depending on the location of the bony landmark chosen as the distal target, and on the size of the pig. CONCLUSIONS: This system may be useful for the repair of abdominal aortic aneurysm whenever preoperative sizing is difficult due to aortic tortuosity, or precluded due to the urgency of the procedure.
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| 2. |
- Chuter, Timothy A M, et al.
(författare)
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Aneurysm pressure following endovascular exclusion
- 1997
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Ingår i: European Journal of Vascular and Endovascular Surgery. - 1532-2165. ; 13:1, s. 85-87
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To assess the effect of stent-graft implantation on the pressure within an abdominal aortic aneurysm. METHODS: Aneurysm exclusion was performed using an aorto-uniiliac stent-graft in eight patients. Following stent-graft implantation, pressure measurements were performed through a catheter adjacent to the graft in the aneurysm. This "aneurysm pressure" was compared with radial arterial pressure. RESULTS: The pressure was lower in the aneurysm than in the radial artery, in all cases. Mean aneurysm pressure was 36.5/33.8 mmHg, while mean radial arterial pressure was 118.5/50.5 mmHg (p < 0.05, for both systolic and diastolic pressures). These findings corresponded with a reduction in the palpable abdominal pulse, and an absence of perigraft perfusion on follow-up computerised tomography. CONCLUSION: Stent-graft implantation produces a fall in the pressure within an abdominal aortic aneurysm.
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| 3. |
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| 4. |
- Ivancev, Krassi, et al.
(författare)
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Abdominal aortic aneurysms: experience with the Ivancev-Malmo endovascular system for aortomonoiliac stent-grafts
- 1997
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Ingår i: Journal of Endovascular Surgery. - 1074-6218. ; 4:3, s. 242-251
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To describe a component-based aortomonoiliac stent-graft system and the first clinical results achieved with this device in endovascular abdominal aortic aneurysm (AAA) repair. METHODS: From November 1993 to October 1996, 45 patients aged 60 to 86 years underwent endoluminal exclusion of true AAAs (median diameter 60 mm) involving the common iliac arteries (median diameter 16 mm right and 15 mm left) using unilimb stent-grafts deployed with the Iancev-Malmo system. RESULTS: Six immediate conversions occurred in the beginning of the series due to endografts that were too short. Complications, including 2 inadvertent renal artery occlusions, 7 kinked grafts, 6 iliac artery dissections, and 3 perioccluder leaks, were prominent features in the first 15 patients. Five patients died in the postoperative period, four of whom were nonsurgical candidates. There were five significant stent-graft migrations: one 3 weeks after surgery due to mechanical injury of the proximal stent and four after 1 year owing to continuous dilation of a wide proximal neck, stent-graft placement in a conical, thrombus-lined proximal neck, and two instances of proximal extension separation from the main graft. Translumbar aneurysm perfusion required embolization in 3 patients. CONCLUSIONS: Despite early complications associated with a learning curve, exclusion of large AAAs using unilimb stent-grafts is feasible. Strict inclusion criteria are necessary in order to improve mortality among nonsurgical candidates and minimize the risk for late migration.
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| 5. |
- Malina, Martin, et al.
(författare)
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Changing aneurysmal morphology after endovascular grafting: relation to leakage or persistent perfusion
- 1997
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Ingår i: Journal of Endovascular Surgery. - 1074-6218. ; 4:1, s. 23-30
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To relate changing abdominal aortic aneurysm (AAA) morphology after endovascular grafting to the presence of leakage, collateral perfusion, and other factors. METHODS: Thirty-five patients who underwent successful AAA endovascular grafting were evaluated. Self-expanding Z-stents and Dacron grafts were applied in bifurcated and aortomonoiliac systems. Postoperative diameter changes were calculated from repeated spiral computed tomographic scans, angiograms, and ultrasonic phase-locked echo-tracking scans during a median 6-month follow-up (interquartile range [IQR] 3 to 12). RESULTS: At 12 months, the diameters of completely excluded aneurysms had decreased 6 mm (IQR 2 to 11; p = 0.006). The proximal graft-anchoring stents had dilated 2 mm (IQR 0.5 to 3.3; p = 0.01). The aortic diameters immediately below the renal arteries but above the stents had not changed. Endoleakage and collateral perfusion (n = 13) were each associated with preserved aneurysm size and a 12 times higher risk of aneurysm dilation. After the leakage or the collateral perfusion had been treated, the aneurysm size decreased. Aneurysms with extensive intraluminal thrombi presented a reduced risk of leakage or perfusion. CONCLUSIONS: The diameters of endovascularly excluded AAAs decrease, except in cases of leakage or perfusion. Careful follow-up of patients with aortic endografts is necessary.
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| 6. |
- Malina, Martin, et al.
(författare)
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Endovascular AAA exclusion: will stents with hooks and barbs prevent stent-graft migration?
- 1998
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Ingår i: Journal of Endovascular Surgery. - 1074-6218. ; 5:4, s. 310-317
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To investigate if stents with hooks and barbs will improve stent-graft fixation in the abdominal aorta. METHODS: Sixteen- to 24-mm-diameter Dacron grafts were deployed inside cadaveric aortas. The grafts were anchored by stents as in endovascular abdominal aortic aneurysm repair. One hundred thirty-seven stent-graft deployments were carried out with modified self-expanding Z-stents with (A) no hooks and barbs (n = 75), (B) 4 5-mm-long hooks and barbs (n = 39), (C) 8 10-mm-long, strengthened hooks and barbs (n = 19), or (D) hooks only (n = 4). Increasing longitudinal traction was applied to determine the displacement force needed to extract the stent-grafts. The radial force of the stents was measured and correlated to the displacement force. RESULTS: The median (interquartile range) displacement force needed to extract grafts anchored by stent A was 2.5 N (2.0 to 3.4), stent B 7.8 N (7.4 to 10.8), and stent C 22.5 N (17.1 to 27.9), p < 0.001. Both hooks and barbs added anchoring strength. During traction, the weaker barbs were distorted or caused intimal tears. The stronger barbs engaged the entire aortic wall. The radial force of the stents had no impact on fixation, while aortic calcification and graft oversizing had marginal effects. CONCLUSIONS: Stent barbs and hooks increased the fixation of stent-grafts tenfold, while the radial force of stents had no impact. These data may prove important in future endograft development to prevent stent-graft migration after aneurysm exclusion.
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| 7. |
- Malina, Martin, et al.
(författare)
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Late aortic arch perforation by graft-anchoring stent: complication of endovascular thoracic aneurysm exclusion
- 1998
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Ingår i: Journal of Endovascular Surgery. - 1074-6218. ; 5:3, s. 274-277
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To describe a fatal case of late aortic perforation by an endograft-anchoring stent. METHODS AND RESULTS: A 69-year-old woman presented 2 years after thoracoabdominal aneurysm repair with a 9-cm dilatation of the descending thoracic aorta proximal to the conventional aortic graft. A 38-mm Dacron graft with multiple Gianturco Z-stents sutured inside was placed transluminally across the aortic arch such that part of the uncovered portion of the proximal stent was partially across the left subclavian orifice. Four months later, the patient died from massive hemorrhage. Autopsy showed that the uncovered portion of the proximal stent had perforated the aortic arch. CONCLUSIONS: This case stresses the need for low-profile stent-grafts and smaller, more flexible introducer systems. Anchoring stents must be flexible, less traumatic, and strong enough to create a watertight seal even in tortuous vessels. To avoid aortic arch damage by thoracic stent-grafts, the proximal stent should be fully covered by the fabric.
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| 8. |
- Malina, Martin, et al.
(författare)
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Quality of life before and after endovascular and open repair of asymptomatic AAAs: a prospective study
- 2000
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Ingår i: Journal of Endovascular Therapy. - 1545-1550. ; 7:5, s. 372-379
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To assess how patients perceive health-related quality of life (HRQOL) after endovascular and open abdominal aortic aneurysm (AAA) repair. METHODS: Forty-two consecutive patients (33 men; mean age 74 years, range 46-81) were assessed prospectively before and after elective endovascular (n = 21) and open (n = 21) AAA repair. Aneurysm morphology dictated the type of repair. The two patient groups were similar regarding age, gender, comorbidities, and cardiopulmonary function. Data concerning surgical trauma were compiled. The Nottingham Health Profile (NHP) score was used to assess the perceived HRQOL (criteria: pain, mobility, sleep, emotion, energy, and isolation) preoperatively and at 5, 30, and 90 days postoperatively. Specific treatment perception questions were added. RESULTS: One patient from each group died, leaving 40 patients to complete the study. Two patients with open repair and 1 patient with endovascular repair were unfit to answer the questionnaire on day 5. The HRQOL improved at 3 months compared with the preoperative values (p < 0.05). No significant difference was found at any time between the open and endovascular groups regarding the NHP score, although the operative time, blood loss, analgesic use, and hospital stay were significantly in favor of endovascular repair. Reinterventions were required in 5 patients with endovascular and 2 patients with open repair. CONCLUSIONS: In general, 3 months after AAA repair, the perceived HRQOL seems better than before treatment. Perceived HRQOL is similar after endovascular and open AAA repair despite greater surgical trauma in open surgery. This may reflect the higher number of reinterventions following endovascular repair but also difficulties in defining HRQOL.
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| 9. |
- Malina, Martin, et al.
(författare)
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Reduced pulsatile wall motion of abdominal aortic aneurysms after endovascular repair
- 1998
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Ingår i: Journal of Vascular Surgery. - 1097-6809. ; 27:4, s. 624-631
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The reduced size of abdominal aortic aneurysms (AAAs) after endovascular repair suggests lowered intraaneurysmal pressure. In the presence of endoleaks, the size is not decreased. Although postoperative intraaneurysmal pressure is difficult to record, the pulsatile wall motion (PWM) of aneurysms can be measured noninvasively. The aim of this study was to assess the PWM of AAAs before and after endovascular repair and to relate the change in the PWM to aneurysmal size and presence of endoleaks. METHODS: Forty-seven patients underwent endovascular repair of an AAA. The aneurysm diameter and PWM were measured with the use of ultrasonic echo-tracking scans preoperatively; at 1, 3, and 6 months; and thereafter biannually. Fifteen aneurysms developed endoleaks, whereas 32 were completely excluded. The leaks were characterized with the use of computed tomographic scanning and angiography. Median follow-up was 12 months (interquartile range, 5 to 24 months). RESULTS: The preoperative PWM of the aneurysms was 1.0 mm (range, 0.8 to 1.3 mm). After complete endovascular exclusion, the PWM was 25% (range, 16% to 37%) of the preoperative value (p < 0.001), and aneurysm diameter decreased by 8 mm (range, 6 to 14 mm) (p < 0.001). After 18 months, no further diameter reduction occurred. In three patients without endoleaks but with enlarging aneurysms, the postoperative PWM showed less reduction (p < 0.05). Aneurysms with endoleaks showed no diameter decrease, and the postoperative PWM was 50% higher than that in the totally excluded cases (p < 0.01). In five patients with transient endoleaks, the PWM was reduced after leakage ceased (p < 0.05). Leaks of various sources displayed similar PWM. CONCLUSION: The size and PWM of aneurysms are reduced after endovascular repair. The diameter reduction may cease after 1.5 years. Endoleaks are associated with higher PWM than expected. Pressure may be transmitted without evidence of leaks.
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| 10. |
- Malina, Martin, et al.
(författare)
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The effect of endovascular aortic stents placed across the renal arteries
- 1997
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Ingår i: European Journal of Vascular and Endovascular Surgery. - 1532-2165. ; 13:2, s. 207-213
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To investigate renal artery patency and renal function after deployment of aortic stents covering the orifices of renal arteries. DESIGN: Prospective open animal study. SETTING: Department of Experimental Surgery at a university hospital. MATERIALS: Twenty-three pigs were used. METHODS: Ten pigs were observed for 1 h after graft-anchoring aortic stents, Gianturco (5) and Palmaz (5), were placed so that the stents covered the renal arterial orifices. In 13 pigs, Gianturco (6) and Palmaz (7) stents without grafts were placed over the renal arteries and left in situ for 7 days. Renal function and blood flow were measured by renograms, iohexol clearance and ultrasonic blood flow meter and patency was verified by angiograms. The kidneys were microscopically examined for signs of ischaemia and microemboli. RESULTS: One renal artery covered by a graft-anchoring Gianturco stent occluded. The remaining renal arteries remained patent without any significant decrease in renal blood flow after stent deployment. Normal renal function and histology was maintained. CONCLUSIONS: Aortic stents placed at the level of the renal arteries do not affect renal blood flow within 1 week in this experimental model. This may prove valuable in endovascular treatment of aortic aneurysms and in other procedures involving stents.
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