Remodeling of proximal neck angulation after endovascular aneurysm repair
ABSTRACT This study investigated the remodeling of proximal neck (PN) angulations of abdominal aortic aneurysms (AAAs) after endovascular aneurysm repair (EVAR).
A 64-row multidetector computed tomography scan of AAAs treated with EVAR was reviewed, and the PN angulation was measured on a volume-rendered three-dimensional image. The computed tomography scan was examined preoperatively, after EVAR at 1 week, 1 month, 6 months, 1 year, 1.5 years, 2 years, and then yearly. The study enrolled 78 patients, comprising 54 Zenith devices (Cook Medical, Bloomington, Ind) and 24 Excluder devices (W. L. Gore and Associates, Flagstaff, Ariz).
PN angulation was 50° ± 20° preoperatively, and after EVAR was 36° ± 14° at 1 week, 32° ± 14° at 1 year, and 28° ± 13° at 3 years. PN angulations ≤60° (n = 70, 77%) were 41° ± 13° preoperatively, 31° ± 12° 1 week after EVAR, 28° ± 12° at 1 year, and 26° ± 13° after 3 years. An angulation >60° (n = 18, 23%) was 78° ± 14° preoperatively, 51° ± 11° 1 week after EVAR, 44° ± 11° at 1 year, and 40° ± 12° after 3 years. The greater the preoperative PN angulation, the greater its reduction immediately after EVAR (r = .72, P < .001). The diameter shrinkage of AAAs with a PN angulation >60° was 3 ± 6 mm after 1 year; a significantly smaller shrinkage than with a PN angulation ≤60° (7 ± 7 mm, P < .05). AAAs with a PN angulation >60° had a larger angulation reduction and a smaller diameter shrinkage after the EVAR procedure. The PN angulation of the 54 AAAs treated by Zenith was 49° ± 22° preoperatively, 34° ± 14° 1 week after EVAR, and 25° ± 13° after 3 years. The corresponding angulation of the 24 AAAs treated by Excluder devices was 52° ± 17°, 41° ± 14°, and 38° ± 9°, respectively. The PN angulation reduction of Zenith and Excluder was similar 1 week after the EVAR procedure. Unlike Excluder, however, the PN angulation in Zenith continued to reduce for a long period at a slow pace. There were no significant correlations between PN angulation reduction and diameter change and between PN length and diameter change (P = .86 and .18, respectively).
Although the instructions for use of most commercially available stent grafts provide for a PN angulation of ≤60°, PN angulation was not a major issue in a midterm follow-up of AAAs with adequate PN length for patients in this series who received a Zenith or Excluder graft.
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ABSTRACT: Endovascular treatment for patients with a proximal neck anatomy outside instructions for use is an ongoing topic of debate in endovascular aneurysm repair. This paper employs the finite element method to offer insight into possible adverse effects of deploying a stent graft into an angulated geometry. The effect of angulation, straight neck length and device oversize was investigated in a full factorial parametric analysis. Stent apposition, area reduction of the graft, asymmetry of contact forces and the ability to find a good seal were investigated. Most adverse effects are expected for combinations of high angulation and short straight landing zones. Higher oversize has a beneficiary effect, but not enough to compensate the adverse effects of (very) short and angulated angles. Our analysis shows that for an angle between the suprarenal aorta and proximal neck above 60°, proximal kinking of the device can occur. The method used offers a engineering view on the morphological limits of EVAR for a clinically used device.Medical Engineering & Physics 09/2014; DOI:10.1016/j.medengphy.2014.08.003 · 1.84 Impact Factor
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ABSTRACT: Endovascular aneurysm repair has revolutionized the therapeutic strategy for abdominal aortic aneurysm. However, hostile proximal aneurysmal neck and tortuosity of access vessels remain challenges in selecting optimal stent-grafts in abdominal aortic aneurysms with difficult anatomy. A 65-year-old woman complained of intermittent abdominal pain for one week. Computed tomography angiogram demonstrated a tortuous infrarenal abdominal aortic aneurysm with a tapered neck and a 136° of infrarenal angulation. Aneurysmal dilatation and severe calcification of bilateral iliac arteries and tortuous aortoiliac access were also showed. Endovascular approach using Endurant stent-graft was attempted at an outside hospital, but failed because of the significant tortuosity of the abdominal aorta and iliac arteries. Since the patient refused to have open aneurysm repair, he was transferred to our hospital for further evaluation and possible EVAR with a different approach. EVAR was performed successfully using Gore Excluder stent-grafts (W.L. Gore & Associates, Flagstaff, AZ, USA). During the procedure, cannulation of the contralateral limb was unable to be achieved because of the tortuous aortoiliac course. Therefore, a snare was inserted from right radial artery, through the contralateral gate, to grasp the wire from left femoral artery. Two iliac stent-grafts were sequentially deployed with the lower end distal to the opening of the left internal iliac artery. Angiography confirmed complete sealing of the aneurysm with patency of bilateral renal arteries and external iliac arteries. The postoperative courses were uneventful and follow-up computed tomography angiogram at 6 months demonstrated patent bilateral femoral and renal arteries without endoleaks or stent migration. Although endovascular repair of aortic aneurysm with hostile neck and tortuous access is rather challenging, choosing flexible stent-grafts and suitable techniques is able to achieve an encouraging outcome.BMC Surgery 12/2015; 15(1):5. DOI:10.1186/s12893-015-0005-5 · 1.24 Impact Factor
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ABSTRACT: PURPOSE: To evaluate the late events and mid-term results after endovascular aneurysm repair (EVAR). METHODS: Between December 2006 and May 2012, 175 abdominal aortic aneurysms were treated by EVAR. Aneurysm-related events were analyzed. RESULTS: The complications that occurred during the EVAR procedure were renal artery occlusion in two patients, access artery injury in two, delivery failure in one, retrograde aortic dissection in one, and death from hepatic failure in one patient. Five adverse endoleaks (four type I, one type III) remained at discharge, and the technical success rate was 97 %. On follow-up, limb occlusion had occurred in five patients. Unilateral renal atrophy was found in three patients, but none of the patients required new hemodialysis. Sac enlargement (≥5 mm) developed in ten patients. Their culprit endoleaks were type Ia in one, II in eight, and V in one patient. Transarterial embolization was performed for three out of the eight type II endoleaks. The rate of freedom from secondary re-intervention was 93 % at 3 and 5 years, respectively. The survival and freedom from aneurysm-related events rates were 74 % at 3 years and 47 % at 5 years. CONCLUSIONS: The mid-term results of EVAR were excellent with a low rate of aneurysm-related deaths, although there were relatively high aneurysm-related event rates. Sac re-enlargement from type II endoleaks was the most common major issue at the mid-term follow-up.Surgery Today 01/2013; 44(1). DOI:10.1007/s00595-012-0472-6 · 1.21 Impact Factor