Endograft Oversizing Research Articles

Outcomes of patients with mild to moderate ischemic mitral regurgitation after coronary artery bypass graft surgery alone.

The chimney technique has been developed for the treatment of complex aortic aneurysms. We analyzed the midterm to long-term outcomes of this approach from a single-center experience. From October 2008 to July 2016, 58 patients underwent endovascular aortic aneurysm repair using the chimney technique. Indications for treatment were thoracic aortic aneurysm (TAA) (N.=11), thoracoabdominal aortic aneurysm (TAAA) (N.=2), pararenal aortic aneurysm (PAAA) (N.=15), aortoiliac/isolated hypogastric artery aneurysm (N.=25), type I endoleak after previous TEVAR/EVAR (N.=4), proximal pseudoaneurysm after AAA open repair (N.=1). Elective (82.8%) and emergent (17.2%) procedures were included. The immediate technical success was 100%. Single, double and triple chimneys were performed in 46, 10, and two patients, respectively. Overall, 61 target vessels (three left common carotid arteries, eight left subclavian arteries, three celiac trunks, three superior mesenteric arteries, 19 renal arteries and 25 hypogastric arteries) were involved. Postoperative mortality was 0. No neurologic complications were registered. Primary patency rate of the chimney stent/stent graft was 98.3%. Low-flow type I endoleak was observed in four patients (6.9%). Postoperative chimney graft re-intervention rate was 1.7%. The median follow-up was 32±20 months (range 3-96 months). Overall estimated survival at 12, 50, and 80 months was 100%, 89% and 44%, respectively. Estimated freedom from endoleak at 1, 12, 24, and 36 months was 96.5%, 95%, 95%, and 93%, respectively. One hypogastric artery stent-graft occluded at the 3rd month of follow-up. No reintervention was performed. Our experience with the chimney technique for aortic aneurysms from the aortic arch to the iliac axis shows promising and durable mid- and long-term results. Endograft oversizing, associated with the chimney graft diameter and length choice remain fundamental to reduce the risk of the most frequent procedure complications: type I endoleak and CG occlusion. The wider use of this technique should be justified in patients considered at high risk for open repair and/or not suitable for the custom-made branched/fenestrated endografts.

The Best Conditions for Parallel Stenting During EVAR: An In Vitro Study

ObjectivesThe aim of this study is to identify which endograft, and to what degree of oversizing, in combination with what type of parallel stent, may result in the most adequate fit in a juxtarenal abdominal aneurysmal neck when using a parallel-stent technique. Materials/MethodsIn-vitro silicon aneurysmal neck models of different diameters, with one side-branch, were constructed. Two different endografts (Medtronic-Endurant Abdominal Stent Graft and Gore-Excluder abdominal aortic aneurysm Endoprosthesis; three diameters each), and two stents (self-expanding Gore Viabahn Endoprosthesis and balloon-expandable Atrium Advanta V12; 6-mm diameter) were tested, applying three endograft-oversizing degrees (15%, 30% and 40%). After remodelling using the kissing-balloon technique at 37 °C, the 36 endograft-stent-oversizing combinations were scanned by computed tomography (CT). The size of the results in gutters, parallel-stent compression and main stent-graft infolding were recorded. ResultsIncreasing oversizing (15%, 30% and 40%) significantly decreased gutter areas (11.5, 6.2, 4.3 mm2, P < 0.001); nevertheless, main endograft infolding of most 40%-oversized stent grafts was detected, particularly with Excluder devices. Lower stent compression, but wider gutters, were observed with the Excluder when compared to Endurant stent grafts, and with V12 when compared to Viabahn parallel stents. The Endurant–Viabahn combination resulted in maximum stent compression (35%). ConclusionsBetter endograft–stent apposition was achieved when using 30% endograft oversizing. Lower stent compression, but wider gutters, were observed with the Excluder stent-graft and V12 parallel stent, achieving maximum stent compression with the Endurant–Viabahn combination.

Suitability of Ruptured AAA for Endovascular Repair

To determine the anatomical suitability and the range of endografts required to undertake an endovascular repair (EVR) program for ruptured abdominal aortic aneurysms. The morphology of ruptured and nonruptured AAAs were compared by retrospective review of computed tomographic scans from 51 patients (47 men; mean age 76 years, range 55-90) with ruptured AAAs and 50 patients (37 men; mean age 74 years, range 57-75) with nonruptured AAAs. Three experienced clinicians reviewed the scans for EVR suitability based on a generic trimodular endograft with suprarenal fixation. Endograft oversizing was assumed to be 10% to 20%. Interobserver agreement was high, with a mean kappa of 0.78 (range 0.75-0.83, p<0.001). In all, 41% of ruptured and 68% of nonruptured AAAs were suitable for EVR (p=0.009). Ruptured AAAs had shorter mean neck lengths (17+/-12 versus 22+/-11 mm, p=0.031) and larger mean aneurysm diameters (75+/-15 versus 63+/-9 mm, p>0.001). Neck length and neck diameter were significantly correlated for ruptured AAAs (r=-0.34, p=0.018). The main contraindication to EVR was hostile neck morphology. A range of endografts with aortic components from 24 to 32 mm and iliac components from 12 to 22 mm would be required to stent 41% of ruptured AAAs. Ruptured AAAs are less suitable for EVR due to differing neck morphology. An EVR program for ruptured AAA requires an inventory of endografts with appropriate aortic and iliac components.

Influence of endograft oversizing on device migration, endoleak, aneurysm shrinkage, and aortic neck dilation: results from the Zenith Multicenter Trial.

Generous endograft oversizing has been associated with propensity for aortic neck dilation and subsequent device migration in endografts without suprarenal fixation. Effects of variable oversizing of endografts with suprarenal fixation have been poorly studied. Three hundred fifty-one patients underwent endovascular AAA repair (EVAR) in a prospective multicenter trial using the Zenith AAA Endovascular Graft, a fully supported bifurcated 3-piece endograft with barb-enhanced suprarenal stent fixation. Blinded core-laboratory measurement of variables was prospectively recorded at predischarge and at 1, 6, 12, and 24 months after the procedure. Potential influence of endograft oversizing on subsequent aortic neck dilation (minor axis), aneurysm shrinkage (major axis), device migration, endoleak, rupture, open conversion, and death were retrospectively studied. Data are given as mean +/- SEM. Risk of endograft migration (>5mm) at 12 months was 2.3% (6/261). However, patients with endograft oversizing of >30% had a 14% (4/29) migration risk compared with those oversized < or =30% (0.9%, 2/232), P <.002. There was zero device migration by the SVS definition (>10 mm or clinical event). Device oversizing >30% was associated with decreased AAA sac shrinkage (48% vs 77%) and with increased sac enlargement (9.5% vs 0.6%) at 24 months when compared with oversizing of < or =30%, respectively (P =.001). Incidence rate of any endoleak at 12 and 24 months was 8.2% (21/256) and 7.1% (12/169), respectively. Oversizing of endografts by >30% was associated with an increased type II endoleak rate (11 vs 4.7%) that failed to reach statistical significance (P =.27). Aortic neck diameters increased significantly by 6 months (P <.001) but then stabilized through 24 months; the absolute changes at 1 (n = 298), 6 (n = 278), 12 (n = 264), and 24 months (n = 171) were 0.66 +/- 0.10 mm (3.0%), 1.32 +/- 0.11 mm (5.6%), 1.38 +/- 0.12 mm (5.9%), and 1.44 +/- 0.16 mm (6.1%), respectively. Linear regression analysis demonstrated no correlation between endograft oversizing and aortic neck dilation at 12 (P =.86) or 24 months (P =.64). Device migration and endoleaks were very infrequent after treatment with the Zenith AAA Endovascular Graft. However, endograft oversizing of >30% was associated with an approximately 14-fold increase in device migration (>5 mm) at 12 months and with a approximately 16-fold increased risk of AAA expansion at 24 months. Although further follow-up will be essential to assess whether these early associations continue, avoidance of excessive endograft oversizing is recommended.

Endograft migration one to four years after endovascular abdominal aortic aneurysm repair with the AneuRx device: A cautionary note

Background: Positional stability of the endograft is essential for long-term durability after endovascular abdominal aortic aneurysm repair (EAR). However, the cumulative risk of delayed endograft migration has been sparsely reported. Method: A total of 91 patients studied underwent EAR with the AneuRx endograft with a minimum 1 year from implantation. Data from a prospective database were assessed for proximal endograft migration, defined as ≥5 mm change from the initial endograft position. Multiple anatomic characteristics were also examined. Sixty-nine patients were alive, with complete follow-up at 1 year, with a mean time from implantation of 33.2 ± 1.1 months. Data are mean ± SEM. Results: Endograft migration occurred in 15 patients, giving a cumulative event rate of 7.2% (5/69) at 1 year, 20.4% (10/49) at 2 years, 42.1% (8/19) at 3 years, and 66.7% (2/3) at 4 years post-EAR ( P = .01). Although the initial aortic neck diameter did not differ between the groups (21.5 ± 0.6 mm vs 21.8 ± 0.3 mm, P = .61), significant ( P <.05), late aortic neck enlargement was seen in patients with migration (25.0 ± 1.6 mm, 26.2 ± 1.2 mm, and 27.0 ± 1.0 mm at 1,2, and 3 years, respectively) but not in nonmigrators. Regression analysis demonstrated a statistically significant ( P < .05) correlation between endograft oversizing and late aortic neck dilation. Overall migration risk was 29.2% in patients oversized >20% and 18.6% in patients oversized ≤20%. Aortic neck angulation (23.4 ± 6.6 degrees vs 23.5 ± 3.3 degrees, P = .99), aortic neck length (25.9 ± 2.5 mm vs 27.0 ± 1.6 mm, P = .74), initial endograft/aortic neck overlap (18.6 ± 2.6 mm vs 19.4 ± 1.4 mm, P = .80) and size of abdominal aortic aneurysm (55.5 ± 1.5 mm vs 54.9 ± 1.4 mm, P = .84) were similar between migrators and nonmigrators, respectively. Secondary endovascular treatment with aortic cuffs was required in five patients with device migration. Conclusions: Device migration after EAR with the AneuRx endograft occurred with significant frequency, the incidence of which increased with the length of follow-up. Late aortic neck dilation was significantly associated with migration. Oversizing of the endograft of >20% may accelerate this late aortic neck dilation. However, the etiologies of endograft migration were likely multifactorial, as the majority (8/15) of patients experiencing migration were oversized <20%. Although endovascular repair of these migrations is usually possible, the long-term durability of these secondary procedures is unknown. Careful surveillance for this endograft failure mode must be an essential component of post-EAR follow-up. (J Vasc Surg 2002;36:476-84.)