A Semiautomated Method for Measuring the 3-Dimensional Fabric to Renal Artery Distances to Determine Endograft Position After Endovascular Aneurysm Repair

PurposeTo report a methodology for 3-dimensional (3D) assessment of the stent-graft deployment accuracy after endovascular aneurysm repair (EVAR).MethodsA methodology was developed and validated to calculate the 3D distances between the endograft fabric and the renal arteries over the curve of the aorta. The shortest distance between one of the renal arteries and the fabric (SFD) and the distance from the contralateral renal artery to the fabric (CFD) were determined on the first postoperative computed tomography (CT) scan of 81 elective EVAR patients. The SFDs were subdivided into a target position (0-3 mm distal to the renal artery), high position (partially covering the renal artery), and low position (>3 mm distal to the renal artery). Data are reported as the median (interquartile range, IQR).ResultsIntra- and interobserver agreements for automatic and manual calculation of the SFD and CFD were excellent (ICC >0.892, pConclusionThe novel methodology using 3D CT reconstructions enables accurate evaluation of endograft position and slope within the proximal aortic neck. In this series, only 44% of endografts were placed within the target position with regard to the lowermost renal artery

Determination of Stent Frame Displacement After Endovascular Aneurysm Sealing

Purpose: To describe and validate a new methodology for visualizing and quantifying 3-dimensional (3D) displacement of the stent frames of the Nellix endosystem after endovascular aneurysm sealing (EVAS). Methods: The 3D positions of the stent frames were registered to 5 fixed anatomical landmarks on the post-EVAS computed tomography (CT) scans, facilitating comparison of the position and shape of the stent frames between consecutive follow-up scans. Displacement of the proximal and distal ends of the stent frames, the entire stent frame trajectories, as well as changes in distance between the stent frames were determined for 6 patients with >5-mm displacement and 6 patients with 5-mm displacement on the 1-year CT as determined by the new methodology, 2 went on to develop a type Ia endoleak in longer follow-up, and displacement progressed to >15 mm for 2 other patients. No endoleak or progressive displacement was appreciated for the patients with 5 mm on the 1-year CT scans reconstructed with the new methodology may forecast impaired sealing and anchoring of the Nellix endosystem

Changes in Aortoiliac Anatomy after Elective Treatment of Infrarenal Abdominal Aortic Aneurysms with a Sac Anchoring Endoprosthesis

ObjectiveEndovascular aortic sealing (EVAS) with the Nellix endosystem (Endologix, Irvine, CA, USA) is a new concept to treat infrarenal abdominal aortic aneurysms (AAAs). By sealing the aneurysm, potential endoleaks may be avoided. Early results of EVAS are good, but no data have been published regarding peri-procedural changes in aortoiliac anatomy. In this study, 27 consecutive patients who underwent elective EVAS repair of an AAA were reviewed.MethodSpecific AAA (diameter, length from renal arteries to aortic bifurcation, supra- and infrarenal neck angulation, AAA volume, thrombus volume, and flow lumen volume), and iliac artery characteristics (length, angulation, location of most severe angulation with reference to the origin of the common iliac artery) were determined from pre- and post-procedural reconstructed computed tomography angiograms.ResultsNo type I or II endoleaks were seen at 30 day follow up. Total AAA volume, suprarenal and infrarenal angulation, as well as aortic neck diameter did not change significantly post-EVAS. AAA flow lumen increased significantly (mean difference −4.4 mL, 95% CI 2.0 to −8.6 mL) and AAA thrombus volume decreased (mean difference 3.2 mL, 95% CI 2.0 to −1.1 mL). AAA length (125.7 mm vs. 123.1 mm), left common iliac artery length (57.6 mm vs. 55.3 mm), and right and left maximum iliac artery angulation (right 37.4° vs. 32.2°; left: 43.9° vs. 38.4°) were reduced significantly and the location of maximum angulation was further from the iliac artery origin post-EVAS, suggesting slight straightening of the aortoiliac anatomy.ConclusionMost aortoiliac anatomic characteristics remained unchanged post-EVAS. Filling of the endobags to a pressure of 180 mmHg may lead to lost thrombus volume in some patients, probably because liquid is squeezed into lumbar or the inferior mesenteric artery. The absolute differences in pre- and post-EVAS aortoiliac lengths were small, so pre-operative sizing is accurate for determining stent length

Method for determining a parameter which is indicative for the position and apposition of a tubular member, such as a stent graft, inserted in a lumen of an anatomical vessel or duct of a patient

Method for determining an apposition parameter which is indicative for the position and apposition of a tubular member, such as a stent graft, inserted in a lumen of an anatomical vessel or duct of a patient, wherein the method comprises the steps of: - providing a numerical three-dimensional patient model of at least a part of the vessel of the patient including the tubular member; - determining at least one vessel morphology parameter from the patient model, which parameter is indicative for the anatomy of a predetermined part of the vessel at or near the tubular member in said vessel with respect to said patient model; - determining at least one tubular member positional parameter from the patient model, which parameter is indicative for the position of a predetermined part of the tubular member in the patient model; - calculating, on the basis of the determined vessel morphology parameter and tubular member positional parameter, the relative position of the tubular member with respect to the vessel as the apposition parameter

The BeGraft Balloon Expandable Covered Stent as a Proximal Extension to an Iliac Branch Device for Endovascular Repair of Isolated Common Iliac Artery Aneurysms.

Introduction Isolated common iliac artery aneurysms (CIAA) are rare and can be treated by endovascular exclusion using iliac branch devices (IBD). The use of a balloon expandable covered stent as a proximal extension to an IBD to allow adequate sealing in the proximal common iliac artery (CIA) for exclusion of isolated CIAA is demonstrated. Report Two patients with isolated CIAA of ≥4.5 cm with a proximal neck length of ≥20 mm (patient A: 26 mm; patient B: 24 mm) and a neck diameter of ≤20 mm (patient A: 16.4 mm; patient B: 15.6 mm) were treated by combining a Zenith IBD with an aortic BeGraft balloon expandable covered stent. After deploying the BeGraft covered stent at 12 mm a second balloon was used to further dilate the proximal part of the stent outside the IBD to allow adequate sealing in the CIA. Completion angiography and follow up computed tomography angiography 1 month post-operatively showed adequate sealing and no endoleaks. Discussion The feasibility of the application of a balloon expandable covered stent as a proximal extension to an IBD for isolated CIAA was demonstrated. It is not necessary to insert an aortic bifurcation endograft, thus reducing procedure time, radiation exposure, contrast use, and cost. A patent inferior mesenteric artery and lumbar arteries can be spared and procedures that require crossing over the aortic bifurcation remain possible. Comorbidity, prior interventions, and disease extension can make this endovascular approach preferred over open repair. Isolated CIAA can be efficiently treated combining the BeGraft balloon expandable covered stent and IBD, which allows proximal sealing in the CIA

A new method for precise determination of endograft position and apposition in the aortic neck after endovascular aortic aneurysm repair

BackgroundFollow-up imaging after endovascular aortic aneurysm repair (EVAR) focuses on detection of gross abnormalities: endoleaks and significant (>10 mm) migration. Precise determination of endograft position and wall apposition may predict late complications. We present a new measurement method to determine precise position and apposition of endografts in the aortic neck.MethodsFour patients were selected from our EVAR database. These patients had late (>1 year) type IA endoleak or >1 cm endograft migration. Twenty patients with uneventful follow-up were measured as controls. The new software adds six parameters to define endograft position and neck apposition: fabric distance to renal arteries, tilt, endograft expansion (% of the maximum original diameter), neck surface, apposition surface, and shortest apposition length. These parameters were determined on preoperative and all available postoperative CT-scans, to detect subtle changes during follow-up.ResultsAll patients with endoleak or migration had increases in fabric distance, tilt, or endograft expansion or decrease of apposition surface. Changes occurred at least one CT scan before the endoleak or migration was noted in the CT reports. The patient without complications showed no changes in position or apposition during follow-up.ConclusionsThe new measurement method detected subtle changes in endograft position and apposition during CT follow-up, not recognized initially. It can potentially determine endograft movements and decrease of apposition surface before they lead to complications like type IA endoleaks or uncorrectable migration. A larger follow-up study comparing complicated and non-complicated EVAR patients is needed to corroborate these results