Secondary Fill Minimizes Gutter Size in Chimney EVAS Configurations In Vitro

Abstract

To investigate in an in vitro model if secondary endobag filling can reduce gutter size during chimney endovascular aneurysm sealing (chEVAS). Materials and Methods: Nellix EVAS systems were deployed in 2 silicone juxtarenal aneurysm models with suprarenal aortic diameters of 19 and 24 mm. Four configurations were tested: EVAS with 6-mm balloon-expandable (BE) or self-expanding (SE) chimney grafts (CGs) in the renal branches of both models. Balloons were inflated simultaneously in the CGs and main endografts during primary and secondary endobag filling and polymer curing. Computed tomography (CT) was performed immediately after the primary and secondary fills. Cross-sectional lumen areas were measured on the CT images to calculate gutter volumes and percent change. CG compression was calculated as the reduction in lumen surface area measured perpendicular to the central lumen line. The largest gutter volume and highest compression were presented per CG configuration per model. Results: Secondary endobag filling reduced the largest gutter volumes from 99.4 to 73.1 mm 3 (13.2% change) and 84.2 to 72.0 mm 3 (27.6% change) in the BECG configurations and from 67.2 to 44.0 mm 3 (34.5% change) and 92.7 to 82.3 mm 3 (11.2% change) in the SECG configurations in the 19-and 24-mm models, respectively. Secondary endobag filling increased CG compression in 6 of 8 configurations. BECG compression changed by −0.2% and 5.4% and by −1.0% and 0.4% in the 19-and 24-mm models, respectively. SECG compression changed by 10.2% and 16.0% and by 7.2% and 7.3% in the 19-and 24-mm models, respectively. Conclusion: Secondary endobag filling reduced paragraft gutters; however, this technique did not obliterate them. Increased CG compression and prolonged renal ischemia time should be considered if secondary endobag filling is used.

Migration After Endovasclar Aneurysm Sealing in Conjunction With Chimney Grafts

“…Theoretically, chEVAS should be better than chEVAR because the compliant endobags fill the space between the Nellix stents and the chimney grafts, reducing the incidence of gutter type Ia endoleak. This advantage of chEVAS has been confirmed in bench models 15 , 16 and subsequently reported in clinical practice, most notably in the ASCEND Registry. 17 …”

“…Bench models and early clinical experience confirmed a low incidence of gutter type Ia endoleaks, potentially because the compliant endobags successfully fill the spaces between the Nellix stents and chimney grafts. 16 – 18 In addition, it has been proposed that chEVAS may have better resistance to migration forces compared with conventional infrarenal EVAS. Factors that might contribute to reduced migration forces include friction force between the Nellix stents, chimney stents, and aortic wall; a healthier aortic sealing zone below the SMA; and a reduced proximal endobag shelf area due to the chimney stents.…”

In Vitro Quantification of Stent-Graft Behaviour During ch-TEVAR

“…To the best of the authors knowledge, there exist only two reports illustrating a volumetric reconstruction of an in vitro chimney-related gutter [13,29], and no reports on either the geometrical changes during the cardiac cycle, or specific to ch-TEVAR. Accordingly, this investigation provides compelling insights into the dynamic geometrical behaviour of gutters.…”

Systematic Review of the Current In Vitro Experience of the Endovascular Treatment of Juxtarenal Abdominal Aortic Aneurysms by Fenestrated and Parallel Endografting

“…A total of 11 studies evaluated the endovascular treatment of jAAA using PG, of which 8 focused on CHEVAR, [14][15][16][17][18]20,23,24 2 on CHEVAS, 19,25 and 1 study compared CHEVAR and CHEVAS techniques in terms of CG geometry and renal artery flow. 26 The degree of MG oversizing was investigated in both papers by Mestres et al when using a single chimney 23 or double/triple chimneys.…”

“…14 Four studies gave information on the external fabrication of the phantoms outsourcing the production to a company. 14,17,19,26 Four studies connected the phantom to a fluid circulation loop to include physiological hemodynamics. 14,17,20,26 Six studies submerged the phantom in gelatine water or saline bath at 37°C in order to simulate physiological conditions.…”