P-024 - IN VITRO EVALUATION OF THE AVAILABLE CHIMNEY STENTS IN THE ENDOVASCULAR REPAIR OF JUXTARENAL ABDOMINAL AORTIC ANEURYSMS BY USE OF SILICON MODELS CONNECTED WITH PULSATILE PUMPING SYSTEM

TOPIC:
Abdominal Aortic Aneurysms
AUTHORS:
Taneva G.T. (Hospital Puerta de Hierro ~ Madrid ~ Spain) , Pitoulias G.A. (Second Department of Surgery, Division of Vascular Surgery, School of Medicine, Aristotle University of Thessaloniki ~ Thessaloniki ~ Greece) , Usai M.V. (St. Franziskus Hospital Dept. Vascular and Endovascular Surgery ~ Muenster ~ Germany) , Donas K.P. (Asklepios Clinic Langen ~ Goethe-University of Frankfur ~ Germany)
Introduction:
The endovascular repair of juxtarenal aortic aneurysms (jAAAs) entitles the chimney technique (chEVAR). Although compelling good clinical outcomes, suboptimal reports have been published, highlighting the lack of standardization in planning and sizing and selection of suitable device combination. Thus, there is need for identification of the possible suboptimal interactions between the devices before their deployment in the human body. However, limited and heterogeneous experimental evidence exists regarding the different chEVAR combinations. In the present in vitro and not by the industry-founded testings, we sought to evaluate the performance of all in vivo published covered or bare-metal chimney stents (CS) in combination with the Endurant II abdominal endograft (Medtronic Inc, Minneapolis, MN, USA) for the treatment of jAAAs.
Methods:
A silicon model based on the angiotomography (CTA) of a successfully chEVAR treated patient was externally fabricated for the here presented purposes. The model was connected to pulsatile pumping system allowing pressure, beat and temperature adjustments. Fluid mimicking the blood viscosity was employed. Nine different MG-CS combinations were tested (1) 6x59 mm Advanta V12 (Getinge Maquet, Mijdrecht, the Netherlands, (2) 6x58 mm BeGraft Plus (Bentley Innomed GmbH, Hechingen, Germany), (3) 6x59 mm VBX (W.L. Gore & Associates Inc., Flagstaff, AZ, USA), (4) 6x58 mm LifeStream (Bard Medical, Covington, GA, USA), (5) 6x56 mm Dynamic (Biotronik AG, Buelach, Switzerland), (6) 6x60 mm Absolute Pro (Abbott Laboratories, Abbott Park, IL, USA), (7) reinforced 6x60 mm Absolute Pro (8) 6 mm x 5 cm Viabahn (Gore) lined with 6x56 mm Dynamic, and (9) 6 mm x 5 cm Viabahn lined with 6x60mm EverFlex (Medtronic) performing CTA evaluation after each implantation. ¬¬Data were analysed blindly two times per observer, by three independent observers experienced in CTA data evaluation and reconstruction. Each blind evaluation for all observers were performed with one month interval between them. The main analysed final parameters were area of gutters, MG and CS maximal compression and the presence of infolding (Fig. 1 and 2).
Results:
The intra and interobserver assessment of correlation by Bland-Altman plot analysis of the obtained values of all measured parameters revealed adequate correlation without statistically significant differences in all cases (p<.05). Therefore, the investigational analysis of the tested parameters could be performed using the mean values of the measurements of the three observers. The smallest gutters area was seen in the combination with Advanta (0.26 cm2) followed by BeGraft Plus (0.34 cm2) (Table 1). The highest MG compression was observed in the combination with LifeStream (14%, D-ratio 0.86) followed by BeGraft Plus (13%, D-ratio 0.86). The smallest MG D-ratio was calculated in the combination with Advanta (0.83). Infolding was observed in all testings. The highest areas of infolding was measured in the combination with LifeStream (0.28 cm2) and BeGraft Plus (0.24 cm2), respectively. The lowest CS compression and highest D-ratio was observed in the combination with BeGraft Plus (4.91%, D-ratio 0.95) (Table 2). The highest CS compression and lowest D-ratio was observed in the combination with Dynamic (31.92%, D-ratio 0.68) and Absolute Pro (31.41%, D-ratio 0.69). BECS showed higher angulations than self-expandable bare-metal stents (p<.001). The Absolute Pro - and reinforced Absolute Pro showed the lowest measured angulation of 59,51º and 91.74º, respectively.
Conclusion:
Each employed CS in the here presented in vitro testings showed significantly different performance favouring the BECS. The lowest area of gutters was observed with after the use of Advanta stent-graft, Compression resistance results showed superiority of the BeGraft plus. BECS showed higher MG compression compared to SE stents. Main graft infolding, which is related to MG oversizing, was seen in all tests underlying the need for prolonged kissing ballooning after deployment to ensure better MG wall apposition. BECS may present more suitable angulation and configuration for chEVAR when craniocaudal positioning of the target vessel is present imploring further investigation and possibly alternative device selection or treatment in transverse or upwards oriented target vessels.
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