Fenestrations of a Standardised Physician Modified Endograft for the Treatment of Complex Abdominal Aortic Aneurysm Demonstrate Similar on Bench Mechanical Performance Compared with a Manufactured Custom Made Device

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OBJECTIVE: This study aimed to evaluate the mechanical behaviour of a standardised fenestrated physician modified endograft (sPMEG) compared with a custom made device (CMD). The structural integrity of standardised fenestrations following bridging stent deployment and flaring as well as durability after fatigue tests were assessed. METHODS: The sPMEG was prepared by fenestrating a Valiant Captivia stent graft system (Medtronic) by creating an electrocautery hole, reinforced with a 0.018" guidewire secured by a 5.0 locking suture. Mechanical performance was assessed with microscopic and radiographic imaging and compared with a CMD fenestration sheet (Cook Zenith Fenestrated, Cook Medical, Bloomington, IL, USA). Integrity was evaluated by measuring fenestration diameter, area, and circularity changes before and after stent deployment and flaring. Additionally, fabric integrity, reinforcement ring stability, suture line integrity, and fenestration to stent apposition were compared. For fatigue testing, the sPMEG was deployed in a three dimensional printed tubular model under fluoroscopic guidance, followed by deployment and flaring of VBX stents (W.L. Gore & Associates, Inc. Newark, DE, USA). The sPMEG fenestrations were exposed to 7.3 million cycles using a controlled benchtop machine. RESULTS: Twenty fenestrations were evaluated (ten sPMEG and ten CMD). In all cases, microscopic evaluation showed a consistent circular shape and structural integrity of the fabric, suture line, and reinforcement ring both before and after stenting and flaring. Compared with the CMD, the median increase in fenestration diameter and surface area after stent flaring was not statistically significant for the 6 mm fenestration (p = .41) but was greater for the 8 mm sPMEG (p = .046) without compromising shape or fenestration to stent apposition. Fatigue testing revealed no structural defects in either group. CONCLUSION: SPMEG fenestrations perform similarly to CMD fenestrations after stenting and flaring, while also ensuring long term integrity. Although limited by in vitro conditions, these on bench tests support the potential clinical application of sPMEG fenestration in urgent complex aneurysm repair.

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