In Vitro Analysis of an Optimal Procedure of Anterograde In Situ Laser Fenestration of Aortic Endografts

Abstract

Introduction - In situ aortic grafts fenestration can be performed by several methods. Retrograde Laser fenestration is used for subclavian artery revascularisation with good results. The anterograde approach can be used for endovascular emergencies. The objective of this bench study was to analyse results of laser fenestration on different aortic grafts, using micro and macroscopic approach. Methods - We studied 4 aortic grafts: Zenith (Cook Medical, Bloomington, IN), Valiant and Endurant (Medtronic Endurant, Minneapolis, Minn), and Excluder (W. L. Gore & Associates, Flagstaff, Ariz). One hundred and thirty-seven holes were created using an Excimer Laser (Spectranetics, Colorado Springs, CO, USA), with several probes’ diameters. Laser probe’s angulation, impulsion’s number and 3 hole’s dilatation’s sequences were evaluated. Macroscopic study was done after deployment of a secondary flaired covered stent. All holes were analysed using an optic microscope after each step until the covered stent’s deployment. Results - Laser probe’s angulation does not modify the created hole’s quality. Creation of a hole requires one activation of the laser on Dacron graft, while several activations are necessary with the Excluder graft. The 0,9mm laser probe is more efficient than the 2.5mm one. Graft’s fibbers spaced from the hole were not distorted by the laser neither by successive dilatation. Optimal sequence to create a continent window was defined: hole creation using a 0,9mm laser probe, pre dilatation with a 2mm standard angioplasty balloon, followed by a dilatation using a 2,5mm cutting balloon, then a 4mm standard balloon dilatation, and finally deployment of a 5 or 6mm secondary flaired covered stent. Study of the windows confirmed the existence of a continent prosthetic collar involving the origin of the covered stent. This collars remained despite excessive angulation of the covered stent. Conclusion - Gore graft is not suitable for laser fenestration regarding the difficulty to create a hole. Optimal sequence for in situ laser fenestration was defined. It seems efficient in terms of sealing. Biomechanical study remains necessary to confirm those findings.