VAM 2023: Endovascular thermal septotomy for chronic post-dissection aortic aneurysm

Aidin Baghbani-Oskouei, MD, and Gustavo S. Oderich, MD, from the University of Texas Health Science Center at Houston, Texas, detail the endovascular thermal septotomy technique for chronic post-dissection thoracoabdominal aortic aneurysms (TAAAs), which featured as a video presentation at the end of the William J. von Liebig Forum yesterday at the Vascular Annual Meeting (VAM) 2023.

Aortic dissection often results in chronic aneurysmal degeneration due to progressive false lumen expansion. Thoracic endovascular aneurysm repair (TEVAR) and other techniques of vessel in­corporation—such as fenestrated-branched or parallel grafts—have been increasingly utilized to treat chronic post-dissection aneurysms. Even in patients with severe true lumen compression, or when vessels originate from the false lumen, this poses technical difficulties.

In these cases, the limited space from a compressed true lumen may result in inadequate stent-graft expansion or restrict the ability to reposition the device or ma­nipulate catheters. Reentrance techniques may be used selectively to assist with target vessel catheterization. Thermal electrocau­tery septotomy is a novel technique that has evolved from the cardiology experience with trans-septal or trans-catheter aortic valve procedures. This technique has been applied in select cases to facilitate the cre­ation of proximal and distal landing zones, to disrupt the septum in patients with an excessively compressed true lumen or with vessels that have separate origins from true and false lumens.

At VAM, we present a video that details the technical pitfalls of thermal electrocau­tery septotomy in a patient with chronic post-dissection aortic aneurysm. The pa­tient presented with isolated enlargement of the iliac artery and modest enlargement of the descending thoracic aorta (3.8 cm). To decrease the risk of spinal cord injury, we recommended endovascular repair of the infrarenal aortic enlargement with left internal iliac preservation using iliac branch endoprosthesis (IBE). The septotomy pro­cedure was used as an adjunct technique to create a suitable proximal landing zone in the infra-renal aorta.

The procedure requires a standard percu­taneous approach using perclose technique. Access is established into the true and false lumen and confirmed with intra-vascular ultrasound (IVUS). A 6F Oscor steerable guiding sheath is positioned in the intended area of septotomy, which due to excessive angulation was at the level of the celiac axis (CA). A 35-mm Amplatz Goose Neck Snare kit is advanced via the ipsilateral approach into the false lumen and opened opposite to the steerable sheath to facilitate orienta­tion during guidewire crossing of the dis­section septum. The orientation between the steerable sheath and snare is confirmed under fluoroscopy in the anteroposterior, lateral, and oblique views. Once the orien­tation is optimized, a 0.018 NaviCross cath­eter and 0.018 Astato hydrophilic guidewire are prepared by removing the guidewire coating and connecting the guidewire to the electrocautery. With the electrocautery set on cut mode at 80 Watts, the guidewire is gently advanced across the dissection membrane without difficulty and promptly snared. The through-and-through guide­wire is retracted along with the NaviCross catheter to allow the creation of a 5mm trapeze-shaped area which is denuded from the coating and readvanced into position.

A second 0.018 NaviCross catheter is advanced via the other end of the 0.018 Astato guidewire to protect structures from thermal injury, allowing only the 5-mm trapeze segment to be exposed. The Astato guidewire is again reconnected to the electrocautery and septotomy is performed extending to the distal end of the septum membrane in the external iliac artery. The septotomy is guided by fluoroscopy and confirmed with IVUS. Once the septotomy was completed, the infrarenal EVAR was performed in standard fashion using Gore Excluder Conformable with bilateral iliac limb extensions and a left Gore IBE device.

This adjunctive technique is useful to facilitate endovascular repair in patients with subacute or post-dissection aneu­rysms but has not been used in the acute setting where the friable membrane may be more prone to disrupt or detach from the aortic wall.