In-Situ Fenestration of a PTFE Thoracic Aortic Stent Graft for Delayed Left Subclavian Artery Revascularization Following Frozen Elephant Trunk Repair of Type A Aortic Dissection

Abstract

Left subclavian artery revascularization during endovascular repair of aortic dissection is often accomplished by left carotid-subclavian artery bypass or transposition. In situ fenestration of thoracic stent grafts provides an alternative method of revascularization without manipulation of the left carotid artery. We describe a case whereby in situ laser fenestration, combined with catheter-directed thrombectomy, was utilized to revascularize a thrombosed left subclavian artery following a frozen elephant trunk repair of type A aortic dissection. A 75-year-old male presented with pericardial tamponade and aortic insufficiency, secondary to type A aortic dissection. Patient underwent an emergent replacement of the aortic root, valve, arch, and ascending aorta in the frozen elephant trunk configuration. The innominate and left carotid arteries were revascularized with a bifurcated bypass graft from the ascending aortic graft. The left subclavian artery (LSCA) was covered with an antegrade deployment of a cTAG stent graft. During the immediate postoperative period, the patient was found to have a dissection of the left common carotid artery (LCCA) and pseudoaneurysm of the bypass graft anastomosis. The left carotid artery was replaced up to the proximal internal carotid. During rehabilitation, the patient developed left subclavian steal syndrome, with a CT angiography demonstrating thrombosis of the subclavian origin, and duplex ultrasound showing a reversal of the left vertebral flow. In order to revascularize the left subclavian artery without using the left carotid as the inflow, the in situ laser fenestration technique was planned. The vertebral artery origin was protected with a neuroclip through a supraclavicular incision. Through a brachial artery cutdown, a 9Fr flex sheath was positioned at the origin of the subclavian artery. A suction thrombectomy catheter was used to create a central channel in the thrombus. A 0.035″ 3.2 mm over-the-wire laser atherectomy catheter was used to create a fenestration through the cTAG stent graft. The subclavian branch stent was stented with an iCast balloon-expandable covered stent, excluding the mural thrombus. The patient recovered well with resolution of symptoms and was discharged home. Postoperative CT scan showed patent left subclavian branch stent and no endoleak across the fenestration of the aortic stent graft. Delayed laser in situ fenestration of a PTFE stent graft can be performed safely. The vertebral artery protection and catheter-directed thrombectomy are important adjuncts to reduce the risk of posterior stroke.