Endovascular Repair of Aortic Dissection Involving the Left Subclavian Artery by Castor Stent Graft: A Multicentre Prospective Trial

Abstract

The left subclavian artery (LSA) origin can be intentionally covered by stent grafts, to provide adequate proximal landing zones during thoracic endovascular repair for Stanford type B aortic dissections (TBADs). To preserve the LSA, a novel single branched stent graft, named "Castor" was designed and a clinical trial conducted to investigate its suitability. From April 2013 to March 2015, 73 patients with TBAD were treated by Castor stent grafts at 11 Chinese tertiary hospitals as part of a single arm prospective clinical trial. There were 50 acute (<2 weeks [68.5%]) and 23 chronic aortic dissections (>2 weeks [31.5%]). The technical success rate was 97% (n=71/73). The two failures were caused by occlusion of the branch section of the stent graft. There were four intra-operative endoleaks (two type Ia, two type B from the LSA). The endoleak rate was 5% (n=4/73). There was one in hospital death and no major complications. The median follow up time was 61 months (range 48-72 months). The mortality was 5% (n=4/73) within one year and 7% within six years (n=5/73). Two deaths were of unknown cause and three were not related to the aorta. Two new entry tears were found on the proximal or distal edge of the stent graft and were retreated endovascularly. Six occlusions of the branch section of the Castor stent graft were found, and the follow up patency rate of the branch section was 93% (n=63/68). Two intra-operative endoleaks were left during follow up and eventually disappeared according to the latest computed tomography angiograms. For patients with TBADs needing anchoring proximal to the origin of LSA, the Castor single branched stent graft may provide an easily manipulated, safe, and effective endovascular treatment.