Technical Feasibility of Arch Branched Endograft Repair in Type A Aortic Dissection with Prior Ascending Aortic Replacement

Introduction - Ascending aortic replacement is a common emergency procedure for treatment of acute type A dissection. Secondary open or endovascular intervention for residual arch pathologies is however difficult due to adhesions, short prosthetic grafts, and distorted anatomy. Aortic arch branched stent graft has emerged as a potential solution for these patients. The aim of this study is to evaluate the technical feasibility of two current aortic arch branch stent grafts in patients who had prior ascending aortic replacement. Methods - All patients who had a prosthetic ascending aortic replacement for acute type A dissection in a single institution between January 2013 and December 2017 were included. Contrast CT images on follow up were analyzed on a 3D workstation. Morphologic parameters were measured individually including: (i) Ascending aorta: diameter, greater and lesser curvature length from the coronary origin, angulation of residual ascending aorta and prosthetic graft. (ii) aortic arch: width and height of the arch, tortuosity index. (iii) supra-aortic branches: diameter, separation, sealing length, dissection, and take-off clock positions. Each patient’s CT scan was individually evaluated for anatomical suitability for the Zenith arch branched device (Cook Medical) and Relay double-branch device (Bolton Medical) according to set selection criteria. Adverse anatomical factors were further identified including prosthetic aortic valve replacement, insufficient proximal landing length, incompatible landing zone diameter, severe angulation of prosthetic ascending aorta, hostile arch branches sealing zone, and insufficient innominate artery (IA) sealing zone. Results - CT images from 56 subjects (45 males, mean age 57±10.8 years) were reviewed. 45 patients had ascending aortic replacement alone, 7 had a Bentall procedure, and 4 underwent David procedure. Based on our evaluation results, 23 patients (41.1%) were good candidates for an endovascular arch branched device. It should be mentioned that two patients were suitable for Relay double-branch device but not for Zenith branched device because the former displays more accommodating for larger proximal landing diameter (<43mm) than the latter (<38mm). Eleven patients (19.6%) were deemed feasible, but prudent pre-operative planning is required due to complicated anatomy. The other 22 patients (39.3%) were unsuitable due to one or more exclusive criteria. Short prosthetic grafts (8), extreme graft angulations (11) and dissected supra-aortic branches (15) were the main reasons for exclusion. Conclusion - Endovascular repair is technically feasible in patients with prior ascending aortic replacement for type A dissection. Incompatible prosthetic ascending aorta and dissecting arch branches are the most common exclusive risk factors.