Towards Endovascular Treatment of Type A Aortic Dissection with Smaller Landing Zones and More Patient Eligibility.

Abstract

OBJECTIVE\nType A or ascending aortic dissection is an acute life-threatening condition with high morbidity and mortality. Open surgery remains standard-of-care. Development of minimally invasive endografts for Type A aortic dissection (TAAD) will require detailed understanding of dissection and aortic root anatomy to determine patient eligibility and optimal device specifications.\n\n\nMETHODS\nComputed tomography images of TAAD cases at our institution from 2012-2019 were identified and three-dimensional reconstructions were performed using OsiriX 10.0 (Bernex, Switzerland). Analysis of key anatomic structures including centerline length measurements, ascending aorta/aortic root dimensions, as well as location and extent of dissection were determined in relation to coronary ostia.\n\n\nRESULTS\nA total of 53 patients were identified (mean±SD age 60.4±17.1 years; 36 male, 17 female), 46 of whom underwent surgery for TAAD. Four patients died within 30 days of surgery. In 47 patients (88.7%), the entry tear was distal to the highest coronary ostium. These cases were retrospectively considered for endovascular intervention with a non-branched, single endograft stent. Proximal landing zone (LZ) was defined as distance from the highest coronary ostium to entry tear: 35/53 (66.0%) had a proximal LZ length ≥2.0cm, 38/53 (71.7%) had proximal LZ length ≥1.5cm, and 42/53 (79.2%) had proximal LZ length ≥1.0cm. Proximal and distal LZ diameters of the sinotubular junction (STJ) and distal ascending aorta regions were (median [1st quartile-3rd quartile]) 3.29cm [2.73-4.10cm] and 3.49cm [3.09-3.87cm], respectively, with length from STJ to innominate takeoff 8.08cm [6.96-9.40cm]. Ascending aorta radius of curvature was 6.48cm [5.27-8.00cm]. 47.2% (25/53) of patients could be treated with a straight tube graft with ≤20% diameter mismatch between the proximal and distal LZ.\n\n\nCONCLUSIONS\nAlmost 80% of patients with TAAD had a proximal LZ ≥1.0cm, and of these, 47.2% had anatomy amenable to endovascular therapy with a non-tapered straight tube graft commercially available devices. To increase patient eligibility for TAAD endovascular intervention, enhanced precision deployment with adequate seal in shorter LZs will be required. Our results serve as a guide for endovascular device specifications designed to treat this devastating condition.