Toward endovascular treatment of type A aortic dissection with smaller landing zones and more patient eligibility.

Abstract

Type A or ascending aortic dissection is an acute life-threatening condition with high morbidity and mortality. Open surgery remains the standard of care. The development of minimally invasive endografts for type A aortic dissection (TAAD) will require a detailed understanding of the dissection and aortic root anatomy to determine patient eligibility and optimal device specifications. Computed tomography images of TAAD cases at our institution from 2012 to 2019 were identified, and three-dimensional reconstructions were performed using OsiriX, version 10.0 (Pixmeo SARL, Bernex, Switzerland). We analyzed key anatomic structures, including centerline length measurements, ascending aorta and aortic root dimensions, and the location and extent of dissection in relationship to the coronary ostia. A total of 53 patients were identified (mean± standard deviation age, 60.4± 17.1years; 36 men and 17 women), 46 of whom had undergone surgery for TAAD. Four patients had died within 30days 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 using a nonbranched, single endograft stent. The proximal landing zone (LZ) was defined as the distance from the highest coronary ostium to the entry tear. Of the 53 patients, 35 (66.0%) had a proximal LZ length of ≥2.0cm, 38 (71.7%) had a proximal LZ length of ≥1.5cm, and 42 (79.2%) had a proximal LZ length of ≥1.0cm. The median proximal and distal LZ diameters of the sinotubular junction (STJ) and distal ascending aorta regions were 3.29cm (interquartile range [IQR], 2.73-4.10cm) and 3.49cm (IQR, 3.09-3.87cm, respectively), with a median length from the STJ to the innominate takeoff of 8.08cm (IQR, 6.96-9.40cm). The median ascending aorta radius of curvature was 6.48cm (IQR, 5.27-8.00cm). Of the 53 patients, 25 (47.2%) could be treated with a straight tube graft with a ≤20% diameter mismatch between the proximal and distal LZs. Almost 80% of the patients with TAAD had had a proximal LZ of ≥1.0cm. Of these patients, 47.2% had anatomy amenable for endovascular therapy with a nontapered straight tube graft using commercially available devices. To increase patient eligibility for TAAD endovascular intervention, enhanced precision deployment with an adequate seal in shorter LZs will be required. Our results can serve as a guide for endovascular device specifications designed to treat this devastating condition.