Pulsatile Deformations of a Conformable Descending Thoracic Aortic Endograft in Aneurysm, Dissection, and Blunt Traumatic Aortic Injury Patients.

Abstract

This study presents analytic techniques to quantify cardiac pulsatility-induced deformations of thoracic aortic endografts in patients with thoracic aortic aneurysm (TAA), dissection (TAD), and blunt thoracic aortic injury (BTAI) after thoracic endovascular aortic repair (TEVAR). We analyzed 19 image data sets from 14 patients treated for TAA, TAD, and BTAI with cardiac-gated post-TEVAR CTs. Systolic and diastolic geometric models were constructed and diametric, axial, and bending deformations were quantified. For patients with cardiac-gated pre-op scans, the damping of pulsatile diametric distension was computed. Maximum localized diametric distension was 2.4±1.0%, 4.2±1.7%, and 5.5±1.6%, and axial deformation was 0.0±0.1%, -0.1±0.3%, and 1.1±0.6% in the endografts of TAA, TAD, and BTAI cohorts, respectively. Diametric distension damping from pre- to post-TEVAR was ~50%. Diametric and bending deformations were localized at certain axial positions on the endograft, and the inner curve bends more than the centerline, especially adjacent to overlapping regions. The presented techniques support investigation of multi-axial endograft deformations between disease causes and geometric locations on the device. Discretized quantification of deformation is needed to define device fatigue testing conditions and predict device durability in patients. This study demonstrates analytic techniques to quantify discretized deformation of thoracic endografts. Cardiac-resolved computed tomography is sometimes acquired for surgical planning and follow-up, however, the dynamic data are not typically used to quantify pulsatile deformations. Our analytic techniques extract the centerline and surface geometry of the stented thoracic aorta during the cardiac cycle, which are used to quantify diametric, axial, and bending deformations to provide better understanding of device durability and impact on the native anatomy.