Enlargement Rate of the Ascending Aorta After Thoracic Endovascular Aortic Repair.

It is known that the elasticity of the thoracic aorta decreases when it is covered with endografts. It remains to be clarified, however, whether endografts in the descending aorta affect aortic stiffening in the ascending aorta. We analyzed 46 patients who underwent thoracic endovascular aortic repair for descending thoracic aortic aneurysm between January 2008 and June 2016. We calculated the preoperative and postoperative rate of enlargement of the mid-ascending aorta using enhanced computed tomography. In 3 of these patients, we evaluated the peak systolic and time-averaged wall shear stress and relative cross-section area change at the level of the mid-ascending aorta using 4-dimensional flow magnetic resonance imaging. The postoperative rate of enlargement of the mid-ascending aorta was significantly greater than the preoperative rate (0.78 [0.31-1.38] mm/y vs 0.32 [0.12-0.60] mm/y; P < 0.001). In 2 of the 3 patients analyzed by 4-dimensional flow magnetic resonance imaging, the waveform of time-averaged wall shear stress had changed, and the relative cross-section area change decreased after thoracic endovascular aortic repair. There were no secondary surgical interventions for the ascending aorta after thoracic endovascular aortic repair. The rate of enlargement of the ascending aorta may be affected by the change in wall shear stress or aortic stiffening after thoracic endovascular aortic repair.