Impact of Aneurysm Repair on Thoracic Aorta Hemodynamics

Abstract

We present pre- and postoperative imaging findings in a 29-year-old man with a bicuspid aortic valve (BAV) with fusion of the right and left coronary leaflets and a 6.1 cm × 6.3 cm ascending aorta aneurysm (Figure 1). The patient underwent a valve-sparing aortic root replacement with a 34-mm Dacron graft and BAV repair with resection of the raphe of the fused leaflet and leaflet shortening of the noncoronary cusp. Figure 1. Sagital ( A ) and axial ( B ) preoperative MRI demonstrating a 6.1×6.3 cm ascending aorta (AAo) aneurysm. To better understand the preoperative flow characteristics in the large aneurysm and the impact of surgical repair and reconstruction on thoracic aorta hemodynamics, time-resolved 3-dimensional phase contrast (4D flow) MRI was performed before and after surgery. The MRI examinations (pre: 3.0 T Skyra, post: 1.5 T Avanto, Siemens, Germany) included both 4D flow MRI (velocity sensitivity pre:150 cm/s, post: 250 cm/s, spatial/temporal resolution pre: 3.14×2.13×3.2 mm3/39 ms, post: 2.88×2.13×2.15 mm3/38ms) and dynamic 2-D cine imaging of the heart (steady-state free precession, spatial/temporal resolution pre: 1.25×1.25×6 mm3/29 ms post:1.8×1.8×6 mm3/39 ms). The study was approved by the local institutional review board, and informed consent was obtained from the patient. Blood flow patterns within the thoracic aorta were visualized using time-resolved 3D pathlines to illustrate complex blood flow dynamics over the entire cardiac cycle (EnSight, CEI). In addition, 3D velocity streamlines drawn tangent to the time-resolved velocity field were used to illustrate instantaneous flow dynamics in the thoracic aorta. Forward and …