Preliminary results by flow-sensitive magnetic resonance imaging after Tiron David I procedure with an anatomically shaped ascending aortic graft

Abstract

We present preliminary data of the vascular hemodynamics in a novel, anatomically shaped ascending aortic graft in comparison to nonoperated individuals by use of 3D magnetic resonance (MR) flow measurements. We examined a 72-year-old male patient after Tiron David I valve sparing aortic root reconstruction and replacement of the ascending aorta (AAo) with an anatomically curved prosthesis. Results from flow-sensitive MR at 3T were compared to 12 age-matched individuals with comparable diameters of the AAo. For 3D flow visualization, streamlines and time-resolved particle traces were applied. A visual analysis of hemodynamic properties including blood flow helicity, vorticity and retrograde flow was performed. In contrast to reported highly disturbed flow of straight aortic grafts in the literature, the patient analysis revealed smooth blood flow through the graft which gave rise to a right-handed helical flow in the reconstructed aorta. In comparison to non-operated volunteers, blood flow helicity was more pronounced. Flow jets or vortices were not encountered. While physiological retrograde flow was seen in the volunteers, it was absent in the patient which may be explained by the altered aortic compliance and thus reduced Windkessel effect. This promising finding will have to prove its validity in further comparative studies.