Thekla Helene Oechtering MD, Presenter: Nothing to Disclose

Michael P Beldoch, Abstract Co-Author: Nothing to Disclose

Carl Frederik Hons, Abstract Co-Author: Nothing to Disclose

Malte Sieren, Abstract Co-Author: Nothing to Disclose

Claudia Schmidtke, Abstract Co-Author: Nothing to Disclose

Peter Hunold MD, Abstract Co-Author: Speaker, Bayer AG Speaker, Koninklijke Philips NV

Hans-Hinrich Sievers MD, Abstract Co-Author: Royalities, B. Braun Melsungen AG

Joerg Barkhausen MD, Abstract Co-Author: Nothing to Disclose

Alex Peter Frydrychowicz MD, Abstract Co-Author: Nothing to Disclose

To evaluate blood flow characteristics in a novel “sinus prosthesis”, a valve-sparing aortic root prosthesis with anatomically shaped sinuses (Uni-Graft® W SINUS, Braun) in comparison to healthy volunteers by means of 4D flow MRI.

13 patients after valve-sparing aortic root replacement with sinus prosthesis (“SP”, 1f, 54±14y) and 13 age-matched healthy volunteers (“Vol”, 11f, 55±6y) were included in this HIPAA-compliant study after approval of the ethics committee and written informed consent. MRI scans were conducted at 3T (Philips Achieva) using a retrospectively ECG-gated 4D Flow sequence with respiratory gating. Flow characteristics were analyzed using GTFlow (v2.1.4, GyroTools) applying streamlines and particle traces to the acquired time-resolved flow field color-coded according to the measured velocity. Presence and extent of secondary flow patterns (vortices, helices) in the aortic sinuses and aorta were graded on a 0-3 scale. Aortic geometry (form, curvature angle at distal anastomosis, diameter, and length) and hemodynamic parameters in 5 planes were assessed.

Presence and extent of sinus vortices were similar between groups: vortices in at least 2 sinuses, vortex size small or medium in 91% of SP, 99% of Vol, tendency towards larger vortices in SP; analysis of datasets with aliasing ongoing (n=6). Regarding geometry, SP patients showed mostly cubic and gothic aortic arches (8/13 and 3/13) whereas Vol presented mostly with a round arch (11/13), substantiated by steeper aortic curvature (SP 102±22°, Vol 84±15°, p<0.05). Patients revealed a longer thoracic aorta (SP 25.0 ± 0.8cm; Vol 22.4 ± 0.7cm; p<0.05) and more secondary flow patterns in the ascending aorta (AAO) than volunteers (SP 1.3±0.5, Vol 0.4±0.5, p<0.05) accompanied by decreased stroke volumes and left ventricular ejection fraction (SP 57,8±7.3%; Vol 65.4±2.8%; p<0.05).

Near-physiological flow characteristics were observed in the sinuses of the sinus prosthesis. The increase of secondary flow patterns in the AAO in patients may be explained by altered aortic geometry due to graft implantation, pointing towards the need for anatomically curved prostheses potentially mitigating unphysiological aortic curvatures.

4D Flow MRI reveals near-physiological sinus flow in sinus prostheses and an increase in aortic flow patterns that may be reduced by curved prostheses affecting aortic curvature to a lesser extent.

Oechtering, T, Beldoch, M, Hons, C, Sieren, M, Schmidtke, C, Hunold, P, Sievers, H, Barkhausen, J, Frydrychowicz, A, 4D Flow MRI: Analysis of Blood Flow in Valve-Sparing Aortic Root Replacement with an Anatomically Shaped Sinus Prosthesis.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045482.html