Time-resolved 3-dimensional magnetic resonance phase contrast imaging (4D Flow MRI) reveals altered blood flow patterns in the ascending aorta of patients with valve-sparing aortic root replacement

• Published in: The Journal of thoracic and cardiovascular surgery Vol. 159; no. 3; pp. 798 - 810.e1
• Main Authors: Oechtering, Thekla H., Sieren, Malte M., Hunold, Peter, Hennemuth, Anja, Huellebrand, Markus, Scharfschwerdt, Michael, Richardt, Doreen, Sievers, Hans-Hinrich, Barkhausen, Jörg, Frydrychowicz, Alex
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.03.2020
• Subjects: 4D flow cardiovascular magnetic resonance; 4D Flow MRI; Adult; Aged; altered hemodynamics; Aorta - diagnostic imaging; Aorta - physiopathology; Aorta - surgery; Aortic Aneurysm - diagnostic imaging; Aortic Aneurysm - physiopathology; Aortic Aneurysm - surgery; Aortic Valve - diagnostic imaging; Aortic Valve - physiopathology; Blood Flow Velocity; Blood Vessel Prosthesis; Blood Vessel Prosthesis Implantation - adverse effects; Blood Vessel Prosthesis Implantation - instrumentation; Case-Control Studies; Female; Hemodynamics; Humans; Imaging, Three-Dimensional; Magnetic Resonance Angiography; Male; Middle Aged; Models, Cardiovascular; Patient-Specific Modeling; Perfusion Imaging - methods; Pilot Projects; Predictive Value of Tests; Prosthesis Design; Prosthesis Failure; Regional Blood Flow; secondary flow patterns; sinus prosthesis; Time Factors; Treatment Outcome; valve-sparing aortic root replacement; VSARR; sinus prosthesis; SV; MRI; VSARR; altered hemodynamics; VOL-A; ARCH; AAO; 2D; DAO; TG; 4D flow cardiovascular magnetic resonance; 4D Flow MRI; secondary flow patterns; SP; valve-sparing aortic root replacement; VOL-Y
• ISSN: 0022-5223; 1097-685X; 1097-685X
• DOI: 10.1016/j.jtcvs.2019.02.127

The aim of this study was to compare aortic flow patterns in patients after David valve-sparing aortic root replacement with physiologically shaped sinus prostheses or conventional tube grafts in healthy volunteers. Twelve patients with sinus prostheses (55 ± 15 years), 6 patients with tube grafts (58 ± 12 years), 12 age-matched, healthy volunteers (55 ± 6 years), and 6 young, healthy volunteers (25 ± 3 years) were examined with time-resolved 3-dimensional magnetic resonance phase contrast imaging (4D Flow MRI). Primary and secondary helical, as well as vortical flow patterns, were evaluated. Aortic arch anatomy as a flow influencing factor was determined. Compared with volunteers, both sinus prostheses and tube grafts developed more than 4 times as many secondary flow patterns in the ascending aorta (sinus prostheses n = 1.6 ± 0.8; tube grafts n = 1.3 ± 0.6; age-matched, healthy volunteers n = 0.3 ± 0.5; young, healthy volunteers n = 0; P ≤ .012) associated with a kinking of the prosthesis itself or at its distal anastomosis. As opposed to round aortic arches in volunteers (n = 16/18), cubic or gothic-shaped arches predominated in patients (n = 16/18, P < .001). In all but 3 volunteers, 2 counter-rotating helices were confirmed in the ascending aorta and were defined as a primary flow pattern. This primary flow pattern did not develop in patients who underwent valve-sparing aortic root replacement. In patients after valve-sparing aortic root replacement, there was an increased number of secondary flow patterns in the ascending aorta. This seems to be related to surgically altered aortic geometry with kinking. Because flow alterations are known to affect wall shear stress, there seems to be an increased risk for vessel wall remodeling. Compared with previous 4D Flow MRI studies, primary flow patterns in the ascending aorta in healthy subjects were confirmed to be more complex. This underlines the importance of thorough examination of 4D Flow MRI data.