Phase contrast 4D flow in bicuspid aortic valves in a porcine model
© Grothoff et al; licensee BioMed Central Ltd. 2015
Published: 3 February 2015
Bicuspid aortic valves (BAV) are associated with aneurysms of the ascending aorta (AAA). It is unclear whether these aneurysms are caused by tissue alterations of the aortic wall or by alterations of blood flow in the ascending aorta due to the bicuspid valve morphology. In this study we analyzed the phase contrast 4D flow characteristics in normal tricuspid aortic valves (TAV) in a porcine model and compared them to the 4D flow patterns after different types of surgical bicuspidalization.
Phase contrast 4D flow measurements of the thoracic aorta were performed in 3 mongrel swine (56 to 73 kg) using a spoiled gradient-echo based sequence prototype on a 3 Tesla MRI system (Verio, Siemens Healthcare, Erlangen, Germany) in supine position with a 16-channel cardiac phase-array coil. After the first MRI scan surgical bicuspidalization of the aortic valve was performed with a fusion of the right and left-coronary (R-L) leaflet in swine 1 and fusion of the right and the non-coronary (R-N) leaflet in swine 2. In swine 3 a congenital BAV of the R-L type was found intraoperatively. After surgery swine 1 and 2 underwent a second 4D flow scan. The 4D scans were analyzed for helical and vortical flow in the entire thoracic aorta and for eccentric flow at the level of the sinotubular junction.
We could show that bicuspidalization of the aortic valve results in substantial changes of blood flow in the AA dependending on the type of leaflet fusion. This porcine model could be used to analyze the contribution of flow alterations in the development of AAA in BAV patients.
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