Aortic valve disease (AVD) presents in the form of stenosis, insufficiency, or congenital defect affecting normal valve function and behavior. Deterioration of valve performance will drastically alter post-valvular 3D blood flow patterns, LV afterload, and potentially aorta structure. Current clinical metrics of disease severity are based on simplified hemodynamic approaches and local anatomical measurements, which, while partially effective, are known to be associated with divergent outcomes in similar classified patients. The aortic valve effective orifice area (EOA), the cross-sectional area of vena contracta, is one of the most frequently used parameters to assess stenosis severity. Compared to other stenotic parameters (e.g. transvalvular gradient, peak jet velocity and valve anatomic orifice area), EOA is less flow dependent and a powerful marker of patient outcome. However, EOA measurements by echo-Doppler is not feasible in up to 20-30% of patients due to technical limitations and/or operator experience. In this respect, we have introduced a robust vortex flow-based method, jet shear layer detection (JSLD), for the accurate estimation of valve EOA. Our goal is to further integrate similar vortex-based parameters with 4D flow MRI, an imaging technique capable of assessing in-vitro and in-vivo 3D hemodynamics with full volumetric coverage of the aorta. 4D flow MRI is widely implemented at our institution via a large-scale, cross-departmental research program coordinated by the members of Northwestern’s Center for Heart Valve Disease. This multidisciplinary effort, focusing on heart valve disease research, affords a unique opportunity to visualize and quantify 3D flow vorticity in a large number of valve disease patients with technology and patient cohorts available to few institutions in North America. For this reason, we propose to investigate novel vortex flow quantification parameters in our existing AVD / 4D flow patient database to test the hypothesis that novel 4D flow-derived vorticity parameters will provide robust correlation to AVD and aortopathy severity.
|Effective start/end date||1/1/14 → 12/31/15|
- American Heart Association Midwest Affiliate (14POST18350019)