Evolution of Precision Medicine and Surgical Strategies for Bicuspid Aortic Valve-Associated Aortopathy

Figure 1. Aortic wall degeneration in BAV (Fedak et al., 2002).

Figure 2. Valve mediated hemodynamics. BAV fusion patterns lay the foundation for changes in aortic outflow and wall shear stress (WSS). Eccentric blood flow from the RL-BAV impinges on regions of dilatation at the tubular ascending aorta wall. Flow from the RN-BAV reflects off the proximal posterior wall and impinges on regions of aortic dilatation within the proximal arch. Adapted with permission (Itagaki et al., 2016).

Figure 3. 4D flow MRI in a control and BAV patient with a right-left (RL) fusion pattern and right-non-coronary (RN) fusion pattern. Note that the RL-BAV exerted significant eccentric aortic outflow jet (but not higher velocity, arrow) compared to TAV. The BAV phenotype (RL vs. RN) greatly influences aortic outflow, which in turn, affects aortic segments exposed to elevated WSS (Figure 4). Adapted with permission (Barker et al., 2012; Guzzardi et al., 2015).

Figure 4. 4D flow & WSS quantification in 15 RN-BAV patients found that 4D flow can detect significant differences (*p < 0.05, **p < 0.001) in aortic WSS distribution compared to 30 TAV controls. (A) Control populations and (B) individual BAV patient. Note the different aortic outflow pattern compared to the RL-BAV patient in Figure 3 (Barker et al., 2012).

Figure 5. Patient-specific WSS heat maps. Healthy atlases are registered to BAV data with tools developed for brain mapping. Maps can be reliably generated, even in patients with complex aortic geometries (as here).

Figure 6. Tissue histopathology. Aortic wall regions are exposed to elevated WSS (middle, red region), due to eccentric transvalvular BAV flow (left). This manifests in the expression of abnormal tissue metrics of aortopathy (right). Adapted with permission (Guzzardi et al., 2015).

Figure 7. Elastin content from Verhoeff–Van Gieson elastin staining for patient pairs and cumulative group means for aortic wall subjected to normal and elevated WSS (Guzzardi et al., 2015).