Abstract 19629: Increased Ascending Aortic Wall Stress in Patients with Bicuspid Aortic Valves
Objective: Patients with bicuspid aortic valves (BAVs) are at increased risk of ascending aortic dilatation, dissection, and rupture.
Hypothesis: We hypothesized that, independent of aortic diameter, pressure load-induced ascending aortic wall stress may be increased in patients with BAVs compared to patients with tricuspid aortic valves (TAVs).
Methods: Twenty patients with BAVs and 20 patients with TAVs underwent electrocardiogram-gated computed tomography angiography. Patients were matched for maximum diameter at the sinotubular junction and in the ascending aorta. The ascending aorta was segmented, reconstructed, and triangulated to create a mesh. A uniform wall thickness (1.7 millimeters (mm)) derived from echocardiogram data was used. Utilizing a uniform pressure load of 120 mmHg, and isotropic, incompressible, and linear elastic triangular elements, finite element analysis (FEA) was performed to predict 99-percentile peak stress. Stress results were normalized by radius, and are presented in mean ± standard deviation.
Results: Maximum sinotubular junction diameter for patients with BAVs and TAVs was 3.7 ± 0.8 centimeters (cm) and 3.7 ± 0.7 cm, respectively (P=.82). Maximum ascending aortic diameter for patients with BAVs and TAVs was 4.2 ± 0.9 cm and 4.2 ± 0.8 cm, respectively (P=.90). Four patients in the BAV group had moderate or worse aortic valve disease, compared to 0 patients in the TAV group. The 99-percentile peak stress of patients in the BAV group was greater than that of patients in the TAV group when normalized by radius (0.31 ± 0.05 megapascals (MPa)/cm versus 0.27 ± 0.03 MPa/cm; P=0.03)
Conclusions: These results indicate that patients with BAVs, regardless of aortic diameter, have greater wall stress in the ascending aorta than patients with TAVs. Differing ascending aortic geometry in patients with BAVs may account for the increased propensity for aortic dilatation, rupture, and dissection observed in these patients.
- © 2010 by American Heart Association, Inc.