Characteristics of aortic root and vascular anatomy in bicuspid versus tricuspid aortic valve anatomy

Background Transcatheter aortic valve replacement (TAVR) is being increasingly performed in patients with bicuspid aortic valve stenosis (AS). Purpose This study sought to compare aortic root, aorta and iliofemoral artery anatomy in patients with bicuspid versus tricuspid AS. Methods 172 patients with bicuspid AS and 331 patients with tricuspid AS underwent pre-procedural computed tomography (CT) evaluation before TAVR. Dimensions, calcification, and tortuosity of the iliofemoral arteries were evaluated and the dimensions of aortic root, aorta, and left subclavian arteries were determined. Results Dimensions of aortic root, aorta, left subclavian, and iliofemoral arteries were consistently and significantly larger in bicuspid than in tricuspid AS (P<0.001). Patients with bicuspid AS had significantly lower subclavian, aorta, and iliofemoral arteries calcification, lower tortuosity index and lower maximal tortuosity angle compared to patients with tricuspid AS (P<0.001 for all) even after adjustment for baseline characteristics (Figure). Compared to tricuspid AS the prevalence of porcelain aorta and aneurysm in the descending aorta and iliofemoral arteries were significantly less common in bicuspid valve anatomy. After adjustment for baseline characteristics Bicuspid valve anatomy was associated with lower odds of vascular calcification (odds ratio (OR) 0.82: 95% CI 0.52–0.93; P=0.001). Conclusions Bicuspid AS was associated with larger dimensions of aortic root, aorta, subclavian, and iliofemoral arteries compared with tricuspid AS. Low vascular calcification and decreased tortuosity index of iliofemoral arteries characterized bicuspid anatomy. Further studies are needed to evaluate the impact of bicuspid vascular anatomy on vascular complications after TAVR. FUNDunding Acknowledgement Type of funding sources: None.

Computational Analysis of Wall Shear Stress Patterns on Calcified and Bicuspid Aortic Valves: Focus on Radial and Coaptation Patterns

Calcification and bicuspid valve formation are important aortic valve disorders that disturb the hemodynamics and the valve function. The detailed analysis of aortic valve hemodynamics would lead to a better understanding of the disease’s etiology. We computationally modeled the aortic valve using simplified three-dimensional geometry and inlet velocity conditions obtained via echocardiography. We examined various calcification severities and bicuspid valve formation. Fluid-structure interaction (FSI) analyses were adapted using ANSYS Workbench to incorporate both flow dynamics and leaflet deformation accurately. Simulation results were validated by comparing leaflet movements in B-mode echo recordings. Results indicate that the biomechanical environment is significantly changed for calcified and bicuspid valves. High flow jet velocities are observed in the calcified valves which results in high transvalvular pressure difference (TPG). Wall shear stresses (WSS) increased with the calcification on both fibrosa (aorta side) and ventricularis (left ventricle side) surfaces of the leaflet. The WSS distribution is regular on the ventricularis, as the WSS values proportionally increase from the base to the tip of the leaflet. However, WSS patterns are spatially complex on the fibrosa side. Low WSS levels and spatially complex WSS patterns on the fibrosa side are considered as promoting factors for further calcification and valvular diseases.

Etiologies of Hemodynamically Significant Aortic Regurgitation and Coronary Cusp Bending: Evaluation by Transesophageal Echocardiography

Background: While the number of patients with aortic regurgitation (AR) has been increasing in the aging society, its etiologies remain to be fully elucidated. Methods: We studied consecutive 126 patients with chronic moderate or severe AR who underwent TEE. After the study subjects were divided into 2 groups by the age of 65 years, AR etiology was examined in each group. Results: In the older group (n = 85), cusp bending was the most frequent cause of AR (48.2%), and right coronary cusp (RCC) was the most common (90.2%). In the younger group (n=41), bicuspid valve was the most frequent cause (36.5%), and cusp bending was less frequent (16.5%). Multivariate analysis revealed that age was the only factor associated with cusp bending. Conclusion: Cusp bending of RCC was the most frequent etiology of AR in the elderly. Because AR caused by cusp bending has a possibility to be mended by aortic plasty, it is important to detect it by TEE especially in the older patients.