Patient-Specific Computational Fluid Dynamics – Assessment of Aortic Hemodynamics in a Spectrum of Aortic Valve Pathologies

Objectives

The complexity of aortic disease is not fully exposed by aortic dimensions alone, and morbidity or mortality can occur before intervention thresholds are met. Patient-specific computational fluid dynamics (CFD) was used to assess effect of different aortic valve morphologies on velocity profiles, flow patterns, helicity, wall shear stress (WSS) and oscillatory shear index (OSI) in the thoracic aorta.

Methods

45 subjects were divided into 5 groups: Volunteers, AR-TAV, AS-TAV, AS-BAV(RL), AS-BAV(RN), where AR=aortic regurgitation, AS=aortic stenosis, TAV=tricuspid aortic valve, BAV=bicuspid aortic valve, RL=right-left cusp fusion, RN=right-non cusp fusion. Subjects underwent magnetic resonance angiography, with phase-contrast MRI at the sino-tubular junction to define patient-specific inflow velocity profiles. Hemodynamic recordings were used alongside MRI angiographic data to run patient-specific CFD.

Results

BAV groups had larger mid-ascending aorta diameters (p<0.05). Ascending aorta flow was more eccentric in BAV (Flow_asymmetry=78.9±6.5% for AS-BAV(RN), compared to 4.7±2.1% for Volunteers, p<0.05). Helicity was higher in AS-BAV(RL) (p<0.05). Mean WSS was elevated in AS groups, highest in AS-BAV(RN) (37.1±4.0 dyn/cm², compared to 9.8±5.4 for Volunteers, p<0.05). The greater curvature of the ascending aorta experienced highest WSS and lowest OSI in AS patients, most significant in AS-BAV(RN) (p<0.05).

Conclusions

BAV displays eccentric flow with high helicity. Presence of AS, particularly in BAV-RN led to higher WSS and lower OSI in the greater curvature of the ascending aorta. Patient-specific CFD provides non-invasive functional assessment of the thoracic aorta, and may enable development of a personalized approach to diagnosis and management of aortic disease beyond traditional guidelines.