Anatomic versus Effective Orifice Area in a Bicuspid Aortic Valve

Seaman, Clara; Sucosky, Philippe

doi:10.1111/echo.12720

Cited by 7 publications

(4 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On this basis, the in vitro approach, which aims at measuring the flow in realistic anatomies using high-resolution flow diagnostic techniques, poses as a legitimate alternative to the in vivo and in silico approaches. Particle image velocimetry (PIV) measurements in TAV and BAV tissue models have reported increased energy loss, flow turbulence and unsteadiness in BAVs as well as increased wall shear stress in BAV AAs (Saikrishnan et al, 2012 ; Yap et al, 2012 ; Seaman and Sucosky, 2014 ; Seaman et al, 2014 ). Laser Doppler velocimetry measurements performed in a physiologic flow loop have revealed increased fluid shear stress frequency on BAV leaflets relative to TAV leaflets (Yap et al, 2012 ).…”

Section: Introductionmentioning

confidence: 99%

Morphotype-Dependent Flow Characteristics in Bicuspid Aortic Valve Ascending Aortas: A Benchtop Particle Image Velocimetry Study

2017

Self Cite

View full text Add to dashboard Cite

The bicuspid aortic valve (BAV) is a major risk factor for secondary aortopathy such as aortic dilation. The heterogeneous BAV morphotypes [left-right-coronary cusp fusion (LR), right-non-coronary cusp fusion (RN), and left-non-coronary cusp fusion (LN)] are associated with different dilation patterns, suggesting a role for hemodynamics in BAV aortopathogenesis. However, assessment of this theory is still hampered by the limited knowledge of the hemodynamic abnormalities generated by the distinct BAV morphotypes. The objective of this study was to compare experimentally the hemodynamics of a normal (i.e., non-dilated) ascending aorta (AA) subjected to tricuspid aortic valve (TAV), LR-BAV, RN-BAV, and NL-BAV flow. Tissue BAVs reconstructed from porcine TAVs were subjected to physiologic pulsatile flow conditions in a left-heart simulator featuring a realistic aortic root and compliant aorta. Phase-locked particle image velocimetry experiments were carried out to characterize the flow in the aortic root and in the tubular AA in terms of jet skewness and displacement, as well as mean velocity, viscous shear stress and Reynolds shear stress fields. While all three BAVs generated skewed and asymmetrical orifice jets (up to 1.7- and 4.0-fold increase in flow angle and displacement, respectively, relative to the TAV at the sinotubular junction), the RN-BAV jet was out of the plane of observation. The LR- and NL-BAV exhibited a 71% increase in peak-systolic orifice jet velocity relative to the TAV, suggesting an inherent degree of stenosis in BAVs. While these two BAV morphotypes subjected the convexity of the aortic wall to viscous shear stress overloads (1.7-fold increase in maximum peak-systolic viscous shear stress relative to the TAV-AA), the affected sites were morphotype-dependent (LR-BAV: proximal AA, NL-BAV: distal AA). Lastly, the LR- and NL-BAV generated high degrees of turbulence in the AA (up to 2.3-fold increase in peak-systolic Reynolds shear stress relative to the TAV) that were sustained from peak systole throughout the deceleration phase. This in vitro study reveals substantial flow abnormalities (increased jet skewness, asymmetry, jet velocity, turbulence, and shear stress overloads) in non-dilated BAV aortas, which differ from those observed in dilated aortas but still coincide with aortic wall regions prone to dilation.

show abstract

Section: Introductionmentioning

confidence: 99%

Morphotype-Dependent Flow Characteristics in Bicuspid Aortic Valve Ascending Aortas: A Benchtop Particle Image Velocimetry Study

2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…A perturbation of this delicate equilibrium can result in the progressive degeneration of the vascular wall and the loss of vessel wall integrity [24] . Interestingly, type-I LR-BAVs have been shown to generate perturbed hemodynamics characterized by a valvular jet skewed toward the non-coronary leaflet and increased shearing friction force [i.e., wall shear stress (WSS)] on the convexity of the thoracic AA [25][26][27][28][29][30][31] . While those observations suggest a role for hemodynamics in the pathogenesis of BAV aortopathy [32][33][34] and despite the clear evidence for the existence of flow abnormalities in BAV aortic wall regions vulnerable to dilation, the causative effects of those abnormalities on the local weakening of the aortic wall have not been fully established.…”

Section: Introductionmentioning

confidence: 99%

Bicuspid aortic valve hemodynamics does not promote remodeling in porcine aortic wall concavity

Atkins

Moore

Sucosky

2016

WJC

View full text Add to dashboard Cite

“…Phase-contrast magnetic resonance imaging (PC MRI) and echocardiographic measurements in BAV patients [7]- [10], as well as in vitro particle-image velocimetry measurements [11]- [13] and in silico simulations in idealized ascending aorta (AA) geometries [14]- [17] have revealed the existence of abnormal helical flow patterns and fluid wall shear stress (WSS) overloads in AA regions vulnerable to aortic medial degeneration. In addition, the particular leaflet fusion type affects the expression of dilation and thinning of the AA downstream of a BAV.…”

Section: Introductionmentioning

confidence: 99%

Effect of Bicuspid Aortic Valve Cusp Fusion on Aorta Wall Shear Stress: Preliminary Computational Assessment and Implication for Aortic Dilation

Cao¹,

Sucosky²

2015

WJCD

Self Cite

View full text Add to dashboard Cite

The bicuspid aortic valve (BAV) is a major congenital valvular abnormality and is associated with a high prevalence of aortic dilation, whose expression depends on the type of leaflet fusion. Although BAV hemodynamics is considered a potential pathogenic contributor, the impact of BAV fusion on ascending aorta (AA) wall shear stress (WSS) remains largely unknown. A fluid-structure interaction approach was implemented to predict the hemodynamics and WSS characteristics in realistic AA models subjected to the flow of a normal tricuspid aortic valve (TAV) and three BAV morphotypes (left-right coronary cusp fusion (LR), right-non coronary cusp fusion (RN) and nonleft coronary cusp fusion (NL)). TAV flow conditions subjected the proximal and middle AA to a streamlined flow typical of flows in bends, while BAV flow conditions generated increased flow helicity. The LR-BAV orifice jet generated flow abnormalities primarily in the proximal AA, which were marked by a uniform WSS overload along the wall circumference and contrasted WSS directionalities on the wall convexity and concavity. Flow abnormalities generated by the RN-BAV and NL-BAV inlet flow conditions were more diffuse and consisted of WSS overloads in the convexity of the proximal and middle AA and contrasted WSS directionalities in the anterior and posterior wall regions. This study demonstrates the impact of the BAV morphotype on AA hemodynamics and provides quantitative evidence for the existence of WSS abnormalities in aortic wall regions prone to dilation.

show abstract

Anatomic versus Effective Orifice Area in a Bicuspid Aortic Valve

Cited by 7 publications

References 3 publications

Morphotype-Dependent Flow Characteristics in Bicuspid Aortic Valve Ascending Aortas: A Benchtop Particle Image Velocimetry Study

Morphotype-Dependent Flow Characteristics in Bicuspid Aortic Valve Ascending Aortas: A Benchtop Particle Image Velocimetry Study

Bicuspid aortic valve hemodynamics does not promote remodeling in porcine aortic wall concavity

Effect of Bicuspid Aortic Valve Cusp Fusion on Aorta Wall Shear Stress: Preliminary Computational Assessment and Implication for Aortic Dilation

Contact Info

Product

Resources

About