Sinus Hemodynamics in Representative Stenotic Native Bicuspid and Tricuspid Aortic Valves: An In-Vitro Study

Hatoum, Hoda; Dasi, Lakshmi Prasad

doi:10.3390/fluids3030056

Cited by 23 publications

(16 citation statements)

References 53 publications

(85 reference statements)

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“…Recent studies by Hatoum et al demonstrated how the evolution of the aortic sinus mechanism can correlate with aortic valve efficiency and energy dissipation [8]. In addition, it was demonstrated that aortic sinus vortices initiation, entrapment and evolution play an important role in sinus stasis and washout [7,[11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Spatiotemporal Complexity of the Aortic Sinus Vortex as a Function of Leaflet Calcification

Hatoum

Dasi

2019

Ann Biomed Eng

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Several studies have shown the variation of aortic sinus structures' hemodynamics with different flow and geometric characteristics. They have also correlated aortic sinus hemodynamics with the progression and evolution of calcific aortic valve disease (CAVD). This study aims at visualizing aortic sinus fluid structure variations as functions of different leaflet calcification degrees and assessing their potential relationship with CAVD. A degenerated 23mm Carpentier-Edwards Perimount Magna valve extracted from a redo-surgery patient was implanted in an aortic root model and tested in a pulse duplicator left heart simulator. The valve has 3 leaflets with 3 different levels of calcium distribution: mild, moderate and severe. High-speed imaging and particle image velocimetry were performed to assess sinus vortices, leaflet tip position and velocity along with shear stress. Results have shown that (a) aortic sinus vortices initiation, entrapment and evolution varied with different calcified leaflet exposure; (b) higher velocities in the sinus were calculated with the mildly calcified leaflet compared to the moderately and severely calcified ones; (c) during systole, the mildly calcified leaflet sinus case shows the most spread-out and higher ranges of shear stress probabilities and highest magnitudes going from (−1.5 to +1.8 Pa) compared with (−1.0 to +1.0Pa) for moderately and severely calcified leaflets. The higher the calcification degree the lower the shear stress range and likelihoods of having higher shear stress. This holds in diastole as well. This study shows the impact of calcification on the aortic sinus flow structures.

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Section: Introductionmentioning

confidence: 99%

Spatiotemporal Complexity of the Aortic Sinus Vortex as a Function of Leaflet Calcification

Hatoum

Dasi

2019

Ann Biomed Eng

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“…31,32,42 Areas of recirculating blood flow under low shear stresses are predisposed to thrombus formation and thrombo-embolism. 32 Several recent studies have shown the importance of blood stasis in the sinus 19,2011,12,[16][17] and the neo-sinus (NS)-a region formed between the TAV leaflet and the native valve leaflet-and its correlation with potential thrombus formation. 13,14,16,34,41,56,60 In particular, two of these studies now show an explicit relationship between the percentage of blood stasis in the NS and the volume of thrombus.…”

Section: Introductionmentioning

confidence: 99%

Predictive Model for Thrombus Formation After Transcatheter Valve Replacement

Hatoum

Singh-Gryzbon

Esmailie

et al. 2021

Cardiovasc Eng Tech

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Purpose-Leaflet thrombosis is a significant adverse event after transcatheter aortic valve (TAV) replacement (TAVR). The purpose of our study was to present a semi-empirical, mathematical model that links patient-specific anatomic, valve, and flow parameters to predict likelihood of leaflet thrombosis. Methods-The two main energy sources of neo-sinus (NS) washout after TAVR include the jet flow downstream of the TAV and NS geometric change in volume due to the leaflets opening and closing. Both are highly dependent on patient anatomic and hemodynamic factors. As rotation of blood flow is prevalent in both the sinus of Valsalva and then the NS, we adopted the vorticity flux or circulation (U) as a metric quantifying overall washout. Leaflet thrombus volumes were segmented based on hypo-attenuating leaflet thickening (HALT) in post-TAVR patient's gated computed tomography. U was assessed using dimensional scaling as well as computational fluid dynamics (CFD) respectively and correlated to the thrombosis volumes using sensitivity and specificity analysis. Results-U in the NS, that accounted for patient flow and anatomic conditions derived from scaling arguments significantly better predicted the occurrence of leaflet thrombus than CFD derived measures such as stasis volumes or wall shear stress. Given results from the six patient datasets considered herein, a threshold U value of 28.0 yielded a sensitivity and specificity of 100% where patients with Gamma < 28 developed valve thrombosis. A 10% error in measurements of all variables can bring the sensitivity specificity down to 87%. Conclusion-A predictive model relating likelihood of valve thrombosis using U in the NS was developed with promising sensitivity and specificity. With further studies and improvements, this predictive technology may lead to alerting physicians on the risk for thrombus formation following TAVR.

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“…The use of synthetic experimental data provides an ideal setting to validate and quantify the accuracy of our model. Ideally, one would select low-resolution in-vivo data as the experimental data, perform DA with CFD, and assess the accuracy of the results with in-vitro measurements such as PIV, which is considered the gold-standard method in experimental fluid mechanics [9] and is commonly used in hemodynamics research [61][62][63][64]. However, unfortunately, this approach does not perform a real validation.…”

Section: Discussionmentioning

confidence: 99%

Integrating multi-fidelity blood flow data with reduced-order data assimilation

Habibi¹,

D’Souza²,

Dawson³

et al. 2021

Preprint

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High-fidelity patient-specific modeling of cardiovascular flows and hemodynamics is challenging. Direct blood flow measurement inside the body with in-vivo measurement modalities such as 4D flow magnetic resonance imaging (4D flow MRI) suffer from low resolution and acquisition noise. In-vitro experimental modeling and patient-specific computational fluid dynamics (CFD) models are subject to uncertainty in patient-specific boundary conditions and model parameters. Furthermore, collecting blood flow data in the near-wall region (e.g., wall shear stress) with experimental measurement modalities poses additional challenges. In this study, a computationally efficient data assimilation method called reduced-order modeling Kalman filter (ROM-KF) was proposed, which combined a sequential Kalman filter with reduced-order modeling using a linear model provided by dynamic mode decomposition (DMD). The goal of ROM-KF was to overcome low resolution and noise in experimental and uncertainty in CFD modeling of cardiovascular flows. The accuracy of the method was assessed with 1D Womersley flow, 2D idealized aneurysm, and 3D patient-specific cerebral aneurysm models. Synthetic experimental data were used to enable direct quantification of errors using benchmark datasets. The accuracy of ROM-KF in reconstructing near-wall hemodynamics was assessed by applying the method to problems where near-wall blood flow data were missing in the experimental dataset. The ROM-KF method provided blood flow data that were more accurate than the computational and synthetic experimental datasets and improved near-wall hemodynamics quantification.

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Sinus Hemodynamics in Representative Stenotic Native Bicuspid and Tricuspid Aortic Valves: An In-Vitro Study

Cited by 23 publications

References 53 publications

Spatiotemporal Complexity of the Aortic Sinus Vortex as a Function of Leaflet Calcification

Spatiotemporal Complexity of the Aortic Sinus Vortex as a Function of Leaflet Calcification

Predictive Model for Thrombus Formation After Transcatheter Valve Replacement

Integrating multi-fidelity blood flow data with reduced-order data assimilation

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