An Inverse Numerical Approach for Modeling Aortic Heart Valve Leaflet Tissue Oxygenation

Mohammadi, Hadi; Mequanint, Kibret

doi:10.1007/s13239-011-0068-0

Cited by 8 publications

(5 citation statements)

References 11 publications

(14 reference statements)

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“…The governing equations of motion for the leafletare solved by fourth order Runge-Kutta method. The heart rate and cardiac output were selected to be 70 beats per minute (bmp) and 6 lit/min, respectively [10]. The ventricular pressure is assumed to decrease from a value equal to the aortic pressure (when the valve is fully opened) and the average aortic pressure is considered to be 16.0 kPa, i.e., 120 mmHg in the closing phase and is assumed to be constant all along.…”

Section: Resultsmentioning

confidence: 99%

Elliptic st. jude bileaflet mechanical heart valves

Mohammadi¹,

Jahandardoost²,

Fradet³

2015

Cardio Vasc Syst

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St. Jude Medical (SJM) bileaflet mechanical valves were approved by the Food and Drug Administration in 1977. The SJM valve design consists of two semicircular leaflets which pivot on hinges. Compared to other mechanical heart valve prostheses such as ball and cage and tilting disk prosthetic valves, it provides good central flow, the leaflets open completely, and the pressure drop across the valve is trivial. However, non-physiological hemodynamics around these valves may lead to red blood cells lysis and therombigenic complications. Also, the regurgitation-flow inSJM valves is almost twice that of the native valves in the aortic position. In this study, we suggest a new design for the stent (housing) of SJM valves in which 15% ovality is applied to the stent whereas its perimeter remains constant. In a pilot study, the hemodynamic performance of the proposed design is analyzed in the closing phaseand compared to that of conventional SJM models. Results show that while the elliptic SJM model offers a shorter closing phase (9.7% shorter), the regurgitation flow remains almost unchanged. In other words, even though the dynamic response of the valve is improved, the regurgitation flow is not decreased. Thus, a more efficient effective orifice area (EOA) is shown to be provided by the proposed model. The preliminary calculations presented in this study justify an improved hemodynamics of elliptic SJM valves compared to conventional models; the proposed design shows promise and merits further development.

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Section: Resultsmentioning

confidence: 99%

Elliptic st. jude bileaflet mechanical heart valves

Mohammadi¹,

Jahandardoost²,

Fradet³

2015

Cardio Vasc Syst

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“…The heart rate and the cardiac output were selected to be 70 beats per minute (bmp) and 6 L/min, respectively. 11 When the valve is fully open, the ventricular pressure is assumed to decrease from a value equal to the aortic pressure and the average aortic pressure is assumed to be 16.0 kPa which is equal to 120 mmHg in the closing phase and is assumed to remain unchanged all along.…”

Section: Methodsmentioning

confidence: 99%

“…Also, turbulence and the overall hemodynamic complexity around the valve could be an issue in SJM valves. 6–11 This study aims at addressing some of these shortcomings associated with the conventional SJM valve.…”

Section: Introductionmentioning

confidence: 99%

Oval housing for the St. Jude Medical bileaflet mechanical heart valve

Mohammadi

Fradet

2017

Proc Inst Mech Eng H

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The St. Jude Medical bileaflet mechanical heart valve was approved by the Food and Drug Administration in late 1970s. The basic idea for the design of the valve is simply two semicircular flat plates pivoting on hinges. The overall performance of St. Jude Medical valves such as blood flow being central, the leaflets opening completely, and the pressure drop across the valve being trivial is satisfactory. St. Jude Medical valves provide an improved hemodynamics compared to the other mechanical heart valve models; however, their non-physiological hemodynamics which may lead to red blood cells lysis and thrombogenicity still remains a major issue. In this study, we hypothesize that applying ovality to the housing might improve their hemodynamics significantly which is based on the fact that the native annulus is oval by nature. A quick but precise numerical model based on the finite strip method was developed by which the regurgitation flow volume and velocity of the proposed design were assessed in the closing phase. The results are satisfactory and an improved hemodynamics is observed. The proposed design can be considered for further numerical and experimental studies and shows promise and merits further development.

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“…Viscoelasticity of blood: Viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deformation [43][44][45][46][47][48][49]. Biomechanics of Human Blood DOI: http://dx.doi.org/10.5772/intechopen.78305…”

Section: Area Compressibility Modulusmentioning

confidence: 99%

Biomechanics of Human Blood

Earl¹,

Mohammadi²

2019

Biomechanics

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Hematology is known as the study of blood regarding health and disease which revolves around issues with red blood cells (RBCs), white blood cells (WBCs), platelets, lymph nodes, blood vessels, bone marrow, and the proteins involved in bleeding and clotting. As biomedical engineers, it is especially vital to understand the mechanics of the various components of blood to avoid unwanted results from implantations such as heart valves. A comprehensive review on the biomechanics of blood is discussed in this chapter. We will also discuss that even though human blood is a non-Newtonian fluid, depending on the instance, it can be considered a Newtonian fluid.

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An Inverse Numerical Approach for Modeling Aortic Heart Valve Leaflet Tissue Oxygenation

Cited by 8 publications

References 11 publications

Elliptic st. jude bileaflet mechanical heart valves

Elliptic st. jude bileaflet mechanical heart valves

Oval housing for the St. Jude Medical bileaflet mechanical heart valve

Biomechanics of Human Blood

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