بررسی عددی روش های افزایش ضریب نوسانی جریان خون ورودی به ریه ها در جراحی فونتن به روش برهم کنش سیال - جامد
رجب زاده اوغاز، حمیدرضا Rajabzadeh Oghaz, Hamidreza
Proposing and Numerical Modeling of Novel Surgical Procedures in Order to Increase Pulsatility Style of TCPC Blood Flow, Using FSI Approach
Rajabzadeh Oghaz, Hamidreza | 2014
- Type of Document: M.Sc. Thesis
- Language: Farsi
- Document No: 45802 (08)
- University: Sharif University of Technology
- Department: Mechanical Engineering
- Advisor(s): Firoozabadi, Bahar; Saidi, Mohammad Said
- Single ventricle anomaly is a congenital heart disease which is characterized by anatomical malformations. The main abnormality that a patient faces is desaturated blood flow, which, without any treatment increases the risk of death. The classical treatment is based on a three stage palliative procedure which should begin from the first few days of patient’s life. The final stage is known as Fontan procedure which directly connects inferior vena-cava to pulmonary arteries without going through the ventricle.This connection is known as Total Cavo Pulmonary Connection (TCPC). After surgery, the single ventricle could supply adequate and saturated systemic blood flow for the body, but TCPC contains a low pressure as well as low flow pulsatility. In this study, we are going to introduce and evaluate some novel procedures that could be a way for increasing the pulsatility index of blood flow. It should be mentioned, that this study is following of previous researches at Bio-Fluid Laboratory at Sharif University.
1. In first part of this study, we have numerically simulated TCPC hemodynamic. Besides, we have evaluated a new methodwherein pulsatile blood would be directed to the TCPC through the stenosed main pulmonary artery (MPA).Comparing the results from FSI and non-FSI approaches, it is found out that incorporating vessel’s compliance to simulation leads to increase in the pulsatility intensity of RPA flow by 10 percent. Conversely to RPA, LPA flow rate in FSI method is more than its equivalent non-FSI approach but no significant changes have been detected in PI of LPA flow. Comparing energy lost has shown that compliance of vessels would reduce the imposed energy loss.
2. On the other hand, the geometry of TCPC is so effective on energy loss and it has recently discovered that the utilization of a new Y-shaped geometry could considerably reduce it.In second part of this study, through the use of Computational Fluid Dynamics (CFD) method, we compared T-shaped (MRI-based) and Y-shaped (computer-generated) geometries to investigate the influence of this modification on pulsation of flow in the pulmonary arteries. Our overall results show that energy loss in Y-shaped geometry is less than T-shaped geometry, but there is no significant difference in flow pulsatility.
3. In third part of this study, we have implemented an idea to place a membrane in the pulmonary artery just distal to the antegrade pulmonary blood flow to induce flow pulsatility in the pulmonary arteries. This membrane can transmit the pulsation without adding extra load to the pulmonary arteries and consequently to the ventricle. The sewn leaflets of pulmonary valve during surgery could function as a membrane. Alternatively, the composite fibrous membranes of PLGA and chitosan prepared by electro-spinning can be implanted. In this work, we have used the flow solid interaction (FSI) simulation to investigate the effect of mechanical properties of the membrane material on the pulsatility of velocity profiles
- Numerical Modeling ; Fontan Operation ; Blood Flow ; Fluid-Structure Interaction ; Pulsatility