This document summarizes research into designing a cavopulmonary pump to support pediatric Fontan patients who have single ventricle physiology. Three unique pump designs were modeled computationally and the Rec-1 design showed the best hydraulic performance with low risks of blood cell trauma. Future work will include blood damage evaluation, design optimization of the Rec-1 model, and experimental testing of a collapsible prototype pump. The overall goal is to develop a temporary ventricular assist device for Fontan patients awaiting heart transplantation.
The treatment of patients with advanced acute heart failure is still challenging.
Intra-aortic balloon pump (IABP) has widely been used in the management of
patients with cardiogenic shock. However, according to international guidelines, its
routinary use in patients with cardiogenic shock is not recommended. This recommendation is derived from the results of the IABP-SHOCK II trial, which demonstrated
that IABP does not reduce all-cause mortality in patients with acute myocardial infarction and cardiogenic shock. The present position paper, released by the Italian
Association of Hospital Cardiologists, reviews the available data derived from clinical
studies. It also provides practical recommendations for the optimal use of IABP in
the treatment of cardiogenic shock and advanced acute heart failure.
Hemodynamic assessment of partial mechanical circulatory support: data derive...Paul Schoenhagen
Partial mechanical circulatory support represents a new concept for the treatment of advanced heart failure. The Circulite Synergy Micro Pump®, where the inflow cannula is connected to the left atrium and the outflow cannula to the right subclavian artery, was one of the first devices to introduce this concept to the clinic. Using computational fluid dynamics (CFD) simulations, hemodynamics in the aortic tree was visualized and quantified from computed tomography angiographic (CTA) images in two patients. A realistic computational model was created by integrating flow information from the native heart and from the Circulite device. Diastolic flow augmentation in the descending aorta but competing/antagonizing flow patterns in the proximal innominate artery was observed. Velocity time curves in the ascending aorta correlated well with those in the left common carotid, the left subclavian and the descending aorta but poorly with the one in the innominate. Our results demonstrate that CFD may be useful in providing a better understanding of the main flow patterns in mechanical circulatory support devices.
The treatment of patients with advanced acute heart failure is still challenging.
Intra-aortic balloon pump (IABP) has widely been used in the management of
patients with cardiogenic shock. However, according to international guidelines, its
routinary use in patients with cardiogenic shock is not recommended. This recommendation is derived from the results of the IABP-SHOCK II trial, which demonstrated
that IABP does not reduce all-cause mortality in patients with acute myocardial infarction and cardiogenic shock. The present position paper, released by the Italian
Association of Hospital Cardiologists, reviews the available data derived from clinical
studies. It also provides practical recommendations for the optimal use of IABP in
the treatment of cardiogenic shock and advanced acute heart failure.
Hemodynamic assessment of partial mechanical circulatory support: data derive...Paul Schoenhagen
Partial mechanical circulatory support represents a new concept for the treatment of advanced heart failure. The Circulite Synergy Micro Pump®, where the inflow cannula is connected to the left atrium and the outflow cannula to the right subclavian artery, was one of the first devices to introduce this concept to the clinic. Using computational fluid dynamics (CFD) simulations, hemodynamics in the aortic tree was visualized and quantified from computed tomography angiographic (CTA) images in two patients. A realistic computational model was created by integrating flow information from the native heart and from the Circulite device. Diastolic flow augmentation in the descending aorta but competing/antagonizing flow patterns in the proximal innominate artery was observed. Velocity time curves in the ascending aorta correlated well with those in the left common carotid, the left subclavian and the descending aorta but poorly with the one in the innominate. Our results demonstrate that CFD may be useful in providing a better understanding of the main flow patterns in mechanical circulatory support devices.
Short term MCS as the parachute... non RCTs in support... but try to launch out of the plane without it ;-)
Slides from the first hospital meeting On the use of MCS systems.
The passage of the Medicare Access and Children’s Health Insurance Program Reauthorization Act of 2015 (MACRA) was meant to be the dawn of a new day in healthcare to help rectify these disparities. For graduate medical education trainees transitioning from practicing in sheltered residency and fellowship environments into independent practice, understanding these new healthcare delivery models will be vital to providing high-quality care to patients.
Short term MCS as the parachute... non RCTs in support... but try to launch out of the plane without it ;-)
Slides from the first hospital meeting On the use of MCS systems.
The passage of the Medicare Access and Children’s Health Insurance Program Reauthorization Act of 2015 (MACRA) was meant to be the dawn of a new day in healthcare to help rectify these disparities. For graduate medical education trainees transitioning from practicing in sheltered residency and fellowship environments into independent practice, understanding these new healthcare delivery models will be vital to providing high-quality care to patients.
Primary mitral valve regurgitation is the second most frequent valve disease in the Western world. Definite treatment is surgical with few controlled studies to rely on. In general mild and mild/moderate regurgitation is well tolerated for years, but severe regurgitation often necessitates valve surgery. It is equally important to rule out severe mitral valve regurgitation, since unnecessary surgery can be avoided, but also rule in severe regurgitation because surgery too late often may be associated with an unfavourable outcome due to poor left ventricular function going unnoticed as a result of the mitral valve regurgitation related low impedance to left ventricular output.
The Norwood procedure is the first of three surgeries required to treat single-ventricle conditions such as hypoplastic left heart syndrome (HLHS). Because the left side of the heart can’t be fixed, the series of surgeries rebuilds other parts of the heart.
The Norwood procedure is performed in the baby’s first or second week of life.to redirect the blood flow.
Three goals for the Norwood procedure:
1, Build a new aorta.
2, Direct blood from the right ventricle through the new aorta and on to the rest of the body.
3, Direct the right ventricle to pump blood to the lungs until the next surgery.
Energy transmission system for artificial heartIshwar Bhoge
In medical implant systems high efficiency and improving the patient’s mobility. Artificial organs and monitoring devices to be implanted into human body for the extension and the improvement of human lives. The implants must operate inside the body for the considerable period and communicate with outside world wirelessly for exchange of medical data and commands. Rechargeable batteries are recharged remotely through the human skin via inductive links. In my project transformer model, a remote power supply for use in the artificial hearts for easy controllability and high efficiency, which can monitor the charging level of the battery has been designed and implemented. To recharge the battery, the electro-magnetic coupling between primary coil and secondary coil has been used. Primary and secondary windings of the transformer are positioned outside and inside the human body respectively. In such a transformer, the alignment and gap may change with external positioning. The coupling coefficient of the transformer is also varying, and so are the tool to large leakage inductances and the mutual inductance. Resonance-tank circuits with varying resonance frequency are formed from the transformer inductors and external capacitors. A control method is proposed to lock the switching frequency at just above the load insensitive frequency for optimized efficiency at heavy loads. Specifically, operation at above resonant of the resonance circuits is maintained under varying coupling coefficient. A transcutaneous power regulator is built and found to perform excellently with high efficiency and tight regulation under variations of the alignment or gap of the transcutaneous transformer load and input voltage.
1. Design & Optimization of Cavopulmonary Pump Support Pediatric Fontan Patient
School of Engineering, Department of Mechanical & Nuclear Engineering.
By Dhyaa Kafagy and Dr. Amy L. Throckmorton
Abstract:
The treatment for single ventricle physiology involves complex, cardiac surgery, resulting
in bypass of the right side of the heart and facilitating passive blood flow through the
lungs. Patients with single ventricle physiology contend with ongoing morbidity and
progressive decline in ventricular function. Heart transplants for these patients are
challenging to obtain, and there are few, if any, therapeutic options. To address the
growing need for alternative support therapies, we designed 3 unique blood pump
geometries for intravascular mechanical circulatory support. Pressure generation,
estimations of blood damage levels, shear stresses, and fluid streamlines were analyzed
using computational methods. All designs met the target pressure generation of 2-25 for a
range of blood flow rates. The Rec-1 design performed far superior to the other
geometries. Shear stress and blood damage levels indicated a low risk of blood cell
trauma.
Introduction:
Fontan is the third stage surgical treatment for a single ventricle patient. Single ventricle
heart patients have insufficient blood flow toward the left and right lungs. In the normal
heart physiology, the Inferior Vena Cava (IVC) is attached to the bottom portion of the
heart. In the Fontan patient, the surgeons literally divides the IVC where it enters the
heart and then stitches a tube to joint the upper end of the IVC to the lower portion of
the left and right pulmonary arteries, essentially, bypassing the right heart. This operation
allows more blood to reach the lungs passively.
The cavopulmonary pump is designed to augment the blood pressure in the IVC to
provide 5-12 mmHg, and about 2-3 L/min. Our pump is a temporary solution to support
the patient circulation waiting for heart transplant.
Motivation:
· Each year, thousands of children are born with single ventricle case.
· The current medical treatment model is three surgical stages:
· Norwood, Glenn and Fontan.
· The Fontan operation: usually doing well by 80%
· The short-term risk:
· Volume overload to ventricle
· Low saturation of oxygen
· Risk of death
· The long-term risk:
· Early heart failure
· No technology available
· Limited heart donors
Goals:
· Design and develop new blood pump geometries for Fontan patients.
· Create a new impeller design that will lead to a collapsible configuration.
· Conduct computational modeling of these new designs.
· Experimental Design and fabrication.
· Compare the computational performance predictions for all of the new designs
numerically & experimentally.
Methods:
· Three unique impellers have been designed to perform as a pediatric cavopulmonary axial blood
pump.
· They were constructed in a three-dimensional computer-aided design modeling using
Solidworks.
· CFD Meshes were generated using 4-5 million tetrahedral mesh elements.
· CFD simulation was conducted using specific blood physical and thermal properties.
· The pump models rotational speed performed at 4000-7000 rpm, to produce 5-38 mmHg, and
flow rate of 1-4 Liters/min.
Modeling of Three Impellers
Single Ventricle Patient [1]
Conclusions:
· The Model Rec-1 shows the best hydraulic performance among the rest of the models
· Most likely to be built in collapsible form
· Continue with CFD studies
· Blood damage modeling
· Transient simulations – time-varying boundary conditions
· Prototype construction and experimental testing
Future Work:
· Conduct Blood damage evaluation
· Optimization Design of the Model Rec_1, to improve the performance.
· Engineer the collapsible form of the pump and evaluate it experimentally.
Positioning of the pump in the IVC
Resources:
1– Single ventricle Patient: www.youtube.com/watch?v=Wnihgojg-9A
CFD Results & Comparison of the hydraulic performance of three models
Mesh Generation
CFD Simulation of 2B Model
Tel: 804-7404934/804-8826413
Email: Dhyaa.Kafagy@gmail.com
Email: Kafagydh@vcu.edu