Computer simulations could lead to better cardiac pump for children with heart defects

September 10, 2012, University of California - San Diego
Alison Marsden, a professor of mechanical and aerospace engineering, examines some of the simulations her research group developped in the StarCAVE imaging space on the UC San Diego campus. Credit: Erik Jepsen, UC San Diego Publications

Structural and mechanical engineers at the University of California, San Diego, are working together to create blood flow simulations that could lead to improvements in the design of a cardiac pump for children born with heart defects. They hope that the design changes will improve young patients' outcomes.

The Berlin Heart is currently the only FDA-approved cardiac pump for young children who can't be outfitted with an adult-sized pump. The device is used to extend a patient's life until a transplant becomes available. Accurate simulations of the way blood flows inside the pump are important because the device is associated with a 40 percent risk of developing blood clots, which can lead to strokes or embolisms. This in turn can have devastating consequences on the children using the pump, who can be anywhere from just a few months old to about 9 years of age. Simulations can be used to make design changes that would lower these risks.

Two researchers at the Jacobs School of Engineering at UC San Diego have combined their strengths to solve this problem. Alison Marsden, a professor of mechanical and aerospace engineering, focuses on the development of blood flow simulation tools that can be used to test and optimize new heart surgery designs on the computer before trying them on patients. Yuri Bazilevs, a professor of structural engineering, focuses on computational science and engineering to develop methods for large-scale, high-performance computing applications.

"This works saves a tremendous amount of time, money and risk," said Dr. Jeff Feinstein, a pediatric cardiologist at Stanford University, who has been working closely with the Jacobs School researchers.

Marsden, Bazilevs and their teams have successfully simulated blood flow within the device. They are now trying to understand how blood clots form inside the pump. The next step is to figure out, through simulations, what design changes are needed to reduce that risk.

The Berlin Heart, a pediatric heart pump, seen on the side where the blood chamber is located. Credit: Jacobs School of Engineering at UC San Diego

"Yuri has been essential in training my team in complex mathematical methods, such as finite element methods, and providing expertise in the development of cutting-edge computational methods," Marsden said. "I interface with the clinical people to identify high-impact applications, and combined we make a great team."

The pump has two chambers: one for blood, another for air, separated by a flexible membrane. The air chamber is pressurized, which drives the membrane to pump the blood. But blood flow created by the device is difficult to simulate because of the interaction of blood, membrane and air.

"Blood vessels are complicated," said Bazilevs, the structural engineer.

He specializes in complex simulations depicting the interaction of several elements. His lab has produced simulations of everything from airflow for wind turbine blades to air flow and water interacting with the hulls of high-speed ships.

"Simulating the heart pump is not simple," Bazilevs said. "Current commercially available codes are not capable of handling such problems, which necessitate the development and implementation of advanced procedures for the interaction of fluid and structure for this class of applications."

"Alison's expertise in applications of computational methods to pediatric cardiology complements my expertise in the formulation and implementation of advanced computational fluid-structure interaction techniques," Bazilevs added. "It is the fact that our skill sets complement each other and Alison's great personality that fuels this collaboration."

Marsden's work focuses on the development of blood flow simulation tools that can be used to test and optimize new heart surgery designs on the computer before trying them on patients. Her group uses patient imaging data, such as CT or MRI scans, to build personalized computer models of the arteries and veins, simulate blood flow and design surgeries that are customized to the patient. Many of the simulation tools used in this research are similar to those originally developed for aircraft design.

Chris Long, a PhD student is working on simulations of blood flow in the Berlin Heart. Credit: Jacobs School of Engineering at UC San Diego

Some of the designs developed in Marsden's lab have been used by pediatric heart surgeons at Stanford to treat children born with only one functioning heart ventricle. She and her students also have developed models of heart damage occurring in Kawasaki Disease in collaboration with physicians at the UC San Diego Medical Center and Rady Children's Hospital.

The collaboration between Marsden and Bazilevs illustrates the inter-disciplinary thinking that is one of the strengths of the Jacobs School.

The new Structural and Materials Engineering building, where both Marsden and Bazilevs are based, is designed to encourage such thinking. It is home to structural, mechanical, aerospace and nanoengineers, as well as visual artists.

"Yuri and I have been co-advising a student, and he is looking forward—for better or worse!—to having both his advisors in the same building," Marsden said.

Explore further: US approves first heart pump for children

Related Stories

US approves first heart pump for children

December 18, 2011
The US Food and Drug Administration has approved a first mechanical cardiac assist device for children that can help keep patients alive as they await a transplant.

Recommended for you

Researchers borrow from AIDS playbook to tackle rheumatic heart disease

January 22, 2018
Billions of US taxpayer dollars have been invested in Africa over the past 15 years to improve care for millions suffering from the HIV/AIDS epidemic; yet health systems on the continent continue to struggle. What if the ...

A nanoparticle inhalant for treating heart disease

January 18, 2018
A team of researchers from Italy and Germany has developed a nanoparticle inhalant for treating people suffering from heart disease. In their paper published in the journal Science Translational Medicine, the group describes ...

Starting periods before age of 12 linked to heightened risk of heart disease and stroke

January 15, 2018
Starting periods early—before the age of 12—is linked to a heightened risk of heart disease and stroke in later life, suggests an analysis of data from the UK Biobank study, published online in the journal Heart.

'Decorated' stem cells could offer targeted heart repair

January 10, 2018
Although cardiac stem cell therapy is a promising treatment for heart attack patients, directing the cells to the site of an injury - and getting them to stay there - remains challenging. In a new pilot study using an animal ...

Two simple tests could help to pinpoint cause of stroke

January 10, 2018
Detecting the cause of the deadliest form of stroke could be improved by a simple blood test added alongside a routine brain scan, research suggests.

Exercise is good for the heart, high blood pressure is bad—researchers find out why

January 10, 2018
When the heart is put under stress during exercise, it is considered healthy. Yet stress due to high blood pressure is bad for the heart. Why? And is this always the case? Researchers of the German Centre for Cardiovascular ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.