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A project with heart

Students research artifical heart valves

Contributing Writer

Published: Tuesday, April 9, 2013

Updated: Tuesday, April 9, 2013 01:04

Pig's heart valve


Seniors Tim Roemer and Andrew Beland work on a pig’s heart as part of the Ex Vivo, or “out of body” portion of their senior project, which studies the flow of the human heart and artificial valve geometries.

Instead of building Formula One racecars, model airplanes or off-road vehicles for their senior project, Tim Roemer’s mechanical engineering group is going biomedical: studying the flow dynamics of the human heart and artificial valve geometries

Roemer’s group is using Ex Vivo and PIV technologies for their project. The group includes seniors Roemer, Andrew Beland, Chloe Garrage, Greg Kopanski, and Jimmy Popovitch

So, why are mechanical engineer seniors researching the biomedical aspects of the human heart? Because heart valves can malfunction, tear and leak. Mitral valve regurgitation occurs when blood leaks into the heart and the flow is disrupted. It can lead to heart swelling, lethargy and activity restriction. 

Artificial valves can be designed to save lives.

According to the Mayo Clinic website, mitral valve regurgitation occurs when “the flaps (leaflets) of the mitral valve weaken, causing blood to leak backward into the left atrium of your heart. If not treated, it can result in heart muscle damage.”

Roemer and his group compiled research from textbooks, published papers and medical websites on mitral valve regurgitation. During their research, they found that more than 3 million people in the United States have it. With over 300 million people in the United States, one percent of the population is affected. 

Christopher White is a professor of mechanical engineering. He is also Roemer’s group advisor. Though the percentage is small, he does not think it explains the issue.

“I think the numbers are significant enough,” White said. “So, if you put it in percentage, it’s not a large percent, but it is a large number of people.” 

Roemer’s group also found that every year over 250,000 people are diagnosed with mitral valve regurgitation. In terms of surgeries worldwide, it translates to over 100,000 valve replacements every year. 

When mitral valve regurgitation is not treated, the heart can swell. In worst-case scenarios, MVR leads to heart failure. 

While this wasn’t the case for Sean-Michael Dunphy, he still experienced a close call. As a baby, he had open-heart surgery.   

“When I was six months old, they did what’s called a balloon operation,” Dunphy said over the phone. Surgeons found that Dunphy’s pulmonary valve was closed and not enough blood was getting to his heart. 

The solution was to put in a valve to open it up. However, the procedure left a tear. Doctors frequently checked on the status of Dunphy’s heart as he aged, he said. 

At age 21, Dunphy’s heart swelled and the tear in his heart spread. Doctors told him that his heart was 175 percent larger than it was supposed to be. They were worried about the elasticity of his heart, Dunphy said.

Because doctors noticed Dunphy’s swollen heart, they performed surgery at Massachusetts General Hospital in Boston after his junior year. The surgery was a success. 

Dunphy is now 24 years old and ran a half marathon in Hampton last September. 

Dunphy’s experience is just one example of how Roemer’s project could be impactful in the biomedical community.

“The main goal of their project is to quantify the performance of various artificial mitral valve geometries,” White said. “So, the measures of performance would be the pressure drops across the valve. So if you have a large pressure drop, your heart has to work harder.” 

In other words, if the group can understand the blood flow through an artificial valve, they can figure out ways to reverse mitral regurgitation. 

Roemer’s interest in the project started at the end of his junior year. Roemer took White’s class, ME 646: Experimental Methods and Data Analysis, where he did preliminary work for his current project.

In ME 646, Roemer worked with three-inch-diameter valves. He used airflow to test the valves. For his current project, Roemer’s group works with life-sized, one-inch-diameter valves and water, which acts like fast-moving blood. 

White was impressed with Roemer’s group work in his ME 646 class, he said. 

“It was probably the best — or at least Top 5— projects that I’ve seen in the seven years that I’ve taught the class. And there’s roughly about 30 projects a year,” White said. “So, this is over 200 projects, and his group was certainly Top 5 that I’ve seen. So, certainly they surprise me by the quality of their work.” 

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