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Nebraska donors contribute more than 500 arteries to research

March 20, 2019

By: Emily Niebrugge

Dr. Alexey Kamenskiy, an engineer, and vascular surgeon Dr. Jason MacTaggart are currently conducting two research projects that use donated arteries. The first aims to determine best treatment options for a disease found in arteries in the leg called peripheral arterial disease.

Peripheral arterial disease can be found in 20 percent of seniors and causes blockages in arteries that supply blood to leg muscles and skin. The exact causes of the disease are not clear, but age, smoking and diabetes are thought to contribute.

When the disease becomes severe, patients start to have pain or weakness when walking, or it can sometimes cause foot ulcers. If symptoms progress, surgery may be needed to re-open or bypass around the blocked artery in the leg.

Unfortunately, the surgery does not always last.

In their project, Kamenskiy and MacTaggart study leg arteries to understand how the disease develops and how best to repair it with interventions and surgery. Often, these kinds of research questions are studied using animal tissues such as mice or pigs.

“We’ve cured many diseases in mice many times, but that doesn’t frequently transfer to people,” MacTaggart said.

The samples from Live On Nebraska allow the doctors to also study disease at various stages and in various groups of people.

“Looking at younger arteries that are just starting to develop vascular disease is a unique opportunity to study the disease process,” Kamenskiy said. “There is no way we can look at these younger arteries otherwise. There typically is no reason for these subjects to even go to the hospital, let alone have a procedure.”

By the time they do need an operation, the disease usually has spread so much that it can kill the leg, requiring an amputation, MacTaggart said.

“It’s like a house that burned down,” he said. “Before modern forensics, how did one find the source that started the fire? If you can be there when the fire is started, you can then begin to understand the true source and possibly prevent it in the future. That’s what we are trying to do with these arteries from younger donors.”

In addition to studying ways to stop the beginnings of peripheral arterial disease, the doctors also hope to find ways to help people who already suffer from the disease.

Metal tubes called stents are typically used to keep arteries from closing again for patients already suffering from peripheral arterial disease. Unfortunately, this may not always last long and the disease may come back and many times re-block the artery in as little as two or three years.

Metal stents that are placed inside the blood vessel are also stiff, while arteries are delicate. Within the leg especially, arteries bend and twist when people walk, and a metal stent continuously rubs and sometimes injures the artery, Kamenskiy said.

“Imagine placing a metal tube inside your mouth and trying to chew,” he said. “The tissues of your mouth are delicate, and the metal mesh tube could tear them. If you’re healthy, your body might succeed in repairing those tears; but if you’re not, you may have a problem of a repair process that never finishes. In the artery, this usually means re-blockage of the vessel.”

To help these patients, small angioplasty balloons are often put on the inside of the artery instead and are used to open the clogged blood vessels in the leg, sometimes all the way down into the foot.

The doctors have utilized more than 575 tissue samples since 2014 to publish studies such as this one they’ve conducted. These samples come from a wide variety of donors, allowing insight into different age groups, people with different medical conditions such as diabetes, and several other characteristics.

Because they have one of the largest peripheral artery tissue libraries, they often share samples and findings nationally and internationally to collaborate with medical professionals and researchers across the world.

“This amplifies a donor’s potential even more,” MacTaggart said, “because collaborating with other facilities and researchers often leads to more discoveries and deeper learning.”

In their second project, the doctors use arteries to investigate ways to stop catastrophic bleeding. This would allow more time to transport trauma victims from the location of injury to a hospital. This is especially important in rural states like Nebraska, where even by helicopter, transport times can be long from a remote area to a hospital.

This also benefits many military members and civilians who endure traumatic deaths that are potentially preventable and related to severe bleeding. Specifically, the researchers are looking at ways to place internal tourniquets that control bleeding from areas of the body that cannot be compressed by conventional tourniquets like on the chest, abdomen or pelvis.

When a major organ or blood vessel is injured, death can occur quickly. Health care providers have limited time to transfer the victim of a trauma such as a car crash or a gunshot wound to a hospital. A common way to currently stop such severe bleeding is to cut the chest open and put a clamp on the aorta to temporarily stop all blood flow and keep the brain and heart alive.

However, this is difficult to do outside of a hospital, where it is often most critically needed. A new technique uses a small incision in the groin to get access to the artery that connects to the aorta. The aorta supplies blood to the entire body.

With this new technique, an elastic balloon is pushed inside the aorta above the site of the injury to temporarily control the bleeding and raise blood pressure to the heart and brain. Because it does not require cutting the chest open, it can be used in areas outside of a hospital for rural residents or for soldiers on the battlefield.

To more safely inflate a balloon inside an aorta, doctors need to know how much pressure should be used to stop the bleeding without injuring or bursting the aorta, which would cause even more trauma.

Kamenskiy and MacTaggart use donated human aortas from Live On Nebraska to understand these characteristics and to study how different amounts of pressure might change depending on a person’s age, sex and other risk factors.

“Without the help and support of Nebraska donors, this project would not have been possible,” Kamenskiy said.

This is part two of a seven-part series outlining the ways organ and tissue donors from Nebraska benefit many through research projects. Look for next week’s contribution discussing the second project that gives insight into artery disease.