If these walls could talk, they’d save lives.
According to the World Health Organization, cardiovascular disease kills more people worldwide than any other medical condition. But thanks to the researchers behind IntraMon, heart disease has a new way to communicate with physicians.
IntraMon, competing in this year’s Invent Oregon Collegiate Challenge and a team consisting of professors Dr. Younes Jahangiri, Dr. Khashayar Farsad, Dr. Sean Kohles, Dr. Rick Weitzel, and Daniel Mullee, a medical student and research assistant, has developed a way for stents to tell smartphones how much they are blocked.
"IntraMon is a wireless implant that can be put in any tubular structure that's put into the human body,” Mullee said. “The purpose of it is that it can detect occlusion of that tubular structure."
Part of a simple circuit, a component within the stent is highly sensitive to a change in pressure—say, from plaque buildup in blood vessels. When the pressure changes, the frequency of electromagnetic radiation that the component uses to communicate will change. A device capable of receiving those messages, like a smartphone, translates and interprets these variations as the level of occlusion, or blockage, within the blood vessel.
This data provides physicians with a critical advantage against the onset of atherosclerosis and other occlusions in the body.
Mullee compared the circuitry to the square stickers commonly found in bookstores that prevent theft. “You could, in fact, have software on your phone, put it up to your stent, your artery, and then get a measurement right there that could be sent directly to your medical professional.”
And IntraMon is completely safe. The stent communicates via electromagnetic radiation, but at a safe level. "It's very, very high frequency,” Dr. Weitzel said. “It's so high that there's no physiological function in the body that could be affected by it.”
"We think it could be a game changer because of the people who are going to benefit from it,” Mullee said.
Nearly 18 million people died from heart disease in 2016, more than any other cause. In the United States, one in every four deaths is cardiovascular. According to the Centers for Disease Control, a heart attack may happen without the victim even being aware of it. An insidious disease sometimes called a “silent killer,” one in five heart attacks is silent. It can strike without any symptoms thanks to the gradual buildup of plaques and fats in veins and arteries.
Over time, the buildup becomes so significant, the opening, or patency, of a blood vessel so small, that it can rupture, sometimes without warning. Stents are designed to prevent this from happening, but they’re a temporary fix and leave much to be desired.
"When you're putting a stent to hold open an artery that's become occluded through atherosclerosis, you know, typical methods of fat being built up, plaque being built up over years,” Mullee said, "the problem is that that metal structure, well, it holds up in the artery, but it also provides a platform for more things to build up on it."
Once a stent is placed, it is subject to the same atherosclerotic buildup that affects arteries in the first place. Called reocclusion, the buildup of fat and plaque happens more quickly on stents than it does on the walls of the structures it props open.
Occlusions and reocclusions can occur in any tubular structure in the body. This commonly implicates blood vessels because atherosclerosis is so widespread. But occlusions also occur in the digestive, urinary and pulmonary systems, and the brain.
"We're planning on using it potentially in VP shunts, which is a shunt that goes from your brain to your abdomen, for example, to remove excess fluid in your brain,” Mullee said.
In veins, IntraMon could make a critical difference. Occlusions there commonly remain undetected, in large part because veins convey blood at a lower pressure.
For example, when a peripheral artery in the leg develops a blockage, the result is claudication, a pain associated with movements like walking. Importantly, the pain doesn’t develop until after the blockage occurs.
“The pain discovery comes later, but the patency has gotten worse and worse,” said Dr. Weitzel, describing the rupture of a vein. "When the pain hits, you may just basically have lost that vein and maybe much more.”
For these reasons, it’s critical for the medical field to have a way of monitoring blockages as they develop in high-risk patients rather than after symptoms occur. By having an earlier detection, Mullee said that IntraMon will reduce mortality and morbidity from cardiovascular disease and improve patient outcomes in other types of occlusions.
That alone is worth the investment, but IntraMon also offers a host of other benefits.
Right now, an angiography, which consists of injecting the blood with dye and taking pictures, is the only way to detect how much plaque is building up in the arteries. "It's not like you just get angiography one time. You get angiography probably multiple times,” Mullee said.
An angiography is an invasive and costly procedure, and it requires medical experts. Not so with IntraMon. “With our device, we would be able to wirelessly sense the degree of occlusion in that stent without having to go through any invasive procedure,” Mullee said.
When patients need fewer angiographies, that means they save money and time in the hospital. When IntraMon’s stent is placed, patients never need an angiography until an occlusion is detected, in which case surgery is probably necessary anyway.
IntraMon could also give patients some role in their own care, a way of feeling connected to the treatment they receive, a unique kind of peace of mind. Doctors debate the risk of providing patients with their own healthcare information, but in some cases it can be useful.
For example, shortly after a stent is placed in an artery, some patients experience phantom chest pains. With IntraMon, they would be able to measure the occlusion and reassure themselves that the stent is fine.
“The value of that is priceless,” Mullee said.
And so are the lives that IntraMon could help physicians save.