New Method for Detecting Arterial Plaque in Development

An infrared image of a living heart showing its temperature variations. This technology is being adapted into catheter form for the detection of "hot" plaques in arteries. A fiber optic catheter is being developed at the Texas Heart Institute that can be threaded through an artery to detect, and possibly treat, plaques that are about to rupture. A rendering of an artery blocked by a thrombus that formed on a ruptured plaque; this is the major cause of heart attacks and strokes. (Photos courtesy of Texas Heart Institute)

Physicians and scientists at the Texas Heart Institute at St. Luke's Episcopal Hospital have discovered a possible way to use infrared technology to predict, and even prevent, heart attacks.

It is fairly well known that over time, and for a variety of reasons, human arteries become damaged by atherosclerosis, the accumulation of plaque on the lining of the arteries. What many people may not know is the rupturing of this plaque, rather than the simple buildup of it, is the main cause of heart attack and stroke. When a plaque ruptures, a thrombus (blood clot) forms that blocks the blood flow and, depending on the location of the obstruction, results in a heart attack or stroke. Predicting when these vulnerable plaques are going to rupture was considered impossible - until now.

"We have determined that those atherosclerotic plaques that are at risk to rupture are inflamed and therefore evidence a slight increase in temperature," says Dr. James T. Willerson, medical director and director of Cardiology Research at the Texas Heart Institute, and co-principal investigator of the project. "Once these plaques are identified, we hope to treat them, thereby preventing heart attack and stroke."

Dr. Willerson and fellow principal investigator, Dr. S. Ward Casscells, associate director, Basic Cardiology Research, Texas Heart Institute, made this discovery by noting the temperature variations on plaques surgically removed from obstructed carotid (neck) arteries. They observed that the temperature was highest in the area at highest risk to rupture.

Drs. Willerson and Casscells' team is developing an infrared, fiber optic catheter system to detect these "hot" plaques. The catheter would be threaded through the artery by way of a small incision in the groin. Infrared images would be sent to a video monitor for the physician to evaluate. The "hot" plaques could then be found and treated.

A potential treatment of these dangerous plaques may be to gently heat them until the cells are "persuaded to go to sleep," which is medically referred to as apoptosis. The detection catheter may ultimately be used to deliver this heat as well. Another possible treatment is gene therapy.

"Because many heart attack and stroke victims do not have symptoms in advance, we are also looking for non-invasive ways to pinpoint these dangerous plaques," adds Dr. Willerson. "We hope this discovery may help prevent some heart attacks and strokes in the future."

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©2006 Texas Medical Center

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