A more effective way to predict heart attacks

Coronary artery disease is the most common type of heart disease in the United States.

It is caused by deposits of atherosclerotic plaques within coronary arteries that supply blood to the heart muscle.

Atherosclerotic plaques are accumulated, lipid-rich (fatty) material and calcifications in the vessel wall, and cause the inside of the arteries to stiffen and become restricted over time.

The most common symptom of coronary artery disease is angina, which causes chest pain or discomfort during physical exertion because the plaques restrict blood flow and oxygen supply to the heart muscle.

Also called stable angina pectoris, this condition may weaken heart function over time, but does not usually cause a sudden heart attack.

Doctors need better ways to detect and monitor these heart diseases, the leading cause of death in industrialized countries.

In a recent study led by Massachusetts General Hospital, researchers developed an improved optical imaging technique that could see differences between life-threatening coronary plaques and those posing a less imminent danger for patients with coronary artery disease.

The study is published in JACC: Cardiovascular Imaging. The lead author Behrouz Shabestari, Ph.D., director of the NIBIB program in Optical Imaging and Spectroscopy.

In the study, the team examined the properties of coronary atherosclerotic plaques in 30 patients with coronary artery disease, searching for indications of plaque instability.

Participants underwent cardiac catheterization including intravascular imaging with optical coherence tomography, to measure the polarization properties of the coronary artery wall.

Intravascular imaging uses light in the near-infrared range to acquire high-definition, cross-sectional images of the vessel wall.

Twelve catheterizations were performed on patients who had been affected by acute coronary syndrome—the higher risk form of the disease, and another 18 on patients with symptoms of stable angina pectoris.

The 30 catheterizations provided multiple plaque images for each procedure, including 342 cross-sectional plaque images and 244 images from the fibrous caps of the atherosclerotic lesions responsible for high risk or stable symptoms.

The high-resolution images enabled the researchers to classify coronary cross-sections into one of seven categories: normal, fibrous, fatty, calcified, thick cap, thin cap, or ruptured cap.

Then, the team used the specialized instrument to determine the polarization properties of the coronary arterial wall.

This is the first-in-human pilot study of intravascular polarimetry and may open new ways to study plaque composition and detecting high-risk patients.

The team says the technique could be a game-changer for cardiologists and their patients, offering refined insight into coronary arterial atherosclerotic lesions with quantifiable imaging data.

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