The U.S. Food and Drug Administration has cleared for marketing a device that a doctor can use to see inside a blood vessel to assess the fat content of the plaque which builds up on the wall of the coronary arteries.

Plaque is a deposit made up of cholesterol-rich fat, calcium, and other substances found in the blood. As plaque accumulates on the artery wall, it reduces blood flow to the heart muscle and increases the risk of blood clots which can lead to a heart attack.

Nearly one million Americans suffer a heart attack every year and about half die. Many heart attacks occur when a fatty coronary plaque ruptures, forming dangerous blood clots. Pathologic studies of patients who died from heart attack have identified a large lipid (fatty) core among features of coronary artery disease that were associated with plaque rupture and thrombosis (blood clots). Research is currently underway to determine how plaques that are prone to rupture can best be identified before they cause a heart attack.

“This is the first device that can help assess the chemical make-up of coronary artery plaques and help physicians identify those plaques with lipid cores, which may be of particular concern,” said Daniel Schultz, M.D., director of the Center for Devices and Radiological Health.

The InfraReDx LipiScan NIR Catheter Imaging System uses infrared imaging to detect lipid core-containing plaques of interest and assess a patient's coronary artery lipid core burden index. The device works by placing a catheter equipped with a fiber-optic laser light into the artery. The device shines the near infrared light delivered through the blood to the artery wall, and measures the light reflected back from the artery wall, a technique called spectroscopy. The reflected wavelengths vary depending on how much fat and other substances are in the plaque in the illuminated portion of the wall.

LipiScan is manufactured by InfraReDx Inc. of Burlington, Mass. The device is cleared for use by physicians who are evaluating patients with symptoms of coronary heart disease during a heart test known as cardiac angiography, to help in detection of plaques that have lipid (fatty) cores.