A device that lets a doctor see inside a blood vessel to assess the fat content of plaque in arteries has been cleared for marketing by the US Food and Drug Administration. The InfraReDx LipiScan NIR catheter imaging system uses near-infrared (NIR) spectroscopy to detect lipid core-containing "plaques of interest" and assess a patient's coronary artery "lipid core burden index," said the manufacturer, InfraReDx Inc. of Burlington, Mass. NIR spectroscopy is commonly used to measure the chemical composition of unknown substances. LipiScan uses advanced optical technology -- much of it developed for telecom uses -- to deliver and retrieve NIR light from coronary plaques. Using a catheter equipped with a fiber-optic laser light into the artery, it shines the NIR light delivered through the blood to the artery wall and measures the light reflected back from the artery wall (spectroscopy). The reflected wavelengths vary depending on how much fat and other substances are in the plaque in the illuminated portion of the wall. The LipiScan console instantly displays the scan results on a “chemogram,” a digital color-coded map of the location and intensity of lipid core-containing plaques in the artery. A Lipid Core Burden Index is also reported, which is a measure of the total amount of lipid core containing plaques of interest. The LipiScan catheter interrogates each artery in less than 2 minutes and does not require the interruption of the flow of blood, the company said. "The availability of this novel tool culminates a decade-long biomedical engineering effort to create an instrument that could perform spectroscopy in the arteries of patients with coronary artery disease," InfraReDx said in a press release. "The identification of the chemical composition of coronary plaques is expected to be of value to cardiologists in the selection of medical, stenting or surgical therapy for coronary lesions. The device is also expected to be of value to the pharmaceutical industry as a means to assess the effect of novel anti-atherosclerotic agents on lipid core plaque burden." The system 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 detect plaques that have lipid (fatty) cores, the FDA said. Plaque is a deposit made up of cholesterol-rich fat, calcium and other substances found in the blood. As it 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," the FDA said. "Many heart attacks occur when a fatty coronary plaque ruptures, forming dangerous blood clots." Pathologic studies of patients who died from heart attacks have identified a large lipid (fatty) core among features of coronary artery disease that were associated with plaque rupture and thrombosis (blood clots), the FDA said. Research is 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 makeup of coronary artery plaques and help physicians identify those plaques with lipid cores, which may be of particular concern,” said Dr. Daniel Schultz, director of the Center for Devices and Radiological Health. "There is a real unmet medical need to identify lipid core containing plaques of interest in the coronary arteries, which before now we could not do,” said Dr. James Goldstein, director of research and education at William Beaumont Hospital in Royal Oak, Mich., who is also an investigator in a clinical trial for the device and a consultant for InfraReDx. “The ability to detect lipid core containing plaques of interest may go a long way in providing information to help prevent heart attacks in the near future." Funding for the development of the LipiScan system was provided by a group of over 80 private investors and Sanderling Ventures. A Series C Funding round in 2007 raised $17 million. For more information, visit www.infraredx.com