April 29 (HealthDay News) -- The InfraReDx LipiScan NIR Catheter Imaging System, a device that helps doctors explore blood vessels to assess the fat content of arterial plaque, has been approved by the U.S. Food and Drug Administration.

Plaque -- made up of cholesterol-laden fat, calcium and other blood substances -- reduces blood flow to the heart when it accumulates on the walls of the blood vessels. This can lead to the formation of clots that can trigger a heart attack.

The newly approved device works by inserting a catheter equipped with a fiber-optic laser light into the artery, measuring the light reflected back from the artery wall. This helps doctors assess the fatty makeup of the plaque that has built up in the artery.

Nearly 1 million Americans have a heart attack each year, and about half die, the FDA said.

LipiScan is produced by InfraReDx Inc., based in Burlington, Mass.