Scanner to Find Fatty Deposits in Vessels Is Approved

By BARNABY J. FEDER
28 april 2008--Federal regulators have approved the sale of a new laser scanning system intended to locate fatty deposits in blood vessel walls that are thought to cause heart attacks.
The maker, InfraRdDx, a privately held company based in Burlington, Mass., said Friday that it expected the system to help doctors avoid placing coronary stents in vessels in ways that might raise the risk of a heart attack.
Stents are metal mesh scaffolds that prop open arteries after angioplasty, the procedure in which tiny balloons are inflated inside blood vessels to clear blockages.
Angioplasty with stenting relieves the chest pain known as angina but it does not normally — contrary to popular belief — do anything to prevent heart attack. Research suggests that heart attacks are not caused by the kind of blockages typically cleared with angioplasty but from the rupturing of thin vessel walls containing fatty deposits known as lipid pools.
Lipid pools may be anywhere in an artery wall, not just where a blockage has formed from the buildup of plaque. Researchers are unsure whether stenting the pools might reduce heart attack risk, but many believe that inadvertently covering only part of a pool probably increases the risk of rupture. And some think it is better to cover the pools with older bare metal stents than the newer drug-coated stents.
Thus, better tools to find the lipid pools could be an important aid to doctors performing angioplasty and crucial for long-term research into whether stenting the pools could save lives by preventing ruptures.
But some researchers say the whole concept of trying to find and treat lipid pools with devices is a waste of time and money. The pools, they say, are a symptom of arterial disease that affects all of the heart’s arteries and indeed the whole circulatory system. They favor efforts to use drugs and lifestyle changes to reduce concentrations of the potentially dangerous lipids throughout the body.
Doctors have tried other ways to locate lipid pools. Approaches include external CT scanners and tiny ultrasound devices inserted on the ends of catheters similar to those used to deploy angioplasty balloons and stents. InfraRdDx said its catheter, which emits near-infrared laser light inside the artery and forms an image from how much is absorbed, could produce a fuller picture of the contents and dimensions of lipids in the vessel walls.
The company’s product, the LipiScan Coronary Imaging System, consists of a $150,000 computer console that analyzes and displays the data gathered by the LipiScan laser catheter, which costs $2,400 and can be used only once.