Burlington, MA- The US FDA has approved a coronary imaging catheter designed to identify plaques that may be prone to rupture, the agency and the device's manufacturer have announced [1,2]. The LipiScan coronary imaging system (InfraReDx) shines near-infrared light on the interior of the vessel wall, analyzes the light reflected back, and identifies lipid-rich plaques by a characteristic spectral signature.

The device's console also produces what the company, in a press release, calls a chemogram—that is, "a digital color-coded map of the location and intensity of lipid-core-containing plaques of interest."

Spectroscopic interrogation of an artery takes "less than two minutes," according to InfraReDx. "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 antiatherosclerotic agents on lipid-core plaque burden."

The InfraReDx statement quotes Dr James Goldstein (William Beaumont Hospital, Royal Oak, MI) as a consultant to the company and an investigator in the catheter's key clinical trial. "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." Detecting such lipid-rich plaques, he says, "may go a long way in providing information to help prevent heart attacks in the near future."  

Dr John A Ambrose (University of California, San Francisco at Fresno), an authority in the role of imaging in acute coronary syndromes who reports having no relevant financial ties to industry, applauds the LipiScan catheter but observed for heartwire that it will probably be "years and years" before enough is known about the natural history of coronary plaques to predict which are likely to rupture.

"You have a technology or technologies in combination that can detect atheroma with a thin fiber cap," Ambrose said. "That's wonderful. The question is, now what? . . . If you have one in 20 that will eventually cause an infarct, does that mean you have to intervene on 20? What about plaque erosions where you don't have a lipid-rich plaque?" Such erosions account for a large percentage of acute coronary thromboses, he observed.

"So it's remarkable that [InfraReDx] has done this, but the technology is ahead of itself," Ambrose said. On the other hand, he observed, the catheter could potentially be used to select appropriate lengths for coronary stents used in individual patients or perhaps to identify patients who might most benefit from aggressive plaque-stabilizing therapy, such as with statins.