Forum Abstract

Near-infrared Diffuse Reflectance Spectroscopy for the Diagnosis of Coronary Atherosclerosis

There is a major unmet medical need for improved methods to detect and characterize coronary atherosclerosis.  Although it is widely accepted that lipid core coronary plaques are responsible for most acute coronary syndromes, standard diagnostic methods which are designed to detect obstructions, fail to characterize the chemical composition of plaques.

This limitation of coronary diagnostic methods is responsible for the inadequacy of early detection and treatment methods for coronary artery disease.  Each year in the US alone, over 200,000 suffer sudden cardiac death and an additional 1,000,000 experience an acute coronary syndrome.  These deadly and costly unexpected events indicate the need for a more effective screening program to detect dangerous coronary atherosclerosis, similar to the effective screening programs developed for prostate, breast and cervical cancer.

Diffuse reflectance near-infrared (NIR) spectroscopy is commonly used in the physical sciences to identify the chemical composition of unknown substances.  A 10 year effort has been conducted to permit the performance of NIR spectroscopy within the coronary arteries of patients undergoing catheterization.  This led to a catheter-based device to detect lipid core plaques that was approved by the FDA in April, 2008 and has now been used in over 250 patients in 8 US hospitals.  Early results indicate that lipid core plaques may be responsible for complications of stenting such as side branch obstruction and distal embolization.  Long term studies have been initiated to determine the natural history of non-obstructive lipid core plaques.

Obstacles to the application of this technology to this unmet need include the need to raise over $85,000,000, the difficulty of obtaining proof of principle in autopsy specimens, the applicability of the autopsy data to clinical data, the time required for FDA approval, a lack of a strong clinical indication for use in the early phase of introduction, a delay in reimbursement due to lack of proof of an effect on clinical outcomes, and the current macroeconomic crisis.  Despite these obstacles the device is gaining acceptance with increasing use in many parts of the United States.

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