Near-infrared spectroscopy could help predict future cardiovascular events risk

In a new study, Infraredx evaluated the ability of intravascular near-infrared spectroscopy (NIRS) to identify lipid core-containing plaques, which are believed to be implicated in most heart attacks, as a means to predict the risk of future major adverse cardiac and cerebrovascular events (MACCE).

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In a new study, coronary artery disease medical device maker Infraredx (Burlington, MA) evaluated the ability of intravascular near-infrared spectroscopy (NIRS) to identify lipid core-containing plaques, which are believed to be implicated in most heart attacks, as a means to predict the risk of future major adverse cardiac and cerebrovascular events (MACCE).

In the study, patients who presented with symptoms associated with limited blood supply to the heart also underwent NIRS imaging to evaluate the lipid core burden index (LCBI) in an artery that was not directly implicated in causing their symptoms. The results demonstrated that patients with an LCBI > 43 in a non-culprit artery had a fourfold risk of MACCE, such as heart attack or stroke, within the following year. In addition, the study concluded that non-culprit vessel LCBI reflects vascular vulnerability of the larger coronary tree.

Lipid-core plaque is a type of fatty coronary artery plaque suspected to be prone to rupture, which leads to the formation of blood clots that can cause heart attacks. Only NIRS can detect lipid-core plaque and provide a quantitative measurement in the form of an LCBI. Intravascular NIRS is commercially available through the company's TVC Imaging System, which is the only FDA-cleared dual-modality imaging system capable of identifying lipid-core plaques using NIRS and providing vessel structure information using enhanced intravascular ultrasound (IVUS).

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Infraredx's TVC Imaging System, a dual-modality imaging system that can identify lipid-core plaques using near-infrared spectroscopy (NIRS).

The ATHEROREMO-NIRS Study, a sub-study of the European Collaborative Project on Inflammation and Vascular Wall Remodeling in Atherosclerosis (ATHEROREMO), is a prospective, single-center, observational study that enrolled 203 patients referred for coronary angiography due to stable angina (chest pain) or an acute coronary syndrome (ACS), a combination of symptoms resulting from the blockage of blood supply to the heart. NIRS imaging was performed and an LCBI measurement was obtained for a pre-defined segment of a non-culprit coronary artery that was at least 40 mm in length and with <50 percent stenosis confirmed by angiography. The primary endpoint was the incidence of MACCE, defined as all-cause mortality, non-fatal ACS, stroke, and unplanned coronary revascularization during one-year follow-up. MACCE not related to the culprit lesion—the site treated during the index procedure—occurred in 21 patients (10.4 percent). In addition, regression analysis demonstrated that men, patients with a history of hypercholesterolemia, stroke, or peripheral artery disease had higher LCBI values.

Full details of the work appear in the Journal of the American College of Cardiology (JACC); for more information, please visit http://content.onlinejacc.org/article.aspx?articleID=2022246.

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