Near-Infrared Spectroscopy May Help Predict CV Outcomes in CAD Patients

Coronary artery disease (CAD) patients with a lipid core burden index (LCBI) equal to or above the median of 43.0, as assessed by near-infrared spectroscopy (NIRS) in a nonculprit coronary artery, have a four-fold risk of adverse cardiovascular events during one-year follow-up, according to a study published Dec. 8 in the Journal of the American College of Cardiology.

A novel, catheter-based technique, NIRS is the only intravascular imaging tool with 510(k) U.S. Food and Drug Administration clearance for identifying lipid core-containing plaques within the coronary artery wall. Despite this clearance, data on the long-term prognostic value of NIRS in patients with CAD has long been unavailable. Filling this informational void, Rohit Oemrawsingh, MD, MSc, Thoraxcenter, Department of Cardiology, ErasmusMC and Cardiovascular Research Institute COEUR, Rotterdam, The Netherlands, and colleagues performed the first prospective, observational and natural history study designed to evaluate the prognostic implications of NIRS-detected increased lipid content in coronary plaques.

Conducting NIRS imaging on a nonculprit coronary artery in 203 patients referred for angiography due to stable angina pectoris or acute coronary syndrome, a one-year follow-up showed that 28 patients sustained a major adverse cardiac and cerebrovascular event, including 21 nonculprit lesion-related events. The one-year cumulative incidence of all-cause mortality, nonfatal acute coronary syndrome, stroke and unplanned coronary revascularization (primary endpoint) was 10.4 percent. Data showed that cumulative one-year rates in patients with a LCBI equal to and above the median (43.0) vs. those with LCBI values below the median were 16.7 percent vs. 4.0 percent (adjusted hazard ratio: 4.04; 95 percent confidence interval : 1.33 to 12.29; p = 0.003).

Given that the results of their study are that of a single-center, the authors conclude that their findings are hypothesis-generating, and that moving forward, larger studies with extended follow-up are warranted.

Sanjay Kaul, MD, FACC, and Jagat Narula, MD, PhD, MACC, write in a corresponding editorial comment, “Other lingering questions remain about NIRS and other imaging tools, such as whether systemic secondary prevention strategies can be tailored based on detection of vulnerable plaques; can we achieve pre-emptive, focal treatment of such plaques safely and cost effectively; will we be able to use findings from imaging tools to guide drug development; and can we incorporate the plaque characteristics we find into a viable global risk score that also integrates clinical and angiographic characteristics with genetic and serum biomarkers to improve the accuracy of our clinical predictions … these questions will need to be answered unequivocally before detection of vulnerable plaque by NIRS, or other invasive or noninvasive imaging tool, could be recommended for the prevention and treatment of cardiovascular disease – and several trials are underway to solve those puzzles. Until then, the intravascular imaging modalities remain just another tool for research.”

Keywords: Acute Coronary Syndrome, Angina, Stable, Angiography, Coronary Artery Disease, Cost of Illness, Lipids, Spectroscopy, Near-Infrared, Stroke, United States Food and Drug Administration

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