Near-infrared spectroscopy-derived lipid core burden index predicts adverse cardiovascular outcome in patients with coronary artery disease during long-term follow-up

Aims: Near-infrared spectroscopy (NIRS) is able to quantify cholesterol within coronary arteries by the lipid core burden index (LCBI). We studied the prognostic value of NIRS-derived LCBI in patients with coronary artery disease (CAD) for adverse cardiac outcome during long-term follow-up. Methods and results: During 2009-2013, NIRS was performed in a non-culprit artery of 275 patients undergoing coronary angiography for acute coronary syndrome (ACS) or stable angina. LCBI was quantified by an independent corelab for the region of interest (LCBI_ROI) and the 4 and 10 mm long segment with the maximum LCBI (MaxLCBI_4mm and MaxLCBI_10mm). The primary endpoint was major adverse cardiac events (MACE), defined as the composite of all-cause death, non-fatal ACS, or unplanned revascularization. Hazard ratios (HR) were adjusted for age, gender, clinical risk factors, and segment plaque burden based on intravascular ultrasound. During a median follow-up of 4.1 years, 79 patients (28.7%) had MACE. There was a statistically significant and independent continuous relationship between higher MaxLCBI_4mm values and a higher risk of MACE. Each 100 units increase of MaxLCBI_4mm was associated with a 19% increase in MACE [hazard ratios (HR) 1.19, 95% confidence intervals (95% CI): 1.07-1.32, P = 0.001]. Continuous MaxLCBI_4mm remained independently associated with MACE after exclusion of target lesion-related events (HR 1.21, 95% CI: 1.08-1.35), as well as after exclusion of adverse events related to the NIRS-imaged coronary segment (HR 1.19, 95% CI: 1.06-1.34). Results for MaxLCBI_10mm were comparable. Conclusion: NIRS-derived LCBI is associated with adverse cardiac outcome in CAD patients during long-term follow-up independent of clinical risk factors and plaque burden.