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 (LCBIROI) and the 4 and 10 mm long segment with the maximum LCBI (MaxLCBI4mm and MaxLCBI10mm). 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 MaxLCBI4mm values and a higher risk of MACE. Each 100 units increase of MaxLCBI4mm 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 MaxLCBI4mm 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 MaxLCBI10mm 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.