Multimodality Intracoronary Imaging With Near-Infrared Spectroscopy and Intravascular Ultrasound in Asymptomatic...

Area of Science:

• Cardiovascular Imaging
• Interventional Cardiology
• Biomarkers of Atherosclerosis

Background:

• High coronary artery calcium scores (CACS) indicate significant coronary atherosclerosis.
• Lipid-rich plaques (LRP) are a key driver of acute coronary events.
• The relationship between CACS and coronary lipid burden requires further investigation.

Purpose of the Study:

• To determine the frequency of large LRP in individuals with high CACS.
• To assess the correlation between CACS and coronary lipid burden.

Main Methods:

• Combined near-infrared spectroscopy (NIRS) and intravascular ultrasound (IVUS) were used.
• 20 asymptomatic individuals with CACS ≥300 Agatston units were studied.
• LRP and lipid core burden index (LCBI) were quantified using NIRS; plaque volume by IVUS.

Main Results:

• Coronary artery calcium scores (CACS) significantly correlated with plaque volume (r=0.69, P<0.0001) but not with lipid core burden index (LCBI) (r=0.24, P=0.07).
• Large LRP (maximum LCBI in 4 mm ≥400) were infrequent, detected in 25% of subjects and 1.9% of segments.
• No LRP were detected in 40% of subjects with high CACS.

Conclusions:

• In individuals with high CACS, coronary artery calcification correlates with total plaque volume but not directly with lipid burden.
• The infrequency of large LRP despite high CACS suggests that calcification may not be a reliable surrogate for lipid-rich, vulnerable plaque.
• These findings have implications for risk stratification in patients with high CACS, as LRP, not calcification, primarily drives acute coronary events.