Atherosclerotic plaques represent the hallmark lesion of atherosclerosis. While some plaques remain asymptomatic, some become obstructive causing stable angina, and others can become vulnerable to rupture and acute thrombosis which may lead to an acute coronary syndrome.1,2
Check out this interactive artery showing the progression of atherosclerosis and vulnerable plaque.
Statin trials using optical coherence tomography (OCT), a catheter-based coronary artery visualization technique, demonstrate that achievement of lower LDL-C levels with more intensive therapy is associated with increased fibrous cap thickness (FCT) and smaller lipid arc, thus favorably improving features of plaque stability.1-3
Patients in the study were stratified according to achieved LDL-C levels (< 50 [87 plaques], 50–70 [81 plaques], 70–100 [117 plaques], < 100 mg/dL [130 plaques]). Data analyzed from the Cleveland Clinic FD-OCT Registry, which included 293 and 122 non-obstructive lipid and fibrous plaques in 280 stable statin-treated CAD patients evaluated by FD-OCT imaging in vessels requiring PCI.
CAD, coronary artery disease; FD-OCT, frequency-domain optical coherence tomography; LDL-C, low-density lipoprotein cholesterol; PCI, percutaneous coronary intervention.
Numerous clinical trials using another imaging technique, Intravascular Ultrasound (IVUS), have assessed the impact of LDL-C lowering on atherosclerotic burden. These studies have demonstrated a direct relationship between LDL-C lowering and reduction in atheroma volume.1-5
LDL-C, low-density lipoprotein cholesterol; PAV, percent atheroma volume.
Different intravascular techniques including optical coherence tomography (OCT) and intravascular ultrasound (IVUS) can be used to visualize atherosclerotic plaques. Each technique offers complementary information about plaque, with IVUS providing insight into plaque volume, and OCT allowing for detection of certain features of plaque vulnerability.1-3
Intravascular ultrasound (IVUS) produces cross-sectional images of the lumen and coronary artery wall using catheter-based ultrasound transducers, reaching 100 μm resolution. Due to deeper tissue penetration, IVUS enables volumetric quantification of atheroma (plaque size) within the entire vessel wall from intima to adventitia, and allows for evaluation of changes in plaque burden over time.
Optical Coherence Tomography (OCT) produces cross-sectional images of the lumen and the superficial (intimal) layer of the arterial wall by measuring near-infrared light intensity reflected from tissue. OCT provides the highest spatial resolution capability (<10μm), allowing for higher sensitivity to detect certain features of plaque vulnerability, including the fibrous cap and the lipid core.
CS, clinical studies; CA, clinically approved for commercial use