Pathology of Coronary Atherosclerotic Plaques and Mechanisms of Plaque Disruption

Abstract

Coronary atherosclerosis with acute thrombosis is the most common cause of sudden cardiac death. Because the disruption of coronary atherosclerotic plaques triggers acute thrombosis, it is important to identify disruptionprone plaques with imaging modalities. The pathology of "plaque disruption" incudes three distinct morphologic entities: plaque rupture, plaque erosion, and calcified nodule. Currently, invasive imaging modalities such as intravascular ultrasound and intravascular optical coherence tomography can identify rupture-prone plaques, or thin-cap fibroatheromas, and calcified nodules, and unveiled that asymptomatic, multiple-plaque ruptures are a frequent complication in patients with coronary atherothrombosis. However, they cannot identify erosion-prone plaques. This article describes the morphological characteristics of coronary plaque disruptions and their possible mechanisms. In addition, the plaque imaging by nuclear medicine is discussed from a pathological viewpoint. Plaque ruptureA plaque rupture is characterized by a luminal thrombus overlying a lipid-rich fibroatheroma with an interrupted thin fibrous cap (Fig. 1a and b). Plaque rupture allows a thrombogenic, necrotized (lipid) core to be exposed to platelets and coagulation factors, resulting in platelet-fibrin thrombus formation (4). Plaque rupture is most likely to occur in plaques with thin fibrous caps (usually <65μm thick), large necrotized cores, abundant macrophages and lymphocytes (4).Thus, a plaque with a thin fibrous cap is thought to be a precursor to plaque rupture, and is referred to as a thin-cap fibroatheroma (5) (Fig. 1c and d). Clinical studies have confirmed that the presence of thin-cap fibroatheromas is an independent risk factor for future cardiovascular events (6).These studies suggest that thin-cap fibroatheromas have rupture-prone plaque morphology. Current imaging modalities, including computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET), intravascular ultrasound (IVUS), intravascular optical coherence tomography (OCT), and intravascular endoscopy are able

Current Clinical Applications of Intravascular Optical Coherence Tomography in Coronary Artery Disease

“…OCT is capable of discriminating three types of unstable plaque morphologies underlying coronary thrombosis such as plaque rupture, erosion, and calcified nodules (3)(4)(5) and the presence of substantive calcium proximal and/or distal to the lesion. An OCT study reported that the frequency of plaque rupture, erosion, and calcified nodules in ACS was 44%, 31%, and 8%, respectively.…”

To determine the frequency of carotid plaques on Doppler USG and associated presenting symptoms at a Tertiary Care Centre, Lahore

“…Atherosclerosis is the main pathological process, can begin early in life and remain asymptomatic for long time periods before presenting clinically. In apparently healthy adults, early detection of atherosclerosis in peripheral arteries and carotid arteries can save a lot of disease burden 3,4 .…”

Vulnerable Plaques Producing an Acute Coronary Syndrome Exhibit a Different CT Phenotype than Those That Remain Silent

“…7 Three distinct pathophysiological mechanisms have been described in the process of plaque destabilization: plaque rupture (65%), plaque erosion (30%), and nodular calcifications (5%). 8 A study based on intracoronary imaging has shown that plaque rupture had triggered STEMI in 72% and NSTEMI in 32% of cases, while plaque erosion had caused STEMI in 28% versus NSTEMI in 48% of patients. In the remainder 20% of NSTEMI cases, the culprit lesion was characterized by nodular calcifications, with no signs of rupture or erosions.…”