atheroma

An atheroma is a focal accumulation of lipid-rich material within the intima of arteries, forming an atherosclerotic plaque. The core is typically lipid-laden and often necrotic, and it may be covered by a fibrous cap composed of smooth muscle cells and extracellular matrix. Inflammation and calcification are common features. The lesion can encroach on the vessel lumen and disrupt blood flow or rupture.

Pathophysiology involves endothelial dysfunction that allows low-density lipoprotein (LDL) particles to infiltrate the intima and become oxidized. Oxidized LDL stimulates an inflammatory response; macrophages ingest lipids and become foam cells, while T cells contribute to inflammation. Smooth muscle cells migrate to the intima and proliferate, producing the fibrous cap and extracellular matrix. Over time, necrotic lipid cores develop and calcifications may form, creating plaques that can be stable or vulnerable to rupture, potentially triggering thrombosis.

Clinical significance derives from the role of atheromas in atherosclerosis. They can cause progressive narrowing (stenosis) of arteries, reducing blood flow, or, if the plaque ruptures, precipitate acute thrombosis. This can lead to myocardial infarction, ischemic stroke, or peripheral artery disease. Some plaques remain asymptomatic but contribute to chronic ischemia or organ dysfunction.

Risk factors and management focus on reducing cardiovascular risk and stabilizing plaques. Major factors include elevated LDL cholesterol, hypertension, smoking, diabetes, obesity, age, male sex, and family history. Treatments center on risk reduction and plaque stabilization: lifestyle modification, statin therapy (with ezetimibe or PCSK9 inhibitors as needed), antiplatelet therapy when indicated, and control of blood pressure and glucose. Revascularization may be considered for significant stenosis or ischemia. Anti-inflammatory strategies are under investigation. Imaging and histology typically reveal a lipid-rich core, a fibrous cap, inflammation, and often calcification.