Arterial plaque is a substance composed of fats, cholesterol, calcium, and other materials in the blood that can accumulate inside your arteries. This buildup, a condition known as atherosclerosis, can narrow the arteries and restrict blood flow. Not all arterial plaque is identical, as the specific composition of a plaque deposit influences its behavior and potential health effects.
Defining Heterogeneous Plaque
The term “heterogeneous” indicates that a plaque is composed of multiple, distinct substances with a varied internal composition. A primary component is a soft, lipid-rich necrotic core, which contains cholesterol crystals, fats, and cellular debris. This core is covered by a fibrous cap, a layer of smooth muscle cells and connective tissue that separates the plaque’s contents from the bloodstream.
Within these plaques are areas of calcification, which are hardened deposits of calcium. Inflammatory cells, such as macrophages, are also present and contribute to the plaque’s development and instability. In contrast, homogeneous plaques are more uniform in their structure, often consisting mainly of fibrous tissue and being more stable.
Associated Health Risks
The primary danger associated with heterogeneous plaque is its instability. The combination of a large, soft lipid core and a thin fibrous cap makes this type of plaque susceptible to rupture. When a plaque has a high concentration of lipids and inflammatory cells, the fibrous cap can become weakened and break open, exposing its contents to the bloodstream.
This rupture triggers the body’s clotting response, and a blood clot (thrombus) can form at the site. If the clot is large enough, it can completely obstruct the artery, cutting off blood supply. In a coronary artery, this blockage can cause a heart attack; if it occurs in a carotid artery supplying the brain, it can result in a stroke.
Identification and Diagnosis
Medical professionals use non-invasive imaging to identify arterial plaque and assess its characteristics. A Carotid Ultrasound uses high-frequency sound waves to create images of the carotid arteries in the neck. This technology allows clinicians to visualize the plaque, measure artery narrowing, and evaluate the plaque’s composition, distinguishing between homogeneous and heterogeneous types.
A CT Angiography (CTA) scan provides a more detailed view. This test combines a CT scan with an injection of contrast material to produce detailed, three-dimensional images of the arteries. A CTA is effective at identifying calcification and can help differentiate between the lipid core and fibrous tissue. Magnetic Resonance Imaging (MRI) can also provide specific information about plaque components like the lipid core and any bleeding within the plaque.
Management and Treatment Approaches
Managing heterogeneous plaque involves strategies aimed at slowing its progression and reducing the risk of rupture. Lifestyle modifications are a foundational part of treatment. Adopting a heart-healthy diet low in saturated fats and cholesterol, engaging in regular physical exercise, and quitting smoking can impact the progression of atherosclerosis.
Medications play a large part in managing the condition. Statins are frequently prescribed to lower LDL (“bad”) cholesterol levels, which can help reduce the lipid content of plaques and stabilize them. Antiplatelet agents, such as low-dose aspirin, may be recommended to reduce the likelihood of blood clot formation. Blood pressure medications are also used to control another risk factor for plaque development.
In cases where a plaque causes severe narrowing of an artery or is deemed unstable, procedural interventions may be necessary. Angioplasty and stenting involve threading a catheter to the blockage, inflating a balloon to open the artery, and placing a stent to keep it open. For significant blockages in the carotid artery, a surgical procedure called carotid endarterectomy may be performed to remove the plaque.