Atherosclerotic calcification is the deposit of calcium within plaques in the arteries, a condition that is part of the broader disease of atherosclerosis. Over time, these plaques, composed of fats, cholesterol, and other substances, harden due to calcium accumulation. This process makes the artery walls stiff and narrow, which can obstruct the flow of blood. This hardening is not a passive buildup but an active biological process.
The Biological Formation Process
Arterial calcification begins with an initial injury to the endothelium, the thin layer of cells lining the arteries. This damage can be caused by factors like high cholesterol, high blood pressure, or smoking. The injury triggers an inflammatory response, leading to the accumulation of lipids, cholesterol, and other substances within the artery wall, forming an early-stage atherosclerotic plaque.
Within these developing plaques, macrophages, a type of white blood cell, arrive at the site of injury to clean up cholesterol but can become overloaded, transforming into “foam cells.” Vascular smooth muscle cells, which normally reside in the middle layer of the artery wall, can migrate into the plaque. Under the influence of inflammatory signals, both macrophages and smooth muscle cells can undergo changes that make them behave like bone-forming cells, known as osteoblasts.
This transformation initiates a process that mirrors bone formation. These altered cells begin to release tiny, membrane-enclosed particles called matrix vesicles, which act as nucleation sites for calcium and phosphate crystals to form. As cells within the plaque die, they release debris that also serves as a foundation for mineralization. Over time, these microscopic crystals grow and merge, leading to the formation of larger, hardened calcium deposits within the plaque.
Associated Health Risks
The presence of calcium within arterial plaques significantly alters the physical properties of the blood vessels. As calcium deposits accumulate, the flexible and elastic artery walls become stiff. This stiffening forces the heart to work harder to pump blood, which can lead to an increase in blood pressure. The loss of elasticity also impairs the artery’s ability to properly expand and contract with each heartbeat.
Extensive calcification is a strong indicator of the overall burden of atherosclerosis and is linked to a higher risk of future cardiovascular events. While some research suggests that dense, stable calcification might help to hold a plaque in place, the process also makes the plaque brittle. This increases the likelihood of plaque rupture, where a piece of the hardened plaque breaks away, leading to a blood clot.
Such a clot can travel through the bloodstream and block blood flow to the heart, causing a heart attack, or to the brain, resulting in a stroke. The amount of calcification is directly correlated with the severity of atherosclerosis and the probability of these events. Therefore, detecting arterial calcification is a predictor of a person’s risk for heart disease.
Methods for Detection
The primary method for detecting and quantifying atherosclerotic calcification is a non-invasive imaging test known as a Coronary Artery Calcium (CAC) scan. This specialized computed tomography (CT) scan uses X-rays to create detailed images of the heart and its arteries. The scan can identify deposits of calcium within the coronary arteries, which supply blood to the heart muscle.
From the CT images, a radiologist calculates a CAC score, which represents the total amount of calcified plaque in the coronary arteries. A score of zero indicates no detectable calcification and a very low risk of a future heart attack. As the score increases, so does the corresponding risk for cardiovascular events. This scoring system provides doctors with a quantitative measure to help assess a person’s risk, often years before any symptoms of heart disease appear.
While calcification may sometimes be incidentally discovered on other imaging tests, such as standard chest X-rays or certain ultrasounds, these methods are not as precise for quantification. The CAC scan remains the standard for accurately measuring the extent of coronary calcification and is a valuable tool in cardiovascular risk assessment.
Current Management Strategies
Management of atherosclerotic calcification focuses not on removing the existing calcium deposits but on slowing the progression of the underlying atherosclerosis. The approach is twofold, combining significant lifestyle changes with medical treatments to address the root causes of the disease.
Lifestyle modifications are a foundation of management. These changes help to lower blood pressure, improve cholesterol levels, and reduce overall inflammation. Recommended adjustments include:
- Adopting a heart-healthy diet low in saturated fats and cholesterol
- Engaging in regular physical exercise
- Achieving or maintaining a healthy weight
- Quitting smoking, as it directly damages the artery walls and accelerates the atherosclerotic process
In conjunction with lifestyle adjustments, various medications are used to manage the disease. Statins are frequently prescribed to lower LDL (“bad”) cholesterol and reduce the inflammation within arteries that contributes to plaque formation. Medications to control high blood pressure, such as ACE inhibitors or beta-blockers, are also commonly used. A doctor might recommend low-dose aspirin to help prevent blood clots, and these treatments help stabilize plaques.