The aortic valve calcium score is a measurement that quantifies the amount of calcium buildup on the aortic valve of the heart. This score serves as an indicator of the valve’s health, helping assess the presence and severity of conditions like aortic stenosis and offering insights into potential cardiovascular concerns.
Understanding Aortic Valve Calcification
The aortic valve is a three-leaflet structure located between the heart’s lower left chamber, the left ventricle, and the body’s main artery, the aorta. Its normal function involves opening to allow oxygen-rich blood to flow from the left ventricle into the aorta with each heartbeat and then closing tightly to prevent blood from leaking backward into the heart. The valve typically opens and closes billions of times over a person’s lifetime.
Calcium deposition on these leaflets is a progressive process that can stiffen the valve. This calcification is not simply due to excessive calcium intake but rather results from metabolic changes within the valve leaflets, similar to the process of atherosclerosis in blood vessels. Injury to the valve leaflets, often from factors like high blood pressure, abnormal lipids, diabetes, and smoking, can trigger inflammation. This leads to cells depositing calcium in an unorganized manner.
How the Score is Determined and Interpreted
The aortic valve calcium score is determined using a non-contrast computed tomography (CT) scan of the heart. This scan uses specific protocols, and the Agatston method, originally developed for coronary artery calcium scoring, is commonly used to quantify the calcium.
During the scan analysis, areas of calcium are identified based on a CT attenuation threshold, often 130 Hounsfield units (HU). A weighting factor is then applied to each calcified area based on its maximum CT attenuation. This weighting factor is multiplied by the area of each calcium lesion, and the sum of these values across all lesions provides the total Agatston score. Calcium from adjacent structures like the mitral valve, aorta, or coronary arteries must be carefully excluded to ensure an accurate aortic valve score.
A higher Agatston score indicates a greater amount of calcification on the aortic valve. While specific thresholds can vary, a score higher than 1,300 AU (Agatston Units) in women or 2,000 AU in men is often considered indicative of severe aortic stenosis. For moderate aortic stenosis, scores of 400 to 1,300 AU in women and 1,000 to 2,000 AU in men may be suggestive. These sex-specific thresholds reflect that women may develop severe stenosis with less calcium burden than men.
Implications of Aortic Valve Calcification
The presence and progression of aortic valve calcification lead to aortic stenosis, where the valve opening narrows. This obstructs blood flow from the left ventricle into the aorta, forcing the heart to work harder.
Over time, the increased workload can cause the left ventricle to thicken and stiffen, potentially leading to heart failure. Symptoms often appear when the stenosis becomes significant and can include chest pain or tightness, particularly with activity, feeling faint or dizzy, or even fainting. Shortness of breath, especially during exertion, and fatigue are also common symptoms.
The aortic valve calcium score helps assess the risk and progression of aortic stenosis. A higher score is associated with more rapid disease progression and a poorer outlook if left untreated. This score is useful when other diagnostic methods, such as echocardiography, are inconclusive, providing an objective measure of calcification severity, complementing other assessments of valve function.
Managing Aortic Valve Calcification
Managing aortic valve calcification involves regular monitoring and addressing risk factors to slow disease progression. For individuals with mild calcification or no symptoms, regular health checkups are recommended to track any changes. Lifestyle modifications are important for managing risk factors.
Adopting a heart-healthy diet, rich in fruits, vegetables, whole grains, and nuts, while being low in salt and unhealthy fats, is beneficial. Engaging in regular physical activity, as advised, can also support overall heart health. Managing conditions like high blood pressure, high cholesterol, and diabetes through diet, exercise, and medication as prescribed can help mitigate the progression of calcification.
When aortic stenosis becomes severe and causes symptoms, medical intervention is typically considered. Medications cannot cure aortic valve stenosis but may be prescribed to manage symptoms or reduce the risk of complications, such as blood pressure medications, blood thinners, or antiarrhythmics. The primary treatment for severe aortic stenosis is valve replacement.
Surgical aortic valve replacement (SAVR) is a traditional open-heart procedure to replace the diseased valve. A less invasive option, transcatheter aortic valve replacement (TAVR), involves inserting a new valve through a catheter, usually via a blood vessel in the groin or chest. TAVR is a common option for many patients, especially older individuals or those at intermediate to high risk for open-heart surgery. The new valve, often made from cow or pig tissue, is positioned within the diseased valve and expanded. While valve repair is rarely used for aortic stenosis, these replacement procedures aim to restore proper blood flow and alleviate symptoms.