Calcification refers to a process in which calcium is deposited on the walls of the coronary arteries, forming a hard and brittle covering over plaque formations. Calcification may also occur around the heart’s four valves, narrowing the valve and leading to conditions such as calcific aortic valve stenosis.

New tests that measure the amount of calcium in plaque may help diagnose heart disease and the risk for stroke, even when a patient shows no outward symptoms. These new tests are noninvasive, relatively inexpensive and take only about 15 minutes. However, it's important to note there are serious limitations to these new tests, especially the use of computed tomography (CT) scanning to develop a coronary artery calcification (CAC) score.

These tests are frequently marketed to the general public by alternative health care practitioners as a method to diagnose early coronary artery disease, before symptoms become clinically apparent (e.g., asymptomatic coronary artery disease). While the CAC can yield important information, especially when combined with other measures of cardiac risk, in general, an elevated CAC alone is not enough to justify drug therapy or further invasive testing in the absence of other signs and symptoms of heart disease. Studies have yet to show any different outcomes

An elevated calcium score may be a helpful indicator that other testing is necessary, but most physicians do not rely solely on these tests for diagnosis. The nuclear stress test and cardiac catheterization (which includes a coronary angiogram) remain the gold standards for assessing the presence and severity of heart disease.

Calcification is a process in which calcium is deposited over arterial plaque. It is one possible stage of atherosclerosis, or “hardening of the arteries.” When atherosclerosis occurs in the coronary arteries, it is called coronary artery disease and is the leading cause of heart attacks. When it occurs in the carotid arteries in the neck, it is associated with increased risk for stroke.

The degree of coronary calcification is often related to the age of the patient. Generally, the percentage of patients with coronary calcification increases with age in patients with or without coronary atherosclerosis.

In recent years, scientists have made great strides forward in understanding the atherosclerotic process. The disease tends to be gradual, often taking decades before the affected person is in danger of cardiovascular or cerebrovascular problems.

In the early stages of the disease, the inner lining of the artery (e.g., the endothelium) is damaged. This causes white blood cells to gather at the site of the injury. This in turn provokes an inflammatory immune response that causes further damage to the artery wall, attracting yet more white blood cells. Over time, the endothelium is compromised and large, toxic LDL cholesterol molecules can penetrate into the artery wall.

The white blood cells and cholesterol, along with cell products, combine to form a lipid foam that penetrates the arterial wall and forms a plaque deposit on the inside of the artery. In the early stages of atherosclerosis, these fatty streaks form the foundation of growing plaque deposits. Fatty streaks have been detected in the arteries of teenagers who were genetically predisposed to develop atherosclerosis.

Calcium becomes involved when calcium deposits collect on these growing atherosclerotic plaques. Calcium is present in the blood and may form a hard, brittle shell over the plaque. This does not happen in all cases of atherosclerosis. Plaque deposits that are covered with calcium may be stable or unstable. Some researchers have suggested that calcified plaque may even be safer than non-calcified plaque, because pieces of it are less likely to break off into the bloodstream (plaque rupture) and cause either a stroke or a heart attack.

The role that calcium deposits play in atherosclerosis has nothing to do with the calcium that comes from food or supplements, so reducing one’s calcium intake will not prevent or treat atherosclerosis.

Calcification itself may not produce any symptoms and may be identified only through tests or surgery. Nevertheless, people with atherosclerosis accompanied by calcification may experience symptoms common to any form of coronary artery disease, such as chest pain or leg pain. However, for many people, such disease produces no symptoms before a heart attack or sudden death.

Age is the most common risk factor for calcification of the arteries, mostly because of the association between age and atherosclerosis. Other risk factors for heavy arterial calcification include:

Calcification may also occur around the heart’s four valves, narrowing the valve and leading to conditions such as calcific aortic valve stenosis.

Calcification is only one aspect of coronary artery disease. It is rarely the only condition a physician considers for a patient with potential heart problems. However, the role of calcium in atherosclerosis has inspired researchers to develop tests to measure the amount of calcium in the arteries. The idea is to measure how much plaque is present in the arteries by how much calcium is present. However, because calcium is not always involved in atherosclerosis, these tests have limitations. In addition, these tests are still being refined, so it remains difficult to accurately and consistently measure arterial plaque without more invasive testing, such as a coronary angiogram. Nevertheless, some tests can provide useful information, even when they have been developed to identify other problems, and they are relatively inexpensive and quick. These tests include:  

• Ultrafast computed tomography (ultrafast CT or electron beam computed tomography [EBCT]) scans. These noninvasive imaging tests take multiple views of the heart and measure the calcium in the arteries. The results of this test can be expressed in several ways, including an Agatston score (the most common), calcium volume score or calcium mass score. This test can sometimes identify atherosclerotic heart disease before symptoms become apparent because it can detect growing plaque lesions before they begin to narrow the artery, thus restricting the flow of blood.
  
  Studies have shown that coronary artery calcification (CAC) scores are positively correlated with the degree of atherosclerosis, and that a complete lack of CAC is highly associated with a lack of atherosclerosis. Thus, patients with elevated CAC scores are likely at increased risk of heart attack caused by coronary artery disease, even if symptoms aren't present. This test may also be of value in an emergency room setting. Studies indicate that the CAC score can help physicians quickly determine which patients require further cardiac testing and which patients are not suffering from cardiac-related conditions. 
  
  

  It is important to note that CT "calcium score" testing is currently being promoted by alternative health practitioners in out-patient settings, often without a physician's referral. These tests can provide valuable information, and may be of some value in predicting future risk for heart attack, especially when combined with other markers of cardiac risk such as the Framingham coronary risk profile and inflammation as measured by a C-reactive protein test. However, treatment decisions are rarely based on CAC scores alone. If an elective CT score finds an elevated CAC score, patients are urged to take these results to a cardiologist for further testing and evaluation, if warranted. A cardiologist will likely assess for symptoms and signs of heart disease, perform an EKG, and order a stress test or CT angiogram. 

  The following Agatston CAC scores are used to classify the degree of calcification:

• • 0 - no artery disease

  • 1 to 99 - mild coronary artery disease

  • 100 to 399 - moderate coronary artery disease

  • over 400 - severe coronary artery disease

Hoping to clarify the situation, the American College of Cardiology Foundation and the American Heart Association in 2007 issued recommendations for the use of CAC scoring. These included:

• Asymptomatic patients with intermediate risk, according to the Framingham criteria, may consider CAC scoring, which sometimes results in risk reclassification.
  
  
• CAC scoring is not recommended for patients in the low risk category, according to the Framingham criteria. As a result, population-wide screening of low-risk people is not recommended.
  
  
• CAC is not recommended for patients in the high risk category because they are likely already being intensively treated and there is no evidence that CAC scoring will change their treatment plan.
  
  
• In patients who have a high CAC score, of more than 400, additional testing is not recommended because, among patients in the high risk category, intensive therapy is already recommended, and among patients in the low risk category, a negative exercise test would confirm the low likelihood of disease.

Beyond coronary artery disease, researchers are continuing to uncover new applications for CT scanning. For instance, CAC scores may also be helpful in differentiating between various kinds of cardiomyopathies. In addition, multiple CAC tests may be able to help monitor the progress of coronary artery disease or the effectiveness of medication, although more studies are needed.

• Dental x-rays. New panoramic dental x-rays have been reported to reveal arterial calcification in the carotid artery, which supplies most of the blood to the head and neck. Panoramic dental x-rays are less expensive than some other methods and expose patients to less radiation. Further research is needed to determine whether they will become a routine screening tool. 
  

• Mammograms. These tests screen for the presence of breast cancer and studies suggest that they may help to detect calcification within the breast artery. The technology behind these tests continues to evolve, and may one day offer routine screening for calcification in this area of the body.

It is important to point out that physicians are not currently using these tests to diagnose heart disease or, in most cases, recommend a course of action. Rather, the presence of calcium as indicated by one of these tests may prompt the physician to recommend more thorough testing, including nuclear stress test and cardiac catheterization.

In the future, as the understanding of atherosclerosis improves and the tests become more sensitive, their role may expand to include:

• Routine screening (such as an annual physical).
  
  
• Patients who experience episodes of chest pain despite a normal nuclear stress test. The ultrafast CT is already used for this in some cases.
  
  
• Patients who have a number of risk factors but no symptoms. The ultrafast CT is already used for this in some cases.
  
  
• Patients whose progress needs to be monitored to determine whether treatment is successfully reducing built-up plaque. Treatment may include lifestyle changes such as an increased level of exercise or taking cholesterol-reducing drugs such as statins. The ultrafast CT is already used for this in some cases.

At the present time, the American Heart Association and American College of Cardiology do not recommend treatment for people with elevated coronary artery calcification (CAC) scores who do not have other signs and symptoms of coronary artery disease. Additionally, studies have not shown that drug therapy (primarily with statins) has been able to lower CAC scores. Similarly, an elevated CAC score is usually not enough to warrant a coronary angiogram among people who do not have additional signs and symptoms of heart disease.

While researchers work to find the most effective way to incorporate CAC scores into clinical practice, however, people who are worried about atherosclerosis and heart attack can take a number of steps to reduce their overall risk. These include:

Catheter interventions may also be used to treat atherosclerosis, whether or not calcification is present. These procedures use a thin tube (catheter) that is inserted through an artery (usually the femoral artery in the upper thigh) and up to the coronary arteries. These interventions include:

• A balloon angioplasty uses a catheter with a balloon at the tip that can be inflated to press calcified plaque back against artery walls. This procedure increases the amount of blood that can pass through the vessel. This procedure cannot be performed if there is excessive calcification because of the risk that pieces of calcified plaque will break off and cause a heart attack during or immediately after the procedure.
  
  A procedure called stenting is often performed in conjunction with the angioplasty. In this procedure, a small, tubular metal structure called a stent is implanted in the newly opened artery. The stent acts as a scaffold that stretches and supports the artery walls, permitting blood to flow freely through the previously blocked vessel and preventing the crushed plaque from rupturing.

• An atherectomy involves one of three catheters, all of which destroy calcified plaque by cutting it away. Although rarer, this technique may be more appropriate for highly calcified plaque deposits that are unsuitable for angioplasty. Depending on the technique used, the residue is pulverized so that it flows harmlessly through the bloodstream, is removed as the catheter is withdrawn, or is vacuumed through the catheter and out of the body. This procedure is more likely to be done if there is excessive calcification.

Among patients with more advanced atherosclerotic disease, surgery may be recommended. The surgeries used to treat atherosclerosis include:

• Endarterectomy. Usually performed in the carotid arteries in the neck, this surgery is used to prevent stroke caused when pieces of plaque break off and travel through the bloodstream until they block an artery. During this procedure, the surgeon opens the artery in the neck and strips away the plaque, then recloses the artery.
  
  
  
  
  
• Bypass surgery. Usually performed in the coronary arteries in the heart, this surgery is used to prevent heart attack caused when blood flow is restricted to the heart muscle by arterial plaque. During this procedure, the surgeon uses segments of healthier blood vessels from elsewhere in the body to bypass the hardened, narrowed or obstructed arteries.
  
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An experimental strategy to remove calcified plaque from the body is chelation therapy. This technique involves the administration of a certain chemical into the body in a series of up to 50 injections that can take several months to complete. The chemical is designed to bond with the calcium and other chemicals in plaque, changing them into less harmful forms that can be safely flushed from the body.

There is at the present time no published scientific report demonstrating that chelation therapy reduces coronary calcification. In fact, there have been recent randomized trials that show that chelation therapy provides no benefit in treatment of atherosclerosis. More research is necessary before concluding whether or not this treatment is a safe and effective option in the treatment of calcification.

To prevent the buildup of plaque, people are generally encouraged to limit as many risk factors as possible by:

• Achieving and maintaining a healthy weight
  
  
• Controlling diabetes
  
  
• Controlling high blood pressure (hypertension)
  
  
• Engaging in regular weight-bearing exercise
  
  
• Refraining from smoking cigarettes, cigars and pipes, and staying away from second-hand tobacco smoke and areas of heavy air pollution
  
  
• Sticking to a healthy diet that is low in fats and oils and cholesterol

High-risk patients (e.g., those with high cholesterol levels) may also be prescribed statins to slow the progression of atherosclerosis, regardless of their coronary artery calcification scores.

Calcium channel blocking medications (e.g., diltiazem, nifedepine, verapamil) do not provide any benefit. These agents work on small calcium channels in the cells but are not involved in calcium deposition.

Preparing questions in advance can help patients have more meaningful discussions with their physicians about their conditions. Patients may wish to ask their doctors the following questions related to calcification:

1. Can I tell if I have calcification?
   
   
2. Can I take any medications to reduce calcification?
   
   
3. Should I regularly have any imaging tests to monitor calcification?
   
   
4. Will calcification return after an angioplasty or bypass surgery?
   
   
5. Should I reduce my calcium intake?
   
   
6. Does medication I take for calcium in my bones affect my arteries?
   
   
7. How does my high blood pressure affect calcification?
   
   
8. If I have arterial plaques now, will they become calcified?
   
   

9. Is it a good idea to have regular coronary artery calcification (CAC) scores computed by an outside lab? How much should I pay for this service?
   
   

10. If I don't have symptoms of heart disease, do you recommend CT scanning at out-patient clinic?