What is coronary artery calcium scoring?
Coronary artery calcium scoring is a screening test that uses a CT scanner to identify coronary artery disease at an early, preclinical stage, years before the occurrence of symptoms. It not only identifies the presence of disease, but also quantifies the amount of calcified plaque, thereby allowing comparison of the results to the normal population. Coronary artery calcium scoring is sometimes referred to as a "heart scan," "ultrafast ct scan," or "EBCT scan."
What is the value of coronary artery calcium scoring?
Patients with an elevated calcium score have an increased risk of cardiac events such as myocardial infarction and sudden death. Patients who are identified as being high risk can modify their lifestyle (i.e. through diet, exercise, cessation of smoking, etc.) or be treated with statins to lower blood cholesterol. These lifestyle changes and treatments can delay and sometimes even reverse disease progression.
Can't I rely on traditional risk factors to predict if my patient has coronary atherosclerosis?
Probably not. Conventional risk factors fail to explain nearly 50% of cardiac events. Studies have shown that calcium scoring is a stronger predictor of cardiac events and that the information it provides is independent of standard risk factors. Unlike conventional risk factors which are only predictors of disease likelihood, calcium scoring is definitive: if calcium is present, there is atherosclerotic disease.
Should every patient get a calcium score?
No. Patients who are known to be high risk (e.g. those with stents or bypass grafts) will not benefit from this test because they should already be treated aggressively. Most experts agree that calcium scoring is of greatest benefit to those patients who are at intermediate risk. Patients who are at intermediate risk are responsible for more than half of all cardiac events. So, it is especially important to decide for these patients whether they need therapy and how aggressive the treatment should be. Patients are at intermediate risk when they have two risk factors, such as age (men > 45 and women > 50) and at least one of the following: positive family history, hyperlipidemia, tobacco use, or hypertension.
If my patient has already had a normal stress test, is there any reason to get a calcium score?
Yes. Stress testing only identifies people with obstructive coronary artery disease (i.e. those with a >50-70% stenosis). It can not differentiate patients who have no coronary artery disease from those who have substantial disease that is not yet obstructive.
Should I order a calcium score on a patient who is having chest pain that may be due to angina?
Probably not. There is generally a poor correlation between the calcium score value and the degree of coronary artery stenosis. Symptomatic patients should probably get a coronary CTA or undergo stress testing to rule out obstructive coronary artery disease.
How is a calcium score performed?
The test takes only a few minutes. It requires no patient preparation and involves no contrast injections. The radiation dose is low, typically 1-2 mSv, which is less than the 3.5 mSv annual background radiation dose that patients receive in New York City. It is also substantially less than the 10-15 mSv dose associated with cardiac stress imaging with SPECT.
Is there a difference in score between multidetector (MDCT) scanners and electron beam (EBCT) scanners?
Researchers have concluded that there is no clinically significant difference between calcium scores obtained with either type of scanner. Compared to the latest generation of MDCT scanners, EBCT scanners have substantially worse spatial resolution and fewer rows of detectors. EBCT scanners are no longer manufactured.
Do insurance companies pay for calcium scoring?
Usually not. Currently, insurance companies and Medicare in New York usually do not pay for calcium scoring.