Myths and Facts About Cardiovascular Disease and Health - Part 2
View All Section Pages
Preventing or predicting heart disease is dependent on a number of factors, including nutrition and exercise. Heart health screenings are another important factor in diagnosing risk factors for heart disease.
Unfortunately, patients often experience uncertainty or anxiety about heart disease screenings. Many times, anxiety or fear about a particular medical screening is simply the result of misinformation or believing a myth about the test in question. Medical myths can arise when patients don’t understand what a particular test can and can’t tell, and what the procedure involves.
In honor of American Heart Association’s Heart Month, Cooper Clinic Director of Clinical Research Nina Radford, MD dispels two common myths in cardiovascular disease risk prevention in this two-part series.
Myth #2: Obtaining a coronary artery calcification (CAC) score with a CT scan involves a lot of radiation exposure.
The modern CT scan machine, called the multidetector computerized tomography (MDCT) scanner can detect the presence of calcification in the heart (coronary) arteries. The amount of calcification in the coronary arteries is measured and quantified as a “CAC score.” This score is one piece of the puzzle in predicting a patient’s risk of heart disease or a coronary event such as a heart attack.
What is a CAC score?
The CAC score reflects the general burden of atherosclerosis in the heart arteries but it does not indicate whether the atherosclerosis is in the form of flow limiting stenoses (a 70 percent or greater blockage) or “lumpy bumpy” disease that lines the artery rather than severely blocks them. A functional test is needed to see whether severe blockages are present such as a standard treadmill stress test, an echocardiogram stress test or a nuclear stress test.
The higher a patient’s CAC score, the higher the risk of having a cardiac event. The American College of Cardiology/American Heart Association (ACC/AHA) guidelines on screening for coronary artery disease indicated that measurement of CAC is reasonable for cardiovascular risk assessment in adults with no symptoms of heart disease who are at low to intermediate risk for heart disease based on the presence of traditional risk factors. Physicians will often use the CAC score as a guide as to how aggressively risk factors ought to be treated (lifestyle changes alone or with medication).
For example, a patient has high cholesterol (despite a very healthy lifestyle) and he and his healthcare provider are discussing whether he ought to take a statin drug. His father died of heart disease at age 48. But his father had a lot of bad habits like smoking, poor diet, uncontrolled high blood pressure and inactivity that the patient blames for the early heart death. The critical question is whether the risk in this family is due to genetics or lifestyle. If the CAC score in the patient is high, the answer to that question is genetics, rather than lifestyle. The high CAC score would influence a physician’s decision to start drug treatment.
Exposure to radiation from CAC
Because the CAC score is measured using CT scanning, it involves exposing the patient to some radiation. There has been a lot of information in the media about the potential health risks of excessive radiation exposure.
While there is some exposure to radiation, the total amount of exposure from a CAC score using CT scanning is equal to about one-third to one-fourth the amount of radiation you are exposed to every year just from living on planet earth. We all are exposed to radiation everyday due to natural background radiation sources such as radon and cosmic rays (from the sun).
This background effective dose of radiation that we are all exposed to is approximately three to 3.5 mSv per year. If you live in Denver, which is a mile closer to the sun compared to living at sea level, the annual radiation dose from background sources is about four mSv. The amount of radiation a patient is exposed to by getting a CT scan to perform a CAC score is about one mSv at Cooper Clinic.
Given that the information about the CAC score could make a big impact on the heart disease prevention plan for a given patient, this small amount of radiation exposure associated with measuring a CAC score should not be alarming to the patient.
If your doctor has recommended any form of diagnostic scanning, it is a good idea for you to discuss radiation exposure from diagnostic testing with him or her when they discuss the risks and benefits of testing.
To learn more about a preventive exam at Cooper Clinic, click here.
Article provided by Cooper Aerobics Marketing and Communications.