The doctor recommends a medication to lower cholesterol but you’re reluctant. Perhaps your cholesterol is elevated, but not by a lot. In these situations, a special computed tomography (CT) scan can better assess your risk of coronary artery disease and help you decide on starting cholesterol lowering medication.
How does it work?
This CT scan determines how much calcium is in the arteries of the heart. Calcium is a major component of plaque and plaque is responsible for causing blockages, known as coronary artery disease. When blockages are large enough, they lead to heart attacks. This test does not diagnose blockages which is the case for a slightly more expensive test called a CT coronary angiogram.
Who benefits from this test?
Doctors commonly rely on a risk calculator to determine the likelihood of developing coronary artery disease that is based on cholesterol levels, presence of high blood pressure, tobacco use, and diabetes. The calculator generates a percentage of ones predicted 10-year risk for heart attack and stroke. In turn, this number is used to determine who benefits most from cholesterol lowering medication. However, it’s a blunt tool that may underestimate a person’s risk of heart disease. This is where coronary artery calcium scoring benefits patients: by better risk stratifying them.
Who shouldn’t get this test?
This test is not for people who have already been diagnosed with coronary artery disease, pregnant patients, and in people under the age of 40. It is also not typically recommended for people defined as low risk (less than 5% risk) by the calculator mentioned above. Some exceptions may apply for low-risk people, such as those with a family history of early coronary artery disease.
How do we interpret the results?
If there is plaque in the coronary arteries, the score will be higher than zero. Conversely, a calcium score of zero correlates with a very low risk of coronary artery disease. Patients with a score of zero do not require cholesterol lowering medication for up to five years. Large clinical trials show that in patients with a calcium score of 100 or above, cholesterol lowering medication significantly reduces the risk of heart attack. The amount of calcium is also presented as a percentile based on age and sex because women and younger people happen to have lower amounts of calcium. A score greater than the 75th percentile is another indication for the use of cholesterol lowering medication.
Medical experts say a CT Calcium Artery Score can help identify patients who have a higher risk of heart attack than predicted by standard risk calculators. There is strong evidence that cholesterol lowering medication reduces the risk of heart attack in patients with elevated calcium scores.