Recently several patients have inquired as to whether I recommended they undergo a CT scan of their heart to assess their risk of coronary artery disease.
The test to which these patients are referring is called a coronary calcium scan and is used to calculate a coronary calcium score. Not all patients require this CT scan of their heart, but in some it can be helpful to assess risk of future heart attack and guide treatment decisions.
So who needs a coronary calcium scan?
The most common method of determining a patient’s 10-year and lifetime risk of a atherosclerotic (cholesterol) related event such as a heart attack or a stroke is by using a validated tool such as the American College of Cardiology’s (ACC) Atherosclerotic Cardiovascular Disease (ASCVD) Risk Calculator (https://tools.acc.org/ascvd-risk-estimator-plus/#!/calculate/estimate/). This calculator gives an estimate as to whether a patient is at low, moderate, or high risk for an atherosclerotic related event; taken together with the patient’s personal risk factors and their family history a recommendation will be made by the physician about whether or not the patient needs medication to help lower cholesterol levels to help reduce their risk.
The coronary calcium scan is useful for people ages 40-70 years old who fall into the moderate category (ASCVD risk 5-7.5%) as it can help further risk stratify and guide treatment recommendations.
Additionally, the ACC’s ASCVD risk calculator (as tends to be the case with many standardized risk stratification tools), tends underestimate women’s risk. For women >50 years old who are calculated to be at low risk but have additional personal or family risk factors, a coronary calcium scan can help give additional information about that woman’s personal health.
Who does not need a coronary calcium scan?
Because CT scans use radiation, even though it is a low amount (about as much as is in a screening mammogram), pregnant women should not have coronary calcium scans. Additionally, should ASCVD risk be very low or high there is no need to pursue a coronary calcium scan as no additional risk stratification is needed to help guide treatment—it is only useful for people whose scores fall in the middle. Finally, it should be noted, that although more and more insurance companies are covering the cost of this study, it often must be pre-approved or paid out of pocket.
Now what is a coronary calcium scan and how is it interpreted?
The coronary calcium scan is preformed by a CT scanner without any contrast dye or intravenous injections. The patient lies flat on a table after having had EKG leads placed on their chest, they are then moved through the scanner and the CT images of the heart and the vessels that supply the blood to its musculature are produced. The vessels that supply the oxygenated blood to the heart are called the coronary arteries. If there is cholesterol plaque build up in the wall of these arteries, they become calcified. If there is enough to lead to a block of blood flow or if a piece of plaque breaks off causing a blockage this is what causes heart attacks. The coronary calcium scan will create a score based on how much calcium build up is seen within the coronary arteries.
Score:
0: no plaque, <5% chance of having heart disease, the risk of heart attack is very low
1-10: small amount of plaque, <10% risk of heart disease, risk of heart attack is low
11-100: some plaque, mild heart disease, moderate risk of heart attack
101-400: moderate amount of plaque, heart disease present, moderate to high risk of heart attack>400: large amount of plaque, >90% risk that plaque is obstructing a coronary artery, risk of heart attack is high
For scores of that have a moderate to high risk of heart attack your doctor will discuss treatment. This will include blood pressure control, cholesterol lowering medications such as statins, control of diabetes, quitting smoking, and other healthy life style activities and may include referral to a Cardiologist, depending on the score and other risk factors.
Hello! My name is Carrie Ward and I am a board-certified Internal Medicine MD and an Assistant Professor of Clinical Medicine at Keck School of Medicine of the University of Southern California. I am passionate about medicine and find fulfillment in the diversity of my work. I spend most of my time in the outpatient setting where I provide patient-focused comprehensive care to an adult population. Additionally, I enjoy mentoring future doctors from the medical school and spending time in the inpatient setting on the teaching service with the interns and residents. Finally, I am a mom of two-year-old twin boys. I have a true appreciation for the complexities of women’s health and how often it can take a back seat when life gets busy. I hope you might find the “Female Health Collective” a helpful resource to you; I am honored to be a part of it and hope you enjoy my contributions!