What is a CT Coronary Artery Calcium Heart Scan?
The coronary artery calcium heart scan is a CT scan of the heart that looks for areas of calcium in the arteries that supply the heart with blood. The amount of calcium detected is then added together to give a score. The more calcium there is, the higher the score. Calcium signifies calcified plaque in the heart arteries. Plaque is the substance that leads to blockages and when it bursts, known as plaque rupture, it is what leads to a heart attack. The point of the CT coronary artery calcium heart scan is to determine the cardiovascular risk of a person. The score is typically obtained in people who are otherwise healthy and don’t have symptoms to try and assess their risk.
What Do The CT Coronary Artery Calcium Scores Mean?
A calcium score of 0 means there is no calcified plaque in the arteries
A calcium score of 1-10 means minimal plaque
A calcium score of 11-100 means mild plaque
A calcium score of 101-400 means moderate plaque
A calcium score of >400 means severe plaque
What Do The CT Coronary Artery Calcium Scores Mean In Terms of Risk?
A calcium score of 0 is felt to be very low risk. The predicted chance of an event across studies is around 1-2% over 10 years. Of course that places people with a calcium score of zero in a low risk group.
A calcium score of 0-100 is still felt to be relatively low risk. With the predicted chance of an event over 10 years estimated to be around 2-6%
A calcium score of 101-400 signifies intermediate risk of an event. The predicted 10-year chance of an event is between 13-16%.
A calcium score of >400 signifies high risk of an event. The predicted 10-year chance of an event is between 22-29%.
A calcium score of >1000 signifies very high risk of an event. The predicted 10-year chance of an event is 37%.
CT Coronary Artery Calcium Scores In Diabetic Patients
In general, patients with diabetes are considered to be at higher cardiovascular risk than patients without diabetes. Patients with diabetes and a coronary artery calcium score greater than 0 are at higher risk than patients with similar scores and without diabetes. In patients with scores of 0, the risk is low even if patients have diabetes.
What To Do With Calcium Scores In Patients Without Symptoms?
The question often asked is should patients with higher than usual calcium scores have further testing such as stress tests. The higher the calcium score, the higher the risk of a stress test being positive. In patients with lower calcium scores and no symptoms, stress testing is generally not considered appropriate. In patients with higher scores, i.e. >400, stress testing may be more appropriate in cases. In general there is no good evidence to take patients with high calcium scores for invasive tests such as heart catheterization.