Scientists are illustrating the power of a low coronary artery calcium (CAC) score in the context of heart disease in a new study published in the Journal of the American College of Cardiology. In light of the new findings, the authors are making an argument for adding a CAC score to the factors considered before doctors prescribe medicine like statins.
Even in the midst of other known risk factors including diabetes, high blood pressure, and bad cholesterol levels, researchers found that minimal calcium buildup in the coronary arteries, which feed blood and oxygen to the heart, lowers an individual’s risk of a “cardiovascular event” to under three percent for at least ten years. More calcium buildup, more risk for heart attack and stroke.
The American Heart Association recommends that people should start to receive statin treatments when they reach a 7.5 percent risk of cardiovascular events based on a CAC score, achieved via a CT scan, which is easy, affordable, and depicts a person’s 10-year risk.
"Our findings suggest that individuals with no calcium buildup in their blood vessels may not have to take statins despite the presence of other risk factors that cause coronary disease,” explained Dr. Parag Joshi.
How does calcium end up in blood vessels in the first place? Plaque buildup as a result of atherosclerosis calcifies over time. Coronary artery calcium is thus a sign of atherosclerosis, coronary heart disease, and coronary microvascular disease.
Calcification in the arteries can be either intimal or medial, which are each associated with different risk factors. In the past, scientists thought coronary artery calcification was benign, a normal result of aging. But they soon realized that it actually causes arterial stiffness, affecting 90 percent of men and 67 percent of women older than 70 years of age.
Risk factors for CAC include high BMI, high blood pressure, glucose disorders, family history of CAC, and chronic kidney disease. CAC is not affected by dietary calcium intake.
The new study examined CT scans from over six thousand people with no history of heart attack or stroke, data obtained from MESA (Multi-Ethnic Study of Atherosclerosis). Half of the participants had no calcium deposits, resulting in their receiving a CAC score of zero. A zero score doesn’t mean zero risk; the risk is just low and not deemed high enough to require statin treatments.
"A CAC score can really add to the clinician-patient discussion over whether or not to start a statin for primary prevention of heart attacks and strokes," Dr. Joshi said. Other factors like family history should be considered, researchers say, because preemptive statin treatment could prevent future heart problems.
Sources: UT Southwestern Medical Center, Journal of Geriatric Cardiology, National Heart, Lungs, and Blood Institute