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Many adults have fatty deposits in heart arteries without knowing

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More than four out of ten adults, ages 50 to 64 years and without known heart disease, have some degree of atherosclerosis, according to a new study, led by researchers from University of Gothenburg.

Atherosclerosis, or the buildup of fatty deposits in blood vessels that supply blood to the heart, is a major cause of heart attacks. A widely used approach to screen people who are at risk for heart disease but who do not yet have symptoms is cardiac computed tomography, commonly known as a cardiac CT scan, for coronary artery calcification (CAC) scoring.

The scan creates cross-sectional images of the vessels that supply blood to the heart muscle to measure the presence and amount of calcium-containing plaque in the coronary arteries. Based on these scans, individuals are given a CAC “score” of 0 to over 400 to estimate their risk for or extent of coronary artery disease.

The higher the score, the greater the risk for having a heart attack, stroke or dying from either one within the next 10 years. However, CAC scoring can miss a percentage of people who are at risk for heart attack even though they have a zero CAC score.

Increased heart attack risk

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Göran Bergström
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“Measuring the amount of calcification is important, yet it does not give information about non-calcified atherosclerosis, which also increases heart attack risk,” said study author Göran Bergström, M.D., Ph.D., professor and senior consultant in clinical physiology in the department of molecular and clinical medicine at the University of Gothenburg’s Sahlgrenska Academy.

Bergström and colleagues compared CAC scoring results with coronary computed tomography angiography (CCTA) scans in more than 25,000 men and women, ages 50 to 64 years as part of the Swedish CArdioPulmonary BioImage Study (SCAPIS) and who had no history of a prior heart attack or cardiac intervention.

CCTA is a radiologic technique that gives a very detailed image of the inside of the arteries that supply the heart with blood. The researchers wanted to determine the prevalence of atherosclerosis in the general population without established heart disease, and how closely the CCTA findings correlated to CAC scores. Data was collected from 2013-2018.

They found CCTA detected some degree of atherosclerosis in more than 42% of the study participants. In 5,2% of those people, the atherosclerosis narrowed the heart’s arteries by 50% or more. In nearly 2% of the adults in the study, the narrowing was so severe that blood flow as obstructed to large portions of the heart.

Silent coronary atherosclerosis

Atherosclerosis started an average of 10 years later in women compared to men. Atherosclerosis was 1.8 times more common in people ages 60-64 vs. those ages 50-54. Participants with higher levels of atherosclerosis seen by CCTA also had higher CAC scores.

The study, published the journal Circulation, includes more than 25,000 adults in Sweden. The data comes from the nationwide, open-access, population-based cohort SCAPIS, Swedish CArdioPulomonary bioImage Study. The main funder of SCAPIS is the Swedish Heart-Lung Foundation.

It is important to know that silent coronary atherosclerosis is common among middle-aged adults, and that it increases sharply with sex, age and risk factors, according to Bergström. “A high CAC score means there is a high likelihood of having obstruction of the coronary arteries. However, more importantly, a zero CAC score does not exclude adults from having atherosclerosis, especially if they have many traditional risk factors of coronary disease,” he said.

A limitation of the study is that it lacks follow-up information about how cardiovascular heart disease develops in this population, which makes it impossible to determine how these findings predict clinical heart disease in this population.

Title: Prevalence of Subclinical Coronary Artery Atherosclerosis in the General Population

Main funder of SCAPIS is the Swedish Heart-Lung Foundation. Link to SCAPIS