In the Forum
A New Calcium Score to Predict Heart Attacks
Volume: 48 (31/05/2008)
A study published in the June issue of the journal Radiology suggests it might be possible to better predict a person’s risk of having a heart attack through a new calcium scoring method. The score has been developed by researchers from the Department of Biostatistics at the University of Washington in Seattle and takes into account not just the amount of calcium in the arteries but also its distribution.Nearly 700,000 patients in the US die each year from heart disease, making it the leading cause of death in the US. Among its various forms, the most common is coronary artery disease, which results from the build-up of calcific plaque in the coronary arteries leading to the heart. Currently this coronary calcium is
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measured only in terms of the amount of calcium present in the arteries; its spatial distribution is not taken into account.
The new scoring method was developed by Dr. Elizabeth Brown and colleagues after studying 6,814 men and women between the ages of 45 and 84. Their Multi-Ethnic Study of Atherosclerosis (MESA) began in July 2000 and lasted for nearly four years. 3,252 of the participants had calcific plaque while 3,416 patients did not and the researchers compared CT image data for these two groups. Another 146 patients who did not have CT image data available were not covered in the final analysis.
Using the data, the researchers developed a calcium coverage score to estimate the percentage of coronary arteries that are covered by plaque. With this score in hand, the researchers followed the participants for an average period of 41 months to establish the link, if any, between distribution of calcium as seen in the CT images and their chances of having a heart attack or another cardiac event.
They found that the calcium coverage score was affected by conditions such as diabetes, hypertension, and dyslipidemia (abnormal concentrations of fats or lipoproteins in the blood). The new score, which also took into account the location of calcium, was also found to be better at predicting future cardiac events compared to current measures.
On average, the researchers found 44 percent higher plaque affected coronary arteries in patients with diabetes compared to those without. If the calcium coverage score doubled, a patient’s risk of having a heart attack or other serious cardiac events increased by 34 percent while their overall risk of any cardiac event jumped by 52 percent.
“Now we know that the location of the calcium in the arteries is particularly important in estimating a patient’s potential risk,” said study leader Dr. Brown. “Currently, physicians only see the result in terms of an overall score designed to measure the amount of calcified plaque. This new approach will provide physicians with a measure of the proportion of the arteries affected.”
“Calcium coverage scoring has the potential to improve our estimate of a patient’s risk for adverse clinical outcomes, such as heart attacks or death," Dr. Brown added.
The new scoring method was developed by Dr. Elizabeth Brown and colleagues after studying 6,814 men and women between the ages of 45 and 84. Their Multi-Ethnic Study of Atherosclerosis (MESA) began in July 2000 and lasted for nearly four years. 3,252 of the participants had calcific plaque while 3,416 patients did not and the researchers compared CT image data for these two groups. Another 146 patients who did not have CT image data available were not covered in the final analysis.
Using the data, the researchers developed a calcium coverage score to estimate the percentage of coronary arteries that are covered by plaque. With this score in hand, the researchers followed the participants for an average period of 41 months to establish the link, if any, between distribution of calcium as seen in the CT images and their chances of having a heart attack or another cardiac event.
They found that the calcium coverage score was affected by conditions such as diabetes, hypertension, and dyslipidemia (abnormal concentrations of fats or lipoproteins in the blood). The new score, which also took into account the location of calcium, was also found to be better at predicting future cardiac events compared to current measures.
On average, the researchers found 44 percent higher plaque affected coronary arteries in patients with diabetes compared to those without. If the calcium coverage score doubled, a patient’s risk of having a heart attack or other serious cardiac events increased by 34 percent while their overall risk of any cardiac event jumped by 52 percent.
“Now we know that the location of the calcium in the arteries is particularly important in estimating a patient’s potential risk,” said study leader Dr. Brown. “Currently, physicians only see the result in terms of an overall score designed to measure the amount of calcified plaque. This new approach will provide physicians with a measure of the proportion of the arteries affected.”
“Calcium coverage scoring has the potential to improve our estimate of a patient’s risk for adverse clinical outcomes, such as heart attacks or death," Dr. Brown added.
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