Using heart CT scans can help personalize treatment in patients whose blood pressure is just above normal or mild high blood pressure.
The scans detect levels of calcium in the heart’s arteries, and the physicians suggest those people with the highest calcium levels would benefit most from aggressive blood pressure treatment, whereas those with little or no calcium may not need to be treated as intensively, depending on their other heart disease risk factors.
In the study, published on Jan. 10 in Circulation, the researchers say these calcium scores allow physicians to go beyond the traditionally calculated risk factors to determine which blood pressure treatment strategy may be most appropriate for a particular patient.
“If a health care provider wants to target blood pressure in a patient with traditional heart disease risk factors and above-normal blood pressure, he or she can look at coronary artery calcium to help with tiebreakerlike decisions,” says J. William McEvoy, M.B.B.Ch., M.H.S., assistant professor of medicine and member of the Ciccarone Center for the Prevention of Heart Disease at the Johns Hopkins University School of Medicine. “Our study, along with others, such as SPRINT and HOPE, positions cardiac risk and coronary artery calcium as helpful ways to determine if a given patient would either benefit from more intensive blood pressure control or do just fine with a more traditional blood pressure target.”
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The researchers divided the participants by their coronary artery calcium scores into one of three groups: those with a score of zero, those with a score of one to 100 and those with a score greater than 100. Then, they looked at the number of heart disease-related events in each calcium score category broken down by blood pressure range and calculated heart disease risk. Low heart disease risk was classified as a less than 15 percent chance of a heart disease event over the next 10 years, and high risk was 15 percent or greater risk of a heart disease event. To get the event rate, the investigators divided the number of events in each category by the amount of people in the study multiplied by the length of time they spent in the study, known as a person-year.
Participants with calcium scores of zero with a high calculated risk of heart disease had a relatively low actual event rate after the 10-year study. In contrast, participants with systolic blood pressure under 140 millimeters of mercury — below the current cutoff for treatment — and rated with a low predicted risk of heart disease who had a calcium score over 100 had a high actual event rate of 19.7 events per 1,000 person-years. Participants with high systolic blood pressure between 160 and 179 millimeters of mercury had high event rates ranging from 20 to 40 heart disease events per 1,000 person-years regardless of their calcium scores.
