Baseline coronary artery calcium (CAC) levels are widely used as surrogate measures for atherosclerotic plaque burden in heart patients and have been proven to predict future cardiovascular events, but researchers who recently studied CAC progression in asymptomatic patients found progression was independently associated with experiencing a composite cardiovascular disease (CVD) event.
Roberto Cardarelli, DO, MHA, MPH, and colleagues studied the association of cardiovascular risk factors with the progression of CAC over a two-year period and published the findings in a recent Journal of the American Board of Family Medicine article. The scientists focused on the relationship between CAC progression and the patients’ experiences of composite CVD events.
Over the span of two years, Cardarelli and co-authors took repeated CAC measurements for 311 asymptomatic patients who were at least 45 years old at the time of the study. The subjects were recruited from a span of primary care clinics, the authors noted, drawn from the North Texas Primary Care Practice-based Research Network, or NorTex. The researchers found CAC scores increased by an average of 24.45 Agatston units during the course of the study, and 30 percent of participants showed CAC progression.
Most strongly associated with CAC progression were dyslipidemia, systolic blood pressure, fasting glucose, existing chronic conditions like diabetes, and non-high-density lipoprotein. Patients who experienced progression were also more than four times more likely to experience a composite CVD event in two years after controlling for known risk factors. Adjusted regression models were all adjusted for age and sex.
“While baseline CAC scores are known to predict future cardiovascular events, the importance and clinical value of changes in CAC are less understood,” the authors wrote. “If CAC progression can be established as a reliable surrogate for increasing risk of atherosclerosis and future events, serial assessment of CAC would have many potential clinical applications.” These applications, the researchers wrote, include identifying patients who could benefit from more aggressive cardiac treatment or further testing.
The study adds information to the ever-growing base of knowledge of CAC and its relationship to cardiovascular disease, Cardarelli and colleagues said in the paper, but even so, a “paucity of data” exists on the subject.
“The limited data to date suggest that CAC progression may be a more accurate predictor of future cardiac risk than its baseline measurement, but there has yet to be a prospective comparison of baseline versus progression of CAC in terms of prognostic value,” they wrote. “While our study only speaks to the association between two-year CAC changes, traditional risk factors and composite CVD events, these findings lay the groundwork for future studies.”