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Measurement of coronary artery calcium stratified patient risk for cardiovascular disease regardless of dyslipidemia burden or definition, researchers found.
When measured across lipid abnormality categories, patients with a coronary artery calcium score of 100 or more had a 22.2 to 29.2 incidents of cardiovascular disease per 1,000 person-years versus 2.4 to 6.2 events per 1,000 person-years among those with arterial calcium scores of 0, according to , of Baptist Health South Florida in Miami Beach, and colleagues.
Action Points
- In this study of patients who were not on baseline medications for dyslipidemia, coronary artery calcium appeared to classify atherosclerotic cardiovascular risk better than counting lipid abnormalities.
- Across the spectrum of dyslipidemia, event rates similar to secondary prevention populations were observed for patients with high coronary calcification, and low calcium scores were indicative of low risk despite high dyslipidemia scores.
Among patients with no lipid abnormalities, those with arterial calcium scores of 100 or more had a higher rate of cardiovascular disease than did those with three lipid abnormalities and an arterial calcium score of 0 (22.2 events versus 6.2 events per 1,000 person years), they wrote online in the journal Circulation.
They added that these findings "may have the potential to help match statin therapy to absolute cardiovascular disease risk." They also noted that arterial calcium scores can help healthcare professionals weigh costs and benefits of statin treatment, especially among those with a history of adverse events from statin treatment.
Researchers have explored alternative methods of measuring heart disease risks. However, using "good cholesterol" as a predictor for those risks has been inconclusive when "bad cholesterol" is controlled by statins.
Other research on artery calcification has shown that a 0 score was not effective on its own in predicting cardiovascular events if patients had other risk factors.
The authors analyzed the effect of arterial calcification on risk for cardiovascular disease across dyslipidemia categories through a population of 5,534 participants in the MESA (Multi-Ethnic Study of Atherosclerosis) study. Patients were ages 45 to 84 and had no cardiovascular disease at baseline.
Baseline measures included a CT scan of the heart for calcium, which was scored by the Agatston method. Patients were informed that they had less than average, average, or greater than average amounts of coronary calcification and that they should discuss the outcome with a healthcare professional.
Additionally, patients had total cholesterol, high-density lipoprotein, and triglyceride measurements taken at baseline, while low-density lipoprotein was estimated, and non-high-density lipoprotein was calculated as total cholesterol minus high-density lipoprotein.
Researchers also recorded three resting blood pressure measures, hypertension, diabetes, smoking status, socioeconomic status, and family history of coronary heart disease.
From baseline, participants were followed up for hospital admission, outpatient diagnosis of cardiovascular disease, or death at 9- to 12-month intervals to record incidence of cardiovascular disease. Events included myocardial infarction, angina resulting in revascularization, resuscitated cardiac arrest, stroke, and cardiovascular death. Results were reported in both an unadjusted model and a model adjusted for age, sex, ethnicity, education, and study site.
Lipid abnormalities included low-density lipoprotein of 3.36 mmol/L or greater, high-density lipoprotein of less than 1.03 mmol/L in men or less than 1.29 mmol/L in women, and triglycerides of 1.69 mmol/L or greater.
Around one third of participants had zero (36%) or one (37%) lipid abnormality, 22% had two abnormalities, and 6% had three abnormalities.
Those with three abnormalities were slightly younger than those with no abnormalities (60.3 versus 62), and the burden of other cardiovascular disease risks generally increased with the number of abnormalities.
Nearly 60% of participants with no lipid abnormalities had no arterial calcification (58%). An increasing number of abnormalities was significantly inversely associated with a calcium score of 0 (P<0.0001).
Cardiovascular disease events occurred in 6% of participants over a median 7.6 years' follow-up. Participants with any arterial calcium accounted for 82% of those events, and more than half of the events (55%) occurred in those with calcium scores of 100 or greater.
Participants with zero or one lipid abnormality made up 65% of those who experienced a cardiovascular disease event.
The authors noted that the study was limited by image acquisition and radiation exposure in imaging of arterial calcium, potential use of preventive therapy after baseline assessment that modified cardiovascular event rates, and lack of data testing the cost-effectiveness or clinical outcomes of adding measurement of arterial calcium in clinical decision-making.
From the American Heart Association:
Disclosures
The study was supported by the National Heart, Lung and Blood Institute.
The authors received support from GE Healthcare and Merck.
Primary Source
Circulation
Nasir K, et al "Dyslipidemia, coronary artery calcium, and incident atherosclerotic cardiovascular disease: implications for statin therapy from the Multi-Ethnic Study of Atherosclerosis" Circulation 2013; DOI: 10.1161/circulationaha.113.003625.