Impact of Coronary Artery Calcium Scanning on Coronary Risk Factors and Downstream Testing: The EISNER (Early Identification of Subclinical Atherosclerosis by Noninvasive Imaging Research) Prospective Randomized Trial
What is the clinical impact of conventional risk factor modification compared to that associated with the addition of coronary artery calcium (CAC) scanning?
The investigators assigned 2,137 volunteers to groups that either did undergo CAC scanning or did not undergo CAC scanning before risk factor counseling. The primary endpoint was 4-year change in coronary artery disease risk factors and Framingham risk score (FRS). They also compared the groups for differences in downstream medical resource utilization.
Compared with the no-scan group, the scan group showed a net favorable change in systolic blood pressure (p = 0.02), low-density lipoprotein cholesterol (p = 0.04), and waist circumference for those with increased abdominal girth (p = 0.01), and tendency to weight loss among overweight subjects (p = 0.07). While there was a mean rise in FRS in the no-scan group, FRS remained static in the scan group (0.7 ± 5.1 vs. 0.002 ± 4.9, p = 0.003). Within the scan group, increasing baseline CAC score was associated with a dose-response improvement in systolic and diastolic blood pressure (p < 0.001), total cholesterol (p < 0.001), low-density lipoprotein cholesterol (p < 0.001), triglycerides (p < 0.001), weight (p < 0.001), and FRS (p = 0.003). Downstream medical testing and costs in the scan group were comparable to those of the no-scan group, balanced by lower and higher resource utilization for subjects with normal CAC scans and CAC scores ≥400, respectively.
The authors concluded that compared with no scanning, randomization to CAC scanning was associated with superior coronary artery disease risk factor control without increasing downstream medical testing.
This trial suggests that CAC scanning can improve cardiac management without incurring significant increase in downstream medical costs. The current study involved the offering of free CAC scans to volunteer subjects. Future large-scale clinical trials are indicated to determine whether these findings are applicable to different patient populations who are suitable candidates for CAC scanning based on clinical consensus and current guidelines, and very importantly to determine whether the beneficial effect of CAC scanning on coronary artery disease risk profiles translates to meaningful reductions in clinical adverse events.
Keywords: Cholesterol, Coronary Artery Disease, Atherosclerosis, Risk Factors, Calcium
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