CAC score education may lower heart disease risk in people with a family history
Key takeaways:
- Using visualized coronary calcium scoring independently reduced plaque progression among patients at intermediate risk vs. usual care.
- Improvements in lipid profiles were also reported.
Visualizing and explaining patients’ risk for coronary artery disease using coronary CT and coronary calcium scoring may improve statin adherence and subsequently lower risk for future CAD events, researchers reported.
The results of the CAUGHT-CAD study of CAC scoring in patients with intermediate CAD risk and a family history of CAD but ineligible for a statin were published in JAMA.
“We find managing asymptomatic patients with a family history of CAD to be quite challenging. Obviously, we apply standard risk scores based on lipids, etc, and treat risk, but there is still the very reasonable anxiety of the patient: ‘My dad died at age 59 and now I am 58. What can I expect?’ We thought CAC would improve risk assessment and especially address the second question based on the ‘power of zero’ — ie, CAC of 0, meaning a very low short-term risk,” Thomas H. Marwick, MBBS, PhD, MPH, professorial research fellow in the imaging research laboratory at Baker Heart and Diabetes Institute in Melbourne, Australia, told Healio. “More generally, we wanted to better understand the role of CAC in risk assessment, communication and adherence in the broader community, seeing CAC evaluation as part of a risk control strategy to identify people that need medication and help them to adhere.”
Design of the CAUGHT-CAD trial
For the CAUGHT-CAD trial, the researchers enrolled 365 asymptomatic participants (mean age, 58 years; 58% men) aged 40 to 70 years with a first-degree relative with symptomatic CAD onset at younger than 60 years or a second-degree relative with CAD at younger than 50 years. None of the participants satisfied contemporary criteria for statin initiation. Participants determined to be of intermediate CAD risk underwent CAC scoring via coronary CT.
Participants were then randomly assigned to CAC score-informed group or usual care. Those in the informed group received CAD education using their CT images and were prescribed lipid-lowering therapy. Those assigned to usual care received some educational materials but were masked to their CAC score. If participants assigned to usual care initiated lipid-lowering therapy during follow-up, it was reported to the study investigators.
“We think CAC should be more widely used in intermediate-risk patients. Remember that half of patients who start on statin for primary prevention do not continue past 12 months. But in the trial, if they were randomized to being shown the CAC in a personalized risk discussion, the conversation moved from ‘I have a risk factor that may or may not be a problem,’ to ‘I have the beginnings of CAD, let’s ensure it doesn’t progress,’” Marwick told Healio. “CAC scoring should be a common response to the question of family history. These people are understandably worried about dying of CAD like their relative. Half of them have a CAC score of 0, and ... have very little to be worried about. They were probably the happiest participants I can remember in a clinical trial. Sometimes this reassurance is transformative for people.”
CAC score-informed patients and CAD progression
At 3 years, participants in the CAC score-informed group showed greater and sustained reductions in total cholesterol (mean, 3 mg/dL vs. 56 mg/dL; P < .001) and LDL levels (mean, 2 mg/dL vs. 51 mg/dL; P < .001) compared with usual care. These reductions in the CAC-informed group were associated with greater risk reduction as measured by Pooled Cohort Equation risk scores (mean, 2.1% vs. 0.5%; P < .001) compared with usual care.
CAC score-informed participants also had less plaque progression compared with usual care, independent of other risk factors including baseline plaque volume, BP and lipids, specifically:
- lower total plaque volume (mean, 24.9 mm3 vs. 15.4 mm3; P = .009);
- lower noncalcified plaque volume (mean, 15.7 mm3 vs. 5.6 mm3; P = .002); and
- lower fibrofatty and necrotic core plaque volume (mean, 4.5 mm3 vs. 0.8 mm3; P = .02).
“The biggest barrier is cost. CAC scoring is not reimbursed by the Medicare Benefits Schedule, so people pay approximately $200 to $250 out-of-pocket. In the current cost-of-living crisis, the people who would benefit most — socially disadvantaged, limited health literacy, high risk for nonadherence, etc — are least able to pay,” Marwick said. “There’s enough evidence to influence practice, or at least to inform shared decision-making. For some reason, CAC scoring seems to be an emotive topic, so some people won’t feel that a single randomized controlled trial is enough. The next step would be an outcomes study, but I doubt there will be the resources to get that done.”
For more information:
Thomas H. Marwick, MBBS, PhD, MPH, can be reached at 99 Commercial Road, Melbourne VIC 3004, Australia.
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