Impact of Coronary Computed Tomographic Angiography Results on Patient and Physician Behavior in a Low-Risk Population

Study Questions:

What are the implications of coronary computed tomographic angiography (CCTA) screening, including its effect on physician prescribing practices and patient use of medications, as well as the impact on downstream secondary testing and cardiac events?

Methods:

The investigators studied asymptomatic patients from a health-screening program. The study population was comprised of 1,000 patients who underwent CCTA as part of a prior study, and a matched control group of 1,000 patients who did not. They assessed medication use, secondary test referrals, revascularizations, and cardiovascular events at 90 days and 18 months. Because subjects were matched, analyses were performed for paired designs. Differences between continuous variables were analyzed with paired t tests, and those between categorical variables using the McNemar test of proportions and the generalized estimating equations method.

Results:

A total of 215 patients in the CCTA group had coronary atherosclerosis (CCTA positive). Medication use was increased in the CCTA-positive group compared with both the CCTA-negative (no atherosclerosis) and control groups at 90 days (statin use, 34% vs. 5% vs. 8%, respectively; aspirin use, 40% vs. 5% vs. 8%, respectively), and 18 months (statin use, 20% vs. 3% vs. 6%, respectively; aspirin use, 26% vs. 3% vs. 6%, respectively). After multivariable risk adjustment, the odds ratios for statin and aspirin use in the CCTA-positive group at 18 months were 3.3 (95% confidence interval [CI], 1.3-8.3) and 4.2 (95% CI, 1.8-9.6), respectively. At 90 days, in the total CCTA group versus controls, there were more secondary tests (55 [5%] vs. 22 [2%]; p < 0.001) and revascularizations (13 [1%] vs. 1 [0.1%]; p < 0.001). One cardiovascular event occurred in each group over 18 months.

Conclusions:

The authors concluded that screening CCTA was associated with increased invasive testing, without any difference in events at 18 months.

Perspective:

In this study, an abnormal CCTA result was associated with more aspirin and statin prescriptions, as well as increased patient medication use at 90 days and 18 months. However, medication use lessened with time, and performance of CCTA was also associated with significantly more secondary testing and invasive revascularization procedures in this asymptomatic cohort, without any difference in cardiac events at 18 months. Thus, the potential benefit of increased medication use in the CCTA group is tempered by the risk of further testing in low-risk patients without any obvious clinical benefit. These data would suggest that screening CCTA does not have any role in low-risk patients.

Clinical Topics: Atherosclerotic Disease (CAD/PAD)

Keywords: Risk, Coronary Artery Disease, Atherosclerosis, Cardiology, Referral and Consultation


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