See It, Believe It, Treat It: The Impact of CT Angiography on CV Prescription Patterns
The presence and severity of CAD as shown by coronary CT angiography (CTA) has been proven capable of predicting future cardiac events and death—independent of CV risk factors—but whether the evidence provokes any change in preventive CV medication use remains unclear. In the current study, Michael K. Cheezum, MD, and colleagues posed the question in a recent study in JACC: "Would presenting patients with graphic evidence of their subclinical CAD prompt any change in use of aspirin, statins, or antihypertensive medications?"
Their comparison of the pre- and post-CTA prescription patterns and subsequent changes in BP and cholesterol measures in 1,125 predominantly low-risk patients without known CAD demonstrated an intensification in medication prescriptions. Predictably, increasing CAD severity on CTA was associated with increased CV risk factors and usage of CV medications, but significant portions of patients with identified CAD were not taking medications at the time of CTA.
After CTA, however, a larger proportion of patients intensified their medication usage or started taking CV medications within 6 months of follow-up; the majority of medication changes in patients with CAD present on CTA were to a more potent statin or an increase in BP medication or aspirin dose. Changes in prescribing patterns were associated with significant improvements in BP and cholesterol measures in patients with CAD on CTA compared to those without CAD. In addition, compared with patients whose medication usage remained the same regardless of CAD presence, patients fared better in all measures when their medication use intensified.
Among the low-risk, symptomatic cohort, the changes in prescribing patterns post-CTA suggests that providers may be making prescribing decisions based on imaging results that identify subclinical CAD, beyond traditional CV risk factors. "In the current health care cost environment, it is important to examine the association of noninvasive CV test results on subsequent changes in medical treatment in the context of socioeconomic factors and access to medical care.... This hypothesis requires further study."
In an accompanying editorial, Y. Chandrashekhar, MD, commented on the impact of imaging modalities in modifying patient and physician behavior, particularly in increasing medication use rates. "Cardiac imaging in general results in increased therapy and the increase is related to the severity of test results," he wrote; however, "even in the positive studies, the magnitude of change in medication use still remains suboptimal." While acknowledging that the benefit in BP and cholesterol reduction at 6 months is welcome, he stressed the need for studies evaluating whether modifying prescriptions based on these data will produce reductions in adverse events in the setting of chronic CAD.
- Cheezum MK, Hulten EA, Smith RM, et al. JACC Cardiovasc Imaging. 2013 April 5. [Epub ahead of print]
- Chandrashekhar Y. JACC Cardiovasc Imaging. 2013 April 5. [Epub ahead of print]
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