CT angiography use ‘unwarranted’ in chest pain patients

Jul 31 2012

By Eleanor McDermid, Senior MedWire Reporter

Using coronary computed tomography angiography (CTA) to triage patients with chest pain reduces time to discharge from the emergency department by nearly a third, researchers report in The New England Journal of Medicine.

But editorialist Rita Redberg (University of California, San Francisco, USA) argues that the study "reveals a deeper flaw in the approach to chest pain in the emergency department."

For the Rule Out Myocardial Infarction/Ischemia Using Computer Assisted Tomography (ROMICAT)-II study, Udo Hoffmann (Massachusetts General Hospital, Boston, USA) and team assessed the diagnostic benefits of coronary CTA in patients with chest pain but negative biomarkers and electrocardiographic findings.

The average length of stay was 23.3 hours for 501 patients randomly assigned to undergo coronary CTA, compared with 30.8 hours for 499 who underwent standard diagnostic procedures (median 8.6 vs 28.7 hours). For patients with a final diagnosis other than acute coronary syndrome, the corresponding stays were 17.2 versus 27.2 hours (median 8.1 vs 26.3 hours).

However, Redberg says that the "underlying assumption" that further testing is needed in these relatively low-risk patients before discharging them to outpatient care is "unproven and probably unwarranted."

This is demonstrated by the fact that just two (0.4%) patients in the CTA group and six (1.2%) in the control group had a major adverse cardiovascular event within 28 days of presentation. Just 8% of all patients had a final diagnosis of acute coronary syndromes.

Thus it is not clear whether coronary CTA was of any benefit to patients who received it, says Redberg. And given the risks associated with CTA and, indeed, other diagnostic procedures such as nuclear stress tests, "clinicians may legitimately ask whether the tests did more harm than good."

Patients in the coronary CTA group received significantly more radiation than those in the control group, at 13.9 versus 4.7 mSv/patient. And despite having undergone CTA, these patients received significantly more additional diagnostic tests than the control group, with 75% versus 68% undergoing one test and 23% versus 11% undergoing at least two tests. This difference persisted when tests performed at follow-up visits within 28 days were included.

Compared with control patients, CTA patients were significantly less likely to undergo functional testing, such as stress echocardiography, but were nonsignificantly more likely to undergo invasive coronary angiography. Costs through 28 days of follow up were no different between the groups.

Redberg therefore concludes that "judicious" outpatient follow-up is "in the best interests of the majority of these patients."

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