SAN FRANCISCO – Coronary CT angiography works better than traditional rule-out approaches for identifying emergency department patients with chest pain who are free of significant coronary disease, according to 1-year results from a randomized comparison of more than 1,300 patients.
The results also show that relying on coronary CT angiography (CCTA) for emergency department assessment of coronary disease is safe, with a 1-year rate of death or myocardial infarction substantially below 1% in patients judged negative for coronary disease by CCTA, Dr. Judd E. Hollander said at the annual meeting of the American College of Cardiology.
Mitchel L. Zoler/IMNG Medical Media
Dr. Judd E. Hollander
The findings confirmed and extended the 30-day results reported a year ago from the same study, the American College of Radiology Imaging Network (ACRIN) PA 4005 study, which randomized 1,370 low- to intermediate-risk patients who presented with chest pain and possible acute coronary syndrome at any of five U.S. emergency departments.
Two-thirds of the patients were randomized to assessment that included CCTA when deemed necessary, while the remaining third underwent more traditional assessment that could include an exercise treadmill test, a stress test with imaging, and stress echocardiography.
While the results supported a role for routine use of CCTA for assessing the types of patients enrolled in the study, Dr. Hollander stressed that a CCTA is not needed for every ED patient with questionable chest pain.
"We try to use this as an exclusionary test for patients who need an exclusionary test," said Dr. Hollander, professor and clinical research director in the department of emergency medicine at the University of Pennsylvania in Philadelphia.
"We want to avoid making this like a d-dimer test [for thrombus] or CT perfusion [for stroke patients], where everyone who comes into the ED with appropriate signs and symptoms gets one. We don’t use CCTA on patients we normally discharge. There is the risk from radiation. You need to ask how much do you need to find out what is going on with the patient sooner rather than later," he said.
During year-long follow-up on 1,368 of the starting ACRIN patients (one patient was lost to follow-up from each randomization group), one cardiac death and one myocardial infarction occurred among the 825 patients randomized to the CCTA arm and declared free of coronary disease, a 0.2% rate that fell within the study’s prespecified safety criterion of less than 1%.
CCTA’s 1-year safety came without any boost in resource use compared with ED chest-pain patients assessed by conventional means. Overall use of cardiac testing, hospital readmissions, revascularization, and ED visits was similar during 1-year follow-up in the two treatment arms, Dr. Hollander said. Further breakdown of the resource-use data showed that the majority of medical activity following the index hospitalization occurred in the 9% of the initial patients identified with coronary disease by CCTA. Fewer resources were used in patients who had questionable coronary disease following CCTA, and the least amount of resource use occurred in patients without coronary disease by CCTA.
Because CCTA categorized 9% of patients in that study arm as having coronary disease compared with 3% of the control group, and since 77% of patients in the CCTA arm were judged free of coronary disease compared with 61% in the control arm, CCTA "shifts resources to where they are most useful, with more coronary artery disease identified and treated and more patients without disease not receiving treatment," Dr. Hollander said.
The initial, 30-day ACRIN report said that 50% of patients managed in the CCTA arm were discharged early from the ED, compared with 23% of the control group (N. Engl. J. Med. 2012;366:1393-403). Patients in the CCTA group also had a substantially shorter average length of stay during their initial hospital visit.
The ACRIN PA 4005 study was sponsored by the Pennsylvania Department of Health and the ACRIN Foundation. Dr. Hollander said that he has also been a consultant to Behring, Janssen, Luitpold, and Radiometer, and that he has received research funding from Abbott, Alere, Brahms, and Siemens.
On Twitter @mitchelzoler