ER Scan Pinpoints 30-Day Heart Risk

Coronary CT angiography predicts cardiovascular risk

(RxWiki News) When patients show up at the emergency room complaining of chest pain, they are usually admitted for a gamut of testing for heart problems, the most serious of which could be a blocked coronary artery. A non-invasive test may help speed up that test.

A coronary CT angiography (CCTA) provides a quick non-invasive peek inside arteries that supply the heart, allowing doctors to safely send patients who are not at imminent heart risk home from the hospital.

"Talk to a cardiologist about the most suitable diagnostic tests."

Dr. Harold I. Litt, chief of cardiovascular imaging in the department of radiology at the Perelman School of Medicine at the University of Pennsylvania and lead author of the study, noted that when emergency rooms are crowded, all patients suffer. He said the study's primary goal was to prove the safety of CCTA so that emergency department doctors feel comfortable sending home patients with negative results from CCTA scans.

About 85 percent of emergency room visits based on chest pain are not actually related to heart problems. However, emergency department physicians' standard for discharging patients with chest pain is that the patient has to have been found to have a risk of less than 1 percent of a heart attack or dying of a heart-related condition within the next 30 days.

Most patients with chest pain are admitted for at least 24 hours to rule out other conditions. When positive results are present, cardiac catheterization is typically performed. This invasive test requires that a thin tube be threaded through the groin into the heart to check for potential clogs in arteries leading to the heart.

During the American College of Radiology Imaging Network (ACRIN) PA 4005 phase four trial, investigators followed 1,393 patients at various medical centers during traditional rule-out care or CCTA, with two-thirds of patients assigned to the CCTA wing. Clinicians made decisions about which tests to offer under the standard rule-out care.

Among the CCTA group, patients received blood tests to measure two substances linked to heart damage, and the risk of heart attack or stroke, and a CCTA. They were discharged if test results were negative.

They found that none of the 640 patients with negative CCTA died or had a heart attack within 30 days following discharge. This finding applied only to patients with low to moderate heart risk, not those with known heart disease, who could require more thorough evaluation.

Use of the CCTA scans also performed better than traditional stress tests in pinpointing patients with coronary artery disease. Of the patients who received CCTA, 9 percent were diagnosed with coronary artery disease, compared to 3 percent in the traditional treatment group. Dr. Litt said this is because stress tests are only positive when the blockage is great enough to block blood flow, while CCTA shows plaque build up in the arteries even without current chest pain.

CCTA had the advantage in other categories as well. Of CCTA patients, 50 percent were discharged rather than admitted compared to 23 percent in the traditional group. In addition, CCTA patients had shorter median hospital stays at 18 hours versus 25 hours, and a shorter median time for discharge with a negative CCTA or stress test at 12 hours compared to 25 hours.

The trial was funded by the Pennsylvania Department of Health and the ACRIN Fund for Imaging Innovation.

It was presented Monday at the American College of Cardiology’s annual scientific sessions, and also simultaneously published in New England Journal of Medicine.

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Review Date: 
March 26, 2012