Triage using coronary CTA permits early discharge from ER

Results of a three-year trial at Massachusetts General Hospital show that half of patients presenting with chest pain but at low or intermediate risk of acute coronary syndrome can be safely discharged following a negative 64-slice coronary CT evaluation.

The Rule-out Myocardial Infarction Using Computer-Assisted Tomography (ROMICAT) study prospectively evaluated 368 patients who underwent contrast-enhanced 64-slice coronary CT angiography after the determination of low or intermediate risk of ACS upon arrival in the emergency room of the Heart Center at MGH. Imaging investigated patients' coronary arteries for the presence of atherosclerotic plaque and significant (>50%) arterial stenosis.

Dr. Fabian Bamberg, an instructor in radiology in the MGH cardiac MR PET/CT program, reported Sunday at the 2008 RSNA meeting that nearly half of the patients had neither plaque nor stenosis. No patient with a negative coronary CTA assessment had a major coronary event in the six months after imaging, producing a negative predictive value of 100%.

Significant stenosis was identified in 18.4% of the patients, a finding that equated with more than an 11-fold increased risk of ACS, Bamberg said.

ROMICAT is the largest single-center trial to date to examine the feasibility of coronary CT to rule out acute coronary syndrome in the emergency room, Bamberg said. Studies presented in previous years at the RSNA conference were typically limited to about 100 patients.

"Our triage criteria really permit a safe discharge home," Bamberg said in an interview. "Patients are not required to be admitted to the hospital. They can be discharged right away."