Simple, quick test can send patient safely home from ER after chest painHouston, TX - 2/9/2010
"It is imperative to accurately diagnose patients who come to the emergency department with chest pain," said Dr. John Mahmarian, cardiologist at the Methodist DeBakey Heart & Vascular Center and principal investigator of the study. "Unfortunately, diagnosing chest pain is often expensive and time-consuming. This new data could save millions of health care dollars and countless hours spent waiting on unnecessary tests."
Mahmarian’s research, which was published online today in the Annals of Emergency Medicine, shows that patients with a coronary artery calcium score of zero can be safely sent home without further cardiac testing.
Coronary artery calcium scoring (CACS) is a simple and readily available test for identifying coronary artery disease. CACS is done with a computed topography (CT) scanner. A CT scan uses x-rays to make a detailed image of the heart, showing calcium build up in the coronary arteries. The images can be read almost immediately after the scan. A CACS of zero correlates with an excellent short-term outcome and predicts a normal SPECT, which is a more advanced imaging test that is usually done following a CACS test.
About the study
Mahmarian’s team conducted a prospective observational cohort study at The Methodist Hospital in Houston, an urban tertiary care hospital, of stable patients presenting to the emergency department (ED) with chest pain of uncertain cardiac etiology. Patients with a normal initial troponin, nonischemic ECG, and no history of CAD had stress myocardial perfusion imaging (SPECT) and CACS within 24 hours of ED admission. Cardiac events were defined as an acute coronary syndrome during the index hospitalization or in follow-up. CACS results were assessed in relation to SPECT findings and cardiac events.
The 1031 patients enrolled had a median CACS of zero (61 percent with CACS of zero). The frequency of an abnormal SPECT ranged from 0.8 percent (CACS of zero) to17 percent (CACS >400). Cardiac events occurred in 32 patients (3.1 percent) during the index hospitalization (N=28) or following hospital discharge (N=4) (mean 7.4 [3.3] months). Only two events occurred in 625 patients with a CACS of 0 (0.3 percent, 95 percent CI 0.04 to 1.1). Both of these patients developed elevated troponins during their index visit, but had normal serial ECG and SPECT studies and no cardiac events at six month follow-up.
The study findings indicate that a majority of patients (61 percent in their sample) evaluated for chest pain of uncertain cardiac etiology have a CACS of zero which predicts both a normal SPECT and an excellent short-term outcome. Properly selected patients similar to those enrolled in this study who have a CACS of zero can be discharged home without further cardiac testing.
For more information on the Methodist DeBakey Heart & Vascular Center, see www.debakeyheartcenter.com. Follow us on Twitter at http://twitter.com/MethodistHosp and Facebook at http://www.facebook.com/methodisthospital.