Coronary Artery Calcium Score to Identify Patients with Chest Pain Who Can Be Discharged

To evaluate whether the coronary artery calcium score (CACS) can help identify patients with chest pain who can be safely discharged without further testing, researchers prospectively identified 1031 adult patients at an urban emergency department (ED) who were admitted for further evaluation of low-risk chest pain (chest pain suggestive of ischemia, negative initial troponin, no new ST elevation or depression on electrocardiogram (ECG), hemodynamic stability, and no history of coronary artery disease). Patients underwent stress myocardial perfusion single-photon emission computed tomography (SPECT) imaging and assessment of coronary artery calcification by noncontrast CT, which is fast, requires no patient preparation, and is completed in a single breathhold helical CT sequence.

The frequency of abnormal SPECT results increased significantly with increasing CACS, and ranged from 0.8% in 625 patients with CACS of 0 to 16.9% in 83 patients with CACS >400. Among five patients with CACS of 0 and abnormal SPECT results, four underwent angiography and had normal coronary arteries. Two of 625 patients (0.3%) with CACS of 0 experienced cardiac events during initial hospitalization or after discharge (mean follow-up, 7.4 months); both patients had elevated initial troponin levels but normal serial ECG and SPECT results. The event rate was 7.4% in patients with CACS >0.