In 2014, a total of 6 887 000 patients came to US emergency departments (EDs) because of symptoms of chest pain, representing 5% of all ED visits. While some of them have clinical evidence of acute coronary syndromes (ACS), many others have no ischemic changes on the electrocardiogram (ECG) and normal cardiac troponin levels. Uncertainty surrounds proper treatment of these low- to intermediate-risk patients.
The 2014 American College of Cardiology/American Heart Association clinical guideline for non–ST-segment elevation acute coronary syndrome gives a class IIa recommendation to noninvasive testing (exercise testing or coronary computed tomographic angiography [CCTA]) in patients with chest pain but no evidence of ischemia. In most cases, however, the results of testing are negative in this low- to intermediate-risk population, and expensive resources may be consumed with no effect on clinical outcome.