Coronary Calcium to Rule Out Obstructive Coronary Artery Disease in Patients With Acute Chest Pain.

Objectives: This study aimed to evaluate the ability of coronary artery calcium (CAC) as an initial diagnostic tool to rule out obstructive coronary artery disease (CAD) in a very large registry of patients presenting to the emergency department (ED) with acute chest pain (CP) who were at low to intermediate risk for acute coronary syndrome (ACS).

Background: It is not yet well established whether CAC can be used to rule out obstructive CAD in the ED setting.

Methods: We included patients from the Baptist Health South Florida Chest Pain Registry presenting to the ED with CP at low to intermediate risk for ACS (Thrombolysis In Myocardial Infarction risk score ≤2, normal/nondiagnostic electrocardiography, and troponin levels) who underwent CAC and coronary computed tomography angiography (CCTA) procedures for evaluation of ACS. To assess the diagnostic accuracy of CAC testing to diagnose obstructive CAD and identify the need for coronary revascularization during hospitalization, we estimated sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV).

Results: Our study included 5,192 patients (mean age: 53.5 ± 10.8 years; 46% male; 62% Hispanic). Overall, 2,902 patients (56%) had CAC = 0, of which 135 (4.6%) had CAD (114 [3.9%] nonobstructive and 21 [0.7%] obstructive). Among those with CAC >0, 23% had obstructive CAD. Sensitivity, specificity, PPV, and NPV of CAC testing to diagnose obstructive CAD were 96.2%, 62.4%, 22.4%, and 99.3%, respectively. The NPV for identifying those who needed revascularization was 99.6%. Among patients with CAC = 0, 11 patients (0.4%) underwent revascularization, and the number needed to test with CCTA to detect 1 patient who required revascularization was 264.

Conclusions: In a large population presenting to ED with CP at low to intermediate risk, CAC = 0 was common. CAC = 0 ruled out obstructive CAD and revascularization in more than 99% of the patients, and <5% with CAC = 0 had any CAD. Integrating CAC testing very early in CP evaluation may be effective in appropriate triage of patients by identifying individuals who can safely defer additional testing and more invasive procedures.