Christopher L Schlett; Dahlia Banerji; Emily L Siegel; Sam J Lehman; Fabian Bamberg; Maros Ferencik; Ian S Rogers; Thomas J Brady; John T Nagurney; Udo Hoffmann; Quynh A Truong
    Massachusetts General Hosp， Boston， MA 
    Background: There is a paucity of data that relate long-term outcomes of patients who present to the emergency department (ED) with chest pain but are ruled out for acute coronary syndrome (ACS) with computed tomography angiography (CTA) features of coronary artery disease (CAD). 
    Methods: We conducted a 2-year phone follow-up of patients who presented to the ED with acute chest pain but were ruled out for ACS， and who underwent a 64-slice coronary CTA during index hospitalization. Results of CTA were stratified as no CAD， non-obstructive CAD， and significant stenosis (>50% luminal narrowing) but not disclosed to patients or caregivers. Primary endpoint was major adverse cardiac events (MACE) defined as cardiac death， myocardial infarction (MI)， or revascularization (REVASC). Secondly， we evaluated the need of workup for recurrence of chest pain symptoms or rule out of MI. These endpoints were verified by review of medical records and Social Security Death Index. 
    Results: Follow-up (median time of 24.3 months) was completed in 303/337 patients (91%; 52±11 years; 60% male; 65% low Framingham Risk Score). During follow-up， MACE occurred in 3 patients (1% event rate; 2 MI， 1 REVASC) and 12% (37/300) of patients without MACE were readmitted. None of the 159 patients (52%) without CAD had a MACE during follow-up. Among 131 patients (44%) who had non-obstructive CAD one MACE occurred (0.8%). Among 13 patients (4%) who had significant stenosis two MACE occurred (15%). Patients with coronary stenosis had higher estimated rate of 2-year MACE than those without (15% vs. 0.4%， p<0.0001) with near 50-fold increase in hazard (HR: 49.7， p=0.001). No difference was found in readmission rate amongst those without CAD， with non-obstructive CAD， and with significant stenosis (11% vs. 14% vs. 9%， p=0.85; respectively). 
    Conclusion: Patients， who presented to the ED with chest pain but were ruled out for ACS， have a very low rate of MACE (1%) at 2-year follow-up. In these patients， absence of CAD as determined by CTA has at least a 2-year MACE-free warranty period， while coronary stenosis despite absence of ACS during index hospitalization is associated with higher risk for MACE. Thus， CTA features of CAD provide excellent long-term prognostic information in chest pain patients from the ED.