Background It is unclear whether an evaluation incorporating coronary computed tomographic angiography (CCTA) is more effective than standard evaluation in the emergency department in patients with symptoms suggestive of acute coronary syndromes. Methods In this multicenter trial, we randomly assigned patients 40 to 74 years of age with symptoms suggestive of acute coronary syndromes but without ischemic electrocardiographic changes or an initial positive troponin test to early CCTA or to standard evaluation in the emergency department on weekdays during daylight hours between April 2010 and January 2012. The primary end point was length of stay in the hospital. Secondary end points included rates of discharge from the emergency department, major adverse cardiovascular events at 28 days, and cumulative costs. Safety end points were undetected acute coronary syndromes. Results The rate of acute coronary syndromes among 1000 patients with a mean (±SD) age of 54±8 years (47% women) was 8%. After early CCTA, as compared with standard evaluation, the mean length of stay in the hospital was reduced by 7.6 hours (P<0.001) and more patients were discharged directly from the emergency department (47% vs. 12%, P<0.001). There were no undetected acute coronary syndromes and no significant differences in major adverse cardiovascular events at 28 days. After CCTA, there was more downstream testing and higher radiation exposure. The cumulative mean cost of care was similar in the CCTA group and the standard-evaluation group ($4,289 and $4,060, respectively; P=0.65). Conclusions In patients in the emergency department with symptoms suggestive of acute coronary syndromes, incorporating CCTA into a triage strategy improved the efficiency of clinical decision making, as compared with a standard evaluation in the emergency department, but it resulted in an increase in downstream testing and radiation exposure with no decrease in the overall costs of care. (Funded by the National Heart, Lung, and Blood Institute; ROMICAT-II ClinicalTrials.gov number, NCT01084239.)

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Background To determine whether high-risk plaque as detected by coronary computed tomography angiography (CTA) permits improved early diagnosis of acute coronary syndrome (ACS) independent to the presence of significant CAD in acute chest pain patients. Objectives The primary aim was to determine whether high-risk plaque features, as detected by CTA in the emergency department, may improve diagnostic certainty of ACS independent and incremental to the presence of significant CAD and clinical risk assessment in patients with acute chest pain but without objective evidence of myocardial ischemia or myocardial infarction. Methods We included patients randomized to the CCTA arm of ROMICAT II trial. Readers assessed coronary CTA qualitatively for the presence of non-obstructive CAD (1-49% stenosis), significant CAD (≥50% or ≥70% stenosis), and the presence of at least 1 of the high-risk plaque features (positive remodeling, low < 30 Hounsfield Units plaque, napkin-ring sign, spotty calcium). In logistic regression analysis, we determined the association of high-risk plaque with ACS [myocardial infarction (MI) or unstable angina pectoris (UAP)] during the index hospitalization and whether this was independent of significant CAD and clinical risk assessment. Results Overall 37 of 472 patients who underwent coronary CTA with diagnostic image quality (mean age 53.9±8.0 years, 52.8% men) had ACS (7.8%; MI n=5, UAP n=32)]. CAD was present in 262 (55.5%) patients [non-obstructive CAD 217 (46.0%) patients, significant CAD with ≥50% stenosis 45 (9.5%) patients]. High-risk plaques were more frequent in patients with ACS and remained a significant predictor of ACS (OR 8.9, 95% CI 1.8-43.3, p=0.006) after adjusting for ≥50% stenosis (OR 38.6, 95% CI 14.2-104.7, p<0.001) and clinical risk assessment (age, gender, number of cardiovascular risk factors). Similar results were observed after adjusting for ≥70% stenosis. Conclusions In patients presenting to the ED with acute chest pain but negative initial electrocardiogram and troponin, presence of high-risk plaque on coronary CTA increases the likelihood of ACS independent of significant CAD and clinical risk assessment (age, gender, and number of cardiovascular risk factors).

Background Main pulmonary artery diameter (mPA) and ratio of mPA to ascending aorta diameter (ratio PA) derived from chest CT are commonly reported in clinical practice. We determined the age and sex-specific distribution and normal reference values for mPA and ratio PA by CT in an asymptomatic community-based population. Methods and Results In 3171 men and women (mean age 51 ± 10 years, 51% men) from the Framingham Heart Study, a non-contrast ECG gated eight-slice cardiac multi-detector CT was performed. We measured the mPA and transverse axial diameter of the ascending aorta at the level of the bifurcation of the right pulmonary artery and calculated the ratio PA. We defined the healthy referent cohort (n=706) as those without obesity, hypertension, current and past smokers, chronic obstructive pulmonary disease, history of pulmonary embolism, diabetics, cardiovascular disease, and heart valvular surgery. The mean mPA diameter in the overall cohort was 25.1 ± 2.8mm and mean ratio PA was 0.77 ± 0.09. The sex-specific 90th percentile cutoff value for mPA diameter was 28.9 mm in men and 26.9 mm in women and was associated with increase risk for self-reported dyspnea (adjusted odds ratio 1.31, p=0.02). The 90th percentile cutoff value for ratio PA of the healthy referent group was 0.91, similar between gender, but decreased with increasing age (range 0.82 to 0.94), though not associated with dyspnea. Conclusions For simplicity, we established 29 mm in men and 27 mm in women as sex-specific normative reference values for mPA and 0.9 for ratio PA.