Diagnostic Accuracy and Clinical Outcomes of ECG-Gated, Whole Chest CT in the Emergency Department

<div><p>Purpose</p><p>The purpose of this study was to assess the diagnostic accuracy and one year prognosis of whole chest, “multiple rule out” CT for coronary artery disease (CAD) in Emergency Department patients.</p> <p>Methods and Findings</p><p>One hundred and two Emergency Department patients at low to intermediate risk of acute coronary syndrome (ACS), pulmonary embolism and/or acute aortic syndrome underwent a research 64 channel ECG-gated, whole chest CT and a standard of care evaluation. Patients were classified with obstructive CAD with either a coronary CT stenosis greater than 50% or a non-evaluable coronary segment. SOC and 3 month follow up data were used to determine an adjudicated clinical diagnosis. The diagnostic ability of obstructive CAD on CT to identify clinical diagnoses was determined. Patients were followed up for 1 year for cardiac events. Seven (7%) patients were diagnosed with ACS. CT sensitivity to detect obstructive CAD in ACS patients was 100% (95% CI 65%, 100%), negative predictive value 100% (96%, 100%), specificity 88% (80%, 94%), and positive predictive value 39% (17%, 64%). Pulmonary embolism and acute aortic syndrome were not identified in any patients. No cardiac events occurred in patients without obstructive CAD over 1 year.</p> <p>Conclusions</p><p>Whole chest CT has high sensitivity and negative predictive value for ACS with excellent one year prognosis in patients without obstructive CAD on CT. The frequency of pulmonary embolism or acute aortic syndrome and the higher radiation dose suggest whole chest CT should be limited to select patients.</p> <p>ClinicalTrials.org #: <a href="http://clinicaltrials.gov/show/NCT00855231" target="_blank">NCT00855231</a></p> </div

Clinical trial protocol and patient evaluation flowchart. ACS = acute coronary syndrome, CAD = coronary artery disease, CT = computed tomography.

<p>Clinical trial protocol and patient evaluation flowchart. ACS = acute coronary syndrome, CAD = coronary artery disease, CT = computed tomography.</p

Presenting Symptoms and SOC Evaluation.

*<p>Patients may have more than one symptom at presentation. ACS = acute coronary syndrome, CAD = coronary artery disease, SOC = standard of care, SPECT = single positron emission computed tomography.</p

Patient-level diagnostic measures of CT by clinical pre-test probability of ACS (A) and by TIMI Risk Score (B).

<p>The pre-test probability of ACS (A) was determined by the clinical judgment of the ED physician caring for the patient. NPV = negative predictive value; PPV = positive predictive value.</p

Non-Cardiac Findings.

<p>Follow up imaging with ultrasound^† and repeat CT* suggested benign findings.</p

Patient enrollment and 3 month outcomes. CABG = coronary artery bypass grafting, CAD = coronary artery disease, IV = intravenous, MI = myocardial infarction, PCI = percutaneous coronary intervention.

<p>Patient enrollment and 3 month outcomes. CABG = coronary artery bypass grafting, CAD = coronary artery disease, IV = intravenous, MI = myocardial infarction, PCI = percutaneous coronary intervention.</p

Patient-Level Diagnostic Measures of CT for Acute Coronary Syndrome.

<p>Two CT scans were non-evaluable and patients were considered to have >70% stenosis. 95% CI = empiric 95% confidence limits, PPV = Positive predictive value; NPV = Negative predictive value.</p

Empiric ROC curve for ordinal coronary CT stenosis quintiles compared to the adjudicated diagnosis of ACS. AUC = area under the curve.

<p>Empiric ROC curve for ordinal coronary CT stenosis quintiles compared to the adjudicated diagnosis of ACS. AUC = area under the curve.</p

Patient Baseline Characteristics.

<p>ACS = acute coronary syndrome, CAD = coronary artery disease, BMI = body mass index.</p