Focused carotid ultrasound to predict major adverse cardiac events among emergency department patients with chest pain.

BACKGROUND AND OBJECTIVE: Point-of-care focused vascular ultrasound (FOVUS), an assessment of carotid artery plaque, predicts coronary artery disease in outpatients referred for coronary angiography. Our primary objective was to determine the diagnostic accuracy of sonographer-performed FOVUS to predict major adverse cardiac events (MACE) within 30 days among patients with suspected cardiac ischemia in the emergency department (ED).

METHODS: We conducted a prospective cohort study of patients with chest pain presenting to a tertiary care ED who had an electrocardiogram and cardiac troponin testing. The primary outcome was a composite of death, acute myocardial infarction, or re-vascularization at 30 days. A sonographer performed FOVUS scans in consenting eligible subjects. Emergency physicians, blinded to the sonographer FOVUS result, performed a second FOVUS on some subjects.

RESULTS: We recruited 326 subjects (age 62.1 ± 13.5 years; 166 (52%) men), 319 of whom completed an FOVUS scan by the sonographer. Of these, 198 (62%) had a positive FOVUS scan and 41 (13%) had a 30-day MACE. The sensitivity was 83% (95% CI 71-94%), specificity 41% (95% CI 36-47%), positive-likelihood ratio 1.41 (95% CI 1.19-1.68), and negative-likelihood ratio 0.41 (95% CI 0.23-0.75). Among 71 subjects also scanned by an emergency physician, the Kappa was 0.50 (95% CI 0.31-0.70), suggesting moderate agreement between sonographer and emergency physician on the determination of significant carotid plaque.

CONCLUSIONS: The presence of carotid plaque on sonographer-performed FOVUS is associated with 30-day MACE in ED patients presenting with chest pain. The prognostic performance of FOVUS is not sufficient to support its use as a stand-alone risk stratification tool in the ED. Future work should investigate FOVUS in conjunction with validated clinical decision rules for chest pain and the impact of enhanced training and quality improvement in the conduct of FOVUS by emergency physicians.

REGISTRATION: This study was registered at clinicaltrials.gov (NCT02947360).