The sonographic protocol for the emergent evaluation of aortic dissections (SPEED protocol): A multicenter, prospective, observational study.

Abstract

An aortic dissection (AoD) is a potentially life-threatening emergency with mortality rates exceeding 50%. While computed tomography angiography remains the diagnostic standard, patients may be too unstable to leave the emergency department. Investigators developed a point-of-care ultrasound (POCUS) protocol combining transthoracic echocardiography (TTE) and the abdominal aorta. The study objective was to determine the test characteristics of this protocol. This was an institutional review board-approved, multicenter, prospective, observational, cohort study of a convenience sample of adult patients. Patients suspected of having an AoD received a TTE and abdominal aorta POCUS. Three sonographic signs suggested AoD: a pericardial effusion, an intimal flap, or an aortic outflow track diameter measuring more than 35 mm. Investigators present continuous and categorical data as medians with interquartile ranges or proportions with 95% confidence intervals (CIs) and utilized standard 2 × 2 tables on MedCalc (Version 19.1.6) to calculate test characteristics with 95% CI. Investigators performed 1314 POCUS examinations, diagnosing 21 Stanford type A and 23 Stanford type B AoD. Forty-one of the 44 cases had at least one of the aforementioned sonographic findings. The protocol has a sensitivity of 93.2% (95% CI 81.3-98.6), specificity of 90.9 (95% CI 89.2-92.5), positive and negative predictive values of 26.3% (95% CI 19.6-33.9) and 99.7% (95% CI 99.2-100), respectively, and an accuracy of 91% (95% CI 89.3-92.5). The SPEED protocol has an overall sensitivity of 93.2% for AoD.