Triple Rule Out CT in the Emergency Department: Clinical Risk and Outcomes (Triple Rule Out in the Emergency Department)

Triple rule out CT protocols (TRO-CT) have been advocated as a single test to simultaneously evaluate major causes of acute chest pain, in particular acute myocardial infarction (MI), acute pulmonary embolism (PE), and acute aortic syndrome. However, it is unclear what patient populations would benefit from a such comprehensive exam and current guidelines recommend tailoring CT protocols to the most likely diagnosis. We retrospectively reviewed TRO-CT scans performed from the Emergency Department (ED) at our institution from April 2021 to April 2022. Charts were reviewed to calculate clinical risk of MI, PE, and acute aortic syndrome using conventional clinical scoring systems (HEART score, PERC score, ADD-RS). TRO-CT findings and 30-day clinical outcomes were recorded from chart review. 1279 patients ED patients scanned with TRO-CT were included in the analysis. 831 patients (65.0%) were at-risk for two or more clinical risk scores. At TRO-CT, 381 (29.8%) patients had obstructive CAD. 91 (7.1%) had acute PE. 7 (0.5%) had acute aortic syndrome. At 30-day clinical follow up, 28 patients (2.2%) had the diagnosis of acute MI (95% CI: 1.5–3.2%). 90 patients (7.0%) had the diagnosis of acute PE (95% CI: 5.7–8.6%). 7 patients (0.5%) had the diagnosis acute aortic syndrome (95% CI: 0.2–1.2%). A low-risk HEART score was associated with a 0.3% 30-day clinical diagnosis of acute MI (95% CI: 0.0–1.6%). Low-risk-PERC was associated with a 2.9% 30-day clinical diagnosis of acute PE (95% CI: 0.7–8.7%). Low-risk ADD-RS was associated with a 0.3% 30-day clinical diagnosis of acute aortic syndrome (95% CI: 0.0–1.8%). We found a high clinical overlap in the presentation of acute MI, acute PE, and acute aortic syndrome based on clinical risk scores. Further studies will be needed to compare a TRO-CT algorithm to a standard-of-care algorithm in patients presenting to the ED.