title: Prevalence of Acute Coronary Syndrome in Patients Suspected for Pulmonary Embolism or Acute Aortic Syndrome: Rationale for the Triple Rule-Out Concept.
abstract: BACKGROUND
  The aims of the study were to evaluate the prevalence of acute coronary syndrome (ACS) among patients presenting with atypical chest pain who are evaluated for acute aortic syndrome (AAS) or pulmonary embolism (PE) with computed tomoangiography (CTA) and discuss the rationale for the use of triple rule-out (TRO) protocol for triaging these patients.
  
  
  METHODS
  This study is a retrospective analysis of patients presenting with atypical chest pain and evaluated with thoracic (CTA), for suspicion of AAS/PE. Two physicians reviewed patient files for demographic characteristics, initial CT and final clinical diagnosis. Patients were classified according to CTA finding into AAS, PE and other diagnoses and according to final clinical diagnosis into AAS, PE, ACS and other diagnoses.
  
  
  RESULTS
  Four hundred and sixty-seven patients were evaluated: 396 (84.8%) patients for clinical suspicion of PE and 71 (15.2%) patients for suspicion of AAS. The prevalence of ACS and AAS was low among the PE patients: 5.5% and 0.5% respectively (P = 0.0001), while the prevalence of ACS and PE was 18.3% and 5.6% among AAS patients (P = 0.14 and P = 0.34 respectively).
  
  
  CONCLUSIONS
  The prevalence of ACS and AAS among patients suspected clinically of having PE is limited while the prevalence of ACS and PE among patients suspected clinically of having AAS is significant. Accordingly patients suspected for PE could be evaluated with dedicated PE CTA while those suspected for AAS should still be triaged using TRO protocol.
authors.affiliation: Department of Radiology & Medical Imaging, Armed Forces Hospital, Southern Region, Saudi Arabia.
authors.forename: Saad Al
authors.initials: SA
authors.lastname: Qahtani
authors.affiliation: Department of Radiology & Medical Imaging, Armed Forces Hospital, Southern Region, Saudi Arabia.
authors.forename: Ahmed Y
authors.initials: AY
authors.lastname: Kandeel
authors.affiliation: Cardio-Thoracic and Vascular Unit, Department of Radiology, University Hospital of Lausanne, Switzerland.
authors.forename: Stephane
authors.initials: S
authors.lastname: Breault
authors.affiliation: Cardio-Thoracic and Vascular Unit, Department of Radiology, University Hospital of Lausanne, Switzerland ; Quantitative Medical Imaging Laboratory, Department of Radiology, University Hospital of Lausanne, Switzerland.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Jouannic
authors.affiliation: Cardio-Thoracic and Vascular Unit, Department of Radiology, University Hospital of Lausanne, Switzerland ; Quantitative Medical Imaging Laboratory, Department of Radiology, University Hospital of Lausanne, Switzerland.
authors.forename: Salah D
authors.initials: SD
authors.lastname: Qanadli
keywords: Acute aortic syndrome; Acute coronary syndrome; Pulmonary embolism; Triple rule-out