Introduction: The RAPID RIP clinical decision aid was developed to identify patients at high-risk for acute aortic syndrome (AAS) who require investigations. It stratifies patients into low (no further testing) intermediate (D-dimer if no alternative diagnosis) and High risk (Computed tomography (CT) aorta). Our objectives were to assess its impact on: a) Documentation of high risk features/pre test probability for AAS b) D-dimers ordered c) CT ordered and d) Emergency department length of stay. Methods: We conducted a prospective pilot before/after study at a single tertiary-care emergency department between August and September 2018. Consecutive alert adults with chest, abdominal, flank, back pain or stroke like symptoms were included. Patients with pain >14 days or secondary to trauma were excluded. Results: We enrolled 1,340 patients, 656 before and 684 after implementation, including 0 AAS. Documentation of pre test probability assessment increased (0% to 3%, p < 0.009) after implementation. The proportion who had D-dimer performed increased (5.8% to 9.2% (p < 0.2), while the number of CT to rule out AAS remained stable (0.59% versus 0.58%; p = 0.60). The mean length of ED stay was stable (2.31+/−2.0 to 2.28+/−1.5 hours; p = 0.45) and slightly decreased in those with pre test probability documented (2.1+/−1.4 p < 0.09). The specificity of the decision aid for CT was 100%( 95%CI 71.5- 100%). If it were applied to all patients with high-risk clinical features of AAS the specificity would be 92.6% (95%CI 90.1-94.6%). Conclusion: Implementation of the RAPID RIP increased documentation of important high-risk features for AAS. The RAPID RIP strategy increased use of D-dimer without increasing the number of CT and had a trend towards decreased length of stay.