Preliminary development of a clinical decision rule for acute aortic syndromes

Abstract

Objective Patients with suspected acute aortic syndromes (AAS) often undergo CT with negative results. We sought clinical and diagnostic criteria to identify low risk patients, an initial step in developing a clinical decision rule. Methods We retrospectively identified all adults presenting to our Emergency Department (ED) from 1/1/2006- 8/1/2010 who underwent CT angiography for suspected AAS without prior trauma or AAS. 1,465 patients met inclusion criteria; a retrospective case-controlled review (ratio 1:4) was conducted. Cases were diagnosed with aortic dissection, intramural hematoma, penetrating atherosclerotic ulcer or ruptured aneurysm. Results 2.7% (40/1,465) of patients who underwent CT had an AAS, 2 additional cases were diagnosed after admission [ED miss rate 5% (2/42)]. Patients with AAS were significantly older than controls (66 vs 59 yrs; p=.008). Risk factors included abnormal chest radiograph [sensitivity 79% (26/33), specificity 82% (113/137)] and acute chest pain [sensitivity 83% (29/35), specificity 71% (111/157)]. None of the 19 patients with resolved pain upon ED presentation had AAS. These data support a two-step rule: first screen for ongoing pain; if present, screen for acute chest pain or an abnormal chest radiograph. This approach achieves a 54% (84/155) reduction in CT usage with a sensitivity for AAS of 96% (95% CI: 89%-100%), negative predictive value of 99.8% (99.4%-100%) and a false negative rate of 1.7% (1/84). Conclusions Our results demonstrate a need to safely identify patients at low risk for AAS who can forgo CT. We developed a preliminary two-step clinical decision rule, which requires validation.

Can the Unenhanced Phase Be Eliminated From Dual-Phase CT Angiography for Chest Pain? Implications for Diagnostic Accuracy in Acute Aortic Intramural Hematoma

“…Three-hundred fifty-four patients were identified and assessed for eligibility on the basis of a pretest probability for acute aortic syndromes [18] (Fig. 3) and subsequent index test; 44 were excluded from the analytic dataset, decreasing the sample size from 354 to 310 cases.…”

“…However, the identification of patients at low risk of acute aortic syndromes is essential to better target CT use in the emergency setting [18].…”

“…Diagram shows proposed two-step screening method to identify patients at high or low risk for acute aortic syndromes according to Lovy et al[18]. CTA = CT angiography.Difference in Unenhanced and Contrast-EnhancedAttenuation (HU)Mean of Unenhanced and Contrast-Enhanced Attenuation (Bland-Altman charts.A and B, Bland-Altman plots of intramural hematoma attenuation show previous correlation (A) and average difference between unenhanced and contrast-enhanced attenuation values for intramural hematoma (B) (p = 0.102).…”

Systematic Review of Aortic Dissection Detection Risk Score Plus D‐dimer for Diagnostic Rule‐out Of Suspected Acute Aortic Syndromes

“…6 Consequently, decision on advanced imaging for suspected AASs is cumbersome, as shown by substantial variability in CTA ordering within emergency physicians, high misdiagnosis rates (up to 39%), and low diagnostic efficiency (as low as 2% of CTA examinations turning out positive in North American series). [7][8][9] For standardized clinical probability assessment of AASs, the reference tool indicated by guidelines is the aortic dissection detection risk score (ADD-RS), based on 12 risk factors organized in three categories (Data Supplement S1, Table S1, available as supporting information in the online version of this paper, which is available at http://onlinelibrary.wiley.com/doi/10. 1111/acem.13969/full).…”

What Is the Specificity of the Aortic Dissection Detection Risk Score in a Low‐prevalence Population?

“…Previous studies validating the ADD‐RS were conducted in a population with a high prevalence of AAS (13%–22.6%; see Data Supplement S1, available as supporting information in the online version of this paper, which is available at http://onlinelibrary.wiley.com/doi/10.1111/acem.13634/full). The population that we are attempting to risk stratify likely has a much lower prevalence . We do not know how the ADD‐RS will perform in a low‐risk population.…”