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Rule Out Dissection
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Rule Out Dissection
Using the Aortic Dissection Detection Risk Score (ADD-RS) and D-dimer to rule out acute aortic dissection in the Emergency Department setting without imaging.
Cooper Kersey, MS3
Columbia P&S EM Sub-I
April 2018
The ADvISED Trial
Scenario
Introduction
As a Sub-I in the ED I found myself including "equal pulses in the upper extremities" in my physical exams to communicate that I had considered an aortic dissection as the diagnosis in patients with chest pain but thought it was less likely.
Clinical Uncertainty
I had heard horror stories of patients who presented with abdominal, back, or chest pain and died within minutes from massive aortic dissections all with "equal upper extremity pulses". Needless to say equal pulses felt like an incomplete method to exclude dissection.
The Great Marauder
Low Sensitivity
Equal pulses on exam doesn't exclude a dissection. The JAMA guide to evidence-based clinical diagnosis found pulse differences between the upper extremities to only be 31% sensitive for detecting aortic dissection.
Thoracic Aortic Dissection. In: Simel DL, Rennie D. eds. The Rational Clinical Examination: Evidence-Based Clinical Diagnosis New York, NY: McGraw-Hill; 2009. http://jamaevidence.mhmedical.com/content.aspx?bookid=845§ionid=61357595.
Low Sensitivity
Imaging to Rule Out
Current guidelines recommend either CTA, MRA, or TEE to rule out dissection. CTA is chosen 60% of the time due to availability and ease of testing.
Hiratzka LF, Bakris GL, Beckman JA, et al. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with Thoracic Aortic Disease: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines, American Association for Thoracic Surgery, American College of Radiology, American Stroke Association, Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, Society of Interventional Radiology, Society of Thoracic Surgeons, and Society for Vascular Medicine. Circulation. 2010;121(13):e266-369.
Imaging to Rule Out
Clinical Question
Clinical Question
We have the Wells Criteria to determine whether imaging is needed to rule out PE in patients with clinically suspicious presentations. Is there a similar scoring system for Aortic Dissection?
Problem
How to avoid imaging?
CT Angiography is estimated to cost $1,000 on average in the U.S.
https://www.mdsave.com/procedures/ct-angiography-cta/d786ffc9
Solution
Risk Calculator
A risk calculator would help identify those patients who truly need imaging to rule out a dissection.
ADD-RS
The Aortic Dissection Detection Risk Score (ADD-RS) gives a patient a score of 0-3 based on whether they have:
1.High risk past medical or family history
2. Concerning description of pain
3. Concerning exam findings
Full Scoring System
Full Scoring System
If patient is positive for any of the findings in a column, then they get one point for that column. Maximum of 3 points, max one per column.
http://rebelem.com/the-advised-trial-a-novel-clinical-algorithm-for-the-diagnosis-of-acute-aortic-syndromes/
ADvISED Trial
Prospective multicenter study that was designed to test the accuracy of an algorithm that combinges the ADD-RS score and a D-dimer value to rule out aortic dissection without imaging.
ADD-RS and
D-Dimer
Risk Stratification
Algorithm
Nazerian P, Mueller C, Soeiro AM, et al. Diagnostic Accuracy of the Aortic Dissection Detection Risk Score Plus D-Dimer for Acute Aortic Syndromes: The ADvISED Prospective Multicenter Study. Circulation. 2018;137(3):250-258.
http://circ.ahajournals.org/content/137/3/250.long
Results
Patients with both an ADD-RS ≤ 1 and a D-Dimer of < 500ng/ml were ruled out for dissection without imaging. 1 in 300 cases of acute aortic dissection were missed with this cutoff.
However it saved 50% of patients with suspected aortic dissection from undergoing CTA.
Results
Reactions
Reactions
I want to hear your reactions to this algorithm.
1. Is 1 in 300 an acceptable miss rate for a diagnosis with such high morbidity and mortality?
2. Why isn't the ADD-RS+ D-Dimer on MDcalc.com?
3. What will it take for this algorithm to enter the mainstrem of EM?
4. Are algorithms slowly replacing clinical reasoning?
4a. If so, is that detrimental or beneficial to a fast-paced, high volume field like Emergency Medicine?
See sidebars for my and others' thoughts on the ADD-RS+ D-dimer algorithm.
Algorithm Limitations
Study Limitations
-No external validation of the algorithm thus far.
-In ADvISED study, high rate of aortic dissection in study patients (13%), could have different results in lower risk population.
-Not all patients in the study had conculsive imaging to confirm whether or not they had an aortic dissection.
-Follow-up was for 14 days which might not be long enough to catch every dissection.
Rebel EM
Rebel EM Reaction
Dr. Rezaie from rebelem.com wrote a very thorough article on the ADvISED trial which outlines more of the details about the study design, inclusion/exclusion criteria, and results. Check it out at the link below.
http://rebelem.com/the-advised-trial-a-novel-clinical-algorithm-for-the-diagnosis-of-acute-aortic-syndromes/
What is the right miss rate?
Miss Rate
Aortic Dissections have very high mortality rates. As high as 1%/hr, leaving 50% of missed diagnosis dead in 3 days and 80% dead in a week.
(Criado FJ. Aortic Dissection: A 250-Year Perspective. Coselli JS, ed. Texas Heart Institute Journal. 2011;38(6):694-700)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3233335/
-Thus a truly missed diagnosis is close to a death sentence.
-With a miss rate of 0.3% and the benefit being avoiding CTA ($1000) in 50% of patients, for 600 patients with suspected dissection, roughly 300 will not be imaged ($3 million saved) and 1 of those 300 will die.
-Is 1 lost life worth $3 million saved?
-These are crude estimations but the sentiment translates no matter what the exact figure is.