Aortic Dissection Detection Risk Score (ADD-RS) and D-dimer
Aortic Dissection Detection Risk Score (ADD-RS) and D-dimer:
🔹 Aortic Dissection Detection Risk Score (ADD-RS)
The ADD-RS was developed as a clinical pre-test probability tool to help clinicians decide which patients with acute chest pain, back pain, syncope, or pulse deficit should undergo further evaluation for acute aortic syndromes (AAS) such as aortic dissection, intramural hematoma, or penetrating atherosclerotic ulcer.
Components
The score is based on 12 risk markers, grouped into 3 categories:
- High-risk conditions
- Marfan syndrome or other connective tissue disorder
- Family history of aortic disease
- Known thoracic aortic aneurysm
- Known aortic valve disease
- Recent aortic manipulation (surgery, catheterization)
- High-risk pain features
- Abrupt onset
- Severe intensity
- Ripping/tearing character
- High-risk examination features
- Pulse deficit or systolic blood pressure differential
- Focal neurological deficit (in combination with pain)
- New aortic regurgitation murmur
- Hypotension/shock
Scoring
- ADD-RS = 0 → No risk markers
- ADD-RS = 1 → One risk marker
- ADD-RS = 2–3 → Two or more risk markers
👉 The higher the score, the greater the pre-test probability of aortic dissection.
🔹 Role of D-dimer
Since acute aortic dissection involves activation of coagulation and fibrinolysis, D-dimer is usually elevated.
- A negative D-dimer (<500 ng/mL) within 24 hours of symptom onset can help exclude acute aortic dissection in low-risk patients.
- However, D-dimer can also be elevated in many other conditions (e.g., PE, MI, infection, cancer).
🔹 ADD-RS + D-dimer Strategy (ADvISED Study, 2018)
- ADD-RS = 0 + negative D-dimer → Very low probability of AAS (negative predictive value >99%).
- ADD-RS = 1 + negative D-dimer → Also reasonably safe for exclusion in many settings.
- ADD-RS ≥1 + positive D-dimer → Further imaging (CTA, MRA, or TEE) required.
Practical Approach
- Calculate ADD-RS (0, 1, or ≥2).
- Check D-dimer if ADD-RS = 0–1.
- If negative → can often rule out AAS.
- If positive → proceed to imaging.
- If ADD-RS ≥2 → proceed directly to imaging (high-risk).
✅ Key Takeaways
- ADD-RS is a simple bedside tool to stratify risk.
- D-dimer adds value in excluding AAS in low–intermediate risk patients.
- Combined approach reduces unnecessary CT scans while maintaining safety.
- Limitation: D-dimer utility decreases after >24h from symptom onset.
Aortic Dissection Detection Risk Score (ADD-RS) & D-dimer — 20 MCQs
Q1 (Recall) Which of the following is NOT a component considered in the ADD-RS categories?
Answer: D. Elevated LDL cholesterol is not part of ADD-RS. ADD-RS uses high-risk conditions, high-risk pain features, and high-risk exam features (e.g., Marfan, abrupt severe pain, pulse deficit).
Q2 (Clinical) A 62-year-old man with sudden severe chest pain radiating to the back, BP 160/90 in right arm and 110/70 in left arm, new diastolic murmur. How many ADD-RS points (categories) does he have?
Answer: C. 2 — He has high-risk pain features (abrupt, severe) and high-risk exam features (pulse/BP differential and new aortic regurgitation murmur). That fits ≥2 risk categories.
Q3 (Recall) Which time window is most relevant for using D-dimer to help exclude acute aortic dissection?
Answer: B. D-dimer is most useful within the first 24 hours — sensitivity declines with time from symptom onset as clot burden and fibrinolytic signals change.
Q4 (Clinical) A 45-year-old with Marfan syndrome presents with sudden chest pain. ADD-RS category count is:
Answer: B. 1 — Marfan is a high-risk condition within one category. Additional features (pain, exam) would add more categories.
Q5 (Recall) In the combined ADD-RS + D-dimer strategy from ADvISED, which combination is considered sufficient to safely rule out an acute aortic syndrome in many patients?
Answer: A. ADD-RS 0 + negative D-dimer has very high NPV and is often used to avoid imaging in low-risk patients.
Q6 (Clinical) A 70-year-old woman with syncope and focal right arm weakness plus severe back pain arrives. Which ADD-RS category is flagged by the neurological deficit?
Answer: B. Focal neurologic deficit in the context of chest/back pain is a high-risk exam feature suggestive of possible branch vessel involvement from dissection.
Q7 (Recall) Typical D-dimer threshold used to “rule out” AAS in many studies is:
Answer: B. A conventional D-dimer cutoff of 500 ng/mL (FEU) is commonly used for exclusion strategies in AAS algorithms.
Q8 (Clinical) A patient with ADD-RS = 1 and D-dimer = 1200 ng/mL — next best step?
Answer: B. Positive D-dimer with ADD-RS ≥1 warrants definitive imaging (e.g., contrast CTA) to evaluate for AAS.
Q9 (Recall) Which of the following is a limitation of relying on D-dimer to exclude AAS?
Answer: C. D-dimer is sensitive but not specific — it’s elevated in PE, MI, infection, cancer, recent surgery, and with age.
Q10 (Clinical) A 58-year-old with chest pain 36 hours ago now has D-dimer 200 ng/mL. How should you interpret the negative D-dimer?
Answer: B. The sensitivity of D-dimer drops with time; a negative result >24 hours after onset is less reassuring and imaging should be considered based on clinical picture.
Q11 (Recall) ADD-RS groups the 12 risk markers into how many categories?
Answer: C. The 12 markers are grouped into 3 categories: high-risk conditions, high-risk pain features, and high-risk exam features.
Q12 (Clinical) A young patient presents with sudden chest pain and a history of recent aortic valve replacement 3 weeks ago. This history is categorized in ADD-RS as:
Answer: B. Recent aortic manipulation (surgery, instrumentation) is a high-risk condition in ADD-RS.
Q13 (Recall) In the ADvISED study, the combined algorithm aimed to reduce unnecessary CT scanning while maintaining safety. Which performance metric is most important for a rule-out strategy?
Answer: C. For exclusion strategies, high sensitivity and high NPV are crucial to avoid missing true cases.
Q14 (Clinical) A patient with sudden tearing chest pain, hypotension, and pulseless lower extremities arrives. ADD-RS category count:
Answer: C. Multiple exam features (hypotension/shock, pulse deficits) and high-risk pain suggest ≥2–3 categories — high pretest probability; urgent imaging and vascular/CT surgery consultation needed.
Q15 (Recall) Which imaging test is most commonly used as the initial definitive diagnostic test for suspected aortic dissection in hemodynamically stable patients?
Answer: B. CTA chest is widely available, fast, and highly accurate for AAS in stable patients; TEE/MRI are alternatives in some scenarios.
Q16 (Clinical) A 50-year-old with chest pain and ADD-RS = 0 has D-dimer = 450 ng/mL. What is the most appropriate immediate action?
Answer: B. ADD-RS 0 + D-dimer <500 is considered low enough risk in many protocols to avoid immediate imaging, considering full clinical context.
Q17 (Recall) Which of these is a high-risk exam feature in ADD-RS?
Answer: C. Pulse deficits or systolic BP differentials between limbs are classic high-risk exam features for possible dissection.
Q18 (Clinical) In a patient with high clinical suspicion (ADD-RS ≥2), a negative D-dimer should:
Answer: B. In high pretest probability (ADD-RS ≥2), imaging should be performed regardless of D-dimer result due to risk of false negatives.
Q19 (Recall) Which statement about the ADD-RS + D-dimer approach is TRUE?
Answer: B. The combined approach reduces unnecessary CT scans in low-risk patients, but clinical judgment remains essential.
Q20 (Clinical) A 66-year-old with abrupt chest pain has ADD-RS = 1. D-dimer returns 480 ng/mL. Which is the best next step?
Answer: B. With ADD-RS = 1 and D-dimer <500, many algorithms permit ruling out AAS if overall clinical evaluation supports low risk — though local protocols and clinical judgment apply.
Notes: ‘D-dimer < 500 ng/mL' refers to conventional FEU cutoff commonly used; local assay units/cutoffs may vary. These questions are educational — follow institutional protocols for patient care.
