What is the approach for risk stratification and management of a patient with suspected aortic dissection, considering their age, medical history, and clinical presentation?

Risk Stratification for Aortic Dissection

Do not rely on clinical decision rules alone to identify low-risk patients with suspected aortic dissection, as even patients with an ADD score of 0 still have a 4-6% risk of dissection. 1

Clinical Risk Assessment Framework

High-Risk Predisposing Conditions

Assess for the following conditions that significantly increase dissection risk: 1, 2

• Marfan syndrome or other connective tissue disorders (Loeys-Dietz, Ehlers-Danlos) 1, 3
• Family history of aortic disease 1
• Known aortic valve disease (particularly bicuspid aortic valve) 1, 3
• Recent aortic manipulation (catheterization, cardiac surgery) 1
• Known thoracic aortic aneurysm 1
• History of hypertension (greatest population attributable risk) 2, 3

High-Risk Pain Features

Evaluate pain characteristics systematically: 1, 2

• Abrupt onset (present in 84% of cases) 2
• Severe intensity (present in 90% of cases) 2
• Tearing or ripping quality (though only 51-64% describe it this way) 2
• Location: Chest pain (80% of Type A), back pain (64% of Type B, 47% of Type A), or abdominal pain (21% Type A, 43% Type B) 2
• Migrating quality (12-55% of cases as dissection extends) 2

High-Risk Examination Features

Perform focused examination for: 1, 4

• Pulse deficit (absent or diminished peripheral pulses) 1
• Systolic blood pressure differential >20 mmHg between arms (measure both arms sequentially) 1, 4
• Focal neurologic deficit with pain 1, 2
• New or unknown murmur of aortic insufficiency 1, 2
• Hypotension or shock 1

The ADD Risk Score Algorithm

Calculate the ADD score (0-3) based on number of risk categories where ≥1 high-risk marker is present: 1, 5

ADD Score Interpretation:

• ADD Score = 0: 4.3-5.9% risk of dissection 1, 5
• ADD Score = 1: 27.3% risk of dissection 5
• ADD Score ≥2: 39.1% risk of dissection 5

Critical Limitation: An ADD score of 0 has a negative likelihood ratio of only 0.22 (95% CI 0.15-0.33), which is insufficient to exclude dissection. 1, 2 Even among 439 patients with ADD score 0,26 (5.9%) had confirmed dissection. 1, 5

Adjunctive Risk Stratification Tools

D-dimer Testing

D-dimer >0.5 µg/mL has high sensitivity (91-100%) but should never be used alone to rule out dissection: 1, 2

False-negative D-dimer occurs in: 1

• Chronic dissections (>2 weeks from symptom onset) 1
• Thrombosed false lumen 1
• Intramural hematoma without intimal flap 1
• Short dissection length 1
• Young patients 1
• Early presentation (<4 hours from symptom onset) 1

Chest Radiograph

Mediastinal or aortic widening is present in only 62.6% of Type A and 56% of Type B dissections. 6 Among patients with ADD score 0 and dissection, 48.6% had widened mediastinum on chest X-ray. 1 A normal chest X-ray does not exclude dissection. 6

Clinical Triad (von Kodolitsch)

The absence of all three features yields only a 7% probability of dissection (LR- 0.07-0.17), but 4% of patients with none of these features still had dissection: 1

1. Aortic pain with sudden onset and/or tearing/ripping quality
2. Mediastinal/aortic widening on chest radiograph
3. Pulse differential or blood pressure differential >20 mmHg

Special Populations Requiring Lower Threshold

Painless Presentations (6.4% of cases)

Consider dissection in patients presenting with: 2

• Syncope (up to 20% of cases) 2
• Stroke or focal neurologic deficits 2
• Acute heart failure from aortic regurgitation 2
• Limb ischemia 2

Higher risk for painless presentation: 2

• Older patients
• Patients on chronic steroids
• Marfan syndrome patients

Women

Women with dissection are: 2

• Older at presentation
• Less likely to present within 6 hours
• Have higher in-hospital mortality (30% vs 21% in men)
• More commonly present with altered mental status

Recommended Approach

For any patient with clinical suspicion (regardless of ADD score): 1

1. Measure blood pressure in both arms (use higher reading for monitoring) 4
2. Obtain D-dimer if available, but do not use negative result to exclude dissection 1
3. Proceed directly to CT angiography if clinical suspicion persists, even with ADD score 0 or negative D-dimer 1, 6
4. Do not use bedside TTE alone to definitively establish or exclude diagnosis (Level B recommendation) 1
5. Initiate immediate surgical consultation or transfer if imaging suggests dissection 1

The decision to pursue advanced imaging must remain at the treating physician's discretion and should not be deferred based on clinical decision rules alone. 1