From the Guidelines
A CT angiography (CTA) for aortic dissection should be performed immediately in any patient with chest pain who has risk factors or clinical features suggesting possible aortic dissection, as it is the preferred modality due to its wide availability, speed, and high sensitivity and specificity for aortic dissection 1.
Key Clinical Features
The clinical features that suggest possible aortic dissection include:
- Sudden-onset, severe, tearing chest or back pain
- Blood pressure differential between arms (>20 mmHg)
- New aortic regurgitation murmur
- Pulse deficits
- Neurological deficits
- Hypotension or shock
- Widened mediastinum on chest X-ray
Patient Risk Factors
Patients with the following risk factors should have a lower threshold for imaging:
- Marfan syndrome
- Family history of aortic disease
- Known aortic aneurysm
- Bicuspid aortic valve
- Recent aortic manipulation
Initial Management
While obtaining the CTA, initial management should include:
- Pain control with IV opioids
- Blood pressure reduction (target systolic 100-120 mmHg) using IV beta-blockers like esmolol (50-300 μg/kg/min) or labetalol (initial 20 mg IV, then 20-80 mg every 10 minutes to maximum 300 mg)
- Vasodilators like nicardipine (5-15 mg/hr) if needed
Rationale for CTA
CTA is preferred over other imaging modalities due to its:
- Wide availability
- Speed
- High sensitivity (>95%) and specificity (>98%) for aortic dissection 1
- Ability to detect the presence and mechanism of aortic branch vessel involvement, as well as vessel patency, signs of malperfusion, pericardial effusion and hemopericardium, periaortic or mediastinal hematoma, and pleural effusion 1
Importance of Prompt Diagnosis
Delaying diagnosis increases mortality, as untreated aortic dissection has a mortality rate of approximately 1-2% per hour in the first 48 hours. Therefore, prompt imaging with CTA is crucial in patients with suspected aortic dissection.
From the Research
Indications for Computed Tomography Angiography (CTA) in Aortic Dissection
- Aortic dissection should be suspected in patients presenting with severe thoracic pain and hypertension 2
- Chest or back pain is the most commonly reported presenting symptom of acute aortic syndrome (AAS), which includes aortic dissection 2
- Patients with suspected aortic dissection require prompt diagnosis and emergency treatment for optimal chances of survival 3
Diagnostic Approach
- Computed tomography (CT) is a reliable tool for diagnosing AAS, with a sensitivity of 100% 2
- Transesophageal echocardiography and magnetic resonance imaging are also sensitive diagnostic tools for AAS 2
- D-dimer may be used as a diagnostic aid, but its sensitivity and specificity vary widely 2, 4
Clinical Presentation
- Aortic dissection often presents with classic symptoms, such as severe tearing chest pain radiating to the back associated with acute hemodynamic compromise 5
- However, painless aortic dissection is an under-recognized entity that requires physician vigilance and awareness to diagnose and quickly treat 5
- Abrupt onset of tearing and sharp chest pains, deficits in pulse, and presence of high-risk factors are highly indicative of aortic dissection 4