What is the workup and management of aortic dissection in the Emergency Department (ED)?

Aortic Dissection Workup and Management in the Emergency Department

Initial Clinical Assessment

In patients with suspected aortic dissection, immediately establish invasive arterial line monitoring, obtain IV access, perform ECG, and initiate continuous three-lead ECG and blood pressure monitoring while simultaneously arranging urgent definitive imaging. 1, 2

Key Clinical Features to Identify

• Sudden, severe chest or back pain described as tearing or ripping in nature is the hallmark presentation 1, 2
• Pulse deficits occur in less than 20% of patients but are highly specific when present 1
• Neurological deficits (loss of consciousness, ischemic paresis) occur in up to 40% of patients with proximal dissection 1
• Diastolic murmur indicative of aortic regurgitation is present in approximately 50% of cases 1
• Syncope without typical pain occurs in up to 20% of acute cases and should raise suspicion 1

Risk Stratification Tool

Use the Aortic Dissection Detection (ADD) score for pre-hospital and ED risk stratification: patients with ADD score ≥1 should be considered high risk and require urgent imaging 1

Immediate Medical Management

Blood Pressure and Heart Rate Control

Administer intravenous beta-blockers as first-line therapy immediately, targeting systolic blood pressure 100-120 mmHg and heart rate ≤60 beats per minute. 1, 2, 3

• Beta-blocker options: IV propranolol, esmolol, metoprolol, or labetalol (labetalol preferred due to combined alpha- and beta-blocking properties) 1, 2
• Critical pitfall: Never administer vasodilators before beta-blockade, as this causes reflex tachycardia that increases shear stress and propagates dissection 1, 4
• If beta-blockers insufficient: Add sodium nitroprusside only after adequate beta-blockade is established 1
• If beta-blockers contraindicated: Use non-dihydropyridine calcium channel blockers (verapamil or diltiazem) for heart rate control 2, 3

Pain Management

• Administer morphine sulfate for pain relief, which also reduces sympathetic stimulation 1, 2, 4

Special Consideration for Malperfusion

• In cases of malperfusion syndrome (stroke, mesenteric ischemia, limb ischemia), higher blood pressure may be tolerated to optimize perfusion to the threatened region 2, 3

Diagnostic Imaging Strategy

Every patient with suspected aortic dissection requires urgent definitive imaging with CT angiography, transesophageal echocardiography (TEE), or MRI—all three modalities have comparable sensitivity and specificity >90%. 1, 2, 4

Imaging Modality Selection

• CT angiography (CTA): Preferred first-line imaging in the ED due to rapid availability, high accuracy (93% sensitivity), and ability to detect alternative diagnoses in 13% of cases 1
• CTA has diagnostic accuracy equivalent to TEE and MRA for excluding thoracic aortic dissection 1
• Transthoracic echocardiography (TTE): Use bedside TTE in profoundly unstable patients to identify cardiac tamponade or immediate life-threatening complications, but TTE alone cannot establish the diagnosis 1, 4
• If TTE is suggestive of dissection: Obtain surgical consultation or transfer to higher level of care immediately while arranging definitive imaging 1

Chest X-Ray Considerations

• Perform chest X-ray in stable patients only (abnormal in 60-90% of cases) 2
• Omit chest X-ray in unstable patients to avoid treatment delays 2

Disposition and Definitive Management

Type A Dissection (Ascending Aorta)

Obtain urgent cardiothoracic surgical consultation immediately for emergency surgical repair—Type A dissection has extremely high mortality (1-2% per hour untreated) and requires emergency surgery to prevent aortic rupture, pericardial tamponade, and relieve aortic regurgitation. 1, 2, 3, 5

• Surgical options include composite graft implantation in ascending aorta with or without coronary artery reimplantation 2, 3
• Historical mortality: 75% die within 2 weeks if untreated, but 5-year survival increases to 75% with successful surgery 6

Type B Dissection (Descending Aorta)

Initially manage Type B dissection medically with aggressive blood pressure and heart rate control unless complications develop. 1, 2, 4

Emergency intervention (preferably TEVAR) is indicated for:

• Malperfusion syndrome 2
• Intractable pain despite medical therapy 2
• Rapidly expanding aortic diameter 2
• Periaortic or mediastinal hematoma 2
• Progression of dissection 2
• Inability to control blood pressure or symptoms 2

Transfer Considerations

Patients with high probability of aortic dissection (ADD score >1) should be transferred directly to a center with 24/7 available aortic imaging and cardiac surgery. 1

• Avoid transferring to non-surgical centers for imaging before transfer to cardiac surgery facility when probability is high—this jeopardizes the patient 1
• Consider activating cardiac surgery during transfer so patient can proceed directly to radiology then operating room 1

Critical Pitfalls to Avoid

• Missing the diagnosis: Aortic dissection is suspected at initial presentation in only 20% of cases due to non-specific presentations 1
• Administering vasodilators before beta-blockade: This causes reflex tachycardia and propagates dissection 1, 4
• Relying on TTE alone: Bedside TTE cannot establish the diagnosis and requires confirmatory imaging 1
• Delaying imaging in stable patients: Even with low clinical suspicion, definitive imaging is required when dissection is in the differential 1, 2
• Using vasopressors in hypotensive patients: Volume administration should be considered first, as vasopressors may propagate false lumen 4

Transition to Definitive Care

• Transfer to ICU for continuous invasive monitoring 1, 4
• After 24 hours of hemodynamic stability: Transition from IV to oral beta-blockers if gastrointestinal transit is preserved 2, 3
• Long-term blood pressure target: <135/80 mmHg with beta-blockers as preferred agents 2