What are the guidelines for managing aortic dissection?

Management Guidelines for Aortic Dissection

Immediate Diagnostic Approach

Obtain CT angiography from neck to pelvis immediately as the first-line imaging modality in all patients with suspected aortic dissection, as it is widely available, accurate, and provides critical information about entry tear location, dissection extent, and complications including malperfusion, dilatation, or rupture. 1

• Transoesophageal echocardiography (TEE) is recommended to guide peri-operative management and detect complications, particularly in unstable patients who cannot be transported for CT 1
• In profoundly unstable patients with suspected cardiac tamponade, perform transthoracic echocardiography immediately and proceed directly to surgery if tamponade is confirmed, without waiting for additional imaging 1

Initial Medical Management (All Types)

Start intravenous beta-blockers immediately as first-line therapy, targeting systolic blood pressure <120 mmHg and heart rate ≤60 beats per minute to reduce aortic wall stress. 1, 2

Specific Beta-Blocker Regimens:

• Esmolol (preferred for short half-life): 0.5 mg/kg loading dose over 2-5 minutes, followed by infusion of 0.10-0.20 mg/kg/min (maximum 0.3 mg/kg/min) 1
• Labetalol (preferred for combined alpha/beta blockade): standard dosing per protocol 2
• Propranolol: 0.05-0.15 mg/kg every 4-6 hours 1
• Metoprolol or atenolol: available but have longer half-lives 1

Alternative Agents:

• If beta-blockers are contraindicated (bronchial asthma, bradycardia, heart failure), use non-dihydropyridine calcium channel blockers (verapamil or diltiazem) 1
• Add sodium nitroprusside (starting at 0.25 μg/kg/min) if beta-blockade alone does not achieve target blood pressure, but never use vasodilators without concurrent beta-blockade as they increase left ventricular ejection force 1

Transition to Oral Therapy:

• After achieving hemodynamic targets with IV therapy for 24 hours, switch to oral beta-blockers if gastrointestinal transit is preserved 1

Type A Acute Aortic Dissection (TAAD) Management

All patients with Type A dissection require immediate emergency surgical repair, as this is a surgical emergency with mortality of 1-2% per hour if untreated. 2, 3

Surgical Approach:

For patients with extensive aortic root destruction, root aneurysm, or known genetic aortic disorder, perform aortic root replacement with mechanical or biological valved conduit. 1

• In patients with partially dissected aortic root but no significant valve leaflet pathology, perform aortic valve resuspension rather than valve replacement 1
• Valve-sparing root repair may be considered in selected patients when performed by experienced surgeons 1
• Perform open distal anastomosis to improve survival and increase false lumen thrombosis rates 1
• For patients without intimal tear in the arch or significant arch aneurysm, perform hemi-arch repair rather than more extensive arch replacement 1
• Consider extended aortic repair with stenting of proximal descending thoracic aorta (frozen elephant trunk technique) if secondary intimal tear exists in the arch or proximal descending aorta, to reduce late distal aortic complications 1

Transfer Considerations:

• Transfer from low-volume to high-volume aortic centers with multidisciplinary teams should be considered if this can be accomplished without significant surgical delay 1

Malperfusion Management in Type A:

Perform immediate aortic surgery in all patients with Type A dissection presenting with malperfusion (cerebral, mesenteric, lower limb, or renal). 1

• In patients with cerebral malperfusion or non-hemorrhagic stroke, immediate aortic surgery should be considered to improve neurological outcome and reduce mortality 1
• For clinically significant mesenteric malperfusion syndrome, consider immediate invasive angiographic diagnostics to evaluate percutaneous malperfusion repair before or directly after aortic surgery in centers with expertise 1

Type B Acute Aortic Dissection (TBAD) Management

Medical therapy with blood pressure and heart rate control is the first-line treatment for all patients with acute Type B dissection. 4, 2

Complicated Type B Dissection:

Emergency intervention with TEVAR (thoracic endovascular aortic repair) is recommended for complicated Type B dissection presenting with: 4, 2

• Aortic rupture or impending rupture
• Malperfusion syndrome (visceral, renal, or lower extremity)
• Refractory pain despite adequate medical therapy
• Rapidly expanding aortic diameter
• Uncontrollable hypertension

Uncomplicated Type B Dissection:

Continue medical therapy with close surveillance for uncomplicated Type B dissection. 4

• In the subacute phase (14-90 days), consider TEVAR in selected patients with high-risk anatomical features including: 1, 4
  • Primary entry tear >10 mm
  • Initial aortic diameter >40 mm
  • Initial false lumen diameter >20 mm
  • Partial false lumen thrombosis

Chronic Type B Dissection:

For chronic TBAD (>90 days) with descending thoracic aortic diameter ≥60 mm, intervention is recommended in patients at reasonable surgical risk. 1, 4

• Consider intervention at ≥55 mm in patients with low procedural risk 1, 4
• Fenestrated/branched stent grafts may be considered for chronic post-dissection thoracoabdominal aortic aneurysms when treatment is indicated 1

Follow-Up Imaging Protocol

After acute aortic dissection, perform imaging at 1,3,6, and 12 months after onset, then yearly if findings remain stable. 4, 2

Specific Protocols:

• After open surgery for acute aortic syndrome: CCT and TTE within 6 months, then CCT at 12 months and yearly thereafter 5
• After TEVAR: Early CCT within 1 month, yearly CCT for first 2 post-operative years, then every 5 years if stable 1
• MRI is preferred for long-term follow-up to avoid radiation and nephrotoxic contrast, though CT is acceptable particularly in patients >60 years 2

Special Populations

Genetic Connective Tissue Disorders:

• Lifelong beta-adrenergic blockade is mandatory for patients with Marfan syndrome, Loeys-Dietz syndrome, or Ehlers-Danlos syndrome to prevent dissection 2, 3

Pregnancy:

• Strict conservative medical management with multidisciplinary team at specialized centers, using drugs with lowest teratogenic impact 2

Critical Pitfalls to Avoid

• Never perform pericardiocentesis before surgery in patients with cardiac tamponade from Type A dissection, as reducing intrapericardial pressure may cause recurrent bleeding 1
• Never use vasodilators without concurrent beta-blockade, as they increase left ventricular ejection force and can propagate dissection 1
• Do not delay surgery in Type A dissection for additional imaging if diagnosis is confirmed by initial modality 1, 2
• Avoid lowering blood pressure excessively if oliguria or neurological symptoms develop, as this may worsen malperfusion 1