What is the management approach for aortic dissection?

Management of Aortic Dissection

The management of aortic dissection is primarily determined by the type of dissection, with Type A (involving ascending aorta) requiring immediate surgical intervention and Type B (distal to left subclavian artery) typically managed medically unless complications develop.

Initial Assessment and Stabilization

• Establish invasive monitoring with arterial line and continuous ECG recording for accurate blood pressure management 1
• Administer intravenous beta-blockers as first-line therapy (labetalol preferred) to target systolic blood pressure <120 mmHg and heart rate ≤60 beats per minute 1
• If beta-blockers are contraindicated, use non-dihydropyridine calcium channel blockers for heart rate control 1
• For severe hypertension despite beta-blockade, add sodium nitroprusside to further reduce blood pressure 1
• Provide pain relief with morphine sulfate and transfer to intensive care unit for appropriate monitoring 1

Type-Specific Management

Type A Dissection (Involving Ascending Aorta)

• Emergency surgical intervention is required to prevent aortic rupture, pericardial tamponade, and relieve aortic regurgitation 2, 1
• Surgical options include:
  • Implantation of a composite graft in the ascending aorta with or without coronary artery reimplantation 2
  • Supracommisural graft implantation when root is normal and valve is intact 2
  • Valve resuspension when commissures are detached (adequate in about 50% of chronic Type A cases) 2
  • Subtotal or total arch replacement when necessary, including reconnection of supraaortic vessels during hypothermic circulatory arrest 2

Type B Dissection (Distal to Left Subclavian Artery)

• Uncomplicated Type B dissections are typically treated conservatively with medical management 2, 3
• Emergency intervention (preferably Thoracic Endovascular Aortic Repair - TEVAR) is indicated for complicated Type B dissection presenting with:
  • Malperfusion syndrome 1
  • Intractable pain 2
  • Rapidly expanding aortic diameter 2
  • Periaortic or mediastinal hematoma (signs of rupture) 2
  • Dissection occurring in a previously aneurysmatic aorta 2

Surgical Management Techniques

• For acute and chronic dissections of the descending aorta:
  • Replacement of affected portions with tubular graft of appropriate length and size 2
  • Standard approach via posterolateral chest incision 2
  • Most surgeons use extracorporeal circulation via left heart bypass 2
  • Moderate hypothermia with equalized perfusion pressures during graft implantation 2

Follow-up Care and Chronic Management

• Switch from intravenous to oral beta-blockers after 24 hours if gastrointestinal transit is preserved 1
• Regular imaging follow-up to monitor for complications such as false lumen expansion or aneurysm formation 1
• Consider reoperation when:
  • Dissected aorta becomes aneurysmatic (5-6 cm in diameter) 2
  • Dissection was improperly repaired initially 2
• For chronic Type A dissection:
  • Surgery indicated if symptoms develop, aortic regurgitation occurs, or aortic diameter exceeds 5-6 cm 2
• For chronic Type B dissection:
  • Surgery indicated if symptoms develop or progressive aortic enlargement reaches 6.0 cm 2
  • Consider endovascular stenting if surgical indication exists and anatomy is suitable 2

Special Considerations

• For patients with hereditary diseases (Marfan syndrome, Ehlers-Danlos syndrome), lifelong beta-adrenergic blockade is recommended for prevention of dissection 1
• In cases of malperfusion, higher blood pressure may be tolerated to optimize perfusion to the threatened region 1
• Pregnant patients require management by a multidisciplinary team at specialized centers, using drugs with the lowest teratogenic impact 1

Common Pitfalls and Caveats

• Delay in diagnosis and treatment significantly worsens prognosis, particularly for Type A dissections 4, 5
• Patients with visceral ischemia have poor prognosis even with TEVAR; early diagnosis and intervention are crucial 3
• The rate of reoperation for Type A dissection is approximately 10% at 5 years and up to 40% at 10 years after primary surgery, with even higher risk in Marfan syndrome patients 2
• Repeat sternotomy requires great care as the aorta is usually unprotected by the pericardium 2