What is the treatment for aortic dissection?

Treatment of Aortic Dissection

Treatment of aortic dissection is determined by anatomic location: Type A dissections (involving the ascending aorta) require emergency surgical intervention, while uncomplicated Type B dissections (descending aorta only) are managed medically with aggressive blood pressure and heart rate control. 1, 2

Immediate Medical Stabilization (All Types)

All patients with aortic dissection require immediate intensive care unit transfer with invasive arterial line monitoring and continuous ECG recording. 1

Hemodynamic Control

• Administer intravenous beta-blockers as first-line therapy (propranolol, esmolol, or labetalol) targeting systolic blood pressure 100-120 mmHg and heart rate ≤60 beats per minute. 1, 2
• If beta-blockade alone is insufficient, add sodium nitroprusside for additional blood pressure reduction. 1, 2
• Critical pitfall: Never use vasodilators without prior beta-blockade, as this causes reflex tachycardia and increases aortic wall shear stress. 1, 3
• If beta-blockers are contraindicated, use non-dihydropyridine calcium channel blockers for heart rate control. 2

Pain Management

• Administer morphine sulfate to reduce sympathetic stimulation and provide analgesia. 1

Type A Dissection (Ascending Aorta) - Surgical Emergency

Emergency surgical intervention is mandatory for all Type A dissections to prevent aortic rupture, pericardial tamponade, and death. 4, 1, 2

Surgical Approach

• Standard approach is median sternotomy with cardiopulmonary bypass. 1
• Surgical options include:
  • Supracommisural graft implantation when the aortic root is normal and valve is intact 2
  • Composite graft implantation in the ascending aorta with or without coronary artery reimplantation 4, 2
  • Valve resuspension (adequate in approximately 50% of chronic Type A cases when commissures are detached) 2
  • Subtotal or total arch replacement when the arch is involved, including reconnection of supraaortic vessels during hypothermic circulatory arrest 1, 2, 3

Technical Considerations

• Dissected layers are conjoined using teflon felt strips or gelatin resorcinol formaldehyde (GRF) glue. 1, 3
• Moderate to deep hypothermia with equalized perfusion pressures during graft implantation is recommended. 4, 1, 3
• Critical pitfall: Avoid pericardiocentesis before surgery in tamponade cases, as reducing intrapericardial pressure causes recurrent bleeding. 3

Type B Dissection (Descending Aorta) - Medical vs. Interventional

Uncomplicated Type B Dissection

Uncomplicated Type B dissections are managed medically with aggressive blood pressure and heart rate control, as there is no proven superiority of surgical or endovascular intervention over medical therapy. 4, 1

• Continue intravenous beta-blockers with the same hemodynamic targets as initial stabilization. 1
• Transition to oral beta-blockers after 24 hours of hemodynamic stability if gastrointestinal function is preserved. 1, 2

Complicated Type B Dissection - Surgical/Endovascular Indications

Surgical or endovascular intervention is indicated for Type B dissections with life-threatening complications. 4, 1

Specific indications include: 4, 1

• Intractable pain despite adequate medical therapy
• Rapidly expanding aortic diameter
• Periaortic or mediastinal hematoma (signs of rupture)
• Peripheral ischemic complications (limb, kidney, or gut ischemia)
• Dissection occurring in a previously aneurysmatic aorta

Endovascular Approach (TEVAR)

• Thoracic endovascular aortic repair (TEVAR) aims to stabilize the dissected aorta by covering the primary entry tear and redirecting blood flow to the true lumen. 1, 5
• Interventional options include: 4
  • Stenting of obstructed branch arteries for static obstruction
  • Balloon fenestration of dissecting membrane plus stenting of aortic true lumen for dynamic obstruction
  • Covered stent placement to seal entry tear and enlarge compressed true lumen

Surgical Approach for Type B

• Posterolateral chest incision is the standard approach, allowing access to the descending aorta down to the eighth intercostal space. 4
• Most surgeons use extracorporeal circulation via left heart bypass. 4, 1
• Replacement of affected portions with a tubular graft of appropriate length and size. 4, 2

Long-Term Management

Medical Therapy

• Target long-term blood pressure <135/80 mmHg with oral beta-blockers. 1, 3
• Lifelong beta-blocker therapy is mandatory for patients with hereditary diseases such as Marfan syndrome or Ehlers-Danlos syndrome. 1, 2

Surveillance Imaging

• Regular imaging follow-up with CT and transthoracic echocardiography is necessary to monitor for false lumen expansion or aneurysm formation. 1, 2, 3
• Recommended schedule: within 6 months, then at 12 months, and yearly if stable. 3

Reoperation Indications

Consider reoperation when the dissected aorta becomes aneurysmatic (5-6 cm in diameter) or when dissection was improperly repaired initially. 4, 1, 2

• For chronic Type A dissection: surgery is indicated if symptoms develop, aortic regurgitation occurs, or aortic diameter exceeds 5-6 cm. 4, 2
• For chronic Type B dissection: surgery is indicated if symptoms develop or progressive aortic enlargement reaches 6.0 cm. 4, 2
• 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. 4, 1, 2, 3

Critical Pitfalls to Avoid

• Never use dihydropyridine calcium channel blockers without beta-blockers due to reflex tachycardia risk. 1, 3
• Never delay surgery for extensive imaging in hemodynamically unstable Type A patients; transesophageal echocardiography can be performed as the sole diagnostic procedure in the operating room. 3
• Repeat sternotomy requires extreme caution as the aorta is usually unprotected by pericardium in reoperation cases. 4, 2, 3