What is the management approach for a patient with aortic dissection?

Management of Aortic Dissection

For patients with acute Type A aortic dissection (involving the ascending aorta), immediate surgical repair is recommended as the definitive management due to the high risk of life-threatening complications such as rupture. 1

Classification and Initial Assessment

Classification Systems

• Stanford Classification:

  • Type A: Involves ascending aorta (regardless of origin site)
  • Type B: Does not involve ascending aorta

• DeBakey Classification:

  • Type I: Originates in ascending aorta, extends at least to aortic arch
  • Type II: Limited to ascending aorta
  • Type III: Originates in descending aorta
    • Type IIIa: Limited to descending thoracic aorta
    • Type IIIb: Extends below diaphragm

Diagnostic Imaging

• CT Angiography: First-line imaging modality with >95% sensitivity and specificity 2
• MRI: Approaching 100% sensitivity and specificity; best for stable patients with contrast allergy or renal dysfunction 2
• Transesophageal Echocardiography (TEE): 99% sensitivity, 89% specificity; suitable for unstable patients who cannot undergo CT 2
• Transthoracic Echocardiography (TTE): Limited sensitivity (59-80%) 2

Initial Management

Immediate Medical Management

1. Blood Pressure and Heart Rate Control:

   • Target heart rate ≤60 bpm and systolic BP between 100-120 mmHg 2
   • First-line agents: IV beta-blockers (propranolol, metoprolol, labetalol, or esmolol) 2
   • Avoid vasodilators before rate control to prevent reflex tachycardia 1

2. Pain Management:

   • Morphine sulfate (0.1-0.2 mg/kg every 4 hours as needed) 2
   • Invasive blood pressure monitoring via arterial line during analgesia 2

3. Management of Hypotension:

   • Volume administration titrated to improve blood pressure 1, 2
   • Vasopressors only if necessary (risk of false lumen propagation) 1, 2
   • Avoid inotropic agents (increase shear stress on aortic wall) 1, 2
   • For cardiac tamponade: Pericardiocentesis only to restore perfusion if patient cannot survive until surgery 1

Definitive Management Based on Dissection Type

Type A Dissection (Involving Ascending Aorta)

1. Urgent surgical consultation as soon as diagnosis is made or highly suspected 1

2. Emergency surgical repair 1, 2:

   • Resect all aneurysmal aorta and proximal extent of dissection 1
   • For partially dissected aortic root: Aortic valve resuspension 1
   • For extensive root dissection: Aortic root replacement with composite graft or valve-sparing root replacement 1
   • Open distal anastomosis is recommended to improve survival and increase false lumen thrombosis rates 1
   • In absence of arch tear or significant arch aneurysm: Hemi-arch repair recommended over extensive arch replacement 1

3. For malperfusion syndromes:

   • Immediate aortic surgery for cerebral, mesenteric, lower limb, or renal malperfusion 1
   • For mesenteric malperfusion: Consider invasive angiographic diagnostics to evaluate percutaneous repair before or after aortic surgery 1

Type B Dissection (Not Involving Ascending Aorta)

1. Medical management is first-line for uncomplicated cases 1, 2:

   • Beta-blockers as cornerstone of treatment 2
   • Add calcium channel blockers or ACE inhibitors/ARBs as needed 2
   • Target systolic BP <120 mmHg and heart rate ≤60 bpm 2

2. Indications for intervention:

   • Life-threatening complications (malperfusion syndrome, progression of dissection, enlarging aneurysm) 1
   • For uncomplicated acute Type B dissection with high-risk features: Consider TEVAR in subacute phase (14-90 days) 1
   • For chronic Type B dissection with descending thoracic aortic diameter ≥60 mm: Treatment recommended for reasonable surgical risk patients 1
   • For chronic Type B dissection with descending thoracic aortic diameter ≥55 mm: Consider intervention for low procedural risk patients 1

Special Considerations

Intramural Hematoma (IMH)

• Treat with aggressive medical therapy including beta-blockers and antihypertensives 1
• Indications for intervention based on anatomic features, clinical presentation, patient comorbidities 1

Traumatic Aortic Injury

• Grade 4 (severe): Immediate repair 1
• Grades 1-2 (minimal): Initial medical therapy with careful surveillance 1
• Grade 2 with progression: Semi-elective repair (24-72 hours) 1

Follow-up and Long-term Management

Imaging Follow-up

• For medically treated Type B AAS or IMH: Imaging at 1,3,6, and 12 months after onset, then yearly if stable 1
• For medically treated PAU: Imaging at 1 month after diagnosis, then every 6 months if stable 1
• After open surgery: Imaging by CCT and TTE within 6 months, then CCT at 12 months and yearly if stable 1
• If no complications within 5 years: CCT every 2 years 1

Long-term Medical Management

• Oral beta-blockers to maintain systolic BP <120 mmHg and heart rate ≤60 bpm 2
• Frequent follow-up (at least monthly) until blood pressure goals achieved 2
• Long-term follow-up until hypertension-mediated organ damage is resolved 2

Pitfalls and Caveats

• Delay in diagnosis significantly increases mortality (75% of untreated Type A dissections die within 2 weeks) 3
• Avoid vasodilator therapy before rate control (can cause reflex tachycardia) 1
• A negative chest x-ray should not delay definitive imaging in high-risk patients 1
• If high clinical suspicion persists despite negative initial imaging, obtain a second imaging study 1
• Consider direct admission to the operating room for diagnosed or highly suspected Type A dissection to reduce time to definitive treatment 4