Aortic dissection management

Aortic dissection management

Aortic dissection management

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🧬 Pathophysiology - Why the Wall Fails

  • Core Defect: A tear in the tunica intima allows high-pressure blood to enter and split the tunica media, creating a false lumen.
  • Histology: Cystic medial necrosis (degeneration) is the hallmark, weakening the aortic wall.
  • Key Associations:
    • Chronic Hypertension (most common, >75%)
    • Genetic: Marfan, Ehlers-Danlos
    • Congenital: Bicuspid aortic valve

⭐ The primary event is an intimal tear, not a ruptured vasa vasorum. Hypertension provides the necessary shear stress.

💥 The Sudden Rip

  • Pain: Abrupt, severe, "tearing" or "ripping" chest pain.
  • Radiation Pattern:
    • Anterior chest → Ascending aorta (Type A).
    • Interscapular back → Descending aorta (Type B).
  • Vascular Signs:
    • Pulse deficits (unequal radial/femoral pulses).
    • BP differential >20 mmHg between arms.
  • Cardiac: New aortic regurgitation murmur (diastolic), hypotension, tamponade.
  • Neurologic: Syncope, stroke, Horner's syndrome, paraplegia.

⭐ A variation in systolic blood pressure >20 mmHg between arms is a classic, high-specificity finding.

🩺 Diagnosis - Spotting the Tear

  • Initial Tests:
    • CXR: Widened mediastinum (>8 cm), pleural effusion.
    • ECG: Rules out primary MI; may show nonspecific changes or inferior MI if RCA is involved.
  • Definitive Imaging:
    • CTA (Chest/Abd/Pelvis): Gold standard for stable patients.
    • TEE (Transesophageal Echo): Best for unstable patients or renal failure.

CXR: A widened mediastinum is the most common finding, but a normal CXR does not rule out dissection.

🚑 Management - Race Against Time

  • Initial Medical Stabilization (ALL types):
    • Admit to ICU, place arterial line for continuous BP monitoring.
    • Primary Goal: Rapidly ↓ BP & ↓ HR to reduce aortic wall stress ($dP/dt$) and limit extension.
    • Targets: SBP 100-120 mmHg, HR <60 bpm, achieved within minutes.
    • Pharmacology Sequence:
      • 1st: IV β-blockers (Labetalol, Esmolol) to control heart rate.
      • 2nd: Add IV vasodilator (Nitroprusside, Nicardipine) if SBP remains elevated.

Beta-blocker BEFORE vasodilator! Isolated vasodilation causes reflex tachycardia, increasing aortic shear stress and worsening the dissection.

  • Definitive Treatment by Type: Stanford Aortic Dissection Classification

dominoes Complications - The Deadly Dominoes

  • Rupture: Most lethal event.
    • Into pericardium → Cardiac Tamponade (Beck's triad: hypotension, JVD, muffled heart sounds).
    • Into pleura → Massive Hemothorax.
  • Malperfusion (Branch Occlusion): Ischemia/infarction of end-organs.
    • Coronary a. → MI (often RCA).
    • Carotid/Vertebral a. → Stroke.
    • Spinal a. → Paraplegia.
    • Renal a. → AKI, severe HTN.
  • Aortic Regurgitation: New diastolic murmur from valve incompetence.

⭐ Cardiac tamponade is the #1 cause of death in Type A dissection. It's a primary indication for emergent surgical intervention.

⚡ Biggest Takeaways

  • Stanford Type A (involving ascending aorta) is a surgical emergency.
  • Stanford Type B (descending aorta only) is managed medically unless complicated (e.g., malperfusion, rupture).
  • Initial management for ALL types: IV beta-blockers (labetalol, esmolol) to target HR <60 & SBP 100-120 mmHg.
  • Add vasodilators (nitroprusside) only after achieving heart rate control to avoid reflex tachycardia.
  • Hypertension is the single most important risk factor.
  • CT angiography is the gold standard for diagnosis in stable patients.

Practice Questions: Aortic dissection management

Test your understanding with these related questions

A 58-year-old man is brought to the emergency department by his family because of severe upper back pain, which he describes as ripping. The pain started suddenly 1 hour ago while he was watching television. He has hypertension for 13 years, but he is not compliant with his medications. He denies the use of nicotine, alcohol or illicit drugs. His temperature is 36.5°C (97.7°F), the heart rate is 110/min and the blood pressure is 182/81 mm Hg in the right arm and 155/71 mm Hg in the left arm. CT scan of the chest shows an intimal flap limited to the descending aorta. Intravenous opioid analgesia is started. Which of the following is the best next step in the management of this patient condition?

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Flashcards: Aortic dissection management

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_____ may present as a palpable, pulsatile abdominal mass that grows with time

TAP TO REVEAL ANSWER

_____ may present as a palpable, pulsatile abdominal mass that grows with time

Abdominal aortic aneurysm

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