What is the recommended diagnosis and management for aortic dissection?

Diagnosis and Management of Aortic Dissection

Emergency surgical intervention is required for Type A aortic dissection to prevent aortic rupture, pericardial tamponade, and relieve aortic regurgitation, while Type B dissection can initially be managed medically unless complications develop. 1, 2

Clinical Presentation

• Pain is the most common presenting symptom of aortic dissection, with abrupt onset and maximum intensity at the beginning, unlike myocardial infarction pain which typically builds gradually 3
• Location of pain varies by dissection type: retrosternal pain in proximal (Type A) dissections and interscapular/back pain in distal (Type B) dissections 3
• The typical patient is a male in his 60s with a history of hypertension 3, 4
• Up to 20% of patients may present with syncope without typical pain 3
• Cardiac failure may become predominant, usually related to severe aortic regurgitation 3
• Pulse deficits or limb ischemia may result from obliteration of peripheral vessels 3
• Cardiac tamponade may cause hypotension and syncope 3

Diagnostic Approach

• Every patient with suspected aortic dissection should undergo urgent definitive imaging 5, 3
• Primary imaging modalities with comparable high sensitivity and specificity include:
  • Transesophageal echocardiography (TEE)
  • Computed tomography (CT)
  • Magnetic resonance imaging (MRI) 5, 6
• In the International Registry of Aortic Dissection (IRAD), CT was the first diagnostic step in 61% of cases, followed by TEE in 33% 1
• For hemodynamically unstable patients, transthoracic echocardiography should be performed immediately, though image quality may be inadequate for definitive diagnosis 1
• Diagnostic goals include:
  • Confirming diagnosis
  • Classifying dissection type and extent
  • Differentiating true and false lumen
  • Localizing intimal tears
  • Assessing branch vessel involvement
  • Detecting aortic regurgitation
  • Identifying extravasation or effusions 1

Initial Management

• Establish invasive monitoring with arterial line and continuous ECG recording 1, 5
• For hemodynamically unstable patients:
  • Intubate and ventilate without delay
  • Perform TEE as the sole diagnostic procedure if needed
  • Avoid pericardiocentesis as an initial step as it may cause recurrent bleeding 1
• Control blood pressure and heart rate:
  • Administer IV beta-blockers as first-line therapy to target systolic BP <120 mmHg and heart rate ≤60 bpm 5, 2
  • If beta-blockers are contraindicated, use non-dihydropyridine calcium channel blockers 5
  • For severe hypertension despite beta-blockade, add sodium nitroprusside 5, 2
• Provide pain relief with morphine sulfate 5, 2
• Transfer to intensive care unit for appropriate monitoring 5, 2

Type-Specific Management

Type A Dissection (Involving Ascending Aorta)

• Emergency surgery is required to prevent:
  • Aortic rupture
  • Pericardial tamponade
  • Myocardial ischemia
  • Severe aortic regurgitation 1, 2
• Surgical options include:
  • Valve-preserving surgery with tubular graft if normal aortic root and valve cusps 1
  • Replacement of aorta and aortic valve (composite graft) if ectatic proximal aorta or pathological valve changes 1
  • Valve-sparing operations with aortic root remodeling for abnormal valves 1
  • Valve resuspension when commissures are detached 2

Type B Dissection (Involving Descending Aorta)

• Medical therapy is first-line treatment 1, 3
• Surgical or endovascular intervention is indicated for:
  • Persistent or recurrent pain
  • Early expansion
  • Peripheral ischemic complications
  • Rupture
  • Malperfusion syndrome
  • Rapidly expanding aortic diameter
  • Periaortic or mediastinal hematoma 1, 5
• Thoracic Endovascular Aortic Repair (TEVAR) is preferred for complicated Type B dissections 5, 3

Special Considerations

• In patients with genetic connective tissue disorders (Marfan, Loeys-Dietz, Ehlers-Danlos syndrome):
  • Lifelong beta-adrenergic blockade is recommended for prevention of dissection 5, 2
  • These patients are at increased risk of dissection at a younger age 3, 4
• In cases of malperfusion, higher blood pressure may be tolerated to optimize perfusion to the threatened region 5, 2
• Pregnant patients require management by a multidisciplinary team at specialized centers 5, 2

Follow-up Care

• Switch from intravenous to oral beta-blockers after 24 hours if gastrointestinal transit is preserved 5, 2
• Regular imaging follow-up is essential to monitor for complications such as false lumen expansion or aneurysm formation 5, 2
• Consider reoperation when the dissected aorta becomes aneurysmatic (5-6 cm in diameter) 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 2

Common Pitfalls and Caveats

• Thrombolytic therapy can be catastrophic if administered to a patient with aortic dissection misdiagnosed as myocardial infarction 3
• Elevated D-dimer may be helpful but should not be used to rule out dissection 3
• Pericardiocentesis in cardiac tamponade may reduce intrapericardial pressure and cause recurrent bleeding 1
• Repeat sternotomy requires great care as the aorta is usually unprotected by the pericardium 2