Innominate Artery Aneurysms

• Incidence and Causes:
  • Rare, accounting for 2–5% of all aortic arch vessel aneurysms and <1% of all peripheral artery aneurysms.
  • Most commonly caused by degenerative disease/atherosclerosis (50% of cases).
  • Other causes: syphilis, tuberculosis, Kawasaki disease, Takayasu arteritis, Behcet disease, connective tissue disorders (e.g., Marfan, Ehlers-Danlos), trauma (pseudoaneurysms), and infection (mycotic aneurysms).
• Presentation:
  • Often discovered incidentally; 25% present with symptoms.
• Symptoms:
  • Pain (from expansion or rupture).
  • Ischemic symptoms: transient ischemic attack (TIA), stroke, limb ischemia, or tissue loss.
  • Compression symptoms: brachial plexus (pain, dysfunction), right recurrent laryngeal nerve (hoarseness), trachea (dyspnea), cervical sympathetic chain (Horner syndrome), or lung apex (hemoptysis).
  • Rupture: Rare (10%), but life-threatening.
• Diagnosis:
  • Physical Exam
    • Supraclavicular bruit, absent pulses, signs of distal embolization, neurologic deficits, or compression symptoms.
  • Imaging
    • CT angiography is the gold standard for evaluating size, thrombus, and anatomical relationships.
• Classification:
  • Type A: Involves only the innominate artery.
  • Type B: Involves the innominate artery and its origin.
  • Type C: Involves the innominate artery, its origin, and the ascending aorta (requires cardiopulmonary bypass).
• Management :
  • Indications for Repair:
    • Symptomatic aneurysms.
    • Asymptomatic saccular aneurysms or fusiform aneurysms >3 cm in diameter.
  • Surgical Repair:
    • Open repair is the standard but involves significant morbidity due to the need for a Median sternotomy or cardiopulmonary bypass.
      • Conduits: Prosthetic grafts (PTFE or Dacron) are preferred, except for mycotic aneurysms where autogenous grafts are used.
  • Endovascular Repair:
    • Less invasive but limited by anatomical constraints (proximal/distal seal zones).
    • Risks: Compression and fracture due to the mobile nature of the thoracic outlet.
    • Stents: Balloon-expandable or self-expanding covered stents may be used selectively.