Persistent Left Superior Vena Cava

• Incidence-uncommon
  
  
  • 0.3% of general population;
  • 4.3-11% of patients with CHD
    
    
• Two types
  
  
  • Persistent left SVC connecting to right atrium via coronary sinus is only common anomaly of SVC (90% of this anomaly)
  • In other 10%, persistent SVC connects to left atrium
    • Most with connection to left atrium have associated ASD or heterotaxy syndromes
    • This produces a right-to-left shunt of a rather small magnitude
      
      
• Etiology
  
  
  • Failure of regression of left anterior and common cardinal veins and left sinus horn
    
    
• Course of persistent left SVC
  
  
  • Draining into right atrium
    • Starts at junction of left subclavian vein and left internal jugular
    • Passes lateral to aortic arch
    • Receives left superior intercostal vein
    • Anterior to left hilum
    • Joined by hemiazygos system
    • Crosses posterior wall of left atrium
    • Receives great cardiac vein to become coronary sinus (common)

Yellow arrows point to left-sided persistent SVC
passing lateral to aortic arch and anterior to left hilum

• Draining into left atrium
  • Starts at junction of left subclavian vein and left internal jugular
  • Passes lateral to aortic arch
  • Receives left superior intercostal vein
  • Anterior to left hilum
  • Joined by hemiazygos system
  • Passes between the left atrial appendage (anteriorly) and the left superior pulmonary vein posteriorly

• Absent / small left brachiocephalic vein (65%)
• Really this abnormality produces bilateral SVCs
• In small percentage, right SVC is absent (10-18%)

Freedom, Culham and Moes, Angiography of Congenital Heart Disease, 1984