Patent foramen ovale

Background

  • Flap-like opening between the atrial septa primum and secundum
  • Occurs at fossa ovalis
  • Persists beyond 1 year of age
  • Inter-atrial communication allows right-to-left cardiac shunting
  • Most patients with isolated PFO are asymptomatic

Clinical Features

  • Stroke or TIA of undefined etiology
    • Consider in young, healthy patients without risk factors for stroke
  • Migraine or migraine-like symptoms
  • Neurologic decompression sickness (seen in scuba divers)
  • Acute myocardial infarction
  • Systemic embolism, such as renal infarction
  • Fat embolism
  • Paradoxical embolism caused by right atrial tumors that increase right atrial pressure
  • Left-sided valve disease in carcinoid syndrome

Differential Diagnosis

Missile embolism types

  • Intrapericardial foreign body
  • Systemic venous embolism
  • Right heart and pulmonary artery embolism
  • Pulmonary vein embolism
  • Left heart embolism
  • Coronary artery embolism
  • Paradoxical embolus (due to patent foramen ovale)

Evaluation

  • Color flow Doppler imaging
    • Small "flame" of color signal may be seen in middle region of atrial septum
  • Contrast echocardiography (Bubble Study)
    • Bolus of agitated saline injected to antecubital vein
    • Microbubbles appear in right atrium
      • Study positive for PFO if microbubbles appear in left atrium within 3 cardiac cycles of their appearance in right atrium
    • Valsalva increases right atrial pressure and facilitates right-to-left shunting if present
  • 2D TEE with contrast provides superior visualization and is preferred
    • Obtain 2E TEE with constrast if suspicion is high and TTE is negative

Management

  • Most patients with incidental or isolated PFO receive no treatment
  • Treatment more common when PFO associated with unexplained neurologic event, but no consensus for treatment exists

Medical Therapy

  • Aspirin therapy alone in low risk patients
  • Warfarin with ASA (INR 2-3) in high-risk individuals

Surgical Closure

  • Indications:
    • PFO more than 25 mm in size
    • Inadequate rim of tissue around defect
    • Percutaneous device failure
  • Advantages of surgical closure
    • Permanent closure of defect
    • Prevents future paradoxical emboli
    • No need for long-term anticoagulation
  • Percutaneous closure
    • Emergency therapeutic option

See Also

External Links

References

emedicine.Medscape.com