Patent Foramen Ovale and Paradoxical Stroke in a Young Cyclist

Figure 4: A single Voxel MRI spectroscopy taken during admission revealing an ischemic infarct.

Discussion
The majority (90%) of strokes that occur annually in the United States are ischemic. PFO is not considered a primary cause of stroke. Cardioembolic events account for 19% and carotid disease accounts for 15% of ischemic strokes; the remainder is cryptogenic. Approximately 40% of cryptogenic ischemic strokes are attributed to PFO. PFO can be detected in 10% to 15% of the population by transthoracic echocardiogram. Autopsy studies show a prevalence of PFO of approximately 26%.¹

A number of pathologic manifestations of PFO have been recently identified, including paradoxical systemic embolism. Neurologic decompression illness (eg, in divers, high-altitude pilots, and astronauts) and migraine headache with aura also have been associated with PFO but are not common findings.^2-4 Most patients with PFO, however, remain asymptomatic because under normal physiologic conditions, PFO allows a small amount of left-to-right shunting without causing significant hemodynamic change.³ consequently, neurologic deficits associated with PFO—such as those seen in this case—are rare.

Differential diagnoses for this patient’s presentation that were ruled out include intracranial or extracranial thrombosis; carotid dissection; and coagulopathies, such as antiphospholipid antibodies.⁵

Management of PFO
There are currently 3 primary options for management of PFO⁶:
  • Medical treatment with anticoagulation or antiplatelet therapy
  • Surgical closure
  • Percutaneous closure

Figure 5:
A TEE shows via doppler the blood flow from the right atrium to the left atrium via a septal defect.

In a study that compared aspirin(Drug information on aspirin) with warfarin(Drug information on warfarin) in the prevention of recurrent cryptogenic ischemic stroke, there was no significant benefit shown in either group.⁷

Although there are currently no randomized clinical trials comparing these 3 treatment methods, closure of PFO appears to have clear benefits over medical therapy in select patients.⁵ Many studies report that transcatheter percutaneous PFO closure is safe and effective, with efficacy that ranges from 86% to 100%.⁷ The procedure is simple, requires only overnight observation, and has replaced surgical closure in all but rare instances.⁸