PFO and stroke: what are the data?

Patent foramen ovale (PFO) is a frequent finding on echocardiography and occurs in over 25% of the population. In young patients with cryptogenic stroke, the frequency is much higher suggesting paradoxical embolization may be responsible for the clinical events. There are conflicting data from studies examining the association between PFO and stroke. The combination of atrial septal aneurysm and PFO, and PFO size and severity of right-to-left shunt may add additional risk but again the data are insufficient for definite conclusions. Available information suggests no difference in subsequent stroke in patients with PFO treated with aspirin or warfarin for secondary prevention. Endovascular closure is technically feasible, but not without the possibility of periprocedural complications. Comparison of medical and endovascular closure of PFOs in patients with stroke is ongoing in 2 major randomized trials.