Background: Percutaneous transcatheter closure of patent foramen ovale has been proposed to prevent recurrent strokes in young adults. Contrast transcranial Doppler ultrasonography provides a functional, semiquantitative evaluation of right-to-left cardiac shunt.
Aims: To evaluate the efficacy of percutaneous closure of patent foramen ovale in suppressing right-to-left shunt (assessed using transcranial Doppler) and in preventing secondary stroke.
Methods: Sixty-six patients less than 55 years of age were selected from 81 consecutive patients evaluated for percutaneous closure of patent foramen ovale after one or more cryptogenic stroke. All patients presented with a right-to-left cardiac shunt and passage of more than 50 microbubbles or curtain pattern on transcranial Doppler. Follow-up tests included cardiac and neurological clinical evaluation, contrast transcranial Doppler, and echocardiography.
Results: Percutaneous closure was successful in all patients, without major persistent side-effects. Before closure, the rate of recurrent stroke events was 16.57 per 100 patient-years; after closure, no recurrent stroke events (including transient ischaemic attacks) occurred during a mean follow-up period of 3.73 years (p=0.0001). Contrast transcranial Doppler detected residual right-to-left cardiac shunt in 25/60 (41.7%) patients evaluated after 12 months; 20.0% of these patients had passage of more than 50 microbubbles on transcranial Doppler.
Conclusion: Contrast transcranial Doppler is a useful tool in the selection of patients for percutaneous closure of patent foramen ovale. The absence of recurrent stroke events after transcatheter closure suggests that this procedure may prevent stroke by changing the foramen ovale configuration, even in cases of persisting shunt. Larger studies are needed to confirm these data.