By Ashley Starkweather, B.S. and Asher Kimchi M.D.

BETHESDA, MD – Patients with a patent foramen ovale (PFO) have been found to have higher incidences of cryptogenic stroke, and secondary prevention has traditionally consisted of anticoagulant drug therapy. However, a new study published by Dr. Stephan Windecker, M.D., et al, at University Hospital in Bern, Switzerland, in the August 18, 2004, issue of the Journal of the American College of Cardiology compares the effectiveness of percutaneous closure of the PFO with standard medical treatment in the prevention of recurrent stroke in these patients.

Windecker suggests that the cause of stroke in these patients involves paradoxical embolism through the PFO, and therefore, surgical closure of the PFO would reduce the incidence of strokes in patients with PFO.

Patients who were admitted to University Hospital between January 1994 and August 2000 with transient ischemic attack (TIA) or ischemic stroke were identified, and presence of PFO was determined. The cerebrovascular event was evaluated to determine if paradoxical embolism was the likely cause. Two treatment groups were then assigned, one using standard medical treatment, such as Coumadin, acetylsalicylic acid, or clopidogrel, and another group that underwent percutaneous PFO closure.

The effectiveness of PFO closure versus drug therapy in these patients appears to depend upon the degree to which complete closure is achieved. In patients who did achieve complete closure of the PFO, risk of recurrent stroke was lower than in patients treated with drug therapy. However, in patients who did not achieve complete closure according to post-operative ultrasound, PFO closure was comparable to drug therapy in prevention of recurrent stroke.

However, these results are preliminary and have yet to be confirmed by a randomized trial. Furthermore, improvements in PFO closure devices and technique may result in a positive impact on clinical outcome in the future, and therefore continued study regarding the link between PFO closure and stroke prevention is needed.