Strokes without a known cause are called cryptogenic strokes. One possible cause of these is a hole in the wall separating the right atrium from the left. Whether fixing this opening, called a patent foramen ovale (PAY-tent foe-RAY-men oh-VAH-lee, PFO) prevents such strokes has yet to be determined. It's possible we'll never have an answer because some doctors, researchers, and stroke victims seem to be convinced that closing a PFO is good medicine. That's why the American Heart Association, American Stroke Association, and American College of Cardiology are urging doctors to enroll patients with cryptogenic stroke in one of the ongoing trials testing the benefits and risks of PFO closure.

These trials include:

• GORE HELEX^TM Septal Occluder for Patent Foramen Ovale Closure in Stroke Patients (Gore REDUCE) in the United States

• Randomized Evaluation of Recurrent Stroke Comparing PFO Closure to Established Current Standard of Care Treatment (RESPECT) in the United States

• Patent Foramen Ovale Closure or Anticoagulants Versus Antiplatelet Therapy to Prevent Stroke Recurrence (CLOSE trial) in France

• Risk of Stroke in Pulmonary Embolism With a Patent Foramen Ovale (PFO-ICEP) in France

If you have had an out-of-the-blue stroke for which your doctor can't really pin down a cause (like smoking or high blood pressure) and you have a patent foramen ovale, consider participating in one of the clinical trials.