Heart surgery may not prevent stroke in patients with patent foramen ovale.

So, will closing the patent foramen ovale surgically prevent strokes in these patients? To find the answer to this question, a study was conducted across several countries which compared patients undergoing the surgical procedure to those who were treated only with medications to prevent clot formation.
The patients included in the study were less than 60 years old with a patent foramen ovale who suffered from a stroke or a milder attack due to obstruction of blood flow to the brain or other organs like the heart. The patients were divided into two groups - one group underwent surgical closure of the patent foramen ovale, while the other received only medications to prevent clot formation. The patients who underwent the surgery also received medications to prevent clot formation. The two groups were followed up for a period of around 4 years.
Though the researchers found a slight decrease in the number of strokes in patients who underwent the surgery, the protective effect of the surgery against stroke was not significant. Thus, they conclude that surgery may not be necessary to reduce stroke and other similar events in patients with patent foramen ovale, who had already suffered a similar event in the past.
Reference:
Percutaneous Closure of Patent Foramen Ovale in Cryptogenic Embolism; Bernhard Meier et al; N Engl J Med 2013.