People with a patent foramen ovale who have a stroke with no known cause and receive proper treatment are not at increased risk for a second stroke compared with people who do not have the heart defect, according to new guidelines published in the April 13th issue of Neurology.

“There was debate within the medical community about whether patient foramen ovales should be closed or managed with medication, so we hoped to resolve that question,” said guideline co-author Scott Kasner, MD. “We found that there is no evidence to support or refute the role of closing a patent foramen ovale. More research is needed to answer this question.”

The guideline also found that people younger than 55 years with both a patent foramen ovale and an atrial septal aneurysm may have an increased risk of a second stroke. An atrial septal aneurysm occurs in roughly 5 percent of people. Up to 70 percent of people with an atrial septal aneurysm also have a patent foramen ovale.

The guideline, which was developed by analyzing all of the scientific research on the topic, also examined the use of aspirin and warfarin to reduce the risk of subsequent stroke. Analysis showed that there is inadequate evidence to determine whether aspirin or warfarin is the better medication to prevent subsequent stroke and death, but that the side effect of minor bleeding is more common with warfarin.

According to the article, more research is needed, particularly on the effects of an atrial septal aneurysm on stroke risk and how the defects should be managed. “We need to learn more about how these abnormalities in the heart cause stroke,” said Kasner. “It is especially important because the prognosis and treatment may depend on this relationship.”

Studies should also be done comparing the results from the use of medications to the use of procedures to close patent foramen ovales, the guideline stated. The first author of the guideline, Steven Messe, MD, said, “Patients with patent foramen ovale and stroke and the physicians who care for them should feel comfortable participating in research to determine the best treatment, given that the current data are equivocal.”

The guideline encourages neurologists to communicate with patients who have had a stroke and are on aspirin or warfarin therapies about their future health risks. The experts agree that patients should know that the presence of a patent foramen ovale does not necessarily signify an increased risk for subsequent stroke, compared to other stroke patients without atrial abnormalities. Patients with stroke and patent foramen ovale should consider participating in research to further address this important medical problem, Kasner said.