EMBARGOED FOR RELEASE UNTIL 4 PM ET, June 23, 2003
Rare Stroke Risk Related to Air Travel
St. Paul, Minn. -
A rare type of stroke can occur as a result of long airplane flights, according to a study in the June 24 issue of Neurology, the scientific journal of the American Academy of Neurology. The type of stroke can occur in people who have a patent foramen ovale, or an opening between two chambers in the heart. The opening is present in about 30 percent of the general population. Air travel increases the risk of developing blood clots in the veins of the legs, which can then enter the bloodstream and block an artery in the lungs, a condition called pulmonary embolism. In some cases, the opening can allow the blood clot to enter the arteries of the brain, causing a stroke. For the study, researchers examined all passengers over an eight-year period who had a pulmonary embolism when they arrived at Charles de Gaulle airport in Paris, France, and were transported to a hospital by a medical transport team. Of the 155 million passengers during that period, 65 people with pulmonary embolus were transported by a medical team. Of those, four people, or six percent of those with pulmonary embolus, had strokes. All four had patent foramen ovales. Patent foramen ovale is a known risk factor for stroke. No other cause of stroke was found in the four patients. All four were on flights lasting at least eight hours. The study provides lessons for both travelers and physicians, according to study author Frédéric Lapostolle, MD, of Avicenne Hospital in Bobigny, France. Travelers on long flights can take steps to help prevent a blood clot from forming, Lapostolle said. Inactivity increases the risk of developing clots. To help prevent clots, travelers can: * Take a walk around the cabin once an hour or so. * Flex and rotate their ankles or rise up and down on their toes. * Wear support stockings to help improve circulation. * Avoid alcohol. * Drink plenty of fluids. Dehydration can contribute to the development of clots. * Talk to their doctor if they have past medical history of cardiac or pulmonary disease. Lapostolle said that physicians should be aware that pulmonary embolism can lead to stroke, particularly after air travel, and should look for signs of the other condition in patients with one condition, as treatment may be different when both conditions are present. The risk of stroke may be higher than found in the study, Lapostolle said, because the study did not include people who died during or immediately after air travel and because pulmonary embolism may have been undiagnosed in people whose main symptoms were consistent with stroke and in patients with minor cardiological and/or neurological symptoms.