A New Theory Behind Dangerous Blood Clot Disorder
WEDNESDAY, April 9, 2003 (HealthDayNews) -- An Italian researcher is offering a theory for the cause of the blood-clotting condition that killed an American journalist covering the war in Iraq.
David Bloom of NBC News died suddenly on Sunday, not of a wound but of a clot that choked off a blood vessel. In his case, it was a blood vessel in the lung. But that pulmonary embolism was a variant of a condition often called "economy class syndrome," because it is linked to prolonged immobility in cramped quarters.
Bloom had been traveling in a vehicle whose interior was designed for safety, not comfort. He had reportedly been complaining of pains in his legs, a classic warning for a blood clot, or thromboembolism. The Iraqi heat also caused dehydration, health experts speculate, which can thicken the blood and promote formation of clots. In economy class syndrome, the classic case is a clot in a leg.
That designation is a misnomer, says Dr. Michael R. Jaff, director of vascular medicine at Lenox Hill Hospital in New York City.
"The name is not a good one because it has been reported in business class and first class," Jaff says. It can also be a threat to travelers in automobiles or buses -- any vehicle that keeps someone immobile for hours.
Embolisms of the kind that killed Bloom are a major health problem, responsible for an estimated 60,000 deaths in the United States each year. The underlying cause that makes people susceptible has been a mystery, with experts conjecturing that genetics are somehow involved.
Now, Italian researcher Dr. Paolo Prandoni is reporting on findings that indicate that thromboembolism is linked to atherosclerosis, the "hardening of the arteries" that leads to heart attack and stroke.
In the study, reported in the April 10 issue of The New England Journal of Medicine, Prandoni and his colleagues performed ultrasound examinations to get images of the carotid artery, the main artery to the brain, in 299 patients with deep venous thrombosis of the legs and 150 healthy people. They report the incidence of plaques, the fatty deposits of atherosclerosis, were more than twice as common in the thrombosis patients as in the healthy people.
"There is an association between atherosclerotic disease and spontaneous venous thrombosis," the journal report says. "Atherosclerosis may induce venous thrombosis or the two conditions may share common risk factors."
"In my opinion," Prandoni says, "the first is more likely, essentially because of its plausibility." Atherosclerosis makes the blood thicker, promoting the formation of clots that can block blood vessels, he says.
"If our hypothesis is correct, the clinical implications are immense," Prandoni says. Anything that can slow the process of atherosclerosis -- such as lifestyle changes such as more exercise or drug treatments to lower cholesterol -- can also help prevent thrombosis, he says.
But that is still a theory, requiring more research on patients with atherosclerosis, he acknowledges. "We have not yet planned such research," Prandoni says. "We are still working to demonstrate our hypothesis."
Jaff sees one immediate implication for patients and their doctors. "In patients with spontaneous deepening thromboembolism, those patients might benefit from an ultrasound examination to see if they have atherosclerosis," he says. "If they do, their physician can be aggressive about controlling risk factors."
He also says that in many cases, prevention of an embolism is simple -- just get up and move around. In aircraft, that would mean a stroll through the cabin. On the ground, it would mean getting out of a car periodically to stretch the legs.
More information
You can learn more about thromboembolisms from the National Library of Medicine. For more on atherosclerosis, visit the American Heart Association.
