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Cocaine-Heart Attack Link Studied

September 13, 1999

CHICAGO (AP) _ Cocaine delivers a ``double whammy″ to the blood stream that may explain how the drug triggers heart attacks in its users, a new study concludes.

Cocaine use ``is even more dangerous than we had previously known,″ said Dr. Arthur Siegel, the study’s lead author. ``Every time a person uses it, it’s like a little bit of Russian roulette.″

Cocaine causes blood to thicken by increasing the number of red blood cells, and by triggering an increase in a protein that causes platelets to stick together, according to the study in today’s issue of the Archives of Internal Medicine.

The ``double whammy″ can cause clotting that can lead to heart attacks and strokes, said Siegel, chief of internal medicine at McLean Hospital outside Boston.

A previous study, released in June, showed cocaine users are 24 times more likely to have a heart attack during the first hour after taking the drug. The new study may help explain why, Siegel said.

His study measured changes in the blood of 21 people for an hour after they sniffed a moderate amount of cocaine, or received it intravenously.

Red blood cell counts increased 4 to 6 percent on average after individuals ingested the drug, due to constriction of the spleen. Cocaine causes the constricting by pumping more red blood cells into the system, Siegel said.

The thickened blood must circulate through already-constricted vessels, creating a potentially dangerous situation, Siegel said. Previous studies have shown that cocaine use causes blood vessels to narrow.

The study suggests that anticoagulants may be useful in treating cocaine-induced chest pains, Siegel said. He said it provides further warning to athletes who might use cocaine, or substances with a similar effect, in an attempt to enhance performance.

While the study’s small sample size made the conclusions preliminary, ``we’re very confident that both of these observations are real,″ he said.

The study also found an average 40 percent increase in a blood protein known as the von Willebrand factor in subjects who received cocaine intravenously. The von Willebrand factor promotes clotting by causing platelets to stick together.

Dr. Steve Frohwein, a cardiologist and assistant professor at the Emory University School of Medicine in Atlanta said several factors _ such as infection, cancer or other toxins _ can lead to clotting.

``Cocaine just stimulates a well known cascade of events,″ said Frohwein, who was not involved in the study.

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