Pubdate: Mon, 13 Sep 1999 Source: Seattle Times (WA) Copyright: 1999 The Seattle Times Company Contact: http://www.seattletimes.com/ Author: Jamie Talan, Newsday STUDY LINKS COCAINE USE TO BLOOD CLOTS If one needs another reason to say no to cocaine, here it is: Harvard scientists have identified two nasty heart-damaging and potentially life-threatening effects that explain why users are at risk for heart disease and stroke every time they take cocaine. "I hope this will be a wake-up call for people who use cocaine," said Dr. Arthur Siegel, an assistant professor of medicine at Harvard Medical School and director of internal medicine at McLean Hospital in Belmont, Mass. "They should know how dangerous cocaine could be." The findings, reported today in the Archives of Internal Medicine, provide a biological explanation of how cocaine puts people at risk. There is no telling how many people suffer these consequences, but doctors estimate that cocaine-related emergency-room visits for chest pain are a major problem. A medical study published earlier this year in Circulation by Harvard researchers found that in the hour after cocaine use, there is an average 25-fold risk of having a heart attack. And others before Siegel have shown that cocaine, a stimulant, constricts the arteries. But Siegel's study of 21 McLean Hospital volunteers, who ingested cocaine nasally or who were injected with it, found that cocaine also helps trigger blood-clot formation. When researchers looked at blood samples taken within minutes and then again two hours after cocaine use, they found a thickening of the blood. The reason: Cocaine causes constriction of the spleen, an organ on the upper left side of the abdomen that manufactures red blood cells. This constriction meant that the spleen had infused new blood cells into the blood vessels. A high red-blood-cell count increases the risk of thrombosis or clotting. Siegel's study found a 4 percent to 6 percent increase in the number of red blood cells after cocaine use. Making matters worse, cocaine also caused an increase in a substance called the von Willebrand factor, which triggers clotting by causing platelets to stick to the lining of the blood vessels. "This is a double-whammy to the blood-clotting system," said Siegel. "This is very dangerous, even for people using it one time." In a study of six men and six women, Siegel and his colleagues discovered that cocaine causes von Willebrand factor to increase 40 percent in just a few minutes. - --- MAP posted-by: Keith Brilhart