Health Scan: Drug-eluting stents may increase risk of heart attacks

Plus, how sleep apnea can make kids sickly and the relationship between brain tumors and family size.

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December 24, 2006 03:54
4 minute read.
Health Scan: Drug-eluting stents may increase risk of heart attacks

stent 88. (photo credit: )

Controversy on the safety of drug-eluting stents - those highly expensive polymer-coated metal mesh cylinders that hold open the coronary arteries of people who have or would otherwise have a heart attack - has raised the blood pressure of doctors and US Food and Drug Administration professionals. Recent studies have claimed that these new-generation stents - which minimize the risk of restenosis (reclogging of the arteries with scar tissue) thanks to impregnated drugs that slowly seep out - pose a slightly higher risk of subsequent thrombosis (blood clots), heart attacks and death compared to non-coated stents. About six million people around the world, including thousands of Israelis, have had these artery supports inserted by angioplasty. The minimally invasive insertion is aimed at avoiding open-heart surgery, which can be risky. There is also a debate about how long patients with stents should continue taking expensive anti-clotting drugs such as Plavix. According to the recent studies, patients with drug-coated stents face a small but meaningfully increased risk of clots. The FDA recently held an urgent meeting of external experts to discuss drug-eluting stents, whose global annual sales exceed $6 billion, and released its own assessment. While drug-eluting stents seem to carry a "small but significant" increased blood clot risk, it said, it was unclear whether this actually means a higher risk of heart attacks. Now, Dr. William Wijns, a Belgian board member of the World Heart Federation and the European Society of Cardiology offers some assurance - at least about the Endeavor polymer-coated stent produced by Medtronic. Wijns, of the University of Louvain in Brussels, was recently in Israel to attend the International Conference of Interventional Cardiology in Tel Aviv. He told The Jerusalem Post that he has inserted thousands of stents of many types in patients. "There are currently about seven or eight types in Europe and Israel." His research has found that Endeavor stents prevent restenosis in the vast majority of patients: Fully 97% of 700 heart patients in the long-term study have not required repeated catheterization or other invasive procedures after three years. The Medtronic stent, he said, has thus shown a very good safety profile. "I myself believe that there could be lateonset thrombosis with stents, but the problem can be solved with drugs like Plavix with aspirin," he said. "The syndrome of patients having heart attacks when they stop one of these drugs is something we were not used to seeing with regular metallic stents. We have to find the right balance between safety and efficacy." SLEEP APNEA CAN MAKE KIDS SICKLY Children diagnosed with sleep apnea suffer from more illnesses and require more medical care, according to a new study by sleep lab researchers at Soroka University Medical Center in Beersheba. It has been known for several years that children whose respiration halts momentarily during sleep have difficulty functioning during the day. Apnea in children can result from asthma or obstruction of the airways due to enlarged adenoids or tonsils. About 10 percent of children snore, according to the Soroka researchers, while about 2.5% suffer from sleep apnea. It can cause growth and development problems or pulmonary hypertension, but the biggest negative result is behavioral problems, a decline in cognitive function, learning difficulties and problems in school. The Beersheba doctors found that children with apnea often start snoring when they are toddlers. Prof. Ariel Trasiuk and colleagues in the sleep lab studied children aged four and five who suffered from apnea and compared them with a control group of unaffected kids. He found those with respiratory problems during sleep use 60% to 90% more medical services than the unaffected group. They require more medications, are more often taken to emergency rooms and are hospitalized longer. Since sleep apnea can be treated with devices that force air into the lungs to keep respiration steady, and by other means, it is important to identify such children as soon as possible. BRAIN TUMORS AND FAMILY SIZE? How many brothers and sisters you have - especially younger ones - could predict your chances of developing a brain tumor, according to a study published in the latest issue of Neurology. This odd finding is the result of the largest population-based study of its kind, which analyzed 13,613 brain tumor cases in Sweden. Those with four or more siblings were twice as likely to develop a brain tumor as people with no siblings. The study also found there was a two to fourfold increase in brain tumor rates among children younger than 15 who had three or more younger siblings, compared to children of the same age who had no siblings. The study did not find an association between the number of older siblings and brain tumors. "Since the size of a family and the number of younger siblings correlate with the incidence of brain tumors, this suggests infectious agents may be causing the disease," said study author Dr. Andrea Altieri of the German Cancer Research Center in Heidelberg. "The number of siblings a person has indicates they were exposed at an early age to infections, since children come in close contact with each other and thereby share exposures to many infectious agents." According to Altieri, the finding that brain tumor rates were higher among people with younger siblings and not older siblings suggests infections or re-infections in late childhood may play an important role in causing the disease, while exposure to infections in infancy, birth to five months old, may be beneficial. Given these findings, researchers say efforts to identify the specific infectious agents that may be causing brain tumors are warranted. "This study represents the only populationbased study providing reliable quantification of the effects of number of siblings on the risk of brain tumors. The 200% to 800% increased risk for people with a high number of younger siblings are stronger than most established risk factors for the disease," Altieri said.


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