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【medical-news】beta受体阻滞剂 利弊再次受质疑
CHICAGO (Reuters) - People given a blood pressure drug known as a beta blocker to reduce heart risks before surgery were one-third more likely to die within a month and had double the risk of stroke compared with those given a dummy pill, Canadian researchers said on Monday.
The study is the largest, most rigorous to date looking at whether beta blockers do more harm than good in reducing surgery-related risks. Other, smaller studies have had mixed results.
"There is a real potential that beta blockers are causing serious harm in the surgical setting," said Dr. P.J. Devereaux of McMaster University in Ontario, whose study appears in the journal Lancet.
"If my mother was undergoing surgery and given a beta blocker, I would be extremely upset based on this evidence."
The findings challenge the long-held belief that giving people a beta blocker before major surgery protects them from heart risks brought on by the stress of the procedure.
Surgery often raises levels of a stress hormone known as catecholamine, which drives up a person's blood pressure and heart rate. "Beta blockers block the effects of increased catecholamines, so the physiological rationale would say they would be beneficial to people," Devereaux said in a telephone interview.
He and colleagues set out to test this idea. They studied more than 8,000 patients in 23 countries at 190 hospitals who were undergoing major surgery unrelated to the heart. People in the study had or were at risk for clogged arteries.
STROKE VS HEART ATTACK
Half were given the beta blocker metoprolol, sold by AstraZeneca as Toprol XL, two to four hours before and 30 days after their surgery. The other half got a placebo.
The doctors were looking for heart complications such as heart-related death, non-fatal heart attacks or a heart-stopping event known as cardiac arrest in which the person survived.
While the study did find people given the drug had fewer heart attacks and abnormal heart rhythms, they also were more likely to die or have a stroke.
The researchers said for every 1,000 people with similar risks undergoing non-cardiac surgery, the drug could prevent 15 people from having a heart attack, three from needing a shock to restore a normal heart beat, and seven from developing a type of heart rhythm known as atrial fibrillation.
But eight more people would die, five would have a stroke, 53 percent would have abnormally low blood pressure and 42 percent would have an abnormally slow heart beat.
"This is an important study because, although the beta blocker reduced the number of heart attacks that occurred following surgery, it caused more strokes, thus on balance causing more harm than good," Peter Weissberg, medical director of the British Heart Foundation, said in a statement.
"This is why it is so important to undertake large clinical trials rather than assuming drugs will only do what is expected of them."
Devereaux, who first presented his findings at the American Heart Association meeting in November, said he expects the study to stir debate about whether it is still wise to give patients a beta blocker before a major surgery.
"It is telling us something we didn't realize in the past," he said.
http://www.reuters.com/article/healthNews/idUSN1230924220080512?sp=true 本人已认领该文编译，48小时后若未提交译文，请其他战友自由认领。 Study finds risks for beta blockers with surgery
beta受体阻滞剂 利弊再次受质疑
CHICAGO (Reuters) - People given a blood pressure drug known as a beta blocker to reduce heart risks before surgery were one-third more likely to die within a month and had double the risk of stroke compared with those given a dummy pill, Canadian researchers said on Monday. 编译：（1038字）
beta受体阻滞剂 利弊再次受质疑
本周一加拿大研究人员报道，与使用安慰剂对照的患者相比，在手术前给予β受体阻断剂——一种抗高血压药——以降低心脏病发病率的患者，其术后30日内死亡的可能性将增大1/3，并且中风的风险将增大一倍。
这是迄今为止最大最严密的一项研究，目的在于观察β受体阻断剂在降低手术相关风险的情况下评价其利是否大于弊。其他小的研究结果错综复杂。
安大略省麦克马斯特大学P.J.Devereaux博士的论文发表在柳叶刀期刊上，他说：“β受体阻断剂在术前准备中有严重伤害患者机体的可能性。”
“根据这个结果，若我母亲实施手术时使用了β受体阻断剂，我会感到极其沮丧的。”
传统观念认为，术前使用β受体阻断剂能够保护患者因过度紧张而导致心脏病发作的风险。但这项研究向传统的观念提出了挑战。
手术时，一种叫做儿茶酚胺的紧张新激素水平将升高，从而升高患者的血压和心率。Devereaux在接受电话采访时说：“β受体阻断剂能够阻止儿茶酚胺水平的升高，因此从生理学理论上应该说对患者是有好处的。”
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作者:admin@医学,生命科学 2010-10-02 19:08
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