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“正常”的血压值或许并不利于预防心脏病

更新时间:2015-11-11 10:02:56 来源:纽约时报中文网 作者:佚名

Data on Benefits of Lower Blood Pressure Brings Clarity for Doctors and Patients
“正常”的血压值或许并不利于预防心脏病

When the federal government announced in September that it had abruptly halted a large blood pressure study because its results were so compelling, doctors were left in frustrating limbo.

今年9月,联邦政府宣布,因研究结果太过惊人,它突然叫停了一个大型血压研究,医生们因此陷入了进退维谷的境地。

The announcement said researchers had found that driving systolic blood pressure to levels far below what current guidelines recommend — less than 120 instead of 140 or 150 millimeters of mercury — can save lives and prevent heart disease and strokes. But they declined to release any data on the number of lives saved, the number of heart attacks prevented, or other critical measures.

声明称,研究人员发现,将收缩压控制在远低于目前建议的水平——低于120,而非140或150毫米汞柱——可以挽救生命,以及预防心脏病和中风。但他们拒绝透露挽救了多少生命,预防了多少心梗,以及其他关键的量度数据。

“How can anyone do anything different tomorrow with regard to blood pressure control without knowing more about what they found?” said Dr. Harlan Krumholz, a cardiologist at Yale, echoing the concerns of other specialists.

“不进一步了解他们的发现,怎么敢在血压控制上做任何不同的尝试?”耶鲁心脏病学家哈伦·克鲁姆霍尔茨(Harlan Krumholz)博士说,这也是其他专家的顾虑所在。

On Monday, reporting at an American Heart Association meeting in Orlando, Florida, and in a paper published simultaneously in the New England Journal of Medicine, study investigators lifted the veil. Among the 9,361 patients followed for an average of 3.2 years, there were 27 percent fewer deaths (155 compared with 210) and 38 percent fewer cases of heart failure (62 compared with 100) among patients who achieved the systolic pressure target of 120 than among those who achieved the current 140 target.

周一,这项研究的调查人员在于佛罗里达州奥兰多市举行的美国心脏协会(American Heart Association)会议上做了报告,同时在《新英格兰医学期刊》(New England Journal of Medicine)发表了一篇文章,揭开了这项研究的面纱。该研究对9361名病人进行了为期平均3.2年的跟踪,结果发现,和将收缩压控制在目前的140的病人相比,控制在120以下的病人,死亡率低27%(155人对210人),出现心力衰竭的几率低38%(62人对100人)。

Systolic pressure is the higher of the two blood pressure numbers and represents pressure on blood vessels when the heart contracts.

收缩压是两项血压指标中更高的那一个,代表心脏收缩时的血压状况。

Overall, there was a 25 percent reduction — 243 compared with 319 — in people who had a heart attack, heart failure or stroke or died from heart disease, Dr. Paul K. Whelton, a principal investigator for the study, said.

这项研究的主要研究员之一保罗·K·惠尔顿(Paul K. Whelton)表示,总体而言,发生心梗、心脏衰竭或死于心脏病的比率可以降低25%(243人对319人)。

The older participants did just as well as younger ones.

年长的参与者跟年轻的情况一样好。

For millions of Americans with high blood pressure, the results could be transforming, said Dr. Marc Alan Pfeffer, a professor of medicine at Harvard who was not affiliated with the study.

没有参与该研究的哈佛大学教授马克·阿兰·费弗尔(Marc Alan Pfeffer)博士表示,这些研究结果会对美国数百万高血压患者产生颠覆性影响。

Before now, Pfeffer said, if a patient older than 50 came into his office with systolic pressure of 136 and a well-controlled risk factor for heart disease like high cholesterol, he would pat the patient on the back and say, “Great job.” Now, he said, he would feel obligated to give the patient more hypertension drugs. Otherwise, he said, “I would have lost the opportunity to help another human being.”

费弗尔表示,这项研究出现之前,遇到年纪超过50岁、收缩压136、并对胆固醇等对心脏病重要风险因素有很好控制的病人,他会拍拍对方的肩膀然后说,“做得不错。”而现在,他会觉得自己有义务给病人开更多高血压药物。否则,他说,“我将错失挽救另一个生命的机会。”

At least 17 million Americans will be affected by the findings right now, calculated Paul Muntner, an epidemiologist at the University of Alabama who was not affiliated with the study.

据没有参与这项研究的阿拉巴马大学流行病学家保罗·芒特纳(Paul Muntner)测算,至少有1700万美国人马上就会受到这些发现的影响。

The study, called Sprint, enrolled patients ages 50 and older with high blood pressure. The patients also had at least one other risk factor for heart disease like smoking or a high cholesterol level, or they had kidney disease, or they were simply 75 or older. Half were assigned to a systolic pressure target below 140, in keeping with today's medical practice. The rest were assigned a target pressure of less than 120. The study was supposed to continue until 2017, but ended abruptly in the summer when researchers announced they had “potentially lifesaving” results.

这项名为Sprint的研究招募年龄50岁及更高的高血压病人参与。这些病人至少还有一项罹患心脏病的其他风险因素,比如吸烟、高胆固醇,患有肾脏疾病或只是年龄大于75岁。其中一半被要求将血压控制在140以下,与现行做法一致。另一半则被要求将血压控制在120以下。这项研究原计划持续到2017年,但今年夏天突然终止,当时研究人员宣布他们发现了有“有可能挽救生命”的研究结果。

Doctors have long wrestled with how low blood pressure should go. Bringing it too far down, particularly in elderly people, can result in complications like dizziness and fainting. According to the results released Monday, about 5 percent of the study's patients, or 220 people, with the 120 blood pressure target had serious complications over the course of the study — blood pressure so low it caused severe dizziness or fainting, or a reversible injury to the kidneys. Among those with the 140 target, 118 had serious complications.

长期以来,医生们一直纠结于该把血压控制在什么水平。如果血压太低,可能导致眩晕、昏厥等并发症,对年纪大的人来说尤其如此。周一发布的结果显示,将血压控制在120的参与者中,有5%——即220人——在研究进行期间出现了严重的并发症——血压过低,导致严重眩晕或昏厥症状,或对肾脏产生不可逆的损伤。在将血压控制在140的参与者中,有118人出现了严重的并发症。

A complication the investigators worried about with blood pressures of 120 or lower — an abrupt drop in blood pressure when people stood up — actually occurred more often in those with the higher systolic pressure target.

研究人员担心血压指标为120或更低的人在起身时出现血压骤降的并发症状,而实际上,这种情况在血压控制目标更高的人身上更容易出现。

“When we put those complications in the context of a 27 percent reduction in total mortality, it seems that the benefits outweigh the risks,” said David M. Reboussin, a biostatistician at Wake Forest Baptist Medical Center and a principal investigator for the study.

“把这些并发症放在可以降低27%的死亡率的大背景下看,似乎益处大于风险,”韦克森林浸会医疗中心(Wake Forest Baptist Medical Center )生物统计学家维·M·勒布桑(David M. Reboussin)说,他是该研究的首席研究员。

There also is the unanswered question of how low blood pressure should go. A few patients in the new study lowered their systolic pressure to 110, but getting it below 120 was a challenge for most people. Wright said it was almost inconceivable that there would be another large study comparing, say, a pressure of 110 to one of 120. “That is a very narrow window,” he said, and the expected differences in outcomes would be small, meaning the study would have to be very large and prolonged.

还有一个问题是,血压究竟应该低到什么程度。在这项新研究中,一些病人将收缩压控制在低于110的水准,而对大多数人而言,保持在120就已经不易。克利夫兰大学医院凯斯医疗中心(University Hospitals Case Medical Center)高血压项目主任、本研究的研究员小杰克逊·J·赖特(Jackson T. Wright Jr.)博士表示,很难想象再进行一个大型研究来对比110和120的血压状况。“这个区隔非常窄,”他说,得到的研究结果的差别会很小,这意味着研究规模要非常大,时间要很长。

Muntner said doctors and patients will have to live with some uncertainty. “We will never have enough clinical trials,” he said.

芒特纳表示,医生和病人只能面对一些不确定性。“临床试验再多也不够,”他说。

Some hypertension experts urge caution. Dr. Michael Alderman, a blood pressure expert at Albert Einstein College of Medicine in New York, calculated that the study results mean six people per 1,000 annually would avoid a heart attack, stroke, or heart failure. That, he says, can make it difficult to know how to advise individual patients. “If there were no, or minimal, harms like a safe one-time vaccination, it would be a no-brainer. But if it means decades-long pill taking by generally healthy folks, the decision gets more difficult.”

一些高血压专家劝诫大家要小心谨慎。纽约艾伯特·爱因斯坦医学院(Albert Einstein College of Medicine)的血压专家迈克尔·奥尔德曼(Michael Alderman)估计,这些研究结果意味着,每年在1000人中有6个人可以避免出现心梗、中风或心脏衰竭。他表示,这会让医生不知如何给病人个体提供建议。“如果它没有危害,或像安全的一次性疫苗接种一样危害很小,医生们就很容易做决定。但如果它意味着健康的人需要连续几十年服用药物,就没那么容易了。”

Krumholz of Yale said that while the study results were exciting, a lower blood pressure should not be seen as a mandate. Getting pressure that low, he said, “comes at some risk.” Doctors will have to talk to patients about their preferences and goals, he said.

耶鲁大学的克鲁姆霍尔茨表示,尽管研究结果让人兴奋,但不应该将更低的血压定为要求。他说,血压那样低,“是有风险的。”医生们必须先和病人就侧重点和目标进行沟通。

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