リンク: Many Defibrillators Implanted Unnecessarily, Study Says - NYTimes.com.
米国では，本当は埋め込み型除細動器が不要な人が，除細動器を入れている場合が少なくない。さて日本では...？
Doctors are implanting high-tech heart devices in thousands of people who probably do not need them, a new study finds. The procedures cost more than $35,000, involve surgery and anesthesia, and may unnecessarily harm some patients.
The devices, called defibrillators, fire an electrical shock to jolt the heart back into a normal rhythm if it starts to beat in a disordered way that can cause sudden death. In people who truly need them, for conditions that can fatally disrupt heart rhythm, defibrillators can be life-saving.
Each year, about 100,000 are implanted in the United States. Former Vice President Dick Cheney received one in 2001.
The new findings fit into a larger pattern of misuse of defibrillators: paradoxically, previous research has also found that many people who need defibrillators do not get them. The reasons are not known, but may include the cost and also a reluctance by both doctors and patients to accept a surgically implanted device, especially if the patient is feeling fine and has no symptoms of the underlying problem.
Professional societies set guidelines that specify when the defibrillators should be used, based on studies showing which patients they help. To find out if doctors have been complying, researchers examined the records of 111,707 people who received the implants at 1,227 hospitals in the United States from January 2006 to June 2009. The records were part of a national registry, and the National Heart, Lung and Blood Institute paid for the study.
The researchers were surprised to find that more than 25,000 people — 22.5 percent of all those who got defibrillators — did not match the guidelines. Most of the patients were 64 to 68. For unknown reasons, blacks and Hispanics were more likely than whites to get defibrillators they probably did not need. At many centers, more than 40 percent of the devices went to patients outside the guidelines.
“I didn’t expect the rate to be that high,” said Dr. Sana M. Al-Khatib, an associate professor of medicine at Duke University and the lead author of the study, which is being published Wednesday in The Journal of the American Medical Association. Dr. Khatib said experts did not expect rigid adherence to the guidelines, and knew that doctors would sometimes make judgment calls for individual patients.
“I’m sure some of these cases were reasonable,” she said. “The physicians did what they thought was best. But even taking that into account, 22.5 percent is way too high.”
Why are doctors not following the expert advice? Apart from the reasonable judgment calls, Dr. Khatib said she thought many doctors did not know the guidelines or understand the evidence behind them, and thought they were helping patients by putting in the devices to save them just in case their heart rhythms went away.
“Take patients who just had a heart attack,” Dr. Khatib said. “Two randomized controlled studies show that defibrillators do not benefit patients who just had a heart attack.
“You have to be cognizant of the evidence out there and learn from what has been published. Not only do we have one clinical trial, we have two. And these patients are more likely to have complications. You’re truly not helping these patients.”
Even so, 37 percent of the devices implanted outside the guidelines went to people who had had heart attacks in the previous 40 days.
Some of those patients will eventually need defibrillators anyway, but 30 to 40 percent will not, said Dr. Alan Kadish, a cardiologist who is president of Touro College (based in New York), and who wrote an editorial accompanying the article in the journal.
The study found that electrophysiologists — cardiologists with extra training in heart-rhythm disorders — were less likely than other doctors to implant defibrillators inappropriately. Both Dr. Kadish and Dr. Khatib are electrophysiologists.
Dr. Kadish said he thought it possible but unlikely that some doctors were implanting devices unnecessarily to make money. Physician fees for the implantation are only $1,000 to $2,000, he said, adding that the device itself costs $20,000 to $30,000, and hospital fees for the procedure are generally about $10,000.
He said that if a defibrillator was recommended, it was reasonable for patients to ask their doctors if they met the guidelines, and also to ask if the doctor was an electrophysiologist.
Implanting the device is not minor surgery, Dr. Khatib said.
“It is an invasive procedure,” she said. “You’re putting wires in the patient’s heart. You’re putting a needle in the subclavian vein next to the lung, threading two wires down to the heart, and implanting the device.
“And in some patients we test the defibrillator by causing the heart to go into a life-threatening rhythm, to make sure the defibrillator can recognize it and shock them out of it. It’s not a minor procedure by any means.”
Patients who did not match the medical guidelines for receiving an implant but were given one anyway were more likely to die in the hospital or suffer complications than people who got the device and met the guidelines.
The death rate for the first group was 0.57 percent; for those who met the guidelines, it was just 0.18 percent. The causes of death were not available, and part of the explanation for the disparity may be that patients given the defibrillators inappropriately were sicker to begin with.
But Dr. Kadish said, “We can’t exclude the possibility that indeed some people are being harmed.”
Even so, he said, the problem of people who need defibrillators not getting them is far worse. He estimated that as many as 100,000 patients a year were missing out on the device, which could save their lives.
“We’re not doing as good a job as we should in putting them in the right people,” Dr. Kadish said.
Both Dr. Khatib and Dr. Kadish said the solution was better education for doctors. Neither wanted hospital panels, insurance companies or the government to be given the power to decide who should receive a defibrillator.
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