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Replacing patients' ailing heart devices a major issue
(Milwaukee Journal Sentinel, The (KRT) Via Thomson Dialog NewsEdge) MILWAUKEE _ Implanted under a muscle in Bob Ryan's stomach is a cardiac defibrillator with a possible defect that could cause the battery to drain suddenly, leaving him unprotected if his ailing heart were to go into a life-threatening arrhythmia.
Because the replacement surgery likely would put him out of commission for a week, Ryan, 53, has opted to leave the device in and check the battery on a regular basis.
But when Eric Schulz found out about a potential defect in his device last year, he moved quickly to have it surgically replaced.
"I didn't give it a second thought," said Schulz, 56, who has seen both his 20-year-old son and 44-year-old sister die of sudden cardiac arrest.
With tens of thousands of defibrillators and pacemakers subject to recalls and advisories in the last two years, doctors and their patients must make calculating decisions about whether and when to replace the devices.
Eye-opening insights into just how often the life-saving devices fail and the problems that arise in replacing them were revealed in three studies published in the latest issue of the Journal of the American Medical Association.
Also, a large organization of doctors who treat arrhythmias released sweeping recommendations to physicians, device-makers, Congress and the Food and Drug Administration on how to monitor and report device malfunctions.
They include a recommendation that device-makers set up independent panels of outside experts to analyze device reliability data.
The manufacturers were told they should use more wireless and remote monitoring technologies to more quickly find faulty devices.
The recommendations from the 4,300-member Heart Rhythm Society are expected to give doctors and patients more timely and clear information about recalls and advisories for implanted pacemakers and defibrillators.
"The current system (for identifying problems) is heavily dependent on industry ...," said Anne Curtis, president of the society and chief of cardiology at the University of South Florida. "Our goal is patient safety."
In one JAMA study, major complications occurred in nearly 6 percent of patients who underwent elective replacement of a potentially defective device.
The complications included serious infections in the pocket under the skin where the device is implanted, severe bruising and pain, and two deaths.
The study involved 533 patients who had devices replaced at 17 centers in Canada.
Infection is the complication that doctors fear the most.
"Infection is the most catastrophic," said James Roth, a cardiologist at Froedtert Memorial Lutheran Hospital in Milwaukee. "Once the pocket is infected, the wires usually are infected."
When an infection occurs, it may require a dicey surgery that involves removing lead wires that have become stuck to the inner lining of the veins through which they run as well as to the heart itself.
And there is reason to believe that serious infections are more common in replacement surgery than with initial implant surgery, said senior author Andrew Krahn, a cardiologist with the University of Western Ontario.
That's because the immune response and blood supply to the implant area (usually under the collarbone) can be diminished in people undergoing replacement, he said.
When device recalls and advisories are issued, doctors say they try to present the pros and cons of whether to replace the device or wait until it reaches the end of its normal lifespan, which usually is about seven years.
"Essentially what you are doing is picking the lesser of two evils," Krahn said.
Over the last two years, 330 devices implanted at Froedtert were the subject of recalls and advisories, but only 26 have been replaced, Roth said.
So far, he said, none of those devices has malfunctioned.
Ryan, who is on his third defibrillator since he was first implanted in 1994, decided to wait it out when he learned last year that his device could short-circuit, resulting in rapid draining of the battery.
With no power, the device would not shock his heart in the event of a dangerous arrhythmia.
But Ryan, a physiologist with the Medical College of Wisconsin, has opted to check the battery regularly with an external magnetic device rather than go through another surgery.
That's partly because his device rests under his stomach muscle and the surgery requires more recovery time than if the device was in the typical position under the collarbone.
"At this point, it's still functioning properly," he said. "I don't think about it."
Still, when devices are recalled it can affect the confidence of patients, said Atul Bhatia, an electrophysiologist who practices at Aurora Sinai Medical Center and St. Luke's Medical Center in Milwaukee.
Bhatia said he has about 55 patients whose devices have been the subject of a recall. About 30 have elected to have the device replaced.
"It threw them into a huge paranoia," he said. "It really broke their confidence."
One of those patients is Schulz, a Milwaukee resident, who was diagnosed with cardiomyopathy in 2000 after the premature deaths of his son and sister in the 1990s.
"It's like a security blanket," he said.
A defibrillator shocks the heart back into a normal rhythm when it goes into a dangerously fast arrhythmia. Most newer devices combine a defibrillator and a pacemaker.
A pacemaker electrically stimulates the heart to beat faster when the heart rate is too slow.
It also can stimulate electrically the two lower chambers of the heart to pump in a synchronized manner.
Both types of devices use a battery-powered generator that is implanted under the skin below the collarbone.
Electrical wires that run through a vein connect the generator to the chambers of the heart.
It is estimated that 300,000 to 400,000 new defibrillators and pacemakers are implanted every year in the United States.
The devices malfunctioned at surprisingly high rates, resulting in 61 deaths in a 13-year period, according to the first large analysis of the reliability of the increasingly popular devices.
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The review found that 17,323 devices (8,834 pacemakers and 8,489 defibrillators) malfunctioned among the 2.25 million pacemakers and 415,780 defibrillators that were implanted in Americans between 1990 and 2002.
That resulted in a combined annual malfunction rate of about seven devices per 1,000 implants, although doctors said the actual rate as well as the number of deaths may be considerably higher because some failures most likely were missed.
The failure rate for defibrillators especially was troubling and undoubtedly much higher than most doctors were aware of, said lead author William Maisel, an assistant professor of medicine at Harvard Medical School.
The malfunction rate for defibrillators was 20.7 per 1,000 implants and more than half of the problems occurred from 2000 through 2002, the last three years of the study.
"Most physicians and patients overestimated the reliability of the devices," Maisel said. "Many physicians were off by a factor of 100."
Pacemakers failed at a rate of 4.6 per 1,000 implants.
A third study found that defibrillator malfunctions increased four times between 1998 and 2002 before decreasing substantially over the following two years.
It found pacemaker reliability has improved considerably.
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Doctors say malfunction rates tend to go up when new, more complicated devices are introduced.
Still, even with the malfunctions and deaths, implanted pacemakers and defibrillators are considered major life-saving advances.
"The chance of the device saving someone's life is about a thousand times greater than the chance of the device failing when it is needed," said Maisel, director of the pacemaker and device service at Beth Israel Deaconess Medical Center in Boston.
Defibrillators cost between $20,000 and $30,000. Pacemakers cost about $5,000.
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(c) 2006, Milwaukee Journal Sentinel.
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