Implantable Cardioverter-Defibrillators Overused

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One in five patients who receive the heart-shocking, life-saving devices known as implantable cardioverter-defibrillators, or ICDs, may be getting them unnecessarily, according to a study published in the Journal of the American Medical Association Tuesday.

The study, which looked at more than 100,000 patients, also found that those who did not meet the guidelines for use of the product but received the devices anyway had a significantly higher risk of in-hospital death than patients who met the criteria.

Using data from the National Cardiovascular Data Registry's on ICD use , researchers at Duke University found that more than 20 percent of patients who receive an ICD fall outside the recommended eligibility guidelines for the procedure.

Clinical trials have demonstrated the effectiveness of ICDs when used in patients with certain forms of heart failure, but the research fails to support a benefit for the device in people still recovering from a heart attack, coronary artery bypass surgery or those with a recent diagnosis of heart failure.

The study concluded that a substantial proportion of the devices end up in patients who fall into one of the categories. What's more, the risk of in-hospital complications was significantly higher in the patients given ICDs outside of the recommendations.

Study authors argued that this extra risk of complications is unacceptable considering the lack of evidence for benefit in patients who fail to meet the guideline criteria.

"[T]hese complications could have significant effects on patients' quality of life and health care use, including length of hospital stay and costs," the authors wrote. "Importantly, these complications resulted from procedures that were not clearly indicated in the first place. While a small risk of complications is acceptable when a procedure has been shown to improve outcomes, no risk is acceptable if a procedure has no demonstrated benefit."

But cardiac experts were split on whether the "off-label" use of ICDs was an acceptable exception to make for certain patients. While some doctors argue that the study should be seen as an impetus for stricter compliance with the evidence-based recommendations, others said they believe that the use of the ICD in certain non-evidence-based circumstances is up to the discretion and expertise of the physician.

"If 'appropriate' is practicing medicine by following the guidelines, then this is clearly not appropriate," said Dr. Brian Olshansky, a cardiac electrophysiologist at University of Iowa Hospitals. "On the other hand, if physicians implanted device due to the fact that they're concerned about the long-term outcome of the patient and weigh the risks and benefits and then decide to implant the device in lieu of the guidelines, this may be appropriate."

Acceptable Exceptions for Cardiac Patients

Unlike a pacemaker, which delivers smalls amounts of electricity to regulate heartbeat, an ICD delivers larger jolts of electricity in order to prevent the onset of sudden cardiac death.

The guidelines concerning when such a device is appropriate may be overruled in certain circumstances, said lead author on the study and researcher for the Duke Clinical Research Institute, Dr. Sana Al-Khatib. But the recommendations are based on multi-centered randomized clinical trials showing that the device does not help under certain conditions.

"The physician has to use his or her judgment -- even the guideline documents allow for these deviations, [but] I would not expect this to account for close to 23 percent of all ICD implants," he said. "Clearly there is room for improvement."

Dr. Richard Besser, chief health and medical editor for ABC News, agreed, noting that considering that the off-label use of ICDs varied from less than 5 percent of all implantations to 55 percent, depending on the center, "improvement needs to focus on interventions at the doctor and hospital level."

How closely doctors should stay to the recommended guidelines and the extent to which the "off-label" ICD usages should be minimized was a matter of debate among cardiac experts.

Given the lack of evidence supporting the utility of these devices outside the guidelines, the off-label use of ICDs is "completely inappropriate," said Dr. Jonathan Steinberg, chief of the Division of Cardiology at St. Luke's-Roosevelt Hospital in New York City and director of Electrophysiology at The Valley Hospital in Ridgewood, N.J. Removing, or explanting the device, is often dangerous, he added, so patients might end up stuck with an unnecessary device, which is a "big issue when it comes time for device replacement and whether a new generator is warranted."

The need for strict adherence to the existing guidelines was less clear to other cardiologists, however, especially given the relatively small difference in risk of complication found by the study. About 3 percent of those outside the recommendations experienced post-procedure complications compared, with 2.41 percent for those within.

"Guidelines are simply recommendations made by a committee of experts, and the guidelines are often out-of-date with relevant clinical practice by the time they make it through the societies and are approved, often a 2-year process," said Dr. Arthur Moss, professor of cardiology at the University of Rochester Medical Center.

"There are always exceptions to guidelines ? and the attending physician-cardiologist is at liberty to make a relevant clinical decision based on the circumstances and risks presented by the patient."

Dr. Paul Friedman, professor of medicine and cardiovascular diseases at the Mayo Clinic in Rochester, Minn., said, "Guidelines combine medical evidence and expert opinion to inform best practices. However, guidelines are just that: guidelines," adding that patients should seek guidance on whether they need one from a physician with training and experience in defibrillator use.

Underestimating the Problem or Overstating the Risk?

By drawing from national registry data, the study provides only a snapshot into the patients receiving ICDs, some cardiologists warned, and so the study results cannot provide the full picture for why so many patients might be getting ICDs outside the recommended guidelines or why the patients might experience more complications.

The increased risk of complication seen in the off-label patients may also result from the severity of the patient's cases more so than the ICD they were given, argued Dr. Peter McCullough, consultant cardiologist and chief academic and scientific officer at St. John Providence Health System, Providence Park Heart Institute, Warren, Mich.

"The observation that these so-called 'inappropriate' ICD patients had higher event rates suggests the doctors were identifying higher-risk patients using their judgment," he said. "These devices save lives. Studies like this call into question the appropriate use of databases in making judgments on the indications for cardiac procedures."

Duke's Al-Khatib agreed that it may be that the patients are sicker or it might just be an issue of timing. A large proportion of "inappropriate" ICD patients were those still recovering from a cardiac event or from a cardiac surgery, so performing the ICD implantation at that time might produce certain extra risks.

What's more, many cardiologists noted that given the lifesaving potential of the devices, the number of patients who should and do not receive an ICD may be more of an issue than those who receive it outside the realms of standard indications.

"[T]he first thing that strikes me is the irony that many of patients who do have an evidence-based, guideline recommended indication for an ICD do not have one, while some patients who fall outside of the guidelines are receiving ICDs," said Dr. William Abraham, director of the Division of Cardiovascular Medicine at Ohio State University.

ICDs for People in Need

Such is one of the limitations of using the National Cardiovascular Data Registry, said Dr. Cam Patterson, director of the University of North Carolina McAllister Heart Institute.

"Registry studies are notoriously difficult to draw conclusions from," he said. "The big challenge is that we get a snapshot of patients who received defibrillators, but we don't get to know anything in this study about patients who might need one but didn't have one implanted.

"We know that over half of individuals who should get an ICD implanted based on guidelines actually don't receive one, for a variety of reasons. This is a far bigger problem."

Follow Dr. Besser on Twitter @DrRichardBesser

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