One-third of costly implanted heart devices may be unnecessary

Updated 10:00 AM January 15, 2007

Research

One-third of costly implanted heart devices may be unnecessary

By Kara Gavin
U-M Health System Public Relations

Medicare will pay for tens of thousands of heart patients to have expensive high-tech devices implanted in their chests this year: implantable cardioverter defibrillators (ICDs), that can shock damaged hearts back into rhythm and prevent the kind of sudden cardiac death that kills 300,000 Americans annually.

But a new U-M led study finds that while many of these patients will benefit from their ICDs, a large number won’t—and a simple heart-rhythm test can tell who’s who.
In fact, the study suggests that if the test were used on the majority of ICD candidates, as many as one-third could be spared the operation to implant a device, without raising their risk of sudden death. That would mean that Medicare could be spared the additional $90,000 lifetime cost of each device compared to best medical therapy.

The study, published in the January issue of the Journal of the American College of Cardiology, is based on data from 768 patients who were candidates for ICDs at Christ Hospital and the Ohio Heart and Vascular Center (OHVC) in Cincinnati. The patients had survived heart attacks but had permanent damage to their heart muscle caused by lack of blood flow, a condition called ischemic cardiomyopathy.

Each patient received a test called microvolt T-wave alternans or MTWA, along with a battery of other tests, during their evaluation. Half the patients went on to receive ICDs, although the MTWA test results weren’t used in the decision-making process. The patients’ health and the causes of any deaths were tracked for up to three years.

After that time, the data were analyzed by researchers from the U-M Cardiovascular Center and VA Ann Arbor Healthcare System, in cooperation with the Ohio team. In all, the results show the MTWA test results accurately predicted which patients would benefit most from an ICD.

“This is the first study to demonstrate that a subset of patients who meet current criteria for defibrillator placement may not benefit at all from ICDs,” says Dr. Paul Chan, senior author and a fellow in cardiovascular medicine at the Medical School. “Use of the MTWA test, which has been covered by Medicare since spring of 2006, could truly help us tell which ICD candidates will benefit most.”

In all, the authors calculate, one life could be saved every two years for every nine ICDs implanted in people with positive or inconclusive MTWA results. But it would take 76 ICD implantations in people with negative MTWA tests to save one life every two years.

Chan and his Ohio colleagues, led by first author Dr. Theodore Chow of the Lindner Clinical Trial Center at Christ Hospital and the OHVC, have studied the use of MTWA in predicting patients’ risk for several years. In addition to Chan and Chow, the study’s authors are Dr. Dean Kereiakes, Cheryl Bartone, Terri Booth, Dr. Edward Schloss, Dr. Theodore Waller, Dr. Eugene Chung, and Dr. Santosh Menon, of Christ Hospital/OHVC, and Dr. Brahmajee Nallamothu, of U-M.

They believe the use of the MTWA test could potentially save a large part of the nation’s ICD costs. But using MTWA testing to determine who will get the most benefit from an ICD still is not standard practice, despite Medicare coverage for one form of the test.

Chan, Chow and their colleagues hope that their study—and larger studies now under way or planned —will lead to routine use of MTWA testing, which is much like a standard treadmill stress test familiar to many heart patients.

Research

One-third of costly implanted heart devices may be unnecessary

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