Publicity surrounding recent ICD defects will spur the the Heart Rhythm Society to develop guidelines on manufacturers' advisories to physicians, FDA's Circulatory System Devices Panel chair says.

"The Heart Rhythm Society should...come up with guidelines - I think both for industry and for physicians - on how to handle these [malfunction reporting] issues," William Maisel, MD, Brigham & Women's Hospital, asserted in a May 25 interview with The Gray Sheet. "These are not stand-alone, one in a million issues. These things come up several times per year, every year."

Maisel has written extensively on regulatory and adverse-event reporting issues related to implantable cardioverter defibrillators and pacemakers. Last year, he published results from a survey of the Heart Rhythm Society (formerly NASPE). The survey polled members' responses to ICD/pacer advisories from firms.

"It is clear that physician management of [advisories] varies greatly and would be facilitated by evidence-based recommendations," Maisel concluded in his write-up of the survey results, printed in the April 2004 issue of the journal PACE.

In hindsight, Maisel's findings were prescient. Guidant released a May 23 "Dear Doctor" letter reporting 26 incidents of "random component failure" in Prizm 2 DR ICDs made prior to a 2002 design modification - roughly 37,000 devices - causing a partial diversion of current in the high-voltage output circuitry.

"In the latest reported event in March of this year, a device from this population was returned after a patient death and was found to have experienced this failure in conjunction with attempted delivery of at least one high-voltage therapy," Guidant explains in the letter, emphasizing that "all events have been reported to the appropriate regulatory bodies."

No adverse events related to the Prizm 2 DR have been reported in the "post-mitigation" population - patients who have devices with the 2002 modification. Furthermore, "the survival of the two populations is not statistically different because the rate of this failure in the pre-mitigation population is stable and very low at 0.002% per service month."

Because the patient's risk of malfunction would not be reduced by replacing the device - and because the replacement procedure carries a roughly 1% risk of complication - the firm chose not to send an advisory to physicians about the death when it occurred. In the May 23 letter, the company advises against replacing the device or altering a recommended quarterly monitoring of ICD patients.

The letter comes three months after Medtronic notified customers of a battery-failure problem that could cause a serious malfunction in up to 1.5% of its Marquis VR/DR ICDs, Maximo VR/DR ICDs, InSync I/II/III Marquis CRT-Ds and InSync III Protect CRT-Ds manufactured between April 2001 and December 2003.

The flaw, which presents roughly 15 times as much risk to patients as the Guidant malfunction, has not caused any major adverse events, Medtronic says (¹ Also see "Medtronic Foresees Gradual ICD Uptake, Reviews Battery Problem" - Medtech Insight, 21 February, 2005., p. 24).

Guidant's "Dear Doctor" letter appeared one day before a May 24 New York Times article on the ICD-related death. The article claims that the company waited until the Times was set to run the story before telling doctors and patients about the death and the 25 other adverse event reports. The Times piece also mentions Medtronic's February advisory.

Maisel told The Gray Sheet that the publicity surrounding the two adverse-event advisories "have the potential to be a catalyst in having HRS...take a leadership position on this issue" of what level of risk merits a letter and in what circumstances physicians should be advised to replace an ICD or pacer.

"Thought leaders" within the Society have already begun informal conversations about developing such standards, according to HRS.

Maisel remarked: "There is no industry standard. I have spoken to each company in the past - the regulatory specialists - about what criteria they use to decide when to notify patients. They certainly don't publicly say that they have a threshold, other than that they certainly report all problems that they think should be intervened upon."

Companies typically issue a "Dear Doctor" letter "if there is a software fix for some computer programming abnormality or if they believe that patients need to be followed more carefully or monitored more carefully in someway or if they should have their device replaced," Maisel explained.

However, "I think the gray area in general - and certainly with this Guidant issue - is that in Guidant's opinion, nothing needed to be done," he said. "But some physicians...don't necessarily agree with that, so that's why we have it on the front page" of the news.

The creation of such guidelines would not only ensure that physicians and manufacturers agree on when an advisory should be issued - it also would help educate doctors on limitations to ICD performance.

"There's an unrealistic expectation or misconception of device reliability," Maisel asserted. In his survey, about 30% of physicians said they would explant a device that had a one-in-10,000 chance of failing. However, a 1/10,000 failure rate "exceeds the reliability of all known devices," according to Guidant.

Physician education should accompany research efforts, according to Maisel. "I also think it should be part of our mission - our being physicians, HRS and industry to improve the reliability of the device. If we're saying one out of 200 or one out of 1,500 - or whatever the number - fail, then that's not good enough, particularly when the devices are going to be going into hundreds of thousands of patients. It's time for device reliability to be an important issue."

Maisel said manufacturers should generally err on the side of caution when deciding which problems to communicate with physicians. Guidant's decision not to proactively communicate the issues with the Prizm 2 DR ICD "was a mistake, although not necessarily on a clinical basis....I think it was a mistake on a trust basis and I think physicians want to know," he opined.

"As a physician taking care of patients, I would like to be the decision-maker with my patient. I don't want some company making a decision for me when they've never met the patient," he added.

Guidant disagrees with the Times article's implication that the company kept reports from doctors. The firm's regular adverse event reports to FDA "are available to every physician. Any notion that we limit access to this data is false," the firm says in a release.

"Guidant met with the physicians involved, and in addition to sharing all of the data regarding the occurrences and mitigation of this rare and unpredictable [malfunction], asked to work with them in the expedited publication of this event in an academic journal, to reach physicians with the accurate data and appropriate context," the firm states.

ICD/Pacer Advisory Standards Should Be Developed – FDA Panel Chair

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