CardioExchange Archive

This week the New England Journal of Medicine published an important perspective piece from Robert G. Hauser of the Minneapolis Heart Institute regarding the St. Jude Riata ICD lead recall.

For those involved in cardiac arrhythmia care, Dr. Hauser needs no introduction. He has effectively served a watchdog role for the ICD industry over the last several years.

It was Hauser who first brought to attention the failures of the Guidant Corporation Prizm 2 DR ICD in 2005. That action had far reaching consequences, including a major New York Times article, a large product recall, and Justice Department fines. The Guidant Corporation was later sold to Boston Scientific.

In 2008, Hauser wrote the seminal article on the Medtronic Fidelis Lead. This lead was found to have excess failures in his clinic, a finding now clearly confirmed in many subsequent studies. Hauser has continued to publish follow up studies showing an increasing failure rate over time. The Fidelis lead recall has had an even more far reaching effect on the medical device industry as well as device doctors and patients.

Now the third large U.S. cardiac rhythm company, St. Jude Medical, has fallen under Hauser’s scrutiny.

In today’s New England Journal of Medicine, Hauser writes a perspective on the Riata and Riata ST ICD Leads. This lead has exhibited a unique form of failure. The leads have been shown to have exteriorization of the inner conductors through the outer silicone jacket of the lead. This was first recognized fluoroscopically in 2008 and has now been shown in multiple centers to occur in up to 15% of these leads. The functional significance of this exteriorization remains uncertain.

Hauser chaired a summit in Minneapolis last month in which a number of centers reported their experience with this lead (here’s my summary of the meeting). At the conference, he concluded with remarks regarding his frustration with the lack of postmarket testing available to guide those managing these leads.

Today’s NEJM perspective amplifies what was said at the Summit. Leading with the frustrated headline “Here We Go Again – Another Failure of Postmarketing Device Surveillance” he goes on to castigate the inadequacy of our current systems to detect and respond to device failure. Doctors today are asking for guidance on how to manage these leads:

Why are we guessing? Why are we placing patients at risk when the tools and technology are available to monitor vital medical devices such as ICDs, heart valves, and coronary stents? The problem is that our current passive postmarketing surveillance system fails to detect significant device defects before large patient populations have been exposed. Consequently, we repeatedly find ourselves reacting ineffectively, even dangerously, to big problems with devices by subjecting patients to care strategies that are not supported by solid clinical evidence.

He goes on to point out that human prospective trials designed to answer critical questions about the long term integrity of the Riata lead have only recently been initiated:

Should the lead be replaced if the conductors are exposed but electrically intact? Is the ETFE coating on the externalized conductors sufficiently robust to perform reliably – that is, to deliver an effective high-energy shock when needed? Is monitoring with or without routine fluoroscopy a safe alternative to prophylactic replacement? What electrical parameters are important to adhere to?

He concludes with a call to industry and FDA to implement active real-time monitoring of devices: “Indeed all manufacturers should conduct postmarketing studies of this type for marketed class III devices that sustain or support life.”

Hauser’s written perspective may be most notable for what he does not call for. Nowhere in the article is there a call to industry or FDA to revamp the premarket approval process. It is worth noting that all high impact device failures in the cardiac rhythm device industry have occurred well after device approval. In most cases, failures have been rare events occurring many years after these devices became clinically available. The industry is littered with high profile device failures, some of which serve now as footnotes or memories from the more gray haired members of the EP community: Medtronic polyurethane pacing leads, Ventitex Cadence ICDs, and Telectronics Accufix pacing leads were all devices that failed well after they had been introduced to the market. It was through case reports from concerned doctors — not the FDA — that these problems were brought to light.

Trying to absolutely prevent the failure of medical devices through the FDA approval process would be challenging to say the least. This would require an anticipation of the potential failure mechanism before the fact to design a study that would detect said defect. Moreover, the number of patients and length of study for these trials would be daunting, impractical, and quite likely prohibitively expensive.

Hauser’s call to enforce a robust, active postmarket surveillance system would allow ongoing innovation and appropriately timed approval of new technology. With the ability to carefully monitor a large population of approved devices “in the field,” sentinel failures could be detected and acted upon as they occur. With public reporting of these events, doctors could draw their own conclusion of whether to keep implanting these devices and prospective studies could then be designed promptly to determine the scope of the problem. That would be a system that protects patients while still allowing innovation.