St. Jude Medical Inc. is seeking a third-party stamp of approval on the safety of its Durata defibrillator leadsin an effort to get out ahead of growing questions in the clinical community based on safety issues with earlier-generation Riata leads.

The company will hand over raw data from three ongoing St. Jude-sponsored registries for the currently marketed Durata lead to the Population Health Research Institute, associated with McMaster University in Hamilton, Ontario, under an agreement announced March 25.

Under the arrangement, St. Jude says, the institute will have complete independence in designing and performing analysis of the Durata data, including data already entered into the registries and new data collected at least for the next two years.

The registries are OPTIMUM, SCORE and DF4, which, St. Jude says, in combination contain information from 10,000 leads implanted at 292 sites, including 24,000 patient-years of data. The registries reflect data from the more than five years that the lead, coated with the company’s proprietary Optim insulation material, has been on the market.

St. Jude's Durata ICD lead.

Photo: St. Jude Medical

The Population Health Research Institute will convene a committee of independent physicians, including a committee chair with no affiliations with the cardiac rhythm management industry, to conduct analyses on an ongoing basis. The committee will work in private, other than an initial meeting with the company to initiate the project, St. Jude says.

The company plans to post all results from the analysis on its website, while the committee members can also independently publish their findings.

Escaping Tarnish?

The announcement comes as the electrophysiology community continues to grapple with fallout from the heightened failure-rate risks associated with St. Jude’s recalled Riata and Riata ST silicone-insulated leads. The company took the leads off the market in 2010. Since then, FDA has formally categorized the action as a class I recall, and St. Jude has affirmed the elevated failure rates associated with abrasion of the silicone material, which can lead to a breach in the insulation layer protecting the conducting wires.

Some electrophysiologists say more data is needed to further inform an appropriate follow-up and care plan for the almost 80,000 patients with active silicone-insulated Riata leads. And some of the same clinicians have raised questions about whether caution is warranted in implanting Durata leads based on the Riata experience.

St. Jude argues that the proprietary Optim insulation does not have the same abrasion issues as the older silicone material. In an analysis issued by the company last November, there were no relevant lead failures reported with the Optim-coated Durata leads, compared to a 0.63% incidence rate with the older silicone-insulated leads.

But the contract for an independent analysis announced last week suggests the company has concluded that more convincing will be necessary.

“On one hand, we think this shows that [St. Jude] management has a high degree of confidence in the Optim-coated leads, but on the other hand, the fact that [St. Jude] needs to take this step may indicate that the Riata problems have tarnished its current leads,” said Mizuho Securities device analyst Michael Matson in a March 26 note.

More Riata Data

Meanwhile, negative data on the older Riata leads continued to filter out last week, including two studies from Minneapolis Heart Institute electrophysiologist Robert Hauser, who has been critical of the Riata leads and the length of time it took St. Jude and FDA to identify problems with the devices.

At the annual American College of Cardiology meeting in Chicago March 25, Hauser presented a study of 105 patients with failed Riata leads, where two-thirds of the leads had multiple defects.

And a separate analysis at ACC presented by researchers from Northern Ireland found that the externalized conductor issue arises in about 2.6% of patients with Riata leads annually, and, cumulatively, 19% of patients have devices with the complication.

On March 26, the journal HeartRhythm posted another analysis from Hauser and colleagues, in which the researchers point to elevated risks tied to problems distinct from the externalized conductor problems that had led to the recall.

Based on an analysis of FDA’s device adverse events database, Hauser and his team identified 22 deaths in Riata patients caused by short-circuits between high-voltage components of the leads, none of which could be attributed to the externalized conductor issue, they said. The findings suggest more attention should be paid to the short-circuit failure, which, though rare, may be a bigger risk to Riata patients compared to externalized conductors, the researchers conclude.

In a response to the HeartRhythm study posted on its website, St. Jude pointed out that two of the 22 deaths identified in the paper were actually duplicate reports, and that seven of the deaths were the result of “lead-to-can abrasion,” which, the firm’s Chief Medical Officer Mark Carlson said, “is the most common cause of abrasion for all leads.”

Further, St. Jude noted that nine of the leads associated with the adverse event reports were not returned to the company, so “we cannot assign a specific failure mechanism to these reports.”

The company reiterated that it is conducting a 500-patient study of patients with the Riata leads to improve its understanding of electrical failures associated with the product. (See Also see "News In Brief" - Medtech Insight, 2 January, 2012..)

Hauser, who has publicly advised caution with the use of the currently marketed Durata leads until more data is available, said he is happy to see St. Jude’s plan for an independent analysis of the Durata data, although it is hard to say at this point whether the effort will provide a definitive answer.

“My first reaction is positive,” he said in an interview. “I think it is a good idea.”

Separately, Hauser is employing a newly developed active surveillance software tool to monitor failure rates associated with Durata. (See Also see "ICD Lead Recall Could Have Come Sooner With Novel Surveillance Tool – Study" - Medtech Insight, 12 March, 2012..)

St. Jude Tries To Get Ahead Of Questions On Durata ICD Leads

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