Aug 21 (Reuters) - Changes that St. Jude Medical Inc made to its heart defibrillator leads do not protect against insulation defects that could potentially lead to device failure and death, according to a report published online on Tuesday in medical journal Europace.
The report, by prominent cardiologist Robert Hauser of the Minneapolis Heart Institute, found that St. Jude's Riata ST Optim and its newer Durata ICD leads had sometimes failed due to insulation problems.
Leads transmit electricity to the heart from the implantable defibrillator, which is designed to deliver a life-saving shock if it detects a dangerous cardiac rhythm.
Hauser's report concluded that his findings were "new and unexpected." Additional studies are needed to determine the incidence of these failures and their clinical implications, the report said.
The newer leads are coated with a material that St. Jude hopes will reduce the risk of insulation abrasions. According to Hauser, that does not appear to be the case.
"The results of this study suggest that Optim, a proprietary copolymer of silicone and polyurethane, does not prevent critical insulation failures in Riata ST Optim and Durata leads that are caused by friction with the can or another device," he said.
Of equal concern, he said, is the fact that these failures occurred in leads that had only been implanted for four years or less.
St. Jude said in a statement: "We have only just accessed the online manuscript and are reviewing the information. We welcome ongoing discussion and research about the performance of our products, and believe it is important to consider all of the available information to understand the clinical performance of a device. To date, the accumulation of data continues to support the overall safety and reliability of our Durata leads."
Last year St. Jude recalled its older-model Riata defibrillator lead amid reports that the silicone coating around the wires eroded at a higher-than-expected rate.
An article by Hauser published in medical journal HeartRhythm linked the leads to 20 patient deaths.