August 17, 2012 — The U.S. Food and Drug Administration (FDA) has published a Safety Communication regarding St. Jude Riata defibrillator leads. The FDA is recommending that people implanted with this device should have an X-ray or other imaging test to help guide treatment. The FDA is also requiring St. Jude to conduct safety studies on its QuickFlex, QuickSite, Riata ST Optim, and Durata ICD leads.
The FDA is requiring St. Jude Medical to perform a three-year post-market surveillance study to better understand premature insulation failure in the leads. The study must address how many patients have insulation failure, whether the failure was detectable with an X-ray, how quickly the insulation fails, how quickly the leads malfunction, and the types of adverse events that occur when a doctor treats a failing or malfunctioning lead.
The Riata and Riata ST defibrillator leads were recalled in November 2011. The QuickFlex and QuickSite were recalled in April 2012. St. Jude claims that the Durata lead does not have the same defect as the Riata.
All four defibrillator leads were recalled because the insulation around the electrical conductor wires could erode or abrade prematurely, allowing the externalization of the electrical wires. When the wires are externalized, there is a risk that they could malfunction, deliver an unnecessary shock, or fail to deliver a shock in an emergency.
The FDA is aware of an increase in lead failures beginning approximately four years after the device is implanted. Defibrillator leads are supposed to last at least ten years.
Externalization doesn’t always cause the lead to be defective, because the wires themselves are insulated. However, it is difficult to determine whether the lead is functional until the patient suffers an adverse event. Imaging tests and voltage tests can help a physician determine whether the device is function.
The FDA is recommending that everyone with a Riata or Riata ST should have a chest X-ray or fluoroscopy test. New images can help detect previously unrecognized insulation problems. If visual abnormalities are identified, the FDA recommends repeat imaging tests to assess the progression of the problem.
The FDA is not recommending routine removal of the leads, because lead extraction surgery has a significant risk of injury or death, especially if the lead has been implanted for a long period of time. According to the FDA, only leads with abnormal imaging and abnormal electrical function should be considered for removal.
The new recommendations come one month after Riata Lead Evaluation Study, conducted by St. Jude, announced in phase-one results that externalization occurred in 24% of large-diameter Riata leads, and 9.3% of small-diameter Riata leads. The company estimates that nearly 80,000 people have these leads in the U.S., and nearly 130,000 have the leads worldwide. It is possible that there are thousands of people who have the externalized leads and are at risk of serious injury.