August 21, 2012 — Dr. Robert Hauser, a cardiologist from Abbot Northwestern Hospital in Minneapolis, MN, is recommending that surgeons should stop using certain defibrillator leads manufactured by St. Jude Medical until more safety studies are conducted. Dr. Hauser’s research suggests that the Optim coating, which is used on the St. Jude Durata and Riata ST defibrillator leads, is breaking down prematurely and may lead to the failure of the defibrillator.
The products in question are part of an implanted heart defibrillator. The device consists of a battery-powered device that monitors the heartbeat, and the lead, which is a wire connected directly to the heart tissue. The lead is responsible for transmitting data to the monitor, and also carrying a high-voltage electrical shock in the event of an emergency.
St. Jude created the Optim coating after finding defects with the coating on Riata defibrillator leads, which the company stopped selling in 2010 and officially recalled in November 2011. The problem with the Riata coating was that it could develop “inside-out” erosion, ultimately leading to externalization of the inner wire conductors. Some studies have found that 24% of large-diameter Riata defibrillator leads become externalized prematurely. The problem with an externalized conductor is that it could possibly malfunction — either failing to deliver a shock, or unnecessarily shocking the patient. However, determining whether the lead is functional can be very difficult. Surgically removing the lead has a significant risk of injury and death.
In the wake of the Riata failure, St. Jude has aggressively defended the safety of the Optim coating, the Durata, and the Riata ST defibrillator leads. A spokeswoman for St. Jude said that research has shown “the overall performance and high reliability of the Durata lead is comparable to other defibrillator leads.” St. Jude’s studies have shown that the Optim coating is 99.9% successful in protecting the leads from abrasion.
However, Dr. Hauser’s study found dozens of reports of an abrasion problem with the Durata and the Riata ST Optim — specifically, 15 reports for the Riata ST, and 37 reports for the Durata. The abrasion occurred within four years of the implant. St. Jude says they have not found any reports linking the Optim to “externalized conductors,” which was the problem with the Riata.
Reports of abrasion do not necessarily mean that the Optim has a fundamental defect, and Dr. Hauser said that patients who implanted with the leads should not be unduly concerned. However, he said, “I think it’s a red flag. I think we need more data. But fundamentally, I’m afraid that this material is not going to perform as advertised.”
Dr. Hauser also published a study which identified three case reports where the Optim coating on the Durata leads wore away. St. Jude challenged the validity of the report. They tried to get the journal to retract the article, but were unsuccessful. They did successfully convince the journal to change the description of the problem — Dr. Hauser described the erosion as “inside-out” erosion, which was the problem with the Riata. St. Jude convinced the journal to use different wording.
Last week, the U.S. Food and Drug Administration (FDA) published a safety communication recommending that patients with the Riata defibrillator leads should undergo routine chest X-rays to check for externalized conductors. The FDA also asked St. Jude to conduct a three-year post-marketing surveillance study of several types of leads — including the Durata and Riata ST Optim.
The study will hopefully answer lingering questions about the safety of the St. Jude defibrillator leads. Nearly 130,000 people have been implanted with the recalled Riata defibrillator lead. Another 278,000 have already been implanted with the Optim defibrillator leads.