Emily Moore, BA and Langan Denhard
Defibrillators are medical devices that treat irregular heartbeats and can prevent sudden cardiac arrest. The 79,000 Americans who were implanted with the Riata or Riata ST Silicone implantable cardioverter-defibrillator (ICD) leads made by St. Jude Medical are left wondering what to do now that the FDA recalled the device in December 2011. This recall was announced a year after the company stopped their sales of the product.
An implantable cardioverter-defibrillator (ICD) is a small electrical device implanted in the chest or abdomen to help treat irregular heartbeats, some of which can cause sudden cardiac arrest. When a person with an ICD experiences an irregular heartbeat, the device will provide an electrical current to “reset” the heart back to a normal rhythm.
St. Jude Medical now reports that the insulation tubing around the conducting wires may wear down when implanted into the body and the wires may poke out of the tubing. With the exposed wires poking through, they may not be able to carry the necessary electrical charge to reset the heart, or alternatively might shock the heart unnecessarily. As a result of this dangerous device failure, the FDA initiated a Class 1 (high risk) recall, which means that the implant can cause death or serious injury.
It is unknown if all the Riata or Riata ST implants have this defect, or what impact the defect will have on the safety or effectiveness of the ICD. The manufacturer claims that less than 1% of the devices have exposed conducting wires and that 85% of the devices with the exposed conducting wires do not seem to cause electrical problems.
However, a report released in late March by Dr. Robert G. Hauser revealed other, less obvious failures of the device. The study indicated that of the 22 patient deaths related to device failure, none were linked to problems with exposed wires. Rather, the majority were a result of short circuits that made the device unable to deliver a shock to restore heartbeat when needed. This defect can often go unnoticed during standard monitoring. The report also notes that 8 patients died while having surgery to remove the device.
To avoid problems, it might seem logical to remove the device and replace it, but the removal of these failed devices was linked to two patient deaths and one serious injury as of December 2011.
St. Jude Medical recommends careful monitoring of ICDs with fully intact tubing, as well as those with wires poking through that do not have any observable electrical problems. In these cases, St Jude does not recommend replacement of the device if there is no evidence of electrical problems for that device. For ICDs with wires exposed that are exhibiting electrical problems, the company leaves it to the doctor and patient to weigh the risks and make an informed decision.
Unfortunately, the manufacturer’s recommendations are not based on meaningful data. Many problems with the devices were not reported and it is unclear how the devices with exposed wires will work when a lifesaving electrical shock is needed. To collect the data needed so that patients and their doctors can make informed decisions, St. Jude Medical began enrolling patients with exposed wires in December 2011 for a study of 500 patients that will evaluate how those devices will function.
In an article published in the New England Journal of Medicine in February 2012, author Dr. Robert G. Hauser says history may be repeating itself. Specifically, he points to the 2007 recall of Medtronic’s Sprint Fidelis Cardiac Leads, a similar life-saving device that was prone to fracture so that it sometimes shocked the patient unnecessarily, and at other times did not deliver a shock when it was necessary. Although 268,000 patients had those faulty devices implanted 5 years ago, the lesson has not been learned.
Another concern is that St. Jude Medical currently sells the Durata ICD lead, which has a similar design to the recalled Riata device. The only difference between these two devices is the polyurethane used in the outer sleeve with silicone, rather than the silicone-only coating of the Riata device. The manufacturer claims that this would reduce the risk of the coating wearing down, yet there is no clear proof that is true.
St. Jude Medical launched the largest post-surveillance program in the history of implantation stimulation devices for Durata 5 years ago. Thus far, the company claims that their system of active registries of follow-up appointments at the 292 participating sites shows Durata to be highly effective and 99.9% free from exposed wires and worn down tubing. However, since the Durata lead has only been on the market for five years, it is likely that most of the patients have had the device for just 2-3 years, and it is possible that problems will arise in the future.
The Riata ICD was originally cleared by the FDA through a supplement to a Premarket Approval or PMA, which is used when the new device is a similar type or design to an existing device that was thoroughly tested and approved to be sold. However, with supplements it is unclear how much pre-market testing is performed and such testing might be limited to bench testing.
While we continue to push for stricter medical device pre-market testing and post-market surveillance, the lives of tens of thousands of Americans are dependent on a device that is no longer safe enough to be sold.
1Hauser, Robert G. “Here We Go Again – Another Failure of Postmarketing Device Surveillance.” New England Journal of Medicine 366.7 (2012): 1-3. Web. 16 Feb. 2012.
2Hauser, Robert G. “Deaths Caused by the Failure of Riata and Riata ST Implantable Cardioverter-Defibrillator Leads.” Heart Rhythm Journal (2012). Web. 12 Apr. 2012.
3St. Jude Medical Inc. FDA Classifies Voluntary Physician Advisory Letter on Riata and Riata ST Silicone Defibrillation Leads as Class I Recall. News Release. 15 Dec. 2011. Web. 16 Feb. 2012.
4Cortez, Michelle Fay. “St. Jude Device Exposes Safety Monitoring Failures, Doctor Says.”Businessweek – Business News, Stock Market & Financial Advice. Bloomberg, 16 Feb. 2012. Web. 16 Feb. 2012.