St. Jude Riata Leads Linked to 22 Deaths, May be More Dangerous than First ThoughtMar 28, 2012 | Parker Waichman LLP
St. Jude's recalled Riata and Riata ST defibrillator leads may be even more dangerous than first thought. According to a new study published in the journal Heart Rhythm, a problem with the Riata leads' silicone insulation may have been responsible for 22 deaths, far more than the number of fatalities linked to the defect that prompted the Riata and Riata ST lead wire recall last December.
The recall had been issued because of reports that the Riata wires were poking through their insulation. According to St. Jude, this could cause the defibrillators to inappropriately shock some patients and fail to deliver necessary therapy to others. At the time of the recall, two deaths and six injuries were linked to externalized conductors.
Now a study conducted by Robert Hauser and colleagues at the Minneapolis Heart Institute has associated a greater number of deaths with the break down of the silicone insulation itself, which can result in dangerous electrical shorts.
“When I went in, I thought I would find more deaths related to externalized cables,” Hauser told The New York Times. “But as it turned out, the externalized cables really didn’t factor in.”
For the study, Hauser and his team analyzed data from the U.S. Food & Drug Administration's (FDA) MAUDE database. The analysis of 105 reports on failed Riata wires found that two-thirds had multiple defects, often up and down their length. In 22 cases, these problems resulted in deaths.
“This is the most difficult and challenging device problem I've seen in 40 years," Hauser told the Pioneer Press. "It's a very unique failure mode. It's never been seen before in a defibrillator or pacemaker lead. And it's very troubling because no one knows what the natural history of this will be."
Hauser also found that the Riata lead defects are not easy to spot, and usually only become apparent when a patient experiences a serious malfunction of their defibrillator. His study also pointed to one of the major issues with managing people with potentially defective Riata leads, finding that 8 patients died during procedures to remove the wires. The FDA has warned against such procedures because they may be even riskier than a malfunctioning lead.
"The problem with this whole defect is there is no easy way to pick it up until an event happens," Hauser told the Pioneer Press.”It's an all-or-nothing situation. We are trying to figure out how to manage these patients, or a way to monitor them safely and effectively."