Danish researchers reported this week that their latest studies of St. Jude Medical‘s (NYSE:STJ) recalled Riata defibrillator leads found that 1 in 10 had poked through their coating in an average of just over 5 years.
The study included 298 Danish patients, representing "virtually every living patient in Denmark who received Riata defibrillator leads," according to Heartwire.
Lead externalization, although troubling, does not necessarily result in failure to provide defibrillation therapy to the patient, researchers noted. Data released by St. Jude last year suggested that internal short circuits, which were more rare than the incidence of exposed wires, were potentially more dangerous than externalization.
In December 2011 the FDA slapped St. Jude’s Riata recall with Class I status, spurring much controversy about revision rates and potentially device-related deaths. St. Jude had started pulling the devices off the shelves a year earlier over concerns of "insulation abrasion," which occurs when the leads’ wires poke through their insulation.
The new Danish study found an average 11% externalization rate at 5.1 years, but failure likelihood ranged widely from 6% externalization in 4.5 years for the Riata 7F leads to 21% failure at 6.4 years for the Riata 8F leads, Heartwire reported.
Those figures fall generally in line with those reported last year by St. Jude itself. In July 2012 the St. Paul, Minn.-based medical device maker released findings from a 720-patient study of Riata leads, finding externalization in 9.3% of smaller-diameter Riata leads and 24.0% of older, larger-diameter Riata models.
In August 2012 the FDA ordered St. Jude to conduct a 3-year postmarket review on its recalled Riata and Riata ST defibrillator leads as well as for its QuickFlex LV CRT, QuickSite LV CRT, Riata ST Optim and Durata leads.
That’s bad news for the medical device giant, which has worked hard to distance its leads, especially the Durata, from the high-profile Riata recall. That has been a tough road, especially since the FDA in November released a report detailing potential issues with the Durata leads.
The FDA’s report detailed 11 problems with manufacturing at St. Jude’s Sylmar, Calf., plant, which manufactures the company’s Durata pacemaker leads. St. Jude CEO Daniel Starks had, just a month prior, cautioned that St. Jude risked a warning from the federal watchdog agency over the Sylmar plant.
Since then the company has been under attack by shareholders who claim St. Jude and its executives have made "false and misleading statements" about the Durata heart implant wires.
Wall Street investors are keeping their eyes peeled for any sign of a problem with the Durata leads. In June, a single report (later debunked) of a Durata lead failure similar to the kind that sank the Riata sent STJ shares plunging 6% in a single day.