St. Jude Medical Inc.’s (NYSE:STJ) Riata family of leads have come under fire again for "insulation breaches" at rates much higher than first reported by the company in a 2010 warning letter.
In a small Irish study of 212 patients with Riata defibrillator leads, 15 percent had confirmed cases of lead wires poking through the silicone rubber insulating cables and making contact with tissue at an average of about 4 years after implantation.
St. Jude, which issued a product warning in December 2010, noted a .47 percent rate of breach at 9 years of use and chose not to issue a recall.
"The frequency of lead malfunction in Northern Ireland appeared to exceed the manufacturer quoted values," Irish researchers said in an abstract issued during the European Society of Cardiology Congress last month. "A significant proportion (15%) of patients with Riata and Riata-ST leads had an insulation breach on screening. Clinically significant events was noted in 20% of patients."
The issue can cause an interruption in the cables’ ability to sense rhythm problems in the heart, which could prevent needed shock therapy or even cause unwanted shocks to a patient’s heart. Normal screenings and X-rays can miss the breach, or abrasion, and a patient may not have any physical clues that the device may be impacted, the Minneapolis Star Tribune reported.
In last year’s warning, a St. Jude spokesperson said the FDA did not view the problem as recall-worthy, and the company advised doctors against removing the leads, which are snaked through a patient’s heart blood vessels.
"Abrasion of silicone defibrillation leads is acknowledged within the clinical community as a well known clinical risk and is well documented in the literature as the number one cause of lead failure across
the industry with reported failure rates ranging from 3 to 10 percent," St. Jude said at the time.
According to the company’s spring product performance report, nearly 77,000 Riata leads remain in U.S. patients alone.
St. Jude did not immediately return requests for comment.