DENVER — Newer iterations of St. Jude defibrillator leads appear to have shed the problems that led to recall of its Riata line, independent registry analysis confirmed.
Freedom from any mechanical failure was 99.4% at 5 years for the company’s Riata ST Optim and Durata leads, John Cairns, MD, of the University of British Columbia in Vancouver, and colleagues found.
Reliability was even better in terms of insulation abrasion at 99.9% freedom from this kind of failure at 5 years, the group reported here at the Heart Rhythm Society meeting.
Insulation abrasion was the problem that led to class I recall of the Riata and Riata ST leads in 2011. The manufacturer responded by bulking up the insulation and adding a compound to the silicon around the wires for the newer Riata ST Optim and Durata leads.
“But because of Riata there was always a little question in the back of our mind,” commented John Day, MD, of the Intermountain Medical Center in Salt Lake City, who was a moderator at the late-breaking HRS session.
These findings for the newer leads were “very reassuring,” he told MedPage Today. But “I also want to see that it’s still performing extremely well at 10 years,” he added.
The track record for lead families that have been around longer — Medtronic’s Quattro Secure and Boston Scientific’s Endotak Reliance — suggests more than 95% reliability at 8 years (Heart Rhythm 2013; 10: 562-563).
Day also pointed out the relatively low number of Optim and Durata leads available for analysis at 5 years, just 551.
The current analysis included three St. Jude registries covering 11,005 unique leads with mean follow-up ranging from 2.3 to 3.5 years.
Most were still on active follow-up as of early 2013, but 36% had been withdrawn, largely due to death or heart transplantation (15% of total) or administrative reasons (12% of total).
The registries involved 6-month follow-up with a patient visit and device interrogation or home transmission of device data. Any adverse events were reviewed by St. Jude, with examination of returned leads, and then Cairns’ independent group adjudicated the data and made a final designation.
Overall, 38 leads had some kind of mechanical failure for a rate of 0.35%.
The most common cause of failure was conductor fracture, which occurred in 24 leads for a rate of 0.22% in the total cohort.
Eight cases of full-thickness insulation abrasion occurred for a rate of 0.07%, although none left the wires externalized outside the insulation sheath.
Another six miscellaneous mechanical failures occurred that didn’t fit in those classifications, for a rate of 0.05%.
At 5 years, freedom from conductor fracture was 99.6% and freedom from externalized conductors was 100%.
One major limitation was the completeness of data analyzed. Not all inactivated leads are explanted, not all the leads that are taken out are sent back in for analysis, and there was no routine fluoroscopy to detect externalized conductors.
A recent study indicated a high rate of electrical failure of recalled Riata and Riata ST leads without breaches in insulation, but Cairns’ analysis looked only at mechanical failure.
Source: MedPage Today.