An independent review of long-term data from a trio of registry studies funded by St. Jude Medical (NYSE:STJ) for defibrillator leads coated with its Optim insulation showed that the devices are largely free of problems that led to a recall for their Riata predecessors.
The study looked at data from registries St. Jude set up between 2006 and 2009 to follow some 10,800 patients implanted with the St. Paul., Minn.-based company’s Durata DF4, Durata DF1 and Riata ST Optim leads.
Researchers at McMaster University’s Population Health Institute examined the data for rates of all-cause mechanical failure and broke them down into subtypes including conductor fracture, insulation abrasion, externalized conductors and other failures. Of the more than 11,000 leads implanted, there were 51 mechanical failures (0.5%) after a median of 3.2 years and a 99.0% survival rate at 5 years, according to the study, published in the December issue of the journal Heart Rhythm.
"Freedom from conductor fracture
was identified in 99.4% and from all-cause abrasion in 99.8% of the
leads, and there were no reports of externalized conductors. There
were no significant differences in survival among Durata DF4,
Durata DF1 and Riata ST Optim leads," the researchers wrote.
“Previous studies showed positive results for Optim leads, but only followed patients for about 2 years and evaluated a significantly smaller number of patients with leads. Our ongoing analyses now include some patients followed for up to 7 years and support existing data that better performance with Optim leads is a reality,” lead author Dr. John Cairns of the University of British Columbia said in prepared remarks. “The data from this study is of great importance to help electrophysiologists make more informed decisions as they relate to the performance of these leads and the management of patients who depend on them.”
A St. Jude Medical representative did not respond to a request for comment.
St. Jude pulled its Riata and Riata ST leads off the shelves in 2010 after finding that some internal conductors had worn through an older version of insulation, a failure that could result in patients receiving unwanted shocks. In November 2011 the company warned
that the Riata leads appeared to fail more frequently than previously reported, leading to Class I recall status with the FDA.
St. Jude hired McMaster’s PHRI and Hamilton Health Sciences in fall 2011 to run independent analyses of the 3 prospective Optim registries it set up, according to the journal. Cairns and his co-authors reported receiving compensation from the company for "time spent on independent reviews and analyses" of the registries, according to Heart Rhythm.
Two other studies published in the journal’s December issue looked at the older Riata models. One, a Danish study that polled nearly 300 Riata patients, found that "Riata patients reported poorer device acceptance (d = −0.28; P = .001) and increased device-related concerns (d = 0.29; P < .001)."
"The Riata advisory is associated with a persistent small reduction in device acceptance and a small increase in device-related concerns with minimal improvement over time. Female sex is a predictor of a high negative advisory impact on general well-being. A need for counseling may arise in vulnerable subsets of patients," the researchers wrote.
The 2nd study, of 295 Riata patients with dwell times of 5.1 years and a baseline of 34 externalized conductors and 19 electrical abnormalities, found that after 1.1 years, 8 leads in the 239 patients who began the trial with no externalizations showed "incident overt EC," with "borderline" EC in 2 leads.
"Fluoroscopic follow-up in 27 patients with baseline EC showed an increase in EC length of 4 ± 1 mm (P<.001) after 1.1 ± 0.3 years. Electrical follow-up in 276 patients with normal baseline electrical function demonstrated 20 incident electrical abnormalities after 1.0 ± 0.3 years, with an incidence rate of 7.1 per 100 person-years (95% confidence interval 4.6–11.0). This rate was significantly higher in leads with baseline EC, with an adjusted incidence rate ratio of 4.4 (95% confidence interval 1.7–11.5, P = .002). In 15 extractions, all leads were removed, with 2 major complications," according to the study. "The development of EC is a dynamic process despite long lead dwell time. ECs are associated with a higher risk of electrical abnormalities. Therefore, lead replacement should be considered, especially in patients with a long life expectancy."
