Take the lead

A recent analysis of Optim-insulated leads for implantable cardioverter-defibrillators (ICDs) reported reassuring results. The study also highlights shortcomings—not with devices, but with people.

Manufacturer St. Jude Medical approached the Population Health Research Institute at McMaster University in Hamilton, Ontario, to conduct an independent review of the more than 11,000 Optim-coated leads implanted since 2006. St. Jude set up three registries in the wake of a recall of Riata and Riata ST silicone defibrillation leads.

The current analysis addressed the Optim-coated Durata and Riata ST Optim leads. The overarching question was whether the new insulation protected against abrasion and conductor externalization. The results: At a median 3.2 years of follow-up, they reported all-cause mechanical failure in 0.46 percent of leads and no cases of externalized conductors.

Lead researcher John A. Cairns, MD, of the University of British Columbia in Vancouver, called the results “very good.” He said in an interview with Cardiovascular Business, “The actuarial survivals of these leads free of mechanical failure at five years is extremely good.”

The findings appeared in the Dec. 1 issue of Heart Rhythm, which also published two related editorials. In a commentary, Christopher R. Ellis, MD, of Vanderbilt Heart and Vascular Institute in Nashville, Tenn., pointed out that only 39 percent of the explanted leads were sent back to St. Jude for a product analysis.

“The persistent problem with ICD lead failure assessment is the failure of consistent product analysis,” he wrote. “It is unfortunate that even in a prospective study, the majority of failed leads could not be assessed for root cause analysis.”

The authors of the second editorial noted that the registries offer an improvement over the FDA’s Manufacturer and User Device Experience (MAUDE) database, which relies on voluntary submission of adverse event reports. MAUDE has been criticized for being a passive vehicle for flagging concerning trends after a device is approved for use in the U.S.

The 39 percent rate in this study far outpaces the historical return rate of 1 percent, wrote Charles Love, MD, of New York University Langone Medical Center in New York City, and Mark Estes II, MD, of Tufts University School of Medicine in Boston. “It is evident that this provides a more accurate assessment of failure rates and the mechanisms of lead failure,” they continued. “In this respect, the approach taken in the Optim registries addresses a major problem with our current postmarketing surveillance system, which often fails to detect lead malfunctions before large populations have been exposed.”

That might be the difference between horrible and bad, though. Building evidence off a 1 percent sample is slow and spotty. The 39 percent return rate certainly is better, but imagine what could be learned if all leads had been available for analysis.

Love and Estes encouraged physicians to report lead failures and to send all removed leads back to manufacturers, whether they had malfunctioned or not.

Everyone wants implanted devices to perform well and be reliable. Here is one way to help make that happen.  

Candace Stuart

Editor, Cardiovascular Business