Study of St. Jude Durata Heart Wire Finds No New Concerns

The insulation coating on St. Jude Medical Inc.’s Durata lead, used to connect a life-saving defibrillator to the heart, can fray when it rubs against another object, according to a study that didn’t raise substantial new concerns about the device.

The study, highly anticipated by investors on Wall Street, was less damaging than expected, Joanne Wuensch, an analyst with BMO Capital Markets, said today in a note to investors. The report from Robert Hauser, a device safety expert and cardiologist at the Minneapolis Heart Institute, didn’t find any evidence of the “taboo” flaws that lead St. Paul, Minnesota-based St. Jude to pull its older Riata wires off the market in 2010, Wuensch said.

The older Riata models were recalled after research showed the electrical wires could break through the insulation coating, potentially leading the device to give off excessive shocks or to fail to work when needed. Newer Durata and Riata ST Optim leads are coated with a stronger insulation known as Optim that was designed to prevent protrusions, called externalized leads.

“While Hauser did not find the taboo externalized lead issue with the company’s Durata lead, it found other problems, including one death, and he concluded that the new coating does not prevent insulation abrasion to the level that the company has suggested,” Wuensch said. “In our view, ICD lead worries are going to dog St. Jude Medical until time passes sufficiently and new products start to command more center stage.”

Known Cause

Abrasion caused by the wires rubbing against each other or the device’s canister is a known cause of failure with all leads, said David Roman, an analyst at Goldman Sachs Group Inc. in New York. The study doesn’t show that the newer St. Jude products are worse than the competition in terms of failures for any reason, and Durata’s performance may be better than some competitor’s products, he said.

“Heading into today, we had viewed publication of Dr. Hauser’s report as an overhang for the shares,” Roman said today in a note to investors. “However, given the largely immaterial nature of the data in the report, we view publication as a clearing event, leading to potential positive momentum in the stock.”

St. Jude declined less than 1 percent to $37.96 at the close in New York. The shares have dropped 7.7 percent in the past 12 months.

Study Details

The article in Europace, a European cardiology journal, examined 52 reports of abrasion seen with St. Jude’s Durata and Riata ST, which are coated with the Optim insulation. The reports were submitted to the U.S. Food and Drug Administration by St. Jude from December 2007 to January 2012.

Since December 2007, doctors have implanted more than 33,000 Riata ST Optim leads and 276,000 Durata leads, according to Amy Jo Meyer, a St. Jude spokeswoman. The device maker has the largest registries in place of any company to monitor the safety of its leads, she said. St. Jude has done its own analysis of the FDA reports, most of which came from the company, and determined that abrasions with its products, their reliability and performance are similar to its rivals, she said.

“We welcome ongoing discussion and research about the performance of our products, and believe it is important to consider all of the available information to understand the clinical performance of a device,” Meyer said in a statement. “To date, the accumulation of data continues to support the overall safety and reliability of our Durata leads.”

Fraying Incidents

Eight of 15 Riata ST leads frayed in a spot where the wire rubbed against the stop-watch-sized metal canister that houses the electrical components of the device. Three abrasions stemmed from friction caused by the wire rubbing against another device, possibly a different wire. The devices failed to work for four patients and one died, the study found.

In a different patient, an internal insulation defect was found, the researchers said.

Twelve of the 37 reports on Durata detailed damage caused when the wires, also known as leads, rubbed against the canisters, while six were caused by friction from another device, the study found. Electrical abnormalities were found in 72 percent of those devices, the researchers said. Other testing found three cases of internal insulation flaws, the study said.

Riata ST Optim and Durata leads “have failed due to insulation abrasions,” and the novel insulation coating didn’t prevent the abrasions from occurring four years or less after the devices were implanted, the researchers concluded. “Studies are needed to determine the incidence of these failures and their clinical implications.”

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