Medtronic Stops Sales of Leads in Defibrillators

posted on:
October 19, 2007

author:
Staff

Medtronic Inc. is halting sales of a popular component used with the company's implantable heart defibrillators because of a fracture risk that may have contributed to five patient deaths, the Fridley-based manufacturer said late Sunday.

Called Sprint Fidelis, the product in question is a lead wire used to connect implantable defibrillators – pager-size devices that generate electrical shocks – to the hearts of patients at risk of sudden cardiac arrest. Defibrillators work by shocking the heart to restore its normal rhythm, and the Sprint Fidelis leads have been used in 268,000 patient cases since 2004.

Doctors have been scrutinizing the product's performance for six months, and Minneapolis researchers published a study in July that raised significant concerns. The fracture problem can cause the defibrillator to deliver unnecessary shocks or not operate at all.

Company officials said they could not discuss specifically how problems with the leads might have contributed to patient deaths, because they lack full information about the cases.

But the decision to stop selling the leads followed a review of performance data showing that 30 months after it was implanted, the Sprint Fidelis products were viable in 97.7 percent of cases – lower than the 99.1 percent viability rate at 30 months for another commonly used Medtronic lead.

The U.S. Food and Drug Administration said late Sunday that it considered Medtronic's action to be a product recall but did not mean to suggest that patients should have their leads surgically removed. Medtronic officials and independent physicians said the risk of removing the Sprint Fidelis leads outweighs the fracture risk.

"We recognize that some patients and health care professionals might inappropriately interpret the word 'recall' to mean that the devices must be surgically removed," said Dr. Daniel Schultz, director of the FDA's Center for Devices and Radiologic Health. "The vast proportion of patients continue to have properly functioning leads."

Implantable defibrillators are the top product line at Medtronic, and the devices already have weathered a series of controversial recalls since 2004 because of problems with batteries in the devices. The market for the $30,000 devices is dominated by companies with strong ties to the Twin Cities, including Little Canada-based St. Jude Medical and Natick, Mass.-based Boston Scientific, which makes implantable defibrillators in Arden Hills.

Boston Scientific last year acquired the Arden Hills business from Guidant Corp., which was criticized by physicians for not promptly disclosing problems with its implantable defibrillators. Medtronic prominently showcased Sunday how it had obtained input from doctors on the faulty leads.

An independent physician panel, for example, yesterday seconded the company's recommendation that patients not seek the removal of their Sprint Fidelis leads. About 235,000 patients currently use the product.

"Our independent panel has been aware of the (issue) and has been watching things carefully over the last six months," said Dr. Kevin Hackett of Columbus Cardiology Consultants, a member of a physician group that advised the company on Sunday's decision. "We felt that this decision was appropriate at this point in time, even though it is a conservative one."

In a letter being sent today to 13,000 physicians, Medtronic said it has pinpointed two spots on the Sprint Fidelis lead that seem prone to fractures – one spot is near the heart itself, while the other is near where the device is implanted.

The difference in the viability rates between the Sprint Fidelis lead and a comparison lead from Medtronic is not yet statistically significant, noted Dr. David Steinhaus, the medical director of Medtronic's cardiac rhythm disease management division. But company officials said they feared it could become so in the future.

"We're aware of five patient deaths where the lead may have been a possible or contributing factor," Steinhaus said "We have identified two places in this lead that we consider to be nonrandom fracture places."

Medtronic has provided patient management recommendations to physicians that should reduce the risk to patients, officials say. The problem does not affect pacemaker patients.

"Whenever anybody has a device implanted, we all have to recognize that the devices are engineered by human beings, and there are times when a component could fail," said Dr. Bruce Lindsay, an electrophysiologist at Washington University in St. Louis and president of the Heart Rhythm Society, the leading group for physicians who implant defibrillators. "But statistically, this is very unlikely."

"The other thing that has to be emphasized is, by monitoring patients, we can usually pick up these failed leads before a lethal event occurs," Lindsay said. "So I think patients should be reassured that this problem has been identified and reviewed carefully."

The Sprint Fidelis lead was launched in fall 2004 and was rapidly adopted because it was specifically designed to be thin and flexible, said Pat Mackin, president of Medtronic's cardiac rhythm disease management business. But the company wrote a letter to physicians in March that first described potential problems with the lead.

In July, Dr. Robert Hauser and colleagues at the Minneapolis Heart Institute published a study that found six out of 583 patients treated locally experienced early failure of their Sprint Fidelis leads. Five of the six patients experienced multiple inappropriate shocks, including one who was inappropriately shocked 25 times.

"Although such shocks are painful and often frightening, they are rarely associated with death or major injuries," Hauser wrote.

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