Boston Scientific pacemakers linked to two deaths subject of FDA safety alert

The U.S. Food and Drug Administration has issued an urgent safety alert after an electric malfunction in some older Boston Scientific pacemakers was linked to two reported deaths and early device replacements.

Boston Scientific said about 13% of devices from its Accolade family of pacemakers built before September 2018 face an increased potential to initiate “safety mode,” a non-programmable backup pacing that may not provide optimal support of a patient’s cardiac condition, the company said in its own urgent notice to doctors. This higher risk occurs when the device reaches approximately four years or less of remaining battery longevity and is the result of “unanticipated concentration of lithium salts resulting from variability of battery assembly techniques,” the company said.

The FDA said in its alert Monday that the agency is working with Boston Scientific to “evaluate the potential risk of this issue in all Accolade pacemaker devices and identify additional mitigation strategies as needed.”

The FDA linked the device problem to a “manufacturing issue.” There have been 697 confirmed malfunctions in the roughly 203,000 affected devices in the market.

Boston Scientific said in a statement that it voluntarily issued an advisory involving the subset of pacemakers “because of the potential for these devices to transition to Safety Mode due to an elevated internal battery impedance.”

“This behavior can occur later in device life and may require early replacement for some patients. No devices within the advisory population remain available for implant and the most common clinical impact has been early device replacement,” the company said.

Boston Scientific has approximately 9,400 employees in Minnesota and its rhythm management business in Arden Hills sent the letter to health care providers.

Normally, a pacemaker system is designed to reserve sufficient battery capacity to support device operations for three months, the company’s notice said. If a device enters safety mode due to high battery impedance, the reserve battery capacity may not be sufficient to support device operations for three months and “should be scheduled for replacement soon thereafter or emergently for patients at risk of harm from Safety Mode parameters,” the company said in its notice.

Boston Scientific said in the letter that it is actively developing a software update for the affected devices designed to detect on the onset of a high impedance battery state and display an alert. Refinement of processing techniques, it added, has reduced the variability of lithium salt concentrations and improved the performance of batteries in pacemakers.

“Physicians following patients with devices included in the advisory population have been given recommendations intended to mitigate the risk of the behavior and will reach out to patients directly if a separate appointment should be made to assess their device,” the company said in the statement.

The affected devices include: Accolade, Proponent, Essentio, and Altrua 2 dual-chamber standard life and DR extended life pacemakers, as well as Visionist and Valitude cardiac resynchronization therapy pacemakers. The company recommended doctors perform emergent replacement for patients who are at risk of harm.