A component supplied by an outside company produces an error that causes the generator to reset and fail to deliver the intended VNS therapy, according to London-based LivaNova. Resets may occur during routine stimulation or heartbeat sensing or during communication with the VNS programming software in a clinical setting. The generator can be turned back on after such instances, but the resets may continue.
This issue most likely to occur within the first 30 days after enabling therapy. Patients using VNS to treat epilepsy or depression may return to baseline seizure frequency or depressive symptoms if the device no longer delivers the intended therapy, LivaNova said. Some may need surgery to replace the generator, the company added in an urgent field safety notice sent to customers Sept. 26.
As of Sept. 12, the number of known and suspected occurrences is 11 out of 1,642 registered implants; the observed occurrence rate of this issue within the potentially affected device population is currently 0.67%. No occurrences of this issue were reported in devices implanted 45 days or longer.
No serious injuries or deaths have been reported to LivaNova as a result of device disablement due to this issue, the company said.