Clinical experience with modified controller software

Data through May 2024

References to the “Modified Controller” refer to the alternate pump start algorithm within the controller software that may be able to restart a pump if the standard controller is unsuccessful in restarting a stopped pump (the availability of this alternate pump start algorithm was communicated via an Urgent Medical Device Communication in June 2022).  The software in the Modified Controller has not been approved as being safe or effective for use by the US FDA or any other regulatory authorities, which means it has not been tested to the same level as software in an approved medical device and comes with risk.  As such, the Modified Controller with unapproved software is not available in all geographies.  The Modified Controller should ONLY be used if the pump has stopped, and the standard, commercially available controller is unsuccessful at restarting the pump.

Outcomes

There have been 20 instances where a controller with the modified algorithm has been used in an attempt to restart an HVAD pump. The pump restarted in 18 of the 20 instances. Of the 18 restarts, two (2) were subgroup 2 patients, five (5) were subgroup 3 patients, and eleven (11) were general population patients. No adverse events have been reported from use of the controller with the modified algorithm in the 18 successful use cases.

Use cases

For the two unsuccessful use cases, both pumps were from the general population, and the clinical information is as follows:

• The first instance in which the controller with the modified algorithm was unsuccessful was for a patient who required a controller exchange in July 2022. This patient’s pump was in the general population and the patient was not a candidate for a pump exchange. The patient’s pump had been off for over 18 hours. After five failed restart attempts using a standard backup HVAD controller, the clinician exchanged to the HVAD controller with the modified algorithm. The pump did not restart after multiple attempts using the controller with modified algorithm. The patient was placed under hospice care.
• The second instance in which the controller with the modified algorithm was unsuccessful was for a general pump population patient who experienced an unexpected pump stop and [VAD Stopped] alarm at home. The patient exchanged their controller to their backup standard controller, which failed to restart the pump. The patient was transferred to the hospital where the controller with the modified algorithm was attempted but was unsuccessful at restarting the pump. The pump remained off for an unknown amount of time and the next day the patient’s pump was exchanged to another commercially available device.

It is not known if any of these results will be typical or representative.