There is a risk of the delivery wire breaking or separating during use. The clot retriever could be left inside the patient’s bloodstream, and this or the attempts made to retrieve the device, can lead to further complications including bleeding, additional blockage of blood vessels, more severe stroke symptoms, or death.

https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm608162.htm