HeartWare International (NSDQ:HTWR) reissued warnings today to remind doctors of serious concerns with its HeartWare Ventricular Assist System.

The company has already received 8 complaints of failed locking mechanisms in the patient driveline connectors, which connect the implanted circulatory assist device to an external controller that powers and monitors the device. In half of those cases, the disconnected driveline connector resulted in a temporary stop in pumping therapy, which HeartWare said "could cause serious injury or death, depending on the function of a patient’s native heart."

None of the patients associated with the 8 complaints were reportedly injured, according to a press release.

HeartWare asked physicians to rigorously check the driveline connectors at the time of implant and at every routine clinic visit to ensure that the device remains connected and that locking components are properly secured. The issue affects only devices manufactured before November 2013, at which point HeartWare implemented manufacturing changes to address the issue.