Regulators in the UK and Hong Kong issued warnings on CircuLite’s Synergy circulatory support system after at least 3 reports that the devices’ inflow cannulae fractured.

The company already halted new implants of the affected system, the Synergy Micro-Pump kit, after it fractured in several patients. The company is investigating the cause of the fracture in the the inflow tube of the device and asking doctors to keep a closer eye on patients already being treated with the Synergy system.

Health safety authorities in Hong Kong and the United Kingdom both issued medical device safety alerts and all implants have been suspended in Europe.

CircuLite is advising patients and physicians to keep an eye out for signs of poor blood flow during routine follow-up exams, and to immediately schedule an x-ray if low flow is suspected. Patients are also advised to go to the hospital immediately if urine turns red or unnaturally dark.

For patients who experience a pump fracture, the pump might need to be removed, leaving them without mechanical circulation support, according to the U.K. notice.