Abbott Vascular has notified a regulatory agency in the U.K. that it has received four reports of the actuator knob in the MitraClip Clip Delivery System being turned in the wrong direction, which can prevent the successful deployment of the clip and possibly require open surgical repair.

The Medicine & Healthcare product Regulatory Agency (MHRA) issued an alert to interventional cardiologists and cardiothoracic surgeons one day before an FDA advisory panel gave the MitraClip a lukewarm endorsement for approval. The Circulatory System Devices Panel voted 3-5 to approve the device, which is percutaneously implanted in high surgical risk patients to reduce mitral regurgitation. In a memorandum, the FDA had outlined concerns with study designs and data in trials that assessed its safety and efficacy.

MHRA said that Abbott Park, Ill.-based Abbott reported four cases where the actuator knob was turned clockwise instead of counter-clockwise as medical personnel attempted to disengage and deploy the clip from the delivery system. That potentially can fracture an internal assembly and prevent the release of the clip. In one case, physicians crossed over to emergency open surgical repair and used surgical bolt cutters and forceps to remove the delivery system.

Abbott informed the agency that it will add a blue arrow on the actuator knob on newer devices that will indicate the correct turning direction. “The manufacturer has also confirmed to the MHRA that they intend to make a number of design changes which should ultimately make it impossible to turn the actuator knob in the wrong direction,” the MHRA notice continued. “The implementation of the design changes will not, however, be completed for up to two years.”

The MitraClip device received CE Mark in 2008 and is commercially available in Europe, but it remains an investigational device in the U.S.