Thoratec Corporation recalled the HeartMate II Left Ventricular Assist System. The HeartMate II is a high speed, electric, axial flow, rotary blood pump. The pump drains blood from the heart.
Thoratec Corporation is initiating a worldwide medical device correction of all serial numbers of the HeartMate II Left Ventricular Assist Systems (HM II LVAS) having Catalogue No. 1355 or 102139, which have been distributed since the beginning of clinical studies in November 2003. Thoratec is voluntarily issuing an Urgent Medical Device Correction notice after confirming 27 reports where wear and fatigue to the percutaneous lead necessitated pump replacement. These reports occurred over five years of clinical experience with 1,972 implants. All patients who have undergone a replacement of the HeartMate II pump survived the operation and were alive at least 30 days postoperatively. In five cases, pump replacement was not feasible and the patients died.
The HeartMate II is a high-speed, axial flow, rotary blood pump. As an axial flow device, the HeartMate II produces no pulsatile action. Weighing 12 ounces (about 375 grams) and measuring about 1.5 inches (4 cm) in diameter and 2.5 inches (6 cm) long, it is significantly smaller than other currently approved devices. As such, it may be suitable for a wider range of patients, including small adults and children.
The internal pump surfaces are a smooth, polished titanium. Within the pump is a rotor that contains a magnet. The rotor assembly is rotated by the electromotive force generated by the motor. The rotor propels the blood from the inflow cannula out to the natural circulation. The pump speed can vary from 6,000 rpm to 15,000 rpm, providing blood flow of up to 10 liters per minute.
The pump can run in two operating modes: fixed speed and auto-speed. In fixed-speed mode, the device operates at a constant speed, which can be adjusted via the system monitor. In the auto-speed mode, the pump speed varies in response to different levels of patient or cardiac activity.