The HeartWare® VAD device, currently available only through clinical trials for bridge-to-transplantation, helps a patient's weakened heart pump blood throughout the body, first by removing blood from the left side of the heart and then by pumping the blood into the aorta. This device has shown much promise and we are now investigating HeartWare® as a destination therapy as well.
HeartWare's® small implantable pump draws blood from the left ventricle and propels it through an outflow graft connected to the patient's ascending aorta. The device is capable of generating up to 10 liters of blood flow per minute.
This VAD has only one moving part—the impeller—suspended within the pump through a combination of passive magnets and bearings. The size of a golfball, the impeller spins at rates between 2,400 and 3,200 revolutions per minute, then works with the HeartWare® system to propel blood from the heart to other parts of the body.
The pump's inflow cannula is integrated with the device, ensuring proximity between the heart and the pump itself. This proximity facilitates ease of implant and helps ensure optimal blood flow. The wide-bladed impeller and clear flow paths may help minimize risk of clotting and damage to blood cells.
How HeartWare® is Implanted
The HeartWare® pump is implanted in the pericardial space, directly adjacent to the heart. There is no surgical pocket required for the pump. Thus patients may have both a relatively short surgery and a quicker recovery.
How HeartWare® is Worn
The pump rests inside the chest and a driveline (cable) exits the skin and connects to an externally worn controller. The controller is powered by a battery pack, consisting of two batteries or one battery plus an adaptor that connects to a wall socket or an automobile outlet. The controller operates the pump and provides the patient with feedback, including signals and alarms, concerning the state of the system. Both the controller and batteries fit in a carrying case can be worn in a waist pack or a shoulder bag.
In 2009, surgeons at NewYork-Presbyterian/Columbia University Medical Center were among the first in the United States to be implant a next-generation artificial heart pump called the DuraHeart™ Left-Ventricular Assist System.
The DuraHeart™ is designed to sustain patients with severe left-ventricular heart failure while they wait for a donor heart transplant and is now being studied in clinical trials as a bridge-to-transplantation.
The DuraHeart™ is considered a third-generation device, with unique features—including a paddlewheel-like component called an impeller that is suspended by an electromagnet—eliminating any bearings or contact points and allowing it to work at slower speeds, potentially reducing device wear and risk of blood cell breakage.
How the DuraHeart™ is Implanted
Because of its small size, the pump fits comfortably inside a pocket created in the upper abdomen. It is connected to the left ventricle and the aorta to help the weakened heart pump blood. The pump is connected by a cable to a rechargeable battery outside the body.
How the DuraHeart™ is Worn
The entire system is designed to be portable and travel easily as patients go about their daily activities. The batteries and controller are worn in a waist pack or shouder bag. The DuraHeart LVAS is built to be durable and simple to use as well as highly portable. Patients can move about freely for up to five hours using two fully charged batteries, and the patient can extend this time simply by carrying extra batteries.