A Left Ventricular Assist Device, commonly known as an LVAD, is a mechanical pump designed to support a heart that has become too weak to effectively circulate blood on its own. It is surgically implanted to help the left ventricle push blood to the rest of the body. LVADs serve as a life-sustaining treatment for individuals with advanced heart failure, improving blood flow and reducing symptoms like fatigue and shortness of breath. These devices do not replace the heart but instead work alongside it, lessening the heart’s workload.
LVAD Components
An LVAD system consists of several distinct parts that work together to provide circulatory support. The primary component is the pump unit, a small, battery-operated mechanical pump surgically placed near the heart. This pump contains an internal rotor or impeller that spins continuously to move blood.
Connected to the pump is a thin cable known as the driveline. This cable extends from the implanted pump through the skin and connects to external components. The driveline provides power to the pump and connects to a controller, a small, portable computer that manages the LVAD’s functions. This controller monitors the pump’s performance and displays important information and alerts. External batteries connect to the controller, providing continuous operation and are often carried in a shoulder bag or on a belt, allowing patient mobility.
Blood Flow Through the Device
The LVAD is strategically positioned to assist the heart’s natural pumping action. One end of the LVAD pump is connected to the apex, or tip, of the left ventricle. This connection allows the device to draw blood directly from the weakened ventricle.
Once blood enters the LVAD pump, the internal impeller rapidly spins, propelling the blood forward. From the pump, the blood is then directed through an outflow graft. This outflow graft is surgically connected to the aorta. By pushing blood into the aorta, the LVAD ensures a continuous flow of oxygen-rich blood, compensating for the heart’s diminished pumping ability.
Device Operation and Management
The LVAD’s continuous operation relies on its external power and control system. The controller, worn outside the body, monitors the pump’s activity and regulates its power. This small computer provides feedback through text displays, indicator lights, and audible alarms, alerting the patient or caregivers to changes in the device’s status.
Power for the LVAD is supplied by rechargeable batteries, which typically provide several hours of operation, often ranging from 4 to 17 hours per pair, depending on the device model. Patients usually carry at least two battery packs to ensure continuous power. When indoors or sleeping, the system can also be plugged into a wall outlet for continuous power, allowing batteries to be recharged. Daily management for patients includes regularly checking battery levels and exchanging depleted batteries, as well as caring for the driveline exit site to prevent infection. Patients are also taught to recognize and respond to various alarms, which may indicate issues such as low battery power or a pump stoppage.