A Left Ventricular Assist Device (LVAD) is a mechanical pump designed to support the heart in individuals experiencing advanced heart failure. This battery-operated device is surgically implanted to help the left ventricle, the heart’s main pumping chamber, circulate blood to the rest of the body, augmenting the heart’s pumping ability.
Understanding Heart Failure
Heart failure occurs when the heart muscle weakens and cannot pump enough blood to meet the body’s demands. Left ventricular heart failure involves the weakening of the left ventricle, the chamber responsible for pumping oxygen-rich blood from the lungs into the aorta and then to the entire body.
When the left ventricle struggles to contract effectively, less blood circulates throughout the body. This reduced pumping can lead to fluid buildup in the lungs, causing symptoms like shortness of breath and fatigue. The heart may try to compensate by enlarging or thickening, which often worsens the problem.
How an LVAD Works
An LVAD is composed of several interconnected parts: a pump unit, an inflow cannula, an outflow graft, a driveline, a controller, and external battery packs. The main pump unit is surgically implanted within the chest, typically near the heart. The inflow cannula, a tube, connects the LVAD pump directly to the left ventricle, allowing blood to enter the device.
Once blood enters the pump, the device actively draws it from the left ventricle. The pump then propels this blood through the outflow graft, which connects to the aorta, the body’s largest artery. This bypasses the weakened left ventricle, delivering oxygenated blood efficiently to the body.
The driveline extends from the implanted pump through the skin, usually in the abdomen, connecting to the external controller. This driveline transmits power to the pump and sends information to the controller. The controller, a small, portable computer, manages the pump’s operation and provides alerts. Power is supplied by rechargeable battery packs, which patients carry externally, or by plugging into an electrical outlet. These batteries typically last between 8 to 14 hours, and patients usually carry spare batteries for continuous operation.
Who Receives an LVAD
LVADs are primarily considered for individuals with advanced heart failure who have limited treatment options.
One common indication is as a “bridge to transplant” (BTT), where the LVAD supports heart function while a patient awaits a heart transplant. This temporary support maintains health and improves organ function until a suitable donor heart becomes available.
Another use is “destination therapy” (DT), a long-term or permanent solution for patients not candidates for heart transplantation due to age or other health conditions. The LVAD helps improve their quality of life and prolong survival.
LVADs can also be used as a “bridge to recovery” (BTR), where temporary support allows the heart to rest and potentially regain some function, potentially avoiding a transplant or permanent device.
Physiological Impact on the Heart
The operation of an LVAD significantly alters the physiology of the failing heart and the circulatory system. By pumping blood from the left ventricle into the aorta, the LVAD directly reduces the workload on the weakened native left ventricle. This reduction in strain allows the heart muscle to rest and can lead to “reverse remodeling,” where the heart may decrease in size and improve its function over time.
The continuous flow of blood ensures vital organs receive adequate oxygen and nutrients. This improved systemic blood flow can alleviate many symptoms associated with heart failure, such as fatigue, shortness of breath, and swelling. The device can also help normalize blood pressure and improve the function of organs like the kidneys, liver, and brain, which may have been compromised by poor circulation.