Mechanical Circulatory Support (MCS) is often required to treat advanced heart failure or acute cardiac crises. These devices assist the heart’s pumping function, ensuring the body receives necessary blood flow to support vital organs. Two distinct technologies used for this purpose are the Left Ventricular Assist Device (LVAD) and the Impella device. While both assist the left ventricle, their design, implantation, and intended duration of use differ significantly. The choice depends entirely on the patient’s specific condition, whether it is a chronic, long-term need or an acute, temporary emergency.
LVAD: Defining Long-Term Circulatory Assistance
A Left Ventricular Assist Device (LVAD) is a sophisticated mechanical pump designed for long-term support of a failing heart. Functioning as a continuous flow pump, the LVAD draws blood from the left ventricle and propels it directly into the aorta, providing steady, uninterrupted blood flow.
Implantation requires open-heart surgery, permanently placing the pump within the chest cavity. An inflow cannula is positioned at the apex of the left ventricle to collect blood. The blood flows through the pump and exits via an outflow graft connected to the aorta.
The power source and control system remain outside the body, connected to the implanted pump via a driveline cable. The patient manages this external equipment, including a controller unit and battery packs worn constantly. This setup allows patients with chronic heart failure to manage their condition outside the hospital for months or even years.
LVADs are utilized in two long-term strategies for advanced heart failure.
Bridge to Transplant (BTT)
This strategy sustains the patient until a donor heart becomes available for transplantation.
Destination Therapy (DT)
This is a permanent strategy for patients ineligible for a heart transplant, relying on the LVAD as a life-sustaining solution.
Impella: Rapid Temporary Heart Support
The Impella device represents a different approach, focusing on immediate, short-term assistance during acute cardiac events. It is a family of miniaturized, catheter-based pumps that provide temporary support as a micro-axial flow pump. The device is inserted percutaneously through a small puncture in an artery, typically the femoral artery in the groin.
The catheter is advanced through the artery, across the aortic valve, and into the left ventricle without open-heart surgery. The device draws blood from the left ventricle and expels it into the ascending aorta, unloading the stressed ventricle and increasing systemic blood flow. This rapid placement allows for quick stabilization of critically ill patients.
Impella devices support patients during acute cardiac crises, such as cardiogenic shock following a severe heart attack, or during high-risk procedures like percutaneous coronary intervention (PCI). The intent is to maintain organ perfusion and allow the heart muscle to recover or stabilize the patient until a definitive treatment plan is established. Support is typically provided for hours or days, though some models can be used for several weeks.
Several models are available (e.g., Impella 2.5, CP, 5.0, and 5.5), selected based on the required flow level and the patient’s anatomy. Higher flow models like the 5.0 and 5.5 often require surgical cutdown for placement through the axillary artery to improve patient mobility.
Contrasting Use Cases and Patient Experience
The fundamental difference lies in the intended duration of support and method of implantation. LVADs are surgically implanted for continuous, long-term support over months or years. In contrast, the Impella is a percutaneously inserted catheter used for short-term support, typically days or weeks, to stabilize patients in acute shock.
The implantation process reflects this difference: the LVAD requires major open-heart surgery, while the Impella is placed less invasively using catheterization, often through the femoral artery. This disparity impacts the patient’s immediate experience. An LVAD patient requires a significant surgical recovery but can then manage the device at home and participate in active, outpatient life.
Impella patients, due to the critical nature of their acute illness, generally require continuous monitoring in the Intensive Care Unit (ICU). However, larger models placed through the axillary artery may allow the patient to ambulate within the ICU while receiving support. The choice of device is driven by the acuity of the condition: Impella for rapid, acute stabilization, and LVAD for chronic, long-term management.
Managing Life with Mechanical Circulatory Support
Patients with either an LVAD or an Impella require careful medical management due to the inherent risks of mechanical support. A major aspect of care for both is anticoagulation therapy to prevent blood clots from forming on device components. For LVAD patients, this involves a long-term regimen, often including warfarin and aspirin, to reduce the risk of pump thrombosis or stroke.
Impella patients also receive systemic anticoagulation to maintain device function during its short-term use. Continuous blood flow through any mechanical pump creates shear stress, which can lead to the destruction of red blood cells, known as hemolysis. This complication must be monitored in both populations.
Specific risks differ based on the device’s design and placement.
LVAD Specific Risks
LVAD patients face the risk of infection at the driveline exit site. Managing the continuous, long-term anticoagulation balance is challenging, increasing the risk for both bleeding events and thrombotic complications.
Impella Specific Risks
Impella patients, due to percutaneous insertion, are more susceptible to complications at the access site, such as bleeding or damage to the blood vessel.