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Questions

  

A.9. What are the different types of temporary percutaneous ventricular assist devices (VADs)?

Answer:

There are two systems available for percutaneous ventricular support:

The most common percutaneous VAD is the Impella system. It comes in several configurations for both left and right ventricular support. It consists of a catheter with an axial flow pump which provides support by propelling blood forward. There are several Impella devices available to support the LV and one device for the right ventricle (RV).

LV support: The most common LV support device is the femoral Impella CP which is usually placed percutaneously in the catheterization laboratory. It is positioned retrograde across the aortic valve to propel blood forward into the ascending aorta. The Impella CP (femoral access) can provide up to 4.3 L/min of flow.

Larger Impella devices that provide higher flows require surgical placement through femoral or axillary access. The Impella 5.5, which supports up to 6.2 L/min of flow, can be implanted surgically via a graft onto the axillary artery or ascending aorta to allow patient mobilization, as the patient does not need to be bed-bound compared to femoral artery inserted devices.

RV support: Impella RP is available for percutaneous right heart support. The Impella RP is a 22 French micro-axial pump approved by the U.S. Food and Drug Administration (FDA) for use in acute right heart failure for up to 14 days. The catheter pump is advanced antegrade under fluoroscopic guidance and positioned across the tricuspid and pulmonary valves through a sheath inserted in the femoral vein. This pump provides right heart support via propelling blood from the inferior vena cava (pump inflow) to the pulmonary artery (pump outflow) at up to 4.0 L/min of flow.

A less commonly used device is TandemHeart, which is inserted percutaneously through the femoral vein to the right atrium, across the inter-atrial septum, and into the left atrium. It can pump up to 4.0 L/min of blood through a continuous-flow centrifugal pump from the left atrium into the lower abdominal aorta or iliac arteries through a femoral arterial cannula. Hemodynamically, the TandemHeart provides a more significant increase CO and blood pressure compared to IABP and decreases RV and LV filling pressures and work. However, the complexity of placement and the high complication rate (vascular injury, bleeding leading to transfusion, sepsis/systemic inflammatory response syndrome, stroke, gastrointestinal [GI] bleeding) have limited its use and popularity.

References