Levacor VAD
How it Works
Operation
The Levacor VAD uses a centrifugal pump, with a bearingless, magnetically levitated impeller. While the first generation axial flow rotary pumps have potentially the smallest size, the pressure/flow characteristics of a centrifugal pump are well suited to the requirements of mechanical circulatory support. Even with the impeller spinning at a constant speed, the flow through the pump varies with the difference between the upstream and downstream pressures. Thus the flow generated by the pump varies with the contraction of the native heart.
Magnetic levitation of the impeller eliminates all wear mechanisms within the pump, allowing high reliability and durability. In addition, it allows relatively large clearances around the impeller, permitting optimized flow around the impeller. This represents a significant advantage over first-generation pumps with blood-lubricated journal bearings or hydrodynamic blood bearings. Journal bearings represent a possible wear mechanism. The tight clearances and high shear rates associates with blood-washed bearings create the potential for damage to blood components of thrombus formation. These problems can be avoided with magnetic levitation of the impeller.
