A Left Ventricular Assist Device (LVAD) is a mechanical pump implanted within the body to take over the blood pumping capability of the left ventricle of the heart. The pump is surgically implanted in the patient’s chest, just below the heart. It is connected to the apex (bottom) of the left ventricle via a tubular conduit that protrudes through the wall of the heart and lies within the ventricular chamber. This conduit channels blood from the ventricle to the pump. The pump outflow is connected via a flexible woven conduit (as is typically used in an aortic graft) to the ascending aorta, the normal pathway for ejection of blood from the heart. The LVAD is powered by and an electrical cable that is passed thorough the patient’s skin and connected to an external motor controller and batteries.
LVADs help patients recover blood flow, suppress the main symptoms of heart failure, and can maintain patients alive for several (up to ten) years. These medical devices are implanted as a bridge-to-transplant or as destination therapy, but are still very risky and are sometimes associated with frequent re-hospitalizations.
The technology currently utilized for pumping blood in an implanted application is typically a continuous flow rotary pump, either turbine-based axial flow pumps or centrifugal pumps, as might typically be used to pump fluids in industrial applications. While these rotary flow pumps provide an adequate outcome, they have certain limitations fundamental to the technology. Complication rates for things like stroke, gastro-intestinal bleeding and infection remain relatively high.
A better fundamental technology is needed to reduce these complications.
CorWave is developing an LVAD that offers significant advantages over the currently available devices. While LVAD technology has improved significantly over earlier generation devices, the use of a high-speed rotary pump fundamentally exposes the blood to relatively high levels of stress and to red cell damage. The active membrane technology offers a solution that pumps blood in a much gentler manner. The fundamentally efficient, elegant design also provides for added advantages in performance, size and cost.
The membrane technology offers the following significant benefits:
- Low shear stress on the blood
- Ability to provide true pulsatile flow
- Lower volume, weight and complexity
The CorWave LVAD is a small implantable pump based on the disc wave membrane. The membrane is positioned between two adjacent surfaces that form the flow channel. The outer diameter of the membrane is fixed in a rigid frame which is connected to a magnet linear actuator. The actuator oscillates the membrane, creating a movement similar to a loud speaker. This sinusoidal oscillating motion sets up a wave on the surface of the membrane, which then transports the blood in the space between the membrane and the surfaces from the outer to the inner diameter of the membrane, on both sides of the membrane. At the center of the membrane the blood exits the pump into the outlet cannula.