History of VADs
The early VADs emulated the heart by using a “pulsatile” action where blood is alternately sucked into the pump from the left ventricle then forced out into the aorta. Devices of this kind include the HeartMate, which was approved for use in the U.S. by the FDA in October 1994. These devices are commonly referred to as first generation VADs.
More recent work has concentrated on continuous flow pumps, which can be roughly categorized as either centrifugal pumps or axial flow impeller driven pumps. These pumps have the advantage of greater simplicity resulting in smaller size and greater reliability. These devices are referred to as second generation VADs. A side effect is that users will not have a pulse or that the pulse intensity will be seriously reduced, and users will need to carry documentation saying that the lack of a pulse does not mean that they are dead.
Third generation VADs suspend the impeller in the pump using either hydrodynamic or electromagnetic suspension, thus removing the need for bearings and reducing the number of moving parts to one.
Another technology undergoing clinical trials is the use of transcutaneous induction to power and control the device rather than using percutaneous cables. Apart from the obvious cosmetic advantage, this reduces the risk of infection and the consequent need to take preventative action. A pulsatile pump using this technology has CE Mark approval (meets European guidelines) and is in clinical trials for U.S. FDA approval.
You must log in to post a comment.