Review of Recent Patents on Foldable Ventricular Assist Devices

Congestive heart failure accounts for a high morbidity worldwide. The only effective treatment for end-stage patients is heart transplantation or, in light of the shortage of suitable donors, an artificial heart or ventricular assist device (VAD). The newer-generation continuous-flow rotary VADs allow for a significant reduction in size and an improvement in reliability. However, the invasive implantation still limits this technology from being offered to critically ill patients. To benefit more heart failure patients, there is a need to develop a long-term VAD which can be implanted via minimally in-vasive procedure. Recently, expandable/deployable devices have been investigated as a potential solution. Such a device can be inserted percutaneously via the peripheral vessels in its collapsed form and operate in its expanded form at the de-sired location. This paper reviews significant patents on foldable VADs using mechanical and/or material means. Me-chanically folded structures adapt joints and links to facilitate the folding process whilst utilization of elastic materials al-lows the structure to be bent or twisted without permanent deformation. Current and future developments of foldable VADs are discussed. Foldable pumps could generate less blood damage and mechanical wear as compared to current miniature percutaneous VADs. Therefore, foldable VADs have the potential for longer-term application and minimally invasive insertion, providing a promising solution for heart failure patients.