6.625 – Long-Term Implantable Ventricular Assist Devices (VADs) and Total Artificial Hearts (TAHs)

Long-term implantable ventricular assist devices (VADs) and total artificial hearts (TAHs) are two of the most sophisticated medical devices ever. This chapter surveys the historical development, evolution, and status of the field, highlighting the four generations of VADs from (1) positive displacement (pulsatile) pumps, through (2) mechanically and (3) hydrodynamically supported rotary blood pumps to (4) pumps whose impellers are fully magnetically levitated. The clinical need and the present and potential future uses of these devices are also highlighted, covering the spectrum from bridge-to-transplant to destination therapy (DT) and potentially bridge-to-recovery. Given their predominant clinical use, long-term implantable LVADs are the primary focus, while TAHs are also described. Anatomical and physiological considerations in device design are outlined. Distinction is made between full-support devices and partial support devices. Key devices representative of each generation are described, including a summary of their design configuration, technological innovations, especially those that are biomaterials related, development status, clinical results, and future plans. The intent is to provide a representative overview to promote an understanding of the field and the various technologies, rather than provide an exhaustive and detailed summary description of every MCS device ever developed.