  A detailed survey of the current trends and recent advances in rotary
mechanical circulatory support systems is presented in this paper. Rather than
clinical reports, the focus is on technological aspects of these rehabilitating
devices as a reference for engineers and biomedical researchers. Existing
trends in flow regimes, flow control, and bearing mechanisms are summarized.
System specifications and applications of the most prominent continuous-flow
ventricular assistive devices are provided. Based on the flow regime, pumps are
categorized as axial flow, centrifugal flow, and mixed flow. Unique
characteristics of each system are unveiled through an examination of the
structure, bearing mechanism, impeller design, flow rate, and biocompatibility.
A discussion on the current limitations is provided to invite more studies and
further improvements.
