title: Rotary piston blood pumps: past developments and future potential of a unique pump type.
abstract: BACKGROUND
  The design of implantable blood pumps is either based on displacement pumps with membranes or rotary pumps. Both pump types have limitations to meet the clinical requirements. Rotary piston blood pumps have the potential to overcome these limitations and to merge the benefits. Compared to membrane pumps, they are smaller and with no need for wear-affected membranes and valves. Compared to rotary pumps, the blood flow is pulsatile instead of a non-physiological continuous flow. Furthermore, the risk of flow-induced blood damage and platelet activation may be reduced due to low shear stress to the blood.
  
  
  METHODS
  The past developments of rotary piston blood pumps are summarized and the main problem for long-term application is identified: insufficient seals. A new approach with seal-less drives is proposed and current research on a simplified rotary piston design is presented. Expert commentary: The development of blood pumps focuses mainly on the improvement of rotary pumps. However, medical complications indicate that inherent limitations of this pump type remain and restrict the next substantial step forward in the therapy of heart failure patients. Thus, research on different pump types is reasonable. If the development of reliable drives and bearings succeeds, rotary piston blood pumps become a promising alternative.
authors.affiliation: a Institute of Applied Medical Engineering , Helmholtz-Institute RWTH Aachen University , Aachen , Germany.|b Department of Thoracic and Cardiovascular Surgery , RWTH Aachen University Hospital , Aachen , Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Wappenschmidt
authors.affiliation: b Department of Thoracic and Cardiovascular Surgery , RWTH Aachen University Hospital , Aachen , Germany.
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Autschbach
authors.affiliation: a Institute of Applied Medical Engineering , Helmholtz-Institute RWTH Aachen University , Aachen , Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Steinseifer
authors.affiliation: a Institute of Applied Medical Engineering , Helmholtz-Institute RWTH Aachen University , Aachen , Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmitz-Rode
authors.affiliation: c Department of Visceral, Transplant and Thoracic Surgery , Medical University of Innsbruck , Innsbruck , Austria.
authors.forename: Raimund
authors.initials: R
authors.lastname: Margreiter
authors.affiliation: d Department of Anatomy, Histology and Embryology , Medical University of Innsbruck , Innsbruck , Austria.
authors.forename: Günter
authors.initials: G
authors.lastname: Klima
authors.affiliation: b Department of Thoracic and Cardiovascular Surgery , RWTH Aachen University Hospital , Aachen , Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Goetzenich
mesh_terms: D002315:Cardiopulmonary Bypass; D006353:Heart-Assist Devices / Q000145:classification / Q000639:trends*; D006801:Humans; D011474:Prosthesis Design
keywords: Rotary blood pump; SCARABAEUS; TORVAD; Wankel engine; mechanical circulatory support; pulsed-flow; rotary piston pump; seal-less drive; total artificial heart; ventricular assist device