title: Completely pulsatile high flow circulatory support with a constant-speed centrifugal blood pump: mechanisms and early clinical observations.
abstract: OBJECTIVE
  Various types of rotary blood pumps (axial flow, centrifugal) have been introduced into clinical use recently. These pumps have different pressure-flow characteristics, and some investigators have noted that a limited pump flow rate and less pulsatility are the problems with the axial flow devices.
  
  
  METHODS
  A new implantable centrifugal blood pump was developed that has an extremely flat pressure-flow curve and is able to produce a significantly high pump flow rate of 20 l/min at a low pressure of 10-30mmHg. When the pressure difference between the left ventricle and aorta decreases during systole, an instant high peak flow is achieved, which results in a higher peak pressure in the aorta (systolic pressure). During the diastolic phase, the left ventricle-aorta pressure difference increases to maximum, and the pump flow rate decreases to minimum. Thus, the pump flow rate becomes completely pulsatile, and the high peak flow provides a higher mean pump flow rate. This pump was applied to two end-stage heart failure patients (dilated cardiomyopathy, New York Heart Association (NYHA) class IV, inotrope-dependent).
  
  
  RESULTS
  The pump was observed to provide completely pulsatile high flow assistance of 6-9 l/min with a constant pump speed. Both patients are currently in NYHA class I after 1 year on the device with no major adverse events.
  
  
  CONCLUSIONS
  The new centrifugal blood pump provides completely pulsatile high-flow circulatory support with a constant pump speed, which solves the current clinical problems with rotary blood pumps.
authors.affiliation: Department of Cardiovascular Surgery, Tokyo Women's Medical University, Kawada-cho, Shinjuku-ku, Japan. syamazak@hij.twmu.ac.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamazaki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Saito
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Kihara
authors.forename: Osamu
authors.initials: O
authors.lastname: Tagusari
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kurosawa
mesh_terms: D000328:Adult; D002311:Cardiomyopathy, Dilated / Q000628:therapy; D004867:Equipment Design; D006353:Heart-Assist Devices; D006801:Humans; D008297:Male; D008875:Middle Aged; D011673:Pulsatile Flow