Effects of surface roughness on mechanical hemolysis

Mitsuo Umezu*, Takashi Yamada, Hiromi Fujimasu, Tetsuo Fujimoto, Manoja Ranawake, Atsuhiko Nogawa, Toshihiko Kijima

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


Previous in vitro hemolysis test results showed that an inlet taper or a round corner in the leading edge of a stenotic connector played an important role in the reduction of hemolysis. However, computational fluid dynamics (CFD) analysis of these results indicated that the shear rate and hemolysis level were not always related to each other. Then, further research was performed, focusing on the effects of surface roughness on hemolysis. The results thus far can be summarized as threefold. First, the rate of hemolysis occurring at an abrupt change in the stenotic section was different if the longitudinal length of the stenosis was changed. The level of plasma-free hemoglobin after 6 h of circulation was decreased from 280 mg/dl to 70 mg/dl when the longitudinal length was shortened from 15 mm to 1 mm. Second, a comparison of hemolysis rates in identical stenotic connectors with differing surface roughness (Ra = 0.45 and 1.35 μm) revealed that a smooth surface achieved as much as an 80% reduction in the rate of hemolysis. Third, the in vitro hemolysis results obtained were further defined through CFD analysis.

Original languageEnglish
Pages (from-to)575-578
Number of pages4
JournalArtificial Organs
Issue number5
Publication statusPublished - 1996
Externally publishedYes


  • Computational fluid dynamics (CFD) analysis
  • Hemolysis
  • In vitro testing
  • Reattachment point
  • Surface roughness

ASJC Scopus subject areas

  • Bioengineering
  • Medicine (miscellaneous)
  • Biomaterials
  • Biomedical Engineering


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