Flow-induced accumulations of von Willebrand factor inside oxygenators during extracorporeal life support therapy

  • BACKGROUND: Shear-induced conformational changes of von Willebrand factor (vWF) may be responsible for coagulation disorder and clot formation inside membrane oxygenators (MOs) during extracorporeal membrane oxygenation (ECMO) therapy. OBJECTIVE: The aim was to identify vWF structures inside clinically used MOs and employ computational fluid dynamics to verify the corresponding flow conditions. METHODS: Samples from gas exchange membranes (GEM) from MOs were analysed for accumulations of vWF and P-selectin-positive platelets using immunofluorescence techniques. Streamlines and shear rates of the flow around GEMs were computed using a laminar steady Reynolds-Averaged-Navier-Stokes approach. RESULTS: Most samples were colonized with equally distributed leukocytes, integrated in thin cobweb-like vWF-structures. Only 25 % of the samples showed extended accumulations of vWF. Computed streamlines showed considerable cross flow between interconnected neighbouring channels. Stagnation points were non-symmetric and contact faces were washed around closely. The occurring maximum shear rates ranged from 2,500 to 3,000 1/s. CONCLUSIONS: If pronounced vWF structures are present, shape and extent match the flow computations well. Computed shear rates bear a critical degree of uncertainty due to the improper viscosity model. If flow conditions inside the MO were sufficient to affect vWF, a more consistent distribution of vWF across the samples should be present.

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Author:Clemens BirkenmaierORCiD, Tamara Steiger, Alois Philipp, Karla LehleORCiD, Lars KrenkelORCiDGND
Parent Title (English):Proceedings of 12th International Conference BIOMDLORE 2018, June 28–30, 2018, Białystok, Poland
Place of publication:Piscataway, NJ
Document Type:conference proceeding (article)
Year of first Publication:2018
Release Date:2023/02/13
Tag:Blood Viscosity; Hemodynamics; Membrane Oxygenator; Shear Rate Induced Coagulation; von Willebrand factor
Institutes:Fakultät Maschinenbau
Regensburg Center of Biomedical Engineering - RCBE
Fakultät Maschinenbau / Labor Biofluidmechanik
research focus:Lebenswissenschaften und Ethik
Licence (German):Keine Lizenz - Es gilt das deutsche Urheberrecht: § 53 UrhG