The hemodynamic forces acting on thrombi, from incipient attachment of single cells to maturity and embolization

• Published in: Journal of biomechanics Vol. 17; no. 4; pp. 287 - 298
• Main Author: Basmadjian, Diran
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1984; Elsevier Science
• Subjects: Biological and medical sciences; Biomechanics. Biorheology; Blood Viscosity; Embolism - etiology; Fundamental and applied biological sciences. Psychology; Hemodynamics; Humans; Hydrostatic Pressure; Rheology; Stress, Mechanical; Tensile Strength; Thrombosis - etiology; Tissues, organs and organisms biophysics; Fibrin; Reaction force; Thrombus; Steady flow; Embolization; Hemodynamics; Formation
• ISSN: 0021-9290; 1873-2380
• DOI: 10.1016/0021-9290(84)90139-8

We consider the steady fluid forces acting on a thrombus from the time of first contact of a single cell with a natural or artificial surface, through the attachment process and growth to embolization. For a hemi-spherical or cylindrical attached cell of height less than 1 100 – 1 20 th of the channel width, shear and tensile stresses are solely dependent on viscosity and on the ratio of average fluid velocity to channel width v t D t (shear rate). Large values of this ratio reduce adhesion and increase embolization. The average shear stress on such cell is ∼ 1–10 Pa (10–100 dyn cm 2), the average tensile stress about three times higher. For other shapes and larger protrusions, stress varies with protrusion height as well. Maturing thrombi composed of cell aggregates embedded in a fibrin mesh do not appear to allow significant fluid flow through their porous structure. The interior forces are then due solely to hydrostatic pressure and initially vary directly with v t D t and inversely with thrombus height H p , thus favouring embolization at an early stage and in arterial systems. Rough surfaces are identified as causing an increase in dwell-time and possibly immobilizing an unattached cell due to ‘negative lift’.