The fluid dynamic effect on protein adsorption in left ventricular assist devices

Area of Science:

• Biomaterials Science
• Cardiovascular Engineering
• Hemodynamics

Background:

• Plasma protein adsorption on artificial surfaces is a critical factor in blood pump performance.
• This adsorption influences platelet adhesion and activation, initiating thrombus formation at the blood-material interface.
• Understanding these interactions is crucial for improving the biocompatibility of blood-contacting medical devices.

Purpose of the Study:

• To investigate the relationship between fluid dynamics, surface characteristics, and plasma protein adsorption in an electrohydraulic left ventricular assist device (LVAD).
• To analyze the impact of protein adsorption on subsequent platelet adhesion.
• To correlate shear rate with protein adsorption and platelet adhesion patterns within the artificial ventricle.

Main Methods:

• In vitro flow visualization using a video camera and image processor.
• Implantation of electrohydraulic LVADs in mongrel dogs.
• Analysis of blood-contacted ventricle segments using scanning electron microscopy (SEM) for platelet adhesion and enzyme-linked immunosorbent assay (ELISA) for quantifying adsorbed proteins (fibrinogen, albumin, IgG).

Main Results:

• A significant vortex was observed in the center of the artificial ventricle.
• Polyurethane blood pumps exhibited varying degrees of protein adsorption and platelet adhesion across different segments.
• Protein adsorption levels correlated with specific regions within the ventricle, influenced by shear rate.

Conclusions:

• Both surface characteristics and intraventricular fluid dynamics, particularly vortex formation, significantly influence plasma protein adsorption.
• Protein adsorption patterns directly affect platelet adhesion and morphology.
• These findings highlight the importance of optimizing LVAD design to minimize adverse hemocompatic events.