Design of artificial vascular devices: Hemodynamic evaluation of shear-induced thrombogenicity

Abstract

Blood-circulating devices such as oxygenators have offered life-saving opportunities for advanced cardiovascular and pulmonary failures. However, such systems are limited in the mimicking of the native vascular environment (architecture, mechanical forces, operating flow rates and scaffold compositions). Complications involving thrombosis considerably reduce their implementation time and require intensive anticoagulant treatment. Variations in the hemodynamic forces and fluid-mediated interactions between the different blood components determine the risk of thrombosis and are generally not taken sufficiently into consideration in the design of new blood-circulating devices. In this Review article, we examine the tools and investigations around hemodynamics employed in the development of artificial vascular devices, and especially with advanced microfluidics techniques. Firstly, the architecture of the human vascular system will be discussed, with regards to achieving physiological functions while maintaining antithrombotic conditions for the blood. The aim is to highlight that blood circulation in native vessels is a finely controlled balance between architecture, rheology and mechanical forces, altogether providing valuable biomimetics concepts. Later, we summarize the current numerical and experimental methodologies to assess the risk of thrombogenicity of flow patterns in blood circulating devices. We show that the leveraging of both local hemodynamic analysis and nature-inspired architectures can greatly contribute to the development of predictive models of device thrombogenicity. When integrated in the early phase of the design, such evaluation would pave the way for optimised blood circulating systems with effective thromboresistance performances, long-term implantation prospects and a reduced burden for patients.

Challenge of material haemocompatibility for microfluidic blood-contacting applications

“…Until now the focus has been primarily on the mechanical experience of the blood and blood-processing functionalities, with the material interactions remaining an afterthought. Although it is true that haemodynamic forces contribute hugely to damage experienced by blood in microfluidic networks, and the methods of protective design have been previously reviewed ( Szydzik et al, 2020 ; Astor and Borenstein, 2022 ; Feaugas et al, 2023 ), devices will not achieve acceptable haemocompatibility without appropriate coating of microchannel surfaces. This review provides a foundational understanding of the significance of material-blood interactions in microfluidic channels and the formation of thrombi, and how coatings can improve haemocompatibility.…”

“…This is particularly interesting in microfluidic devices where the flow conditions are highly specific, predictable, and can be manipulated with close precision. The methods by which this can be achieved have been summarised in a recent review ( Feaugas et al, 2023 ).…”

Membrane-based microfluidic systems for medical and biological applications

“…These novel membranes would deflect compensating changes in pulmonary blood pressure and recreate cylindrical-like vascular geometries eliminating blood stagnation zones at the corners of the microchannels. 240…”

“…These novel membranes would deflect compensating changes in pulmonary blood pressure and recreate cylindrical-like vascular geometries eliminating blood stagnation zones at the corners of the microchannels. 240 2) An optimized vascular network coupled with effective surface modifications and coatings to minimize the foreign body response of the device. 241 The functions of the heart and arteries are mechanical rather than chemical, thus an effort to recreate in the systems the forces and stresses produced by the blood flow on the walls of the cardiovascular vessels is mandatory.…”

Membrane-based microfluidic systems for medical and biological applications

“…1) A compliant membrane module with flexible yet resistant polymer membranes that are mechanically similar to the blood-gas membrane in the lung. These novel membranes would deflect compensating changes in pulmonary blood pressure and recreate cylindrical-like vascular geometries eliminating blood stagnation zones at the corners of the microchannels 226 .…”