Performance changes of venous valves following tissue treatment with novel in vitro system

Abstract

Objectives The purpose of this study is to test venous valve performance and identify differences between native tissue and replacement devices developed with traditional tissue treatment methods using a new in vitro model with synchronized hemodynamic parameters and high-speed valve image acquisition. Methods An in vitro model mimicking the venous circulation to test valve performance was developed using hydrostatic pressure driven flow. Fresh and glutaraldehyde-treated vein segments were placed in the setup and opening/closing of the valves was captured by a high-speed camera. Hemodynamic data were obtained using synchronized hardware and virtual instrumentation. Results Geometric orifice area and opening/closing time of the valves was evaluated at the same hemodynamic conditions. A reduction in geometric orifice area of 27.2 ± 14.8% (p < 0.05) was observed following glutaraldehyde fixation. No significant difference in opening/closing time following chemical fixation was observed. Conclusions The developed in vitro model was shown to be an effective method for measuring the performance of venous valves. The observed decrease in geometric orifice area following glutaraldehyde treatment indicates a decrease in flow through the valve, demonstrating the consequences of traditional tissue treatment methods.

Glutaraldehyde fixation of venous valve tissue: A benchmark for alternative fixation methods

“…As previously mentioned, an increase in collagen crosslinking due to glutaraldehyde fixation has also been found to increase tissue stiffness that results in decreased venous valve performance in vitro . 17 Therefore, the ideal xenograft for a bioprosthetic venous valve requires optimizing stability while maintaining native valve mechanical properties. This makes shrink temperature an important consideration in xenograft development to evaluate the degree of crosslinking and thermal stability independent of the mechanical properties.…”

“…While current glutaraldehyde fixation techniques can be adjusted for long-term endurance with cardiac valves, for venous valves, this fixation technique has resulted in decreased valve performance in vitro. 17,18 Specifically, Easson et al 17 demonstrated a significant increase in the stiffness of glutaraldehyde treated venous valves that led to a decrease in the geometric orifice area during performance testing at physiological flow rates. This poses a significant problem in the venous system, where the environment consists of much lower pressure and flow compared to the arterial, that may accelerate the failure of bioprosthetic venous valves.…”

Current development of bovine jugular vein conduit for right ventricular outflow tract reconstruction

“…The captured valve behaviours (e.g. opening time and geometric orifice area) were able to reflect the property difference between various BJV tissues (such as fresh and glutaraldehyde-treated) ( Easson et al, 2019 ). Fatigue property is one of the key indicators of the durability of a BJVC, and the ISO 5840 (2021) standard prescribes guidelines on fatigue assessment of heart valves ( ISO, 2021 ).…”