By Katherine Kozloski, Contributor to Vein Bews and www.VeinsVeinsVeins.com and and Jorge Santiago Dominguez, MD, Contributor to Vein News
Tissue-engineered transcatheter vein valve
Researchers from The University of Minnesota investigated the efficacy of a new biologically-engineered vein valve inserted using a Nitinol stent in vitro (outside the body). The goal of this research is to address chronic venous insufficiency by providing an effective alternative procedure to surgicalvein valve repair.
How was the valve made?
The tissue-engineered transcatheter vein valve (TEVV) was made using bovine fibrinogen (a protein from cattle), ovine dermal fibroblasts (connective tissue cells from sheep), thrombin (an enzyme in the blood that causes clotting), and calcium chloride to form a fibrin gel (protein that impedes the flow of blood).
The mixture was injected into a mold with a Nitinol stent, which is a stent used very often in medical procedures.
After further development and processing of the valve, it was made into a bileaflet design similar to bileaflet heart valves.
Does it work?
The TEVV was tested by simulating cardiac conditions in a pulse duplicator system to evaluate hydrodynamic properties.
The TEVV had forward pressure drops in the range of 2-4 mmHg (meaning the vein maintains pressure) and no regurgitation.
The valve was crimped to 50% of its original diameter for 15 minutes, and after crimping was fatigue-tested for 1 million cycles. There was no degradation of valve performance or any visual damage to the matrix.
The TEVV held over 60 0mm Hg backpressure after the durability testing. Normal physiological pressures are not proposed to exceed 300 mm Hg, showing that the valve would be able to withstand normal blood pressure spikes in an organism.
Reference: Syedain ZH, Jenson AC, Patel PS et al. Tissue-engineered transcatheter vein valve. Biomaterials 2019; 216:119229