In Vitro Evaluation of a New Autologous Valve-Stent for Deep Venous Incompetence

Abstract

Purpose:

To report the results of in vitro hydrostatic bench testing of a new vein-stent combination to correct deep venous incompetence.

Methods:

Twelve valves were constructed from a modified Palmaz stent encased in a segment of great saphenous vein harvested from patients during routine varicose vein surgery. An in vitro flow circuit was set up to evaluate opening and closing pressures (in cm H₂O), and the valve was subsequently subjected to repetitive cycles of increasing prograde flow and reflux pressures. Duplex scanning was used to evaluate valve closure time and detect any possible reflux.

Results:

The valve mechanism required only 1 to 3 cm H₂O for opening and 2 to 4 cm H₂O for closing. Prograde flow of up to 1000 mL/min passed easily through this valve, which remained competent with reflux pressures up to 180 cm H₂O. Mean valve closure time was 0.15±0.07 seconds. Unligated side branches or damage from dissection impaired the competence of 3 valves.

Conclusion:

This new vein-stent valve functions as a normal deep vein valve, requiring only minimal pressures for opening and closing. It allows high flow passage and still remains competent at high reflux pressures. This valve may provide a minimally invasive solution for the correction of deep venous incompetence using autologous material. Further in vivo evaluation will be mandatory.