Percutaneous prosthetic venous valves: current state and possible applications.

The small-intestinal submucosa square-stent bicuspid venous valve has shown the most promising results of all of the artificial venous valves developed. In long-term experimental studies in sheep, 25 valves were placed into the jugular veins and 88% exhibited good function, whereas 12% had decreased function because of valve tilting. Only 4% had partial thrombosis in the tilted valve. Valves also were placed in 3 patients. The bicuspid venous valves remained patent without thrombosis or other complications. Proper sizing and proper placement of the valves was critical to their function. The valve construction needs to be improved to prevent occasional tilting during their deployment.