A percutaneous approach to deep venous valve insufficiency with a new self-expanding venous frame valve

Abstract

Purpose: To ascertain if a percutaneously delivered venous valve bioprosthesis (PVVB) can be implanted in the porcine venous system and function without complications.

Methods: The PVVB is a glutaraldehyde-preserved, valve-bearing venous xenograft sutured inside a memory-coded nitinol frame (diameter 10, 12, or 14 mm). In 10 50-kg pigs, the external jugular vein was exposed, and a 16-F introducer sheath was positioned in the common iliac vein. One PVVB was inserted and deployed in each iliac vein under fluoroscopic control. After PVVB implantation, all animals were randomly given either vitamin K antagonists (1-2 mg/d) (group I) or a combination of aspirin (150 mg/d) and clopidogrel (75 mg/d) (group II), which were shown in a preliminary pilot study to be the most effective anticoagulation regimens in the pig model. Ascending and descending completion phlebograms were performed. PVVBs were evaluated with phlebography at 4 weeks to assess patency and competence; all PVVBs were explanted and processed for histological analysis.

Results: In 8 animals, the PVVB was successfully deployed in both the left and right iliac veins. In 2 pigs, only 1 PVVB was inserted due to vascular anomalies. Completion phlebography demonstrated 18 patent and competent valves. At 2 weeks, bleeding complications occurred in 3 group I pigs; all 5 animals were terminated to prevent further complications. Of the 8 valves in this group, 7 were patent (3 competent) by phlebography; 1 PVVB had migrated due to known undersizing of the stent frame. At 4 weeks, group II (5 pigs, 10 valves) analysis revealed 5 patent (3 competent) valves; no bleeding complications occurred in this group. Histology showed thrombosis as the cause of occlusion in all 5 non-patent valves from group II.

Conclusions: Deployment of a glutaraldehyde-fixed bovine vein sutured to a self-expanding nitinol stent in the porcine iliac vein is technically feasible. Development of a venous bioprosthesis that can be placed percutaneously may have important clinical applications as an endovascular treatment for chronic venous insufficiency when it is due to valvular incompetence.