Second-generation percutaneous bioprosthetic valve: A short-term study in sheep

Abstract

To eliminate occasional tilting of the original bioprosthetic venous valve (BVV) a second-generation BVV has been developed. This study was performed to evaluate deployment, stability, and short-term function of the second-generation BVV in an animal model. A second-generation percutaneously placed BVV consisting of a square stent and lyophilized small intestinal submucosa attached to a second square stent (DS BVV) or Z-stent (ZS BVV) were tested. DS BVVs (n = 32) were constructed with a nitinol (n = 28) or stainless steel double stent (n = 4), and ZS BVVs (n = 16) were made of nitinol (n = 8) or stainless steel (n = 4). BVVs were implanted percutaneously through a femoral vein approach into the jugular vein in 24 female sheep with an over-the-wire 13F or 10F delivery system. All BVVs were placed across the natural valve of the proximal jugular vein. Deployment, stability, and function of BVVs were studied at immediate venography with contrast medium injections peripheral and central to the BVVs. Animals underwent follow-up venography and were sacrificed at 6 weeks (n = 24). Gross pathologic examination was performed. Jugular vein diameter ranged from 9.8 to 14.4 mm (mean, 12.1 +/- 1.2 mm) in 24 sheep. The 10-mm to 12-mm valve was deployed in 27 jugular veins, and the 12-mm to 14-mm valve was deployed in 21 jugular veins. No tilting was seen at placement of 48 BVVs into the jugular veins, and all valves exhibited good function on immediate venograms. Angiographic competency for the nitinol and stainless steel ZS BVV (100%) was similar to that for the nitinol DS BVV (92.3%; P = .488) but was significantly better than for the stainless steel DS BVV at 6 weeks (50%; P = .03). Dysfunction of 4 valves was caused by either nitinol DS BVV oversizing (n = 2) or intimal hyperplasia with the stainless steel DS BVV (n = 2). Placement without tilting appears essential for proper valve function. The second-generation BVV enables placement without tilting. Exact matching of valve size with vein diameter is necessary for good valve function. At present there are no widely accepted surgical or percutaneous treatment options for deep chronic venous insufficiency. A manufactured, percutaneously implantable, nonimmunogenic and nonthrombogenic bioprosthetic venous valve that remains patent and competent over time is an attractive alternative to direct venous valve reconstruction or transplantation. our results and the potential for effective treatment with bioprosthetic venous valves warrants clinical research in carefully selected patients and may lead to an effective, minimally invasive treatment for deep chronic venous invasive treatment for deep chronic venous insufficiency.