Significance of Spatial Orientation of Percutaneously Placed Bioprosthetic Venous Valves in an Ovine Model

Abstract

To investigate two spatial orientations of a percutaneously placed bicuspid second-generation bioprosthetic venous valve (SG-BVV) in the jugular vein (JV). Twelve SG-BVVs, consisting of small intestinal submucosa attached to a nitinol frame were placed across a natural valve (NV) in the distal JV in six sheep. Six SG-BVVs were oriented as NV leaflets (group A) and the other six SG-BVVs were rotated 90 degrees to NV leaflets (group B). SG-BVV function was studied by venography performed immediately after placement and at 5 weeks after placement. Animals were killed at 5 weeks, and gross examinations were performed. Desired valve orientation after deployment was seen in all SG-BVVs. In group A, all valves exhibited good valve function on immediate and 5-week venography. At gross examination, leaflets were attached mostly at the valve base and free cusp areas were similar in both cusps with a mean of 154.8 mm2 +/- 45.6 for one cusp and 142 mm2 +/- 53.4 for the other cusp (P = .188). In group B, all valves showed good function on immediate venography and in five valves prior to killing. Valve attachment to the vein wall in this group involved a longer segment of leaflets and their free areas were smaller with a wide variety of cusp sizes. Mean free leaflet areas of opposing cusps measured 106.3 mm2 +/- 36.5 and 66.1 mm2 +/- 34.6, respectively (P = .025). Difference in leaflet areas between group A and group B was significant (P = .019). Proper spatial orientation of the SG-BVV at deployment is important for valve function and should have the same orientation as the NV.