Replacing the Anterior Mitral Valve Leaflet With Autologous Jugular Vein in a Sheep Model.

BACKGROUND: This study evaluated the use of an autologous vein graft, supported by expanded polytetrafluoroethylene (ePTFE) chordae tendineae, to replace an anterior mitral valve leaflet.

METHODS: A double-layered autologous jugular vein graft, supported by ePTFE chords, was used to create an anterior mitral valve leaflet in 21 sheep. Mitral valve function was monitored with echocardiography for up to 10 months. Surviving sheep were euthanized between 6 and 10 months later, and vein implants were examined histologically.

RESULTS: One sheep died intraoperatively. Fourteen sheep had trace to mild mitral regurgitation (MR), 5 had mild to moderate MR, and 1 had moderate to severe MR. Ten sheep died between 2 days and 6.2 months. Echocardiography at 6 months showed MR progression in 8 of 11 sheep. The vein leaflet developed intimal fibroplasia and fibrous proliferation in response to the increased stress on the tissue, but the vein remained flexible without shortening or contracture. The 6- to 10-month vein implants showed viability with intact endothelium, myofibroblasts, collagen, and elastin. A normal healing pattern was seen at the suture lines, and no calcification was observed in the vein leaflet apart from the ePTFE sutures.

CONCLUSIONS: Autologous vein has the potential to function as a mitral valve leaflet substitute because it adapted morphologically and remained viable in the intracardiac position. Technical refinement in creating and implanting the leaflet is needed to improve the progression of MR.