Experimental mitral valve replacement with a heterograft aortic valve in a rigid metal ring

Abstract

A mitral valve replacement is described in which a heterograft (pig) aortic valve is supported in a rigid metal ring having three spurs to support the commissures. The ring frame is completely covered by the heterograft, and no artificial material is in contact with the blood stream. Completely fabricated and tested for competency beforehand, it requires only one row of interrupted sutures-after the manner of the Starr-Edwards prosthesis-for insertion, and can be used in either the mitral or the aortic position. Experimental results in the dog indicate that the valve may require only temporary anticoagulation to cover the immediate post-operative period.The success, in suitable cases, of the homograft aortic valve placed in the sub-coronary position (Ross, 1962(Ross, , 1963(Ross, , 1964(Ross, , 1967Barratt-Boyes, 1964) and the problems associated with metal and plastic prostheses (Bjork and Malers, 1964;Hughes, 1965;Kloster, Bristow, and Griswold, 1965) have prompted much research towards replacing the diseased mitral valve with a homograft mitral valve. This has proved more difficult than aortic valve replacement. The problem is mainly related to difficulties of insertion and matching of chordal and annulus dimensions both acutely, in anticipation of a subsequent change of dimensions post-bypass, and in the long run, as the left ventricle becomes smaller after successful correction. This problem is lessened in the experimental animal, where the normal valve can be matched or a larger valve used, but, in spite of this, the results of mitral homograft replacement in animals are not good (Hubka, SIska, and Holec, 1967;Pappas, Titus, Berghuis, McKenzie, and Ellis, 1966). Replacement with 'mitral valves' fashioned from autologous fascia lata accurately matched for size is no better (Flege, Rossi, Auer, and Ehrenhaft, 1967).Another approach, which avoids the problems associated with chordal dimensions and ventricular fixation, is to use semi-lunar valves. Experimentally, the mitral valve has been replaced with an autologous pulmonary valve (Lower, Stofer, and Shumway, 1961)

Mitral valve replacement by calf aortic heterograft and its clinical evaluation

“…The problem of mitral valve replacement by a biological graft was solved by the insertion of the aortic homo-or heterogenous valve into the mitral ostium in an inversed position, performed by Murray, Shumway Proctor [t4,21]). Therefore studies have been undertaken to use prongs of half rigid Teflon or metal rings.…”