Degenerative changes in glutaraldehyde preserved pericardium used for the experimental replacement of anterior chordae of mitral valve.

Plastic repair of the mitral valve after rupture of the anterior chordae can only be performed when less that one third of the anterior leaflet has lost its chordal support. This experimental study was designed to examine a method for chordal replacement utilizing gluteraldehyde preserved pericardium (Bovine pericardium supplied by Hancock Laboratories). The correct length of the "new chorda" was determined by the use of anatomical rules. In applying these rules we adopted the hypothesis that the chordae were under tension throughout diastole. The anterior chordae were replaced in eight dogs. At the end of the procedure the valve was tested and found to be competent in every case. Two dogs died before restudy because of the development of bacterial endocarditis confirmed histologically. Five dogs were restudied four months to two years after chordal replacement. There was no evidence of mitral incompetence and the mean left atrial pressure was within the normal range in each of the five dogs restudied. Histological examination of the new chordae demonstrated both cartilage formation and calcification. Electron microscopy demonstrated excellent healing of both suture sites with ingrowth of native collagen fibres between the fibres of the preserved pericardium. We conclude that excellent haemodynamic results can be obtained after chordal replacement and are maintained in spite of degenerative changes. Early calcification is known to occur in biological materials implanted in dogs and the use of this technique in man will be determined by the specific biological environment.