Influence of anterior mitral leaflet second-order chordae on leaflet dynamics and valve competence

Background. Chordal transposition is used in mitral valve repair, yet the e ffects of second-order chord transection on valve function have not been ex tensively studied. We evaluated leaflet coaptation, three-dimensional anter ior mitral valve leaflet shape, and valve competence after cutting anterior second-order chordae. Methods. In 8 sheep radiopaque markers were affixed to the left ventricle, mitral annulus, and leaflets. Animals were studied immediately with biplane videofluoroscopy and echocardiography before (Control) and after (Cut2) se vering two anterior second-order "strut" chordae. Leaflet coaptation was as sessed as separation between leaflet edge markers in the midleaflet and nea r each commissure (anterior commissure, posterior commissure). Anterior lea flet geometry was determined 100 milliseconds after end-diastole from three -dimensional coordinates of 13 markers. Results. Anterior leaflet geometry changed only slightly after chordal tran section without inducing mitral regurgitation. Leaflet coaptation times wer e 79 +/- 17 and 87 +/- 22 milliseconds at the anterior commissure; 72 +/- 2 1, 72 +/- 19 milliseconds at midleaflet, and 71 +/- 12 and 75 +/- 8 millise conds at the posterior commissure (p = NS) for Control and Cut2, respective ly. Conclusions. Cutting anterior second-order chordae did not cause delayed le aflet coaptation, alter leaflet shape, or create mitral regurgitation. Thes e data indicate that transposition of second-order anterior chordae ("strut " chordae) is not deleterious to anterior leaflet motion per se. (C) 2001 b y The Society of Thoracic Surgeons.