Mitral valve dysfunction resulting from thickening and stiffening of artificial mitral valve chordae

There is little information about changes in mitral valve function caused by thickening and stiffening of artificial chordae during follow-up. Using serial echocardiographic examination, we evaluated thickening and stiffening of artificial chordae and the effect of those changes on mitral valve function.

Between November 1986 and November 1993, 40 patients underwent mitral valve repair with artificial chordae using glutaraldehyde-tanned xenograft pericardium (GTXP) or polytetrafluoroethylene suture (PTFE). Seven GTXP patients and 20 PTFE patients underwent serial echocardiographic examination after surgery and were included in the final analysis. Thickening and stiffening of the artificial chonlae were classified according to echocardiographic changes after surgery: grade 1, no change; grade 2, thickening and/or stiffening without impairment of the motion of the mitral valve leaflet; and grade 3, thickening and stiffening that impaired motion of the mitral valve leaflet. The mean follow-ups in patients with GTXP and PTFE were 6.0 and 3.6 years, respectively. During follow-up, there were 2 GTXP patients with grade 2 thickening and stiffening and 4 patients with grade 3. There were 6 PTFE patients with grade 2 thickening and stiffening and 2 patients with grade 3. Grade 3 occurred earlier in GTXP than in PTFE patients (P < .05). Mitral valve area in GTXP patients decreased from 2.5 +/- 0.4 to 2.1 +/- 0.3 cm2 (P < .05); however, mitral valve area in PTFE patients showed no significant change during follow-up (2.1 +/- 0.4 to 2.0 +/- 0.4 cm2, P = NS).

Although mitral valve repair with artificial chordae is useful, more attention should be paid to mitral valve function resulting from thickening and stiffening of artificial chordae.