Effect of cutting second-order chordae on in-vivo anterior mitral leaflet compound curvature

Filiberto Rodriguez, Frank Langer, Katherine B. Harrington, Frederick A. Tibayan, Mary K. Zasio, David Liang, George T. Daughters, Neil B. Ingels, D. Craig Miller

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Background and aim of the study: Leaflet curvature determines leaflet stress. In order to assess the influence of second-order chordae (2°CT) on anterior mitral valve leaflet (AMVL) geometry, AMVL curvature was measured before (Baseline) and after (CUT) cutting the 2°CT. Methods: Miniature radiopaque markers were sutured onto the AMVL in eight sheep: four along the central-meridian from mid-septal annulus to the free-margin; and one each at the 2°CT insertion. Biplane videofluoroscopic data were acquired (open-chest) before and after CUT. Marker-triplet 3-D coordinates were used to calculate radii-of-curvature at LVPmax along the central-meridian (ROCm) and across the AMVL belly (commissure-commissure axis, ROCc-c). Results: CUT did not change LVPmax (111 ± 12 versus 106 ± 11 mmHg; p = 0.19). At baseline, the AMVL central-meridian had compound curvature: Convex to the left ventricle near the annulus (-ROCm) and concave near the free-margin (+ROCm). After CUT, the AMVL flattened: ROCm increased near the annulus (from -1.37 ± 0.52 to -12.58 ± 29.04 cm; p = 0.02), but did not change near the edge. In the commissure-commissure axis, ROCc-c was concave to the left ventricle at baseline and increased after CUT in all eight animals. In five sheep, ROCc-c was increased (from 1.93 ± 1.01 to 2.80 ± 1.36 cm; p = 0.03), but in three sheep ROCc-c was increased and inverted (from 3.65 ± 2.17 to -1.72: ± 0.53 cm; p = 0.03), becoming convex to the left ventricle. Conclusion: Compound curvature along the AMVL central-meridian appears to be an intrinsic leaflet property that persists even without support from second-order chordae, whereas concave curvature in the commissure-commissure axis is more dependent on intact second-order chordae. Leaflet compound curvature must be incorporated into future finite element models to characterize leaflet stresses accurately. The importance of second-order chordae in maintaining leaflet shape must be considered during mitral repair. A larger ROC increases leaflet stresses, while reversal of ROC changes tensile stress to compressive stress; this might trigger deleterious leaflet remodeling after chordal cutting.

Original languageEnglish (US)
Pages (from-to)592-602
Number of pages11
JournalJournal of Heart Valve Disease
Issue number5
StatePublished - Sep 2005
Externally publishedYes

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


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