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Author Notes:

Ajit P. Yoganathan, 313 Ferst Dr., Atlanta, GA 30332, Ph. (404) 894-2849, Fax. (404) 894-4243, ajit.yoganathan@bme.gatech.edu

The authors would like to additionally thank James “Jim” McEntree for fabricating the titanium annuloplasty ring core and dedicate this manuscript in his memory.

Authors reported no conflicts of interest.

Subjects:

Research Funding:

We would like to acknowledge grants awarded from the National Heart, Lung, and Blood Institute (HL73021, HL63954 and HL090661).

Keywords:

  • Science & Technology
  • Life Sciences & Biomedicine
  • Technology
  • Biophysics
  • Engineering, Biomedical
  • Engineering
  • Mitral valve
  • Mitral annuloplasty
  • Transducer
  • Strain gage
  • Mitral valve repair
  • REGURGITATION
  • REPAIR

In-vivo mitral annuloplasty ring transducer: Implications for implantation and annular downsizing

Tools:

Journal Title:

Journal of Biomechanics

Volume:

Volume 46, Number 14

Publisher:

, Pages 2550-2553

Type of Work:

Article | Post-print: After Peer Review

Abstract:

Mitral annuloplasty has been a keystone to the success of mitral valve repair in functional mitral regurgitation. Understanding the complex interplay between annular-ring stresses and left ventricular function has significant implications for patient-ring selection, repair failure, and patient safety. A step towards assessing these challenges is developing a transducer that can be implanted in the exact method as commercially available rings and can quantify multidirectional ring loading. An annuloplasty ring transducer was developed to measure stresses at eight locations on both the in-plane and out-of-plane surfaces of an annuloplasty ring's titanium core. The transducer was implanted in an ovine subject using 10 sutures at near symmetric locations. At implantation, the ring was observed to undersize the mitral annulus. The flaccid annulus exerted both compressive (-) and tensile stresses (+) on the ring ranging from -3.17 to 5.34. MPa. At baseline hemodynamics, stresses cyclically changed and peaked near mid-systole. Mean changes in cyclic stress from ventricular diastole to mid-systole ranged from -0.61 to 0.46. MPa (in-plane direction) and from -0.49 to 1.13. MPa (out-of-plane direction). Results demonstrate the variability in ring stresses that can be introduced during implantation and the cyclic contraction of the mitral annulus. Ring stresses at implantation were approximately 4 magnitudes larger than the cyclic changes in stress throughout the cardiac cycle. These methods will be extended to ring transducers of differing size and geometry. Upon additional investigation, these data will contribute to improved knowledge of annulus-ring stresses, LV function, and the safer development of mitral repair techniques.

Copyright information:

© 2013 Elsevier Ltd. All rights reserved.

This is an Open Access work distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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