External approach to in vivo force measurement on mitral valve traction suture

Abstract Background Force measurements on the mitral valve apparatus have been reported from in vivo and in vitro studies. Recent reparative techniques for ischemic mitral valve insufficiency call for papillary muscle relocation. This study describes a device to measure forces generated on traction sutures utilized for this purpose. Methods The transducer design was based on a modified caliper with strain gauges attached. Finite element computer simulation was employed to optimize the signal output. The system was designed to facilitate investigation of the effects of shortening GoreTex traction suture that was extended from near the fibrous trigones of the mitral valve through the papillary muscles. The suture was exteriorized out through the left ventricle in a porcine setup ( n =11) and attached to the dedicated device for simultaneous papillary muscle relocation and traction suture force measurement. Results The transducer demonstrated excellent signal strength, linearity, and durability. Peak force was seen at the onset of the systolic isovolumic contraction ( p