Biomechanical characteristics of different methods of neo‐chordal fixation to the papillary muscles

Abstract

Background and Aim of the Study: Several techniques have been described for neochordal fixation to the papillary muscles without any reported clinical differences.The objective of this study is to compare in vitro the biomechanical properties of four of these common techniques. Methods:We studied the biomechanical properties of expanded polytetrafluoroethylene neo-chordal fixation using four techniques: nonknotted simple stitch, nonknotted figure-of-eight stitch, knotted pledgeted mattress stitch, and knotted pledgeted stitch using commercially available prefabricated loops. Neo-chordae were submitted to a total of 20 traction-relaxation cycles with incremental loads of 1, 2, and 4 N. We calculated the elongation, the force-strain curve, elasticity, and the maximum tolerated load before neo-chordal failure. Results:The elongation of the neo-chordae was lowest in the simple stitch followed by the figure-of-eight, the pledgeted mattress, and he commercially prefabricated loops (p < .001). Conversely, the elastic modulus was highest in the simple stitch followed by the figure-of-eight, the pledgeted mattress, and the prefabricated loops (p < .001). The maximum tolerated load was similar with the simple stitch (28.87 N) and with the figure-of-eight stitch (31.39 N) but was significantly lower with the pledgeted mattress stitch (20.51 N) and with the prefabricated loops (7.78 N). Conclusion:In vitro, neo-chordal fixation by nonknotted simple or nonknotted figure-of-eight stitches resulted in less compliance as opposed to the use of knotted pledgeted stitches. Fixation technique seemed to influence neo-chordal biomechanical properties, however, it did not seem to affect the strength of the suture when subjected to loads within physiological ranges.

Utilization of Engineering Advances for Detailed Biomechanical Characterization of the Mitral–Ventricular Relationship to Optimize Repair Strategies: A Comprehensive Review

“…However, all the suture pull-out forces observed in their experiments vastly exceeded the forces usually observed for the primary or secondary chordae tendineae [159]. A recent study by Fernández and colleagues showed that different techniques of anchoring the neochords at the papillary muscles may influence neochordal biomechanics; however, this is not the case when reviewing the loading conditions within the physiological range [160]. Classically, neochords are affixed to the papillary muscle tips, restoring more normal mechanics; however, recent biomechanical evidence suggests that alternative implantation into the apical or posterior myocardium may provide satisfactory mitral valve repair, as well [38,146,161].…”

Different methods of neo‐chordal fixation to the papillary muscle: Do they have any influence on the chordal biomechanical characteristics?

“…Pre-measured neo-chordae (loop technique), also present in the market and ready-to-use, have facilitated and propagated mitral repair by using this technique. 12 In this paper, Fernandez et al, 15 This is an interesting experimental in vitro design study aiming to evaluate and to compare different stitching techniques in use to anchor PTFE neo-chordae to papillary muscles during mitral valve repair. In my opinion, the greatest limitation of this study is its in vitro design.…”

“…In this paper, Fernandez et al,15 Santiago de Compostela, Spain and from Kingston, Canada, present an interesting in vitro study focusing on the first of the technical details of neo-chordae implantation previously mentioned, that is the attachment on the papillary muscle. They compared different stitching techniques in use to anchor neo-chordae to papillary muscles and evaluated the impact of each method on the biomechanical properties of PTFE.…”