It is of utmost importance to implant neochordae of correct lengths. A custom suture ruler calliper (Geister Medizintechnik GmbH, Tuttlingen, Germany) (Fig. 17.2a) is used to measure (mm) the distance between the papillary muscle body and leaflet “free margins” at chord insertion sites. This device can also be used to make the loops (Fig. 17.2b). For a reference point, we use the P₁ segment routinely (Fig. 17.3). In most cases P₁ does not prolapse: however, when it is redundant the MV annular plane is used as an alternative reference. Pre-fabricated PTFE loops (10–26 mm) are available in the operating room for immediate use (Fig. 17.4). Loops are pre-fabricated by our nurses using a specialized knotting device (Geister Medizintechnik GmbH, Tuttlingen, Germany) or the suture ruler shown in Fig. 17.2.

Neochord-papillary muscle security is obligatory and must mirror native chord anatomy and function. The two “base” sutures should be passed in an anterior to posterior direction through the papillary muscle in parallel and toward the respective prolapsed segment (Fig. 17.5a). The knotted end of the loop should be tied opposite the prolapsing leaflet surface (Fig. 17.5b). We have a motto, “Take it (the knot) to the other side”; thus free loop ends must arise from the papillary muscle and project toward the mitral valve orifice center. They should not cross the midline of the anterior leaflet (Fig. 17.6). Correct loop spacing must be established along the leaflet edge to avoid interaction and/or distortion of native chords. At the papillary muscle site, PTFE ends should tied be over a small felt pledget to avoid ischemia (Fig. 17.5b).