Mitral Annuloplasty Sizing: Engineering Design Basis for a Scientific Clinical Approach.

For over half a century, our method of annuloplasty ring sizing for mitral (tricuspid) repair has remained unchanged. Commercially available sizers provide the surgeon estimates but no objective measurement. This manuscript defines the engineering design process for a novel, objective sizing system and illustrates its clinical application. An early cadaver animal heart model was developed to validate the sizer's ability to both manipulate and measure coaptation length. An overview of the design process is presented to establish why the paired-ring sizing method is able to deliver precise mitral leaflet coaptation length measurements. The method of clinical application of a novel surgical technique is illustrated in detail. Preliminary animal heart validation results demonstrated the sizer's ability to effectively manipulate mitral annular structure and correctly predict changes in coaptation length. Because the paired-ring sizing technique allows coaptation length to be accurately measured and controlled, it has the potential—pending further study—to serve as the basis for a scientific annuloplasty sizing approach.