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

INTRODUCTION: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.