DynaRing: A Patient-Specific Mitral Annuloplasty Ring With Selective Stiffness Segments

Abstract

Annuloplasty ring choice and design are critical to the long-term efficacy of mitral valve (MV) repair. DynaRing is a selectively compliant annuloplasty ring composed of variable stiffness elastomer segments, a shape-set nitinol core, and across diameter filament. The ring provides sufficient stiffness to stabilize a diseased annulus while allowing physiological annular dynamics. Moreover, adjusting elastomer properties provides a mechanism for effectively tuning key MV metrics to specific patients. We evaluate the ring embedded in porcine valves with an ex-vivo left heart simulator and per-form a 150 million cycle fatigue test via a custom oscillatory system. We present a patient-specific design approach for determining ring parameters using a finite element model optimization and patient MRI data. Ex-vivo experiment results demonstrate that motion of DynaRing closely matches literature values for healthy annuli. Findings from the patient-specific optimization establish DynaRing's ability to adjust AP and IC diameters and saddle height by up to 8.8%, 5.6%, 19.8%, respectively and match a wide range of patient data.

The Application of Precision Medicine in Structural Heart Diseases: A Step towards the Future

“…It is a selectively compliant annuloplasty ring constructed using elastomer segments of various thicknesses, a nitinol core, and a cross diameter filament. Preliminary results have shown DynaRing's capability to adapt to both anterior-posterior and inter-commissural diameters; thus, it could fit in a wide range of different mitral valves [68]. However, larger studies for further validation are required.…”