Evaluating Novel Annuloplasty Ring Designs in a Pathophysiological Animal Model

Area of Science:

• Biomedical Engineering
• Cardiovascular Research
• Medical Device Design

Background:

• Annuloplasty ring dehiscence is a significant failure mode after ischemic mitral regurgitation repair.
• Understanding the biomechanical forces on annuloplasty rings is crucial for improving device durability.

Purpose of the Study:

• To compare the performance of annuloplasty ring designs with varying stiffness.
• To investigate annular forces and their spatial distribution to mitigate ring dehiscence.

Main Methods:

• Five annuloplasty ring types (rigid, flexible, COM-Flex, POST-Flex, ALPM-Flex) with different stiffness were tested.
• Force transducers measured suture forces after undersized ring implantation in diseased animal models (N=31) at varying left ventricular pressures.

Main Results:

• POST-Flex rings exhibited the highest anterior annular forces.
• Flexible rings showed significantly lower posterior forces compared to rigid and COM-Flex rings.
• COM-Flex and ALPM-Flex rings demonstrated moderate anterior and posterior forces, with COM-Flex showing better force distribution away from the posterior annulus.

Conclusions:

• Annuloplasty ring design significantly influences the distribution of annular forces.
• COM-Flex rings appear most effective in mitigating posterior annular stress, potentially reducing dehiscence risk.
• This study provides valuable data on annular loading complexities for future device development.