Background and aim of the study: The biodegradable ring was recently developed for mitral and tricuspid annuloplasty. The study aim was to assess the histological biocompatibility of the biodegradable ring and orifice area growth in a porcine model.
Methods: The smallest (size 16) biodegradable ring was implanted into the tricuspid annulus of 16 juvenile pigs. All animals were followed up by transthoracic echocardiography to evaluate tricuspid valve function. Animals were sacrificed at one, three, six, nine and 12 months after implantation. Macroscopic and histological analyses were performed on three sections per ring implantation site. Parameters from the study group were compared to those obtained from control animals that underwent cardiopulmonary bypass without ring implantation.
Results: Histological examination showed that the biodegradable ring was gradually replaced by fibrous

tissue, with complete hydrolytic degradation within six months. The thickness of the dense fibrous tissue reached that of the initial ring at 12 months. No fibrous tissue development was observed in control animals. Echocardiography showed no signs of tricuspid valve dysfunction, a preserved ventricular contractility, and physiological growth of the tricuspid valve orifice. Macroscopic measurement of the valve orifice area confirmed that the generated fibrous tissue allows for physiological growth of the native annulus.
Conclusion: The concept of annulus remodeling using a biodegradable ring which preserves the growth potential of the native annulus opens new perspectives for valve repair procedures in the pediatric population. An undoubted contribution is also made to evolving annuloplasty technology.

The Journal of Heart Valve Disease 2006;15:783-790