Proportion Among The Segments Of The Normal Tricuspid Valve Annulus: Parameter For Valve Annuloplasty [proporção Entre Os Segmentos Do Anel Da Valva Tricúspide Normal: Um Parâmetro Para Realização Da Anuloplastia Valvar]

Objective: The purpose of this study was to determine the proportions among the segments of the human tricuspid valve annulus. Methods: A descriptive autopsy study was made of 30 human hearts without fixation, within six hours of death, without congenital or acquired lesions and without tricuspid regurgitation. Tricuspid valve insufficiency was excluded by the infusion of pressurized water in the right ventricle with the pulmonary valve closed. Digital images of the tricuspid ring in its anatomical position and after flattening were analyzed by specific software. The mean measurements and ratios were compared in the two different situations. Results: The mean measurements of the perimeter, septal and antero-posterior segments of the tricuspid ring in the anatomical position were: 105 mm (± 12.7), 30.6 mm (± 3.7) and 74 mm (± 9.4), respectively. When flattened, the mean measurement of the perimeter was 117.5 mm (± 13.3) and the sizes of the septal, anterior and posterior segments were 32 mm (± 3.7), 46.3 mm (± 8.3) and 39.1 mm (± 8.5), respectively. The mean ratio between the antero-posterior and septal segments was 2.43 (± 0.212) in the anatomical position and when flattened it was 2.67 (± 0.304). Statistical differences were observed in the measurements of the perimeter (p<0.0001), septal segment (p=0.003) and antero-posterior segment (p