Proportion among the segments of the normal tricuspid valve annulus: parameter for valve annuloplasty

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: 105mm (&plusmn;12.7), 30.6mm (&plusmn;3.7) and 74mm (&plusmn;9.4), respectively. When flattened, the mean measurement of the perimeter was 117.5mm (&plusmn;13.3) and sizes of the septal, anterior and posterior segments were 32mm (&plusmn;3.7), 46.3mm (&plusmn;8.3) and 39.1mm (&plusmn;8.5), respectively. The mean ratio between the antero-posterior and septal segments was 2.43 (&plusmn;0.212) in the anatomical position and when flattened it was 2.67 (&plusmn;0.304). Statistical differences were observed in the measurements of perimeter (p<0.0001), septal segment (p=0.003) and antero-posterior segment (p<0.0001) in both situations. Statistical differences also occurred in the ratios between the antero-posterior and septal segments (p=0.0005). CONCLUSION: The proportion between the septal and antero-posterior segments of the normal human tricuspid valve is 1:2.43. Flattening the tricuspid ring to measure the segments, changes the values and the ratios between them.OBJETIVO: Determinar a proporção existente entre os segmentos do anel da valva tricúspide normal em humanos. MÉTODO: Foram estudados 30 corações de cadáveres humanos não formolizados, com menos de 6h de período post-mortem, sem lesões congênitas ou adquiridas e com valvas tricúspides continentes. A continência valvar foi confirmada por injeção de água sob pressão no interior do ventrículo direito estando a valva pulmonar fechada. Fotos digitais da valva tricúspide com o anel valvar íntegro, e após secção e retificação, foram avaliadas por programa de computador. Compararam-se as medidas médias e as razões entre elas nas condições de anel íntegro e retificado. RESULTADOS: Com o anel valvar íntegro, os valores médios do perímetro, segmento septal e ântero-posterior foram 105mm (&plusmn;12,7), 30,6mm (&plusmn;3,7) e 74mm (&plusmn;9,4), respectivamente. Com o anel valvar retificado, os valores médios foram 117,5mm (&plusmn;13,3), 32mm (&plusmn;3,7), 46,3mm (&plusmn;8,3) e 39,1mm (&plusmn;8,5), respectivamente para perímetro, segmento septal, anterior e posterior. As razões médias entre o segmento ântero-posterior e o septal foram 2,43 (&plusmn;0,212) e 2,67 (&plusmn;0,304), respectivamente, em anéis íntegros e retificados. Houve diferenças significantes nas medidas do perímetro (p<0,0001), do segmento septal (p=0,003) e do segmento ântero-posterior (p