[Univentricular heart with left morphology with permeable atrio-ventricular valves. Study of the bulbo-ventricular foramen with color echo-Doppler. Importance for the surgical repair].

INTRODUCTION AND OBJECTIVES: Bidimensional and color-coded Doppler echocardiography were used to study 19 patients with univentricular heart, permeable atrioventricular valves, muscular bulbo-ventricular foramen and an anterior rudimentary chamber. We evaluated the influence of the foramen upon the size of the great vessels, and in consequence the most appropriated surgical techniques. MATERIAL AND METHODS: The foramen was measured in two projections at the end of the systolic period, and its area was calculated, according to the body surface, with the formula S = pi (D1/2 x D2/2). Indexes lower than 2 cm2/m2 were considered as restrictive. We studied 19 patients that presented a mean age of 11 +/- 12 years (range 1 day-39 years). The patients were classified in two groups. Group A: patients who had transposition of the great vessels (13 cases). Group B: patients who had normal connection of the great vessels (6 cases). Each group was classified in two subgroups: subgroup 1, patients who presented a restrictive foramen, and subgroup 2, patients who presented a normal foramen. In this study, we evaluated the associated cardiac anomalies. RESULTS: Group A. Thirteen cases. The index value for the whole group was 2.47 +/- 1.18 cm2/m2. The first subgroup included 6 cases with a restrictive foramen, 2 patients presented pathology of the arch. Four patients had a pressure gradient between the ventricle and the rudimentary chamber beyond 20 mmHg. The index of this subgroup was 1.68 +/- 0.39 cm2/m2, the median was 1.7. Seven cases, with a normal foramen, were included in the second subgroup, six of them had pulmonary valve stenosis, and the other one had undergone a pulmonary artery bandage 2 months before. Only one patient had a gradient pressure at the foramen beyond 20 mmHg. The index for this second subgroup was 3.34 +/- 0.83 cm2/m2. GROUP B: Six patients with normal connection of the great vessels were included. The index was 1.56 +/- 1.17 cm2/m2. The first subgroup included 3 cases with a restrictive foramen. The index was 0.72 +/- 0.29 cm2/m2 (range 0.41-1) and the median was 0.75. Pressure gradient between the ventricle and the rudimentary chamber was greater than 20 mmHg. Three patients with a normal foramen were in the second subgroup and here, the index was under normal limits 2.4 +/- 0.52 cm2/m2 (range 2.1-3), the median was 2.1. One patient underwent a pulmonary artery bandage two months before. CONCLUSIONS: Bulbo-ventricular foramen size/body surface index may exert an influence on the size of the vessel connected to the rudimentary chamber. The index vary in a negative way with the evolution time, or in those cases with transposition of the great vessels after a pulmonary artery bandage. Whenever the foramen is restrictive, the pulmonary artery or the aorta have a smaller diameter and the pressure gradient between the ventricle and the rudimentary chamber rises.