Análise do padrão de resistência de territórios vasculares maternos e conceptuais, no primeiro trimestre da gravidez

Abstract

Investigamos transversalmente a circulacao retrotrofoblastica, arterias uterinas, arterias umbilicais, aorta e cerebrais fetais em 182 gestacoes normais, entre 5 e 12 semanas, utilizando a ultra-sonografia transvaginal com Doppler colorido. Os fluxos conceptuais foram avaliados segundo a morfologia de suas OVF, seus IR e IP; ja no territorio materno, analisamos o IR retrotrofoblastico e das arterias uterinas alem de correlacionarmos estas com a lateralidade do corpo luteo. Todos os dados foram agrupados por semanas de gestacao. Pudemos detectar fluxos em todas as arterias uterinas, o IR medio foi de 0,83 (+/-0,10) com reducao gradativa ao longo das semanas (P<0,0001); as arterias uterinas ipsilaterais ao corpo luteo apresentaram IR menor nas semanas 6, 8, 9 e 10 (P<0,05), sugerindo osequestroo de fluxo por parte deste. O espaco retrotrofoblastico apresentou fluxos com IR medio de 0,48 (+-0,08), tambem apresentando reducao com o evoluir da gestacao (P<0,0001). Os fluxos conceptuais foram detectados inicialmente nas arterias umbilicais e aorta a partir de 6 semanas, e nas cerebrais a partir de 7 semanas. O IP medio no territorio umbilical foi de 2,58 (+-0,47), no aortico 2,61 (+/-0,39) e no cerebral, 2,37 (+/-0,47); a presenca de fluxos ate o final do ciclo cardiaco na 12a semana foi observada em 33,3%, 22,2% e 99,4% respectivamente. Houve reducao dos IP e IR nos tres territorios, mais significante no territorio cerebral. Nossos achados e a analise de relatos da literatura nos encorajam a pensar que a ausencia de fluxos telediastolicos embrionarios inicialmente nao se deva a aumento de resistencia vascular ajusante, mas ao baixo debito cardiaco associado a baixa resistencia vascular que provavelmente existe no periodo embrionario

Color Doppler transvaginal ultrasonography was applied to transversally investigate retrotrophoblastic, uterine arteries, umbilical arteries, aorta, and fetal brain circulation in 182 normal pregnancies between 5 and 12 weeks. Embryo / fetal flows were evaluated according their RI, PI and Time Velocity Waveform morphologies; in maternal research retrotrophoblastic and uterine artery RI was utilized besides correlating these to the laterality of the corpus luteous. All data was grouped by pregnancy week. Flows could be detected in all uterine arteries; average RI was 0.83 (± 0.10) with progressive reduction throughout the weeks (P<0.0001); uterine arteries ipsilateral to the corpus luteous presented lower RI on weeks 6, 8, 9 and 10 (P<0.0001), suggesting flow capture by the corpus luteous. The retrotrophoblastic space showed flows with an average RI of 0.48 (± 0.08), also showing reduction as pregnancy progressed (P<0.0001). Conceptual flows were initially detected in umbilical arteries and aorta starting from the sixth week on and in the cerebral arteries starting on the seventh week. Average PI in the umbilical territory was 2.58 (± 0.47), in the aortic territory 2.61 ( ± 0.39), and in the cerebral territory 2.37 (± 0.47). Flow presence up to the end of the cardiac cycle on the twelfth week was detected in 33.3%, 22.2% and 99.4% respectively. There was PI and RI reduction in the three territories. Our findings and the analysis of related literature encourage us to think that the absence of embryonic end-diastolic flows is not initially due to downstream vascular resistance increase, but to the low cardiac debit associated to the low vascular resistance probably present in the embryonic stage.