ABSTRACT
RESUMEN Introducción. Los embarazos gemelares son clasificados en dos grupos: monocoriónico (MC) y dicoriónico (DC). Los gemelos MC tienen 5 a 6 veces más riesgo de tener un resultado perinatal adverso. Se publica el estudio de un grupo de 22 placentas de pacientes con embarazo gemelar monocoriónico que presentaron complicaciones como síndrome de transfusión feto-fetal (STFF), secuencia de anemia policitemia (TAPS), perfusión arterial reversa (TRAP) y restricción de crecimiento intrauterino selectivo (RCIU-s). Objetivo . Determinar los tipos de anastomosis predominantes en las placentas con síndrome de transfusión feto-fetal, secuencia de anemia policitemia, síndrome de perfusión arterial reversa y restricción de crecimiento selectivo. Metodología . Se aplicó la técnica de inyección vascular placentaria para el reconocimiento de las anastomosis. Resultados . El número medio de anastomosis por placenta en el STFF (que fue la complicación más severa) fue de 8,2 ± 2,2. Las anastomosis AV y VA predominaron en un 83%. Hubo signos de discordancia placentaria en 30% de las placentas, y un 40% de placentas presentaron cordón de inserción velamentosa. Conclusiones. Las anastomosis vasculares no solo están implicadas en la etiología de las principales patologías propias de gestaciones monocoriónicas, sino que también influyen en su manejo. Creemos que un adecuado estudio placentario de cada uno de estos casos mediante la técnica de inyección vascular placentaria sería indispensable en los centros que aspiran a desarrollar manejos diferenciados de terapia fetal para cada una de estas complicaciones.
ABSTRACT Introduction: Twin pregnancies are classified into two groups: monochorionic (MC) and dichorionic (DC). MC twins are 5 to 6 times more likely to have an adverse perinatal outcome. The study of a group of 22 placentas from patients with monochorionic twin pregnancy who presented with complications such as feto-fetal transfusion syndrome (FFTS), twin anemia polycythemia sequence (TAPS), twin reverse arterial perfusion syndrome (TRAP) and selective intrauterine growth restriction (sIUGR) is presented. Objective: To determine the predominant types of anastomoses in placentas with feto-fetal transfusion syndrome, twin anemia polycythemia sequence, reverse arterial perfusion syndrome and selective intrauterine growth restriction. Methodology: The placental injection technique was applied for the recognition of anastomoses. Results: The mean number of anastomoses per placenta in STFF, which was the most severe complication, was 8.2 ± 2.2. The AV and VA anastomoses predominated in 83%. There were signs of placental discordance in 30% of placentas, and 40% of placentas presented velamentous cord insertion. Conclusions: Vascular anastomoses are not only involved in the etiology of the main pathologies of monochorionic gestations, but also influence their management. We believe that an adequate placental study of each of these cases by means of the placental vascular injection technique would be essential in centers that aspire to develop differentiated fetal management for each of these complications.
ABSTRACT
INTRODUCTION: Thanks to shared circulation in monochorionic twins, single intrauterine fetal death (IUD) may lead to acute feto-fetal transfusion (aFFTR). The objective of the study was to describe our model of aFFTR simulation after IUD in monochorionic (MC) twins. METHODS: Prospective study analyzed 99 fresh MC placentas with the physiological course. A specially designed protocol was used for the preparation and analysis of the placentas. A pair of infusion sets fixed together using a mechanical mercury sphygmomanometer cuff was connected to the cannulated umbilical arteries. The tonometer was pressurized up to 30 and 40 mmHg. A positive finding of aFFTR was determined as the amount exceeding 1 ml of dye flowed out of the umbilical cord simulating a dead fetus. The number and types of anastomoses, types, and distances between cords insertions, and the size of the placental areas for each fetus were also statistically analyzed. The placental angioarchitecture with and without proven aFFTR was statistically compared, odds ratio (OR) and multivariable logistic analysis were performed. RESULTS: A total of 49/99 (49.5%) cases of aFFTR was proven, and the average transfusion time of 1 ml was 30 s (19-46 s). aFFTR was present in 49/78 (62.8%) of placentas with arterio-arterial (AA) anastomosis. The median diameter of AA anastomoses with the present, and absent aFFTRF was 2.0 mm and 1.0 mm, respectively. The proven interfetal transfusion was 8%, 31%, and 61% in AA anastomoses with a diameter below 0,5 mm, 0,5-1,5 mm, and above 1,5 mm, respectively (p < 0,001). AA anastomoses diameter >1.5 mm had OR of 44.2 (95% CI 5.54-352.39). In the case of coexistence of AA anastomosis and umbilical cord distance ≤5th percentile, the aFFTRF occurred in 90.9%. DISCUSSION: The potential risk of aFFTR in monochorionic twins is mainly due to the presence and nature of AA anastomoses. The diameter and length of the vessels play a crucial role, which is clinically related to the distance of the umbilical cords insertions.
