0000000000040930
AUTHOR
Michael Tchirikov
Monochorionic twin pregnancy: screening, pathogenesis of complications and management in the era of microinvasive fetal surgery
Objective The management of monochorionic (MC) twin pregnancies varies in different medical centers. This paper compares screening methods to predict the complications of the MC twin pregnancy and different treatment methods. Methods We performed a literature search without language restriction in Cochrane library and PubMed (1970-2009). Case series and cohort screening studies, pathogenesis and management of complications of MC pregnancy were included. Results Elevated risk for intrauterine fetal death (IUFD) and twin-to-twin transfusion syndrome (TTTS) can be detected sonographically. Monitoring of MC pregnancies at increased risk and regular training sessions for the operating team combi…
Cardiac output following fetoscopic coagulation of major placental vessels in fetal sheep.
Objectives To measure changes in cardiac output (CO) after partial cord occlusion in fetal sheep in order to investigate pathophysiological fetal adaptation mechanisms in a simulated acute placental insufficiency model under standardized conditions, with the aim of finding relevant methods for monitoring human fetuses during stress situations. Methods We used minimally invasive, percutaneous endoscopic techniques to close umbilical vessels in mid-gestational fetal sheep. Placental blood flow was reduced by preferentially closing first arterial and then the concomitant venous umbilical vessels within a short time interval. The investigations were carried out on 11 pregnant ewes at a median g…
Neonatal outcome following long-distance air travel for fetoscopic laser coagulation treatment of twin-to-twin transfusion syndrome
Abstract Objective To investigate the impact of undertaking long-distance air travel to a specialized medical center while pregnant in order to undergo fetoscopic laser coagulation (FLC) for twin-to-twin transfusion syndrome (TTTS). Methods A retrospective cohort study was conducted of women with TTTS who travelled by air (n = 16) or land (n = 61) to the Centre of Perinatal Diagnosis and Microinvasive Fetal Surgery, Mainz, Germany, between January 1, 2006, and December 31, 2010. All women underwent FLC on arrival at the study center. Neonatal outcome, postoperative neonatal survival rates, and rates of adverse effects were recorded. Results The postoperative survival rate for a single twin …
A combination of umbilical artery PI and normalized blood flow volume in the umbilical vein: Venous–arterial index for the prediction of fetal outcome
Abstract Objective The objective was to assess the diagnostic power of the umbilical venous–arterial index (VAI) as a combination of the pulsatility index in the umbilical artery and the normalized blood flow volume in the umbilical vein for the prediction of poor fetal outcome. Study design This was a prospective clinical study in which the umbilical artery PI (UAPI), the normalized umbilical vein blood volume flow rate ( n UV; ml/min/kg estimated fetal body weight), the venous–arterial index (VAI; n UV/UAPI), and the pulsatility index (PI) in the umbilical artery (UA), uterine artery (utA), middle cerebral artery (MCA), and aorta were determined in 181 fetuses once (at between 17 and 41 w…
Dilation of the ductus venosus by stent implantation increases placental blood perfusion in fetal sheep.
The reduction of resistance to flow in the ductus venous (DV) and a decrease of blood supply to the liver serve for the survival of the fetus during hypoxia. The present study investigated the influence of the increased diameter of the DV on placental blood perfusion.In 15 ewes with twin pregnancies at gestational ages of 117 +/- 4 days, a stent (4 or 5 mm) was placed into the DV of 1 twin (DV(stent) group) under ultrasound guidance. Blood flow rates in the umbilical vein (UV) and DV of both fetuses were measured using Doppler ultrasound. Eight pairs of twin fetuses were included for the final analysis.The dilatation of the DV increased the blood flow volume rate passed through the DV from …