F. Slaghekke

Prevalence, size, number and localization of vascular anastomoses in monochorionic placentas

INTRODUCTION Most monochorionic (MC) twin pregnancies have an uncomplicated course, but some develop severe complications including selective intrauterine growth restriction (sIUGR), twintwin transfusion syndrome (TTTS) and twin anemia-polycythemia sequence (TAPS). The underlying pathogenesis of these various complications is associated with the ubiquitous presence of vascular anastomoses in MC placentas. METHODS The aim of this study was to estimate the prevalence, number, size and localization of the anastomoses in sIUGR, TTTS and TAPS placentas compared to normal MC placentas using color dye injection. We excluded MC twin pregnancies treated with fetoscopic laser surgery or selective feticide. RESULTS A total of 235 placentas fulfilled the inclusion criteria: 126 normal MC, 47 TTTS, 46 sIUGR and 16 spontaneous TAPS. Median number of anastomoses in normal MC, sIUGR, TTTS and TAPS placentas was 8 (IQR: 4-12), 8 (IQR: 5-14), 7 (IQR: 5-11) and 4 (IQR: 3-5), respectively. The prevalence of arterio-arterial (AA) anastomoses in normal MC, sIUGR, TTTS and TAPS placentas was 96%, 98%, 47% and 19%, respectively. We found AV anastomoses to be evenly distributed along the vascular equator in all MC placentas except in TAPS cases, where anastomoses were mostly localized near the margin. We also found that, in sIUGR and TTTS placentas, AA anastomoses tended to be at the center of the placenta. CONCLUSION The present study shows that the prevalence, size, number and localization of the various types of anastomoses differ between normal MC, sIUGR, TTTS and TAPS placentas.

Arterio-Arterial Anastomoses do not Prevent the Development of Twin Anemia-Polycythemia Sequence

Monochorionic twin pregnancies are associated with increased perinatal morbidity and mortality. The vascular placental anastomoses in these pregnancies can cause severe complications. We describe a case of twin anemia-polycythemia sequence (TAPS) with an atypical placental angioarchitecture. During pregnancy serial ultrasound examinations of both twins revealed no amniotic fluid discordance and no abnormal Doppler ultrasound measurements (umbilical cord pulsatility index and middle cerebral artery peak systolic velocity). The twins, born at 33 + 3 weeks gestation after spontaneous onset of labour, were found to be anemic and polycythemic, respectively. Placental examination with colored dye injection showed, apart from small ateriovenous anastomoses, an arterio-arterial anastomosis. As arterio-arterial anastomoses have not been described in cases with spontaneous TAPS to date, it was postulated that such anastomoses carried a protective effect against the development of this complication.

Laser surgery as a management option for twin anemia–polycythemia sequence

To evaluate the effectiveness of laser treatment for antenatally detected twin anemia–polycythemia sequence (TAPS) compared with intrauterine transfusion or expectant management.

Arterio-arterial vascular anastomoses in monochorionic placentas with and without twin-twin transfusion syndrome.

We performed a matched case-control study to analyze the placental angioarchitecture, in particular the diameter of arterio-arterial (AA) anastomoses in monochorionic placentas from pregnancies with twin-twin transfusion syndrome (TTTS) compared to a control group of uncomplicated monochorionic placentas. Placental angioarchitecture was analyzed using colored dye injection. AA anastomoses were detected in 37% (14/38) of TTTS placentas versus 91% (209/228) in control placentas (p < 0.001). The median diameter of AA anastomoses in the group with and without TTTS was 1.9 mm and 2 mm, respectively (p = 0.711). In conclusion, our findings show that AA anastomosis occur less frequently in TTTS placentas, supporting the concept of the protective role of AA anastomoses in TTTS. However, the size of the AA anastomosis, when present, does not appear to influence the pathophysiology of the disease.

Neurodevelopmental outcome in twin anemia–polycythemia sequence after laser surgery for twin–twin transfusion syndrome

To evaluate the long‐term neurodevelopmental outcome in children who developed twin anemia–polycythemia sequence (TAPS) after fetoscopic laser surgery for twin–twin transfusion syndrome (TTTS).

Intrauterine transfusion combined with partial exchange transfusion for twin anemia polycythemia sequence: Modeling a novel technique

INTRODUCTION Twin anemia-polycythemia sequence (TAPS) is a newly described disease in monochorionic twin pregnancies, characterized by large inter-twin hemoglobin differences. Optimal management for TAPS is not clear. One of the possible treatment modalities is intrauterine blood transfusion (IUT) in the donor with or without combination of partial exchange transfusion (PET) in the recipient. METHODS We applied a computational model simulation to illustrate the mechanism of IUT with and without PET in TAPS occurring after laser surgery for twin-twin transfusion syndrome (TTTS). Model simulations were performed with the representative anastomotic pattern as observed during laser intervention, and after placental dye injection. RESULTS The model was tested against different cases where IUT was combined with PET for the treatment of post-laser TAPS. Model simulations using the observed anastomotic pattern showed a significant reduction of hyperviscosity in the recipient after IUT/PET compared to IUT without PET. DISCUSSION In this model simulation we show that the addition of PET to IUT reduces the severity of polycythemia in the recipient. PET may thus be important to prevent complications of hyperviscosity. CONCLUSION This model simulation shows the beneficial effect of PET for the recipient in TAPS cases treated with IUT.

Placental share and hemoglobin level in relation to birth weight in twin anemia- polycythemia sequence

INTRODUCTION Twin anemia-polycythemia sequence (TAPS) is a newly described form of chronic twin transfusion. Previous observational studies noted a discordance between birth weight and individual placental share in TAPS. The purpose of this study was to investigate if fetal growth in monochorionic (MC) twins with TAPS is determined by placental share or by the net inter-twin blood transfusion. METHODS All consecutive MC twin placentas of live-born twin pairs with and without TAPS examined at our center between June 2002 and February 2014 were included in this study. Hemoglobin (Hb) levels and individual placental share were evaluated at birth and correlated with birth weight share. We excluded MC twin pregnancies with twin-twin transfusion syndrome. RESULTS A total of 270 MC twin pregnancies (TAPS group, n = 20; control group without TAPS, n = 250) were included in this study. Donors with TAPS had a lower birth weight than recipients in 90% (18/20) of cases, but a larger placental share in 65% (13/20) of cases. In the TAPS group, birth weight share was positively correlated with Hb share at birth (P < 0.01) but not with placental share (P = 0.54). In the control group without TAPS, birth weight share was strongly correlated with placental share (P < 0.01) but not with Hb share (P = 0.14). DISCUSSION A relatively larger placental share may enable the survival of the anemic twin in TAPS. CONCLUSION In contrast with uncomplicated MC twins, fetal growth in MC twins with TAPS is determined primarily by the net inter-twin blood transfusion instead of placental share.

Simulator training in fetoscopic laser surgery for twin-twin transfusion syndrome: a pilot randomized controlled trial

To evaluate the effect of a newly developed training curriculum on the performance of fetoscopic laser surgery for twin–twin transfusion syndrome (TTTS) using an advanced high‐fidelity simulator model.

Simulator training in fetoscopic laser surgery for TTTS: a pilot randomized controlled trial

To evaluate the effect of a newly developed training curriculum on the performance of fetoscopic laser surgery for twin–twin transfusion syndrome (TTTS) using an advanced high‐fidelity simulator model.

Iatrogenic perforation of intertwin membrane after laser surgery for twin-to-twin transfusion syndrome

To evaluate management and outcome of iatrogenic monoamniotic twins (iMAT) compared with twins with intact intertwin dividing membranes after laser surgery for twin‐to‐twin transfusion syndrome (TTTS).