Spontaneous Twin Anemia-polycythemia Sequence Research Articles

Treatment of Twin Anemia Polycythemia Sequence with Donor Transfusion and Partial Recipient Exchange Transfusion: Procedural Considerations and Outcomes.

Background: Intrauterine transfusion (IUT) of the donor and partial exchange (pET) of the recipient is a temporizing treatment for pregnancies with Twin Anemia Polycythemia Sequence (TAPS). We aimed to provide a detailed description of the procedural approach and outcomes for sequential donor IUT and recipient pET in TAPS. Methods: Retrospective study of spontaneous TAPS referred to the Johns Hopkins Center for Fetal Therapy treated with donor IUT followed by recipient pET utilizing a double-syringe setup. Procedural characteristics and outcomes as well as the accuracy of existing transfusion formulas were analyzed and compared with the literature. Results: 5 of 78 patients with spontaneous TAPS underwent a total of 19 combined IUT/pET procedures (median first procedure to delivery interval 5.6 weeks [interquartile range IQR 1.9-6.0]). One pET was stopped due to fetal deceleration. The patients were delivered at 33.0 weeks [IQR 31.9-33.3] with two survivors and no neonatal transfusion requirements. The IUT volume was 48 mL [IQR 39-63 mL] and the pET volume was 32 mL [IQR 20-50], utilizing aliquots of 5-20 mL for the latter (p = 0.021). For the IUTs, the assumption of a fetal blood volume below 150 mL/kg underestimated the required transfusion volume. For the pETs, all formulas required adjustment of the dilution volume based on bedside testing (p < 0.05 for all). Conclusions: Donor transfusion followed by partial exchange in the recipient can prolong pregnancy in spontaneous TAPS and obviate the need for neonatal transfusion. A double-syringe setup facilitates efficient saline exchange. Because the accuracy of volume formulas is limited, bedside testing is recommended to achieve the target hemoglobin.

Perinatal outcomes of fetoscopic selective laser photocoagulation for spontaneous twin-anemia polycythemia sequence.

Antenatal management of monochorionic pregnancies complicated by twin anemia polycythemia sequence (TAPS) remains sub-optimally defined. Our objective was to evaluate the safety and efficacy of fetoscopic selective laser photocoagulation with respect to fetal and neonatal survival. A case series is reported with patients referred to the Texas Children's Fetal Center for evaluation and management of suspected spontaneous TAPS without concomitant twin-to-twin syndrome from 2014 to 2023. All evaluations were performed by our team and patients with stage II-IV TAPS were offered expectant management, intrauterine transfusion, or laser therapy. Cases of post-laser TAPS were excluded from this study. Pregnancy and neonatal outcomes were obtained from electronic medical records. During a 10-year time period, 18 patients presented to our center for the management of TAPS. Thirteen patients had stage II-IV TAPS (13/18, 72%) and elected to proceed with laser photocoagulation. All procedures were completed, and "solomonization" was performed for 12/13. Normalization of middle cerebral artery Dopplers in both fetuses was noted after all cases. There was one intrauterine fetal death of the 26 viable fetuses after laser treatment, which was complicated by selective growth restriction. Most patients (12/13) were delivered by Cesarean section at a mean gestational age of 29±3weeks. Subsequently, there was one ex-donor neonatal death in an infant who had prenatal hydrops. Overall, 30-day postnatal survival was 24/26 fetuses (92.3%). In the setting of spontaneous TAPS, laser therapy is feasible and appears to be an effective approach with overall favorable perinatal outcomes.

Large proximal intertwin vascular anastomoses as a rare cause of twin anaemia-polycythaemia sequence (TAPS): case report

Background: Twin anaemia-polycythaemia sequence (TAPS) is a form of chronic twin-to-twin transfusion syndrome (TTTS) secondary to slow unidirectional blood flow across minuscule arteriovenous (AV) anastomoses. We present a case of presumed TAPS secondary to unusual, large, proximal anastomoses. Case report: Monochorionic diamniotic (MCDA) twins were born at 25+6 weeks gestation following intrauterine fetal demise. Ultrasound scan two weeks beforehand showed mild growth discordance (0.7%) with normal amniotic fluid volumes. At post-mortem, Twin 1 (825g) appeared pale and Twin 2 (770g) plethoric. Placental examination revealed side-by-side, fused cord insertions at the extreme placental edge, with one artery-to-artery (AA) anastomosis close to the cord insertion and one umbilical vein-to-umbilical vein (UV-UV) anastomosis within Twin 1's cord. All chorionic veins drained into Twin 1’s UV proximal to the anastomosis. Discussion: TAPS is characterised by anaemia in the donor twin and polycythaemia in the recipient twin without oligohydramnios or polyhydramnios and is typically caused by very small (<1 mm diameter) AV anastomoses. To our knowledge, this is the first reported case of TAPS associated with large AA and UV-UV anastomoses. The possibility of acute exsanguination from Twin 1 into Twin 2 following the demise of Twin 2 cannot be excluded. Reference 1. Tollenaar LSA, Slaghekke F, Lewi L, et al. Spontaneous twin anemia polycythemia sequence: diagnosis, management, and outcome in an international cohort of 249 cases. Am J Obstet Gynecol 2021; 224: 213.

Neonatal management and outcome in complicated monochorionic twins: What have we learned in the past decade and what should you know?

Monochorionic (MC) twin pregnancies are at increased risk of neonatal morbidity and mortality due to the shared placenta with vascular connections that can give rise to various complications, including twin-twin transfusion syndrome, twin anemia polycythemia sequence (TAPS), selective fetal growth restriction, and other hematological imbalances at birth. Each complication presents its own challenges and considerations in the neonatal period. Measurement of hemoglobin levels and reticulocyte count is required to establish a correct diagnosis. Placenta dye injection is needed to properly distinguish between the various conditions. Risk factors for adverse outcome in MC twins include prematurity, severe cerebral injury, and the type of MC pregnancy complication. We, therefore, recommend cerebral ultrasound examinations in all complicated MC twins at birth to rule out a severe brain injury. Lastly, we strongly encourage screening for hearing loss using automated auditory brainstem response in all spontaneous TAPS donors to prevent permanent speech development delay.

Perinatal outcome of pregnancy complicated by twin anemia-polycythemia sequence: systematic review and meta-analysis.

To report the perinatal outcome of monochorionic diamniotic (MCDA) twin pregnancies complicated by twin anemia-polycythemia sequence (TAPS), according to the type of TAPS (spontaneous or postlaser) and the management option adopted. MEDLINE, EMBASE and The Cochrane Library databases were searched for studies reporting on the outcome of twin pregnancies complicated by TAPS. Inclusion criteria were non-anomalous MCDA twin pregnancies with a diagnosis of TAPS. The primary outcome was perinatal mortality; secondary outcomes were neonatal morbidity and preterm birth (PTB). The outcomes were stratified according to the type of TAPS (spontaneous or following laser treatment for twin-twin transfusion syndrome) and the management option adopted (expectant, laser surgery, intrauterine transfusion (IUT) or selective reduction (SR)). Random-effects meta-analysis of proportions was used to analyze the data. Perinatal outcome was assessed according to whether TAPS occurred spontaneously or after laser treatment in 506 pregnancies (38 studies). Intrauterine death (IUD) occurred in 5.2% (95% CI, 3.6-7.1%) of twins with spontaneous TAPS and in 10.2% (95% CI, 7.4-13.3%) of those with postlaser TAPS, while the corresponding rates of neonatal death were 4.0% (95% CI, 2.6-5.7%) and 9.2% (95% CI, 6.6-12.3%), respectively. Severe neonatal morbidity occurred in 29.3% (95% CI, 25.6-33.1%) of twins after spontaneous TAPS and in 33.3% (95% CI, 17.4-51.8%) after postlaser TAPS, while the corresponding rates of severe neurological morbidity were 4.0% (95% CI, 3.5-5.7%) and 11.1% (95% CI, 6.2-17.2%), respectively. PTB complicated 86.3% (95% CI, 77.2-93.3%) of pregnancies with spontaneous TAPS and all cases with postlaser TAPS (100% (95% CI, 84.3-100%)). Iatrogenic PTB was more frequent than spontaneous PTB in both groups. Perinatal outcome was assessed according to the management option adopted in 417 pregnancies (21 studies). IUD occurred in 9.8% (95% CI, 4.3-17.1%) of twins managed expectantly and in 13.1% (95% CI, 9.2-17.6%), 12.1% (95% CI, 7.7-17.3%) and 7.6% (95% CI, 1.3-18.5%) of those treated with laser surgery, IUT and SR, respectively. Severe neonatal morbidity affected 27.3% (95% CI, 13.6-43.6%) of twins in the expectant-management group, 28.7% (95% CI, 22.7-35.1%) of those in the laser-surgery group, 38.2% (95% CI, 18.3-60.5%) of those in the IUT group and 23.3% (95% CI, 10.5-39.2%) of those in the SR group. PTB complicated 80.4% (95% CI, 59.8-94.8%), 73.4% (95% CI, 48.1-92.3%), 100% (95% CI, 76.5-100%) and 100% (95% CI, 39.8-100%) of pregnancies after expectant management, laser surgery, IUT and SR, respectively. The present meta-analysis provides pooled estimates of the risks of perinatal mortality, neonatal morbidity and PTB in twin pregnancies complicated by TAPS, stratified by the type of TAPS and the management option adopted. Although a direct comparison could not be performed, the results from this systematic review suggest that spontaneous TAPS may have a better prognosis than postlaser TAPS. No differences in terms of mortality and morbidity were observed when comparing different management options for TAPS, although these findings should be interpreted with caution in view of the limitations of the included studies. Individualized prenatal management, taking into account the severity of TAPS and gestational age, is currently the recommended strategy. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

VP39.09: Placental trichotomy and starry‐sky liver as early signs of spontaneous twin anemia polycythemia sequence in a monochorionic‐triamniotic pregnancy

VP39.09: Placental trichotomy and starry‐sky liver as early signs of spontaneous twin anemia polycythemia sequence in a monochorionic‐triamniotic pregnancy

Feasibility of fetal left modified myocardial performance index in twin anemia polycythemia sequence and perinatal outcomes after antenatal intervention

Objective To evaluate the feasibility and clinical value of fetal left modified myocardial performance index (Mod-MPI) in assessment and management of prenatal twin anemia polycythemia sequence (TAPS). Methods We retrospectively reviewed fetuses with TAPS diagnosed prenatally between 2015 and 2019 at Asan Medical Center. Doppler ultrasound evaluation including the peak systolic velocity (PSV) of the middle cerebral artery (MCA) and fetal echocardiography including left Mod-MPI were evaluated and followed up after antenatal management. Results Among 10 cases of fetal twin pregnancies with prenatal TAPS, six were spontaneous and four were post-laser TAPS. Left Mod-MPI was abnormal in one or both twins of nine cases (90%) including all post-laser TAPS (n = 4) and 83.3% of spontaneous TAPS (n = 5). Three recipients, one donor and three former recipients/new donors had elevated left Mod-MPI values, and one donor, one recipient, two former donors/new recipients had decreased values. Antenatal intervention was performed in eight cases with intrauterine transfusion (n = 4), fetoscopic laser surgery (n = 2), radiofrequency ablation (n = 1), and intrauterine transfusion followed by radiofrequency ablation (n = 1). The remaining two cases were either delivered or managed expectantly. MCA-PSV and left Mod-MPI became normal on the follow-up scans in all cases except the delivered case. There were four fetal deaths: two occurred spontaneously and two were selectively terminated by radiofrequency ablation. Overall perinatal survival per fetus was 80% (16/20) and the median gestational age at delivery was 34.4 (range, 29.2–37.4) weeks. Neither postnatal death nor neurodevelopmental delay occurred during a median follow-up of 13 months (range, 0.25–60 months). Conclusion Fetal left Mod-MPI was useful for assessment of compromised fetal cardiac function in cases with prenatal TAPS. Application of fetal left Mod-MPI in prenatal staging of TAPS might help evaluate the severity of TAPS and decide timely antenatal intervention.

Longer distance between umbilical cord insertions is associated with spontaneous twin anemia polycythemia sequence.

The aim of the study was to investigate the placental characteristics in spontaneous twin anemia polycythemia sequence. A retrospective case-control study of spontaneous twin anemia polycythemia sequence, twin-to-twin transfusion syndrome and normal monochorionic diamniotic twin pregnancies was performed. The primary outcome was placental characteristics. The prevalence of artery-artery anastomoses in spontaneous twin anemia polycythemia sequence and twin-to-twin transfusion syndrome groups was significantly lower than in the normal monochorionic diamniotic twin group (40.0% vs 33.3% vs 88.8%, respectively, P<.001). The total number of vascular anastomoses in the spontaneous twin anemia polycythemia sequence group (with range given in parentheses) was significantly lower than in the two control groups (3 [1-6] vs 5 [1-14] vs 6 [1-20], P=.001/<.001/.794). The number of artery-vein anastomoses in the spontaneous twin anemia polycythemia sequence was significantly lower than in the two control groups (2 [1-5] vs 4 [1-13] vs 5 [1-19], P=.011/.001/1.000). The total diameter of all vascular anastomoses was significantly smaller in the spontaneous twin anemia polycythemia sequence than in the two control groups (0.9mm [0.3-4.7] vs 5.2mm [0.8-24.6] vs 7.3mm [1.0-25.1], P<.001/<.001/.104), as was the total diameter of artery-to-artery anastomoses (0.5mm [0.3-1.3] vs 2.0mm [0.5-11.8] vs 2.3mm [0.7-9.7], P=.003/<.001/1.000) and the total diameter of artery-to-vein anastomoses (0.8mm [0.3-2.1] vs 4.6mm [0.8-15.3] vs 4.0mm [0.2-21.8], P<.001/<.001/1.000). The ratio between the distance of the two umbilical cords insertion points and the placental maximum diameter in the spontaneous twin anemia polycythemia sequence group was significantly larger than in the two control groups (0.78 [0.49-0.99] vs 0.64 [0.32-1.00] vs 0.55 [0.05-1.00], P=.033/<.001/.138). In spontaneous twin anemia polycythemia sequence placentas, the number of superficial vascular anastomoses is lower, their diameter is smaller and the distance between the two umbilical cord insertion points is longer.

Prevalence of placental dichotomy, fetal cardiomegaly and starry-sky liver in twin anemia-polycythemia sequence.

ABSTRACTObjectiveTo investigate the prevalence of three additional ultrasound markers, placental dichotomy, cardiomegaly and ‘starry‐sky’ liver, in monochorionic twin pregnancy with twin anemia–polycythemia sequence (TAPS).MethodsAll monochorionic twin pregnancies, diagnosed antenatally with TAPS at our center between 2006 and 2019, were reviewed retrospectively for the presence of placental dichotomy, cardiomegaly in the donor twin and a starry‐sky liver in the recipient twin. TAPS was diagnosed based on delta middle cerebral artery (MCA) peak systolic velocity (PSV) > 0.5 multiples of the median. The primary outcome was the prevalence of placental dichotomy, cardiomegaly, starry‐sky liver and at least one of these markers in both spontaneous and post‐laser TAPS. The secondary outcome was the prevalence of these ultrasound markers according to the antenatal stage of TAPS.ResultsA total of 91 monochorionic twin pregnancies with TAPS were eligible for analysis. Placental dichotomy was observed in 44% (40/91) of TAPS cases. A total of 70% (64/91) of the TAPS donors developed cardiomegaly and a starry‐sky liver was identified in 66% (53/80) of the TAPS recipients. The prevalence of cardiomegaly and starry‐sky liver was roughly comparable between spontaneous and post‐laser TAPS (69% (33/48) vs 72% (31/43) and 64% (25/39) vs 68% (28/41), respectively). Pregnancies with spontaneous TAPS showed a higher prevalence of placental dichotomy compared with post‐laser TAPS (63% (30/48) vs 23% (10/43)). At least one of the three ultrasound markers was detected in 86% (78/91) of TAPS cases, meaning that 14% (13/91) of cases presented solely with discordant MCA‐PSV values. There was a trend towards increased prevalence of all three ultrasound markers with increasing antenatal TAPS stage.ConclusionsPlacental dichotomy, fetal cardiomegaly and a starry‐sky liver are commonly found in TAPS pregnancy. Investigating the presence of these ultrasound markers can be of additional help in improving antenatal detection of TAPS in monochorionic twin pregnancy. © 2019 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Treatment and outcome of 370 cases with spontaneous or post-laser twin anemia-polycythemia sequence managed in 17 fetal therapy centers.

ABSTRACTObjectiveTo investigate the antenatal management and outcome in a large international cohort of monochorionic twin pregnancies with spontaneous or post‐laser twin anemia–polycythemia sequence (TAPS).MethodsThis study analyzed data of monochorionic twin pregnancies diagnosed antenatally with spontaneous or post‐laser TAPS in 17 fetal therapy centers, recorded in the TAPS Registry between 2014 and 2019. Antenatal diagnosis of TAPS was based on fetal middle cerebral artery peak systolic velocity > 1.5 multiples of the median (MoM) in the TAPS donor and < 1.0 MoM in the TAPS recipient. The following antenatal management groups were defined: expectant management, delivery within 7 days after diagnosis, intrauterine transfusion (IUT) (with or without partial exchange transfusion (PET)), laser surgery and selective feticide. Cases were assigned to the management groups based on the first treatment that was received after diagnosis of TAPS. The primary outcomes were perinatal mortality and severe neonatal morbidity. The secondary outcome was diagnosis‐to‐birth interval.ResultsIn total, 370 monochorionic twin pregnancies were diagnosed antenatally with TAPS during the study period and included in the study. Of these, 31% (n = 113) were managed expectantly, 30% (n = 110) with laser surgery, 19% (n = 70) with IUT (± PET), 12% (n = 43) with delivery, 8% (n = 30) with selective feticide and 1% (n = 4) underwent termination of pregnancy. Perinatal mortality occurred in 17% (39/225) of pregnancies in the expectant‐management group, 18% (38/215) in the laser group, 18% (25/140) in the IUT (± PET) group, 10% (9/86) in the delivery group and in 7% (2/30) of the cotwins in the selective‐feticide group. The incidence of severe neonatal morbidity was 49% (41/84) in the delivery group, 46% (56/122) in the IUT (± PET) group, 31% (60/193) in the expectant‐management group, 31% (57/182) in the laser‐surgery group and 25% (7/28) in the selective‐feticide group. Median diagnosis‐to‐birth interval was longest after selective feticide (10.5 (interquartile range (IQR), 4.2–14.9) weeks), followed by laser surgery (9.7 (IQR, 6.6–12.7) weeks), expectant management (7.8 (IQR, 3.8–14.4) weeks), IUT (± PET) (4.0 (IQR, 2.0–6.9) weeks) and delivery (0.3 (IQR, 0.0–0.5) weeks). Treatment choice for TAPS varied greatly within and between the 17 fetal therapy centers.ConclusionsAntenatal treatment for TAPS differs considerably amongst fetal therapy centers. Perinatal mortality and morbidity were high in all management groups. Prolongation of pregnancy was best achieved by expectant management, treatment by laser surgery or selective feticide. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Spontaneous twin anemia polycythemia sequence: diagnosis, management, and outcome in an international cohort of 249 cases

Twin anemia polycythemia sequence is a chronic form of unbalanced fetofetal transfusion through minuscule placental anastomoses in monochorionic twins, leading to anemia in the donor and polycythemia in the recipient. Owing to the low incidence of twin anemia polycythemia sequence, data on diagnosis, management, and outcome are limited. This study aimed to investigate the diagnosis, management, and outcome in a large international cohort of spontaneous twin anemia polycythemia sequence. Data from the international twin anemia polycythemia sequence registry, retrospectively collected between 2014 and 2019, were used for this study. A total of 17 fetal therapy centers contributed to the data collection. The primary outcomes were perinatal mortality and severe neonatal morbidity. Secondary outcomes included a risk factor analysis for perinatal mortality and severe neonatal morbidity. A total of 249 cases of spontaneous twin anemia polycythemia sequence were included in this study, 219 (88%) of which were diagnosed antenatally and 30 (12%) postnatally. Twin anemia polycythemia sequence was diagnosed antenatally at a median gestational age of 23.7 weeks (interquartile range, 9.7-28.8; range, 15.1-35.3). Antenatal management included laser surgery in 39% (86 of 219), expectant management in 23% (51 of 219), delivery in 16% (34 of 219), intrauterine transfusion (with partial exchange transfusion) in 12% (26 of 219), selective feticide in 8% (18 of 219), and termination of pregnancy in 1% (3 of 219) of cases. Perinatal mortality rate was 15% (72 of 493) for the total group, 22% (54 of 243) for donors, and 7% (18 of 242) for recipients (P<.001). Severe neonatal morbidity occurred in 33% (141 of 432) of twins with twin anemia polycythemia sequence and was similar for donors (32%; 63 of 196) and recipients (33%; 75 of 228) (P=.628). Independent risk factors for spontaneous perinatal mortality were donor status (odds ratio, 3.8; 95% confidence interval, 1.9-7.5; P<.001), antenatal twin anemia polycythemia sequence stage (odds ratio, 6.3; 95% confidence interval, 1.4-27.8; P=.016 [stage 2]; odds ratio, 9.6; 95% confidence interval, 2.1-45.5; P=.005 [stage 3]; odds ratio, 20.9; 95% confidence interval, 3.0-146.4; P=.002 [stage 4]), and gestational age at birth (odds ratio, 0.8; 95% confidence interval, 0.7-0.9; P=.001). Independent risk factors for severe neonatal morbidity were antenatal twin anemia polycythemia sequence stage 4 (odds ratio, 7.9; 95% confidence interval, 1.4-43.3; P=.018) and gestational age at birth (odds ratio, 1.7; 95% confidence interval, 1.5-2.1, P<.001). Spontaneous twin anemia polycythemia sequence can develop at any time in pregnancy from the beginning of the second trimester to the end of the third trimester. Management for twin anemia polycythemia sequence varies considerably, with laser surgery being the most frequent intervention. Perinatal mortality and severe neonatal morbidity were high, the former especially so in the donor twins.

Short- and long-term outcomes of preterm spontaneous twin anemia-polycythemia sequence.

Background In monochorionic twin pregnancy, placental anastomosis and inter-twin blood transfusion can result in specific complications, such as twin-twin transfusion syndrome (TTTS) and twin anemia-polycythemia sequence (TAPS). It is well established that adverse outcomes are increased in TTTS, but reports on the neonatal and long-term outcomes of TAPS are lacking. The objective of this study was to evaluate the neonatal and neurodevelopmental outcomes in spontaneous TAPS. Methods The study population consisted of monochorionic twin pregnancies with preterm birth (24-37 weeks of gestation) between November 2003 and December 2016 and in which cord blood was taken at the time of delivery. According to the result of hemoglobin in cord blood, the study population was divided into two groups: a spontaneous TAPS group and a control group. Neonatal and neurodevelopmental outcomes were compared between the two groups. Results During the study period, 11 cases were diagnosed as spontaneous TAPS (6.4%). The TAPS group had lower gestational age at delivery and had a higher risk for cesarean delivery. However, neonates with TAPS were not at an increased risk for neonatal mortality and significant neonatal morbidity. In addition, the frequency of severe cerebral lesion during the neonatal period and the risk of cerebral palsy at 2 years of age were not different between the two groups. Conclusion The spontaneous TAPS diagnosed by postnatal diagnostic criteria was not associated with the increased risk of adverse neonatal and neurodevelopmental outcomes. Further studies are needed to evaluate the morbidity of antenatally diagnosed TAPS.

High risk of long-term neurodevelopmental impairment in donor twins with spontaneous twin anemia-polycythemia sequence.

To evaluate the long-term neurodevelopmental and behavioral outcomes in surviving infants of pregnancies with spontaneous twin anemia-polycythemia sequence (TAPS), to compare outcome between donors and recipients, and to investigate potential risk factors for neurodevelopmental impairment (NDI). This was a retrospective study of a consecutive cohort of spontaneous-TAPS survivors delivered between 2005 and 2017 at the Leiden University Medical Center, The Netherlands. Neurological, motor, cognitive and behavioral development were assessed at a median age of 4 years. The primary outcome was NDI, which was a composite outcome of cerebral palsy, deafness, blindness and motor and/or cognitive delay. NDI was subdivided into two grades of severity: mild-to-moderate and severe NDI. Outcome was compared between surviving donor and recipient twins. Logistic regression analysis was used to assess risk factors for NDI. Forty-nine twin pregnancies complicated by spontaneous TAPS were eligible for inclusion. The perinatal survival rate was 83% (81/98) of twins. Neurodevelopmental assessment was performed in 91% (74/81) of surviving twins. NDI occurred in 30% (22/74) of TAPS survivors, and was found more often in donors (44%; 15/34) than in recipients (18%; 7/40) (odds ratio (OR), 4.1; 95% CI, 1.8-9.1; P = 0.001). Severe NDI was detected in 9% (7/74) of survivors and was higher in donors compared with recipients (18% (6/34) vs 3% (1/40)), although the difference did not reach statistical significance; P = 0.056). Donors demonstrated lower cognitive scores compared with recipients (P = 0.011). Bilateral deafness was identified in 15% (5/34) of donors compared with 0% (0/40) of recipients (P = 0.056). Parental concern regarding development was reported more often for donor than for recipient twins (P = 0.001). On multivariate analysis, independent risk factors for NDI were gestational age at delivery (OR, 0.7; 95% CI, 0.5-0.9; P = 0.003) and severe anemia (OR, 6.4; 95% CI, 2.4-17.0; P < 0.001). Surviving donor twins of pregnancies complicated by spontaneous TAPS have four-fold higher odds of NDI compared with recipient cotwins, are at increased risk of cognitive delay and have a high rate of deafness. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Clinical outcome and placenta characteristics of spontaneous twin anemia-polycythemia sequence

Objective: To investigate the clinical outcome and placental characteristics of spontaneous twin anemia-polycythemia sequence (sTAPS). Methods: Twelve cases with sTAPS delivered in Peking University Third Hospital from May 2013 to August 2016. The data of ultrasound characteristics, gestational age at delivery, and 1 minute Apgar score were analyzed, retrospectively. Placental superficial vascular anastomoses, placental territory discordance and the ratio of umbilical cords insertion distance to the longest placental diameter were also analyzed. Results: (1) Only 1 case of sTAPS was diagnosed prenatally, the others were diagnosed postnatally because the fetal middle cerebral artery(MCA) doppler was not measured regularly. Five cases were complicated with selective intrauterine growth restriction (sIUGR). The median gestational age at delivery was 32.8 weeks (31-37 weeks) . The pregnancies were terminated because 3 cases were sIUGR type Ⅰ, 1 case was sIUGR type Ⅱ, 1 case was sIUGR type Ⅲ, 2 cases were fetal distress, 2 cases were severe pre-eclampsia, 2 cases were premature rupture of membrane, 1 case was fetal hydrops with abnormal doppler waveforms of ductus venouses. (2) When 5 sIUGR cases were excluded, there was no difference between the twins in birth weight [1 797 g (940-2 620 g) , 1 648 g (980-2 500 g) ; P=0.688]. The hemoglobin (Hb) level in all donor was significantly lower than recipient (P=0.000) and the inter-twin Hb difference was 147.6 g/L (84.0-216.0 g/L). While the reticulocyte percentage in donor was significantly higher than recipient (P=0.013) and reticulocyte percentage ratio was 3.60 (1.04-7.50). Five donor newborns had neonatal asphyxia, including 1 severe asphyxia, while no asphyxia happened in the recipient twins. (3) Arterio-arterial (A-A) anastomoses, veno-venous (V-V) anastomoses, arterio-venous (A-V) anastomoses were found in 3, 1 and 11 placentas, respectively. The total number of anastomoses was 2 (1-5) and the total diameter was 1.1 mm (0.4-2.1 mm), including 0 (0-1) A-A anastomoses with 0.2 mm (0.0-0.9 mm) in diameter and 2 (0-5) A-V anastomoses with 0.7 mm (0.0-2.1 mm) in diameter. The placental territory discordance was 0.17 (0.02-0.40) and the ratio of umbilical cords insertion to the longest placental diameter was 0.82 (0.34-0.99). Conclusions: The pathogenesis of sTAPS might result from slow and chronic blood transfusion from donor to recipient through a few minuscule vascular anastomoses in the placenta. In all monochorionic twins, especially sIUGR cases, MCA doppler should be monitored closely in the second and third trimester, in order to diagnose and manage sTAPS in time.

Re: Review of the correlation between blood flow velocity and polycythemia in the fetus, neonate and adult: appropriate diagnostic levels need to be determined for twin anemia-polycythemia sequence. A. Lucewicz, K. Fisher, A.Henry and A. W. Welsh. Ultrasound Obstet Gynecol 2016; 47: 152-157.

Linked Comment: Ultrasound Obstet Gynecol 2016; 47: 152–157 Lucewicz and colleagues review the fetal, neonatal and adult literature on the use of a decreased middle cerebral artery peak systolic velocity (MCA-PSV) to diagnose fetal polycythemia. They conclude there is too little evidence to assume reduced MCA-PSV in polycythemic fetuses and therefore a decreased MCA-PSV should not be part of the definition of twin anemia–polycythemia sequence (TAPS). An accurate diagnosis of TAPS is important because this transfusion imbalance occurs in about 5% of monochorionic twin pregnancies and, if undiagnosed, may lead to late intrauterine demise or long-term morbidity1. In TAPS, one twin becomes progressively anemic and the other becomes increasingly polycythemic due to a chronic transfer of red blood cells via minuscule and usually unidirectional anastomoses. Whereas twin–twin transfusion syndrome (TTTS) is essentially a severe amniotic fluid discordance prior to fetal viability, spontaneous TAPS is characterized by severe hemoglobin discordance after fetal viability. TAPS can also occur as a complication of incomplete laser surgery in which minuscule, usually unidirectional, anastomoses are missed. This iatrogenic form of TAPS generally manifests itself within 1 to 5 weeks after the procedure and complicates up to 13% of surviving twin pairs. TAPS is diagnosed antenatally based on the presence of an elevated MCA-PSV (>1.5 multiples of the median (MoM)) in the anemic donor in combination with a decreased MCA-PSV (≤ 1MoM) in the polycythemic recipient. Although an MCA-PSV > 1.5 MoM has been validated to diagnose fetal anemia, data are lacking on a decreased MCA-PSV to predict fetal polycythemia. Whereas fetal anemia occurs in different scenarios, such as alloimmunization, parvovirus infection, fetomaternal hemorrhage and the anemic twin of a TAPS pair, polycythemia is a problem only in the setting of TAPS and thus in about 1 in 10 000 pregnancies. The strength of the report by Lucewicz and colleagues is that it exposes this knowledge gap; although both fetal and neonatal data seem to support the concept that polycythemia reduces blood flow velocity in the brain. A limitation of the report is that it does not bring forward any new data to fill the gap. However, in June last year, a joint publication by three European tertiary care centers2 showed that an MCA-PSV ≤ 1 MoM (according to the reference ranges by Klaritsch et al.3) accurately predicts polycythemia in the setting of TAPS with a sensitivity of 94% (95% CI, 71–99%) and a specificity of 100% (95% CI, 91–100%). Therefore, an MCA-PSV > 1.5 MoM in one twin coinciding with an MCA-PSV ≤ 1 MoM in the other remains the best antenatal definition for TAPS – until a better alternative is found.

Atypical twin-to-twin transfusion syndrome: prevalence in a population undergoing fetoscopic laser ablation of communicating placental vessels

The diagnosis of twin-to-twin transfusion syndrome (TTTS) usually relies the presence of polyhydramnios in one sac with concomitant oligohydramnios in the other sac in a monochorionic diamniotic twin pregnancy. However, TTTS does not always show a linear progression and may present with cardiac compromise or critically abnormal Doppler velocimetry ineither fetus before fluid measurements meet the typically used cutoff. The aim of this study was to investigate the prevalence of atypical presentations of TTTS in a population undergoing laser fetoscopy. We performed a retrospective review of our database of TTTS laser fetoscopy from 2003 to the present. Our center is the regional referral center in the Pacific Northwest for minimally invasive treatment of complicated monochorionic twin pregnancies. Cases were labeled as "atypical" if fluid discordance did not meet formal TTTS criteria (oligohydramnios defined as maximum vertical pocket [MVP] <2 and polyhydramnios defined as MVP >8 before 20 weeks and >10 after 20 weeks). The rationale for consideration of laser fetoscopy was other evidence of severe TTTS such as significant cardiac compromise, evidence of twin anemia polycythemia sequence (TAPS), or persistent critically abnormal cord Dopplers. Three hundred seventy-nine cases of fetoscopic laser ablation for TTTS and its variants were available for review. Sixteen cases were excluded for a triplet pregnancy, 4 due to septostomy prior to referral to our center, 3 for monoamniotic pregnancy, and 11 for previous laser fetoscopy. Three hundred forty-five cases remained for evaluation. Among these, 25 cases were identified as "atypical," equaling 7.24% of our population. Eleven of these were for stage 3 recipient disease, 3 were for stage 4 recipient disease, 4 were for stage 3 both in recipient and donor, 4 were for stage 3 donor disease, and 3 were for spontaneous TAPS. In TTTS, severity of fetal compromise does not consistently correlate with fluid abnormalities meeting established criteria. This may be especially true in rapidly progressing cases. Attempts at rigid diagnostic amniotic fluid criteria may underestimate the severity and incidence of TTTS. This underscores the importance of careful surveillance, including arterial and venous Doppler velocimetry, of all monochorionic pregnancies.

Color Difference in Placentas with Twin Anemia-Polycythemia Sequence: An Additional Diagnostic Criterion?

Objective: To determine the color intensity difference between the 2 placental shares in monochorionic placentas with twin anemia-polycythemia sequence (TAPS). Methods: We evaluated all digital pictures of TAPS placentas examined at our center and compared them to a control group of uncomplicated monochorionic placentas. We determined the color intensity of individual placental share on the maternal side of each monochorionic placenta using an image processing program and calculated the color difference ratio (CDR). Results: Digital pictures of 19 TAPS and 19 uncomplicated monochorionic placentas were included in this study. The TAPS group consisted of 12 spontaneous TAPS placentas (63%) and 7 post-laser TAPS placentas (37%). The median CDR in the group with TAPS was significantly higher than in the control group, 2.73 (range 1.73-6.36) versus 1.09 (range 1.00-1.35), respectively (p < 0.01). We found a positive correlation between CDR and inter-twin hemoglobin (Hb) difference in the TAPS group (R = 0.66, p < 0.01) but not in the control group (R = 0.04, p = 0.87). Conclusion: TAPS placentas have a significantly higher CDR compared to uncomplicated monochorionic twin placentas. Large inter-twin Hb differences in TAPS are associated with higher CDR.

EP07.10: Are the current antenatal diagnostic criteria for twin anemia polycythemia sequence adequate?

We describe two cases of spontaneous twin anemia polycythemia sequence (TAPS). In Case 1, TAPS was suspected at 21 weeks because of discrepancy in placental echogenicity in two portions of the placenta. However, the antenatal (AN) diagnostic criteria for TAPS were not met. MCAPSV of the recipient was low but that of the donor was never >1.5 MoM. The diagnosis was confirmed after delivery. In Case 2, MCAPSV of the twins at 30 weeks were 0.89 and 1.42 MoM respectively. The placental echogenicity was normal. Routine monitoring two weeks later found single intrauterine death (IUD). MCAPSV of the surviving fetus dropped to 0.7 MoM. The placental portion of the dead fetus was thick and echogenic while that of the surviving fetus was thin and hypoechoic. There was no liquor discrepancy. The findings were suggestive of TAPS with IUD of the donor. The efficacy of AN diagnosis of TAPS by Slaghekke's proposed criteria of MCAPSV >1.5 MoM in the donor and <1.0 MoM in the recipient has not been studied. Cases fulfilling these diagnostic criteria must have an intertwin MCAPSV difference of >0.5 MoM. In both of our cases, the MCAPSV of the donors were below 1.5 MoM. But the intertwin MCAPSV difference was consistently >0.5 MoM after 21 weeks in Case 1 and in Case 2, the difference was also >0.5 (0.53) MoM at 30 weeks. If an intertwin MCAPSV difference of >0.5 MoM is used for diagnosis, TAPS could be picked up in Case 2 so that intensive monitoring and early intervention would prevent IUD of the donor. In Case 1, although TAPS was diagnosed by discrepancy in placental echogenicity, this finding may not appear before serious complications occur as in Case 2. Our cases illustrated that an intertwin MCAPSV difference of >0.5 MoM may detect TAPS better than the absolute MCAPSV cutoffs. To avoid inclusion of cases with anemia or polycythemia alone, MCAPSV cutoffs are still needed but the current donor cutoff may need to be lowered. Further studies are required for confirmation.

752: Spontaneous twin anemia-polycythemia sequence (sTAPS) with twin twin transfusion syndrome (TTTS) treatment by fetoscopic laser surgery (FLS)

sTAPS can occur as a unique disease or can complicate typical TTTS. Middle cerebral artery (MCA) Doppler studies are not currently part of the routine evaluation of monochorionic twins since they are not used in the Quintero staging system for TTTS. As such the true incidence of sTAPS remains unknown at this time. We aimed to compare the clinical characteristics and outcomes between sTAPs with or without TTTS vs. TTTS alone.

Incidence of spontaneous twin anemia-polycythemia sequence in monochorionic-diamniotic twin pregnancies: Single-center prospective study.

The purpose of this study was to prospectively estimate the incidence of spontaneous twin anemia-polycythemia sequence (TAPS) in monochorionic-diamniotic twin pregnancies. We prospectively examined umbilical cord hemoglobin (Hb) and reticulocyte count of consecutive monochorionic-diamniotic twin pregnancies delivered at Seirei Hamamatsu General Hospital from December 2006 to September 2013. We excluded cases of twin-twin transfusion syndrome, intrauterine fetal demise, and missing data (Hb and reticulocyte count missing from the medical record). TAPS was diagnosed using the postnatal criteria of intertwin Hb difference >8.0 g/dL and reticulocyte count ratio >1.7. Acute feto-fetal hemorrhage was defined as Hb difference >7 g/dL and reticulocyte count ratio <1.7. A total of 185 monochorionic-diamniotic twin pregnancies were included in this study. Three fulfilled the diagnostic criteria for postnatal TAPS, and one fulfilled the diagnostic criteria for acute feto-fetal hemorrhage. The incidence of spontaneous TAPS in monochorionic-diamniotic twin pregnancies was 1.6% (3/185) at Seirei Hamamatsu General Hospital.