Severe cerebral injury in a recipient with twin anemia-polycythemia sequence

Magnetic resonance imaging of intracranial anomalies in pregnancies complicated by twin anemia-polycythemia sequence

PURPOSE

To describe fetal brain Magnetic Resonance Imaging (MRI) findings in a large series of monochorionic (MC) pregnancies complicated by Twin Anemia-Polycythemia Sequence (TAPS) prenatally diagnosed, so to characterize the potential intracranial complications associated with this condition, their frequency and potential treatment options.

METHODS

This is a retrospective study of MC twin pregnancies complicated by TAPS and undergone fetal MRI in a single institution from 2006 to 2023. MRI control was performed and post-natal ultrasound (US) or MRI were available.

RESULTS

1250 MC pregnancies were evaluated in our institution. 50 pregnancies (4%) were diagnosed with TAPS, 29 underwent a fetal brain MRI. 13/29 pregnancies (44.8%) demonstrated brain findings at MRI in at least a twin. Neuroradiological findings were detected in 14/57 twins (24.6%). We detected four main categories of findings: hemorrhagic lesions, T2-weighted white-matter hyperintensities (WMH), brain edema-swelling and venous congestion. Nineteen findings were present in the anemic and three in the polycythemic twins, with a statistically significant ratio between the two groups (p-value = 0.01). Intrauterine MRI follow-up demonstrated the sequalae of hemorrhagic lesions. A complete regression of brain swelling, veins prominence and T2-WMHs was demonstrated after treatment. Postnatal imaging confirmed prenatal features.

CONCLUSIONS

Our work demonstrates that TAPS-related MRI anomalies consisted in edematous/hemorrhagic lesions that occur mostly in anemic rather than in polycythemic twins. Fetoscopic laser surgery could have a potential decongestant role. Therefore, prenatal MRI may help in counselling and management in TAPS pregnancies, especially for the planning of therapy and the monitoring of its efficacy.

Twin Anemia-Polycythemia Sequence (TAPS): From Basic Research to Clinical Practice

Twin pregnancy is associated with an increased risk of perinatal and maternal complications, and early establishment of the chorionicity type defines this risk. In monochorionic (MC) pregnancies, the fetuses share the same placental mass and exhibit vascular anastomoses crossing the intertwin membrane, and the combination and pattern of anastomoses determine the primary clinical picture and occurrence of future complications. Twin Anemia-Polycythemia Sequence (TAPS) was first described in 2006 after fetoscopic laser surgery in twin-to-twin transfusion syndrome (TTTS) twins, and in 2007, the first spontaneous cases were reported, recognizing TAPS as an individualized vascular identity in fetofetal transfusion syndromes. There are two types of TAPS: spontaneous (3-5%) and iatrogenic or postlaser (2-16%). TAPS consists of small diameter arteriovenous anastomoses (<1 mm) and low-rate, small-caliber AA anastomoses in the absence of amniotic fluid discordances. There are certain antenatal and postnatal diagnostic criteria, which have progressively evolved over time. New, additional secondary markers have been proposed, and their reliability is being studied. The best screening protocol for TAPS in MC twins is still a matter of debate. This review provides a survey of the relevant literature on the epidemiology, vascular pathophysiology, underlying hemodynamic factors that regulate mismatched vascular connections, and diagnostic criteria of this condition. The aim is to increase awareness and knowledge about this recently identified and frequently unrecognized and misdiagnosed pathology.

Fetal and neonatal brain injury in twins complicated by twin anemia polycythemia sequence

OBJECTIVES

To determine the rate of fetal and neonatal brain lesions and define risk factors for such lesions in pregnancies complicated by Twin Anemia Polycythemia Sequence (TAPS).

METHODS

A retrospective cohort study of monochorionic twin pregnancies which were diagnosed with TAPS in a single tertiary medical center between 2013 and 2021. Pregnancies were followed with fetal brain neurosonogram every 2 weeks and fetal brain MRI (magnetic resonance imaging) was performed when indicated at 28-32 weeks of gestation; post-natal brain imaging included neonatal brain ultrasound. Pregnancies with pre- and post-natal brain lesions were compared to those without such findings.

RESULTS

Overall, 23 monochorionic diamniotic pregnancies were diagnosed with TAPS over the study period resulting in perinatal survival of 91.3% (42/46). In 6/23 (26%) pregnancies and 7/46 (15.2%) fetuses pre- or post-natal brain lesions were detected, of whom five were the polycythemic twins and two were the anemic twins. Brain findings included intra-cerebral hemorrhage and ischemic lesions and were diagnosed prenatally in 6/7 (85.7%) cases. No risk factors for severe brain lesions were identified.

CONCLUSIONS

TAPS may place the fetuses and neonates at increased risk for cerebral injuries. Incorporation of fetal brain imaging protocols may enhance precise prenatal diagnosis and allow for accurate parental counseling and post-natal care.

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

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Twin Anemia Polycythemia Sequence in a Dichorionic Twin Pregnancy Leading to Severe Cerebral Injury in the Recipient

Twin anemia polycythemia sequence (TAPS) is a form of chronic imbalanced feto-fetal transfusion through minuscule placental anastomoses leading to anemia in the TAPS donor and polycythemia in the TAPS recipient and has been reported only in monochorionic twins. We report a very unusual case of TAPS which developed in a dichorionic twin pair, born at a gestational age of 33+2. Twin 1 (recipient) was polycythemic and had a hemoglobin value of 22.4 g/dL, whereas twin 2 (donor) was anemic with a hemoglobin value of 9.8 g/dL and an increased reticulocyte count (72‰). Color dye injection of the placenta revealed the presence of a deep-hidden small veno-venous anastomosis. Dichorionicity was confirmed on histologic examination. Aside from respiratory distress syndrome, the donor twin had an uncomplicated neonatal course. The recipient twin developed a post-hemorrhagic ventricular dilatation requiring treatment with a ventriculoperitoneal shunt and Rickham reservoir. This report shows that in dichorionic twins, placental anastomoses can be present, which can lead to the development of TAPS with severe consequences. Therefore, when a pale and plethoric dichorionic twin pair is born, a complete diagnostic work-up is required, including a full blood count with reticulocytes and placental injection, to investigate the presence and nature of potential underlying feto-fetal transfusion. Once the diagnosis of TAPS has been established, cerebral ultrasound, hearing screening, and long-term follow-up are strongly recommended as these twins have increased risk for severe cerebral injury, hearing loss, and long-term neurodevelopmental impairment.

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

BACKGROUND

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.

OBJECTIVE

This study aimed to investigate the diagnosis, management, and outcome in a large international cohort of spontaneous twin anemia polycythemia sequence.

STUDY DESIGN

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.

RESULTS

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).

CONCLUSION

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.

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

OBJECTIVE

To 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).

METHODS

This 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.

RESULTS

In 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.

CONCLUSIONS

Antenatal 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.

Middle Cerebral Artery Doppler Velocimetry for the Diagnosis of Twin Anemia Polycythemia Sequence: A Systematic Review

Twin anemia polycythemia sequence (TAPS) is a rare complication of monochorionic diamniotic (MCDA) twins. Middle cerebral artery peak systolic velocity (MCA-PSV) measurements are used to screen for TAPS while fetal or neonatal hemoglobin levels are required for definitive diagnosis. We sought to perform a systematic review of the efficacy of MCA-PSV in diagnosing TAPS. Search criteria were developed using relevant terms to query the Pubmed, Embase, and SCOPUS electronic databases. Publications reporting diagnostic characteristics of MCA-PSV measurements (i.e., sensitivity, specificity or receiver operator curves) were included. Each article was assessed for bias using the Quality Assessment of Diagnostic Accuracy Studies II (QUADAS II) tool. Results were assessed for uniformity to determine whether meta-analysis was feasible. Data were presented in tabular form. Among publications, five met the inclusion criteria. QUADAS II analysis revealed that four of the publications were highly likely to have bias in multiple areas. Meta-analysis was precluded by non-uniformity between definitions of TAPS by MCA-PSV and neonatal or fetal hemoglobin levels. High-quality prospective studies with consistent definitions and ultrasound surveillance protocols are still required to determine the efficacy of MCA-PSV in diagnosing TAPS. Other ultrasound findings (e.g., placenta echogenicity discordance) may augment Doppler studies.

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.

Dispelling Myths about Antenatal TAPS: A Call for Action for Routine MCA-PSV Doppler Screening in the United States

In the United States, routine middle cerebral artery peak systolic velocity (MCA-PSV) Doppler screening for the detection of antenatal twin anemia-polycythemia sequence (TAPS) is not recommended. The current and only national clinical guideline from the highly-influential Society for Maternal-Fetal Medicine states that, “There is no evidence that monitoring for TAPS with MCA PSV Doppler at any time, including > 26 weeks, improves outcomes, so that this additional screening cannot be recommended at this time.” We argue this recommendation has disproportionate influence on patients and the care they are offered and receive. We use current evidence to highlight and dispel pervasive myths surrounding antenatal TAPS and the value of routine MCA-PSV screening. An ethical framework that illustrates the importance of giving patients the opportunity for routine screening is presented. Findings demonstrate that: (1) both spontaneous and post-laser TAPS is a serious, potentially life-threatening complication, (2) treatment for TAPS is effective and includes expectant management, intrauterine transfusion (IUT), or surgery, (3) and routine MCA-PSV, which has satisfactory diagnostic accuracy, is currently the only way to provide early detection of TAPS. We conclude that routine TAPS screening is a medically proven valuable resource that should be offered to patients in need and to the clinicians who are trying to act toward their benefit.

Fetal stroke and cerebrovascular disease: Advances in understanding from lenticulostriate and venous imaging, alloimmune thrombocytopaenia and monochorionic twins

Fetal stroke is an important cause of cerebral palsy but is difficult to diagnose unless imaging is undertaken in pregnancies at risk because of known maternal or fetal disorders. Fetal ultrasound or magnetic resonance imaging may show haemorrhage or ischaemic lesions including multicystic encephalomalacia and focal porencephaly. Serial imaging has shown the development of malformations including schizencephaly and polymicrogyra after ischaemic and haemorrhagic stroke. Recognised causes of haemorrhagic fetal stroke include alloimmune and autoimmune thrombocytopaenia, maternal and fetal clotting disorders and trauma but these are relatively rare. It is likely that a significant proportion of periventricular and intraventricular haemorrhages are of venous origin. Recent evidence highlights the importance of arterial endothelial dysfunction, rather than thrombocytopaenia, in the intraparenchymal haemorrhage of alloimmune thrombocytopaenia. In the context of placental anastomoses, monochorionic diamniotic twins are at risk of twin twin transfusion syndrome (TTTS), or partial forms including Twin Oligohydramnios Polyhydramnios Sequence (TOPS), differences in estimated weight (selective Intrauterine growth Retardation; sIUGR), or in fetal haemoglobin (Twin Anaemia Polycythaemia Sequence; TAPS). There is a very wide range of ischaemic and haemorrhagic injury in a focal as well as a global distribution. Acute twin twin transfusion may account for intraventricular haemorrhage in recipients and periventricular leukomalacia in donors but there are additional risk factors for focal embolism and cerebrovascular disease. The recipient has circulatory overload, with effects on systemic and pulmonary circulations which probably lead to systemic and pulmonary hypertension and even right ventricular outflow tract obstruction as well as the polycythaemia which is a risk factor for thrombosis and vasculopathy. The donor is hypovolaemic and has a reticulocytosis in response to the anaemia while maternal hypertension and diabetes may influence stroke risk. Understanding of the mechanisms, including the role of vasculopathy, in well studied conditions such as alloimmune thrombocytopaenia and monochorionic diamniotic twinning may lead to reduction of the burden of antenatally sustained cerebral palsy.

Intrauterine Interventions for the Treatment of Twin Anemia-Polycythemia Sequence: A Systematic Review

BACKGROUND

Twin anemia-polycythemia sequence (TAPS) is a complication of monochorionic, multiple gestation pregnancies in which blood shunting through placental anastomoses results in chronic anemia in one fetus and chronic polycythemia in another. The outcomes of different treatment modalities for TAPS are not well known.

OBJECTIVE

To determine the outcomes of the intrauterine interventions used to treat TAPS.

STUDY DESIGN

A systematic literature search of MEDLINE, EMBASE, and CENTRAL was performed in June 2016. Primary outcomes were mortality, morbidity, and adverse perinatal outcomes. Data were summarized in the form of weighted means, and statistical difference was determined.

RESULTS

Twenty-one articles were identified for inclusion in this review and were composed of 105 cases of TAPS. In the cases presented in the literature, there was no statistically significant difference in mortality, morbidity, or emergent Caesarean section rates between expectant management, intrauterine transfusion (IUT), and laser ablation therapy. Laser ablation therapy and IUT were found to have a significantly lower rate of adverse perinatal outcomes when compared to expectantly managed cases.

CONCLUSIONS

The literature looking into the treatment of TAPS is very limited, with no randomized controlled trials and only one includable comparative study. Based on the data in the case report and case study literature, there is no mortality difference between any of the treatment modalities. Expectant management may be associated with an increase in adverse perinatal outcomes when compared to laser therapy and IUT. More comparative studies are needed to assist clinicians in adopting an evidence-based approach to the treatment of TAPS.

Prenatal diagnosis of spontaneous twin anemia-polycythemia sequence and postnatal examination of placental vascular anastomoses

Twin anemia-polycythemia sequence (TAPS) is characterized by a wide discrepancy of hemoglobin between two monochorionic fetuses without sign of twin oligo-polyhydramnios sequence. A primiparous woman with monochorionic diamniotic twin transferred for preterm labor. Ultrasonographic evaluation at 32+3 weeks of gestation revealed increased middle cerebral artery-peak systolic velocity (77.4 cm/sec, 1.69 multiples of median) in donor and decreased in recipient twin (36.4 cm/sec, 0.79 multiples of median), the twin was diagnosed with TAPS. Repeated cesarean section was performed at 32+5 weeks of gestation following preeclampsia and preterm labor. After delivery, TAPS was confirmed through neonatal hematologic examination. There were no signs of acute hemorrhagic shock or brain injury. Placental evaluation via dye infusion and barium angiogram revealed one arterioarterial anastomoses with six arteriovenous anastomoses of placenta. We report a prenatally diagnosed case of spontaneous TAPS with arterioarterial and arteriovenous anastomoses and suggest careful monitoring of monochorionic twin and opinion on placenta vascular architecture.

Can middle cerebral artery peak systolic velocity predict polycythemia in monochorionic-diamniotic twins? Evidence from a prospective cohort study

OBJECTIVE

The antenatal diagnosis of twin anemia-polycythemia sequence (TAPS) in monochorionic-diamniotic (MCDA) twin pregnancies is based on elevated peak systolic velocity in the middle cerebral artery (MCA-PSV) in the donor twin and decreased MCA-PSV in the recipient twin. However, the association between these parameters and polycythemia has not yet been established. The aim of this study was to determine whether MCA-PSV can predict polycythemia in MCDA pregnancies.

METHODS

This was a prospective cohort study of MCDA pregnancies recruited at 14-18 weeks' gestation from a single tertiary care center between January 2011 and June 2014. Fetal MCA Doppler waveforms were recorded every 2 weeks from 18 weeks' gestation until delivery. Only those with an MCA-PSV measurement within 1 week of delivery were included in the analysis. Neonatal hematocrit level was determined in all twins from venous blood obtained within 4 h of delivery. Polycythemia was defined as a hematocrit of > 65%, and anemia as a hematocrit of < 45%. TAPS was diagnosed when an intertwin hemoglobin difference of > 8 g/dL and reticulocyte count ratio of > 1.7 were observed.

RESULTS

Of 162 MCDA pregnancies followed during the study period, 69 had an MCA-PSV measurement within 1 week of delivery and were included in the study. Twenty-five neonates were diagnosed with polycythemia and nine twin pairs met the criteria for TAPS. In a pooled analysis, MCA-PSV was negatively correlated with neonatal hematocrit (P = 0.017, r = -0.215) and was significantly higher in anemic fetuses than in normal controls (1.15 multiples of the median (MoM) vs 1.02 MoM, respectively; P = 0.001). However, MCA-PSV was similar among polycythemic and normal fetuses (0.95 MoM vs 1.02 MoM, respectively; P = 0.47). Intertwin difference in MCA-PSV (delta MCA-PSV) was positively correlated with intertwin hematocrit difference (P = 0.002, r = 0.394). Moreover, twin pregnancies with an intertwin hematocrit difference of > 24% had a significantly greater delta MCA-PSV than did those with an intertwin hematocrit difference of ≤ 24% (delta MCA-PSV, 19 vs 5 cm/s; P < 0.001).

CONCLUSIONS

MCA-PSV is not significantly decreased in polycythemic MCDA twins. However, delta MCA-PSV is associated with a large intertwin difference in hematocrit, and its use may be better than conventional methods for the risk assessment of TAPS. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

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

BACKGROUND

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 in either fetus before fluid measurements meet the typically used cutoff.

OBJECTIVE

The aim of this study was to investigate the prevalence of atypical presentations of TTTS in a population undergoing laser fetoscopy.

STUDY DESIGN

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.

RESULTS

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.

CONCLUSION

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.

Twin Anemia Polycythemia Sequence: Current Views on Pathogenesis, Diagnostic Criteria, Perinatal Management, and Outcome

Monochorionic twins share a single placenta and are connected with each other through vascular anastomoses. Unbalanced inter-twin blood transfusion may lead to various complications, including twin-to-twin transfusion syndrome (TTTS) and twin anemia polycythemia sequence (TAPS). TAPS was first described less than a decade ago, and the pathogenesis of TAPS results from slow blood transfusion from donor to recipient through a few minuscule vascular anastomoses. This gradually leads to anemia in the donor and polycythemia in the recipient, in the absence of twin oligo-polyhydramnios sequence (TOPS). TAPS may occur spontaneously in 3-5% of monochorionic twins or after laser surgery for TTTS. The prevalence of post-laser TAPS varies from 2% to 16% of TTTS cases, depending on the rate of residual anastomoses. Pre-natal diagnosis of TAPS is currently based on discordant measurements of the middle cerebral artery peak systolic velocity (MCA-PSV; >1.5 multiples of the median [MoM] in donors and 8 g/dL), and at least one of the following: reticulocyte count ratio >1.7 or minuscule placental anastomoses. Management includes expectant management, and intra-uterine blood transfusion (IUT) with or without partial exchange transfusion (PET) or fetoscopic laser surgery. Post-laser TAPS can be prevented by using the Solomon laser surgery technique. Short-term neonatal outcome ranges from isolated inter-twin Hb differences to severe neonatal morbidity and neonatal death. Long-term neonatal outcome in post-laser TAPS is comparable with long-term outcome after treated TTTS. This review summarizes the current knowledge after 10 years of research on the pathogenesis, diagnosis, management, and outcome in TAPS.

Fetal Intra-Peritoneal Transfusion for the Management of Very Early Spontaneous Twin Anemia-Polycythemia Sequence in an Obese Patient With a Whole Anterior Placenta

Twin anemia-polycythemia sequence (TAPS) is a rare condition in monochorionic twin pregnancies. Small intertwin placental vascular communications allow transfusion, which results in a hemoglobin difference in the twins in the absence of oligohydramnios or polyhydramnios. We report here a case of TAPS diagnosed at 17 weeks’ gestation in an obese patient (BMI 42) with a whole anterior placenta. The only possible treatment at this stage of pregnancy was intra-uterine transfusion (IUT), which was repeated weekly until photocoagulation of placental anastomoses was feasible. Fetoscopic laser surgery is the only curative treatment, but is challenging in TAPS because of the absence of polyhydramnios and the presence of minuscule anastomoses. An anterior placenta and high BMI can make the procedure even more challenging. This case report demonstrates that very early and rapidly progressing TAPS with technically complicated conditions (elevated BMI and anterior placenta) can be successfully managed with IUT until laser procedure is achievable.

Evaluation of the Utility of in utero Treatment of Twin Anemia-Polycythemia Sequence

OBJECTIVE

The aim of this study is to evaluate the interest in the in utero treatment of twin anemia-polycythemia sequence (TAPS).

METHODS

The obstetrical and neonatal data on all cases of TAPS followed up in our institution between 2006 and 2013 were reviewed. Statistical analyses were conducted using Bayesian methods.

RESULTS

Twenty cases of TAPS were included. Laser therapy or intrauterine transfusion (IUT) was performed on the donor twin in 9 cases. Eleven cases were included in the 'nontreated' group (managed expectantly or diagnosed at birth). The gestational age at diagnosis was lower in the group with treated TAPS [difference (diff) = -22.20 days (-57.13, 14.28), probability (Pr) (diff >0) = 10.6%]. The rate of preterm premature rupture of membranes was higher in the group with treated TAPS [diff = 22.5% (-14, 57), Pr (diff >0) = 89%], but overall mortality was similar. The interval between diagnosis and delivery was longer [diff = 44.37 days (9.41, 77.90), Pr (diff >0) = 99.2%], the TAPS resolution rate was higher [diff = 49.9% (12, 81), Pr (diff >0) = 99.4%], and the neonatal transfusion rate was lower [diff = -30.5% (-60, 0), Pr (diff >0) = 2.6%] in the treated group.

CONCLUSION

In utero treatment for TAPS is associated with a higher resolution rate of TAPS and a longer time between diagnosis and birth, but overall mortality is the same as with expectant management.

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

OBJECTIVE

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).

METHODS

Neurological, motor and cognitive development was assessed in a consecutive cohort of TTTS survivors treated with laser surgery between 2004 and 2011 and complicated by post-laser TAPS. Primary outcome was neurodevelopmental impairment, a composite outcome including any of the following: cerebral palsy, bilateral deafness, blindness, severe motor and/or cognitive developmental delay (>2 SD below the mean). A risk analysis on cognitive outcome was performed.

RESULTS

During the study period, 33/306 (11%) monochorionic twin pairs developed TAPS after laser surgery for TTTS. Survival was 53/66 (80%). Long-term outcome was assessed in 47/53 (89%) children. The incidence of neurodevelopmental impairment was 4/47 (9%), occurring in one donor (1/20; 5%) and three recipients (3/27; 11%) (P=0.63). Mild-to-moderate cognitive delay, i.e. scores below 85, was detected in 8/47 (17%) children. Risk factors for low cognitive scores were low gestational age at birth (P=0.02) and low birth weight (P<0.01). The lowest cognitive scores were detected in the subgroup of TAPS survivors treated with intrauterine transfusion (median score, 82.5).

CONCLUSIONS

Neurodevelopmental impairment and cognitive delay were found in almost one in five children surviving post-laser TAPS. Better treatment and, ideally, prevention of this complication after laser treatment for TTTS is urgently needed.

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

OBJECTIVE

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

METHODS

All monochorionic twin pregnancies with TAPS managed between 2005 and 2013 in two European fetal therapy centers were evaluated. The outcomes of TAPS cases treated primarily with laser surgery were compared with the outcomes of cases managed expectantly or treated with intrauterine transfusion.

RESULTS

In this retrospective study 52 cases of TAPS were detected antenatally and were managed with either laser surgery (n=8; 15%) or intrauterine blood transfusion (n=17; 33%) or expectantly (n=27; 52%). Perinatal survival in the laser group was 94% (15/16) vs 85% (29/34) in the intrauterine-transfusion group and 83% (45/54) in the expectant-management group (P=0.30). The rates of severe neonatal morbidity in liveborn neonates in the laser, intrauterine-transfusion and expectant-management groups were 7% (1/15), 38% (12/32) and 24% (12/50), respectively (P=0.17). There was a significant reduction in respiratory distress syndrome in cases treated by laser. No severe postnatal hematological complications were detected in the laser group compared with 72% (23/32) in the intrauterine-transfusion group and 52% (26/50) in the expectant-management group (P<0.01). Median time between diagnosis and birth was 11 weeks in the laser group compared to 5 weeks after intrauterine transfusion and 8 weeks after expectant management (P<0.01). After injection of colored dye no residual anastomoses were found in the laser group.

CONCLUSIONS

Laser surgery for TAPS appears to improve perinatal outcome by prolonging pregnancy and reducing respiratory distress syndrome. Larger, adequately controlled studies are needed to reach firm conclusions on the optimal management of TAPS.

Treatment of Complicated Spontaneous Twin Anemia-Polycythemia Sequence via Fetoscopic Laser Ablation of the Vascular Communications

Monochorionic diamniotic twins share a single placenta and have intertwin vascular communications that link the circulatory systems of the twins together. Twin anemia-polycythemia sequence (TAPS) is an atypical form of twin-twin transfusion syndrome (TTTS) caused by net transfer of blood from one fetus to the other and is characterized by large intertwin hemoglobin differences in the absence of oligohydramnios and polyhydramnios. This condition may develop spontaneously (sTAPS) or as a result of residual vascular communications after prior laser surgery. Because of the relatively low prevalence and lack of clinical awareness, the natural history of sTAPS is unclear and the antenatal treatment remains controversial. Case series of sTAPS have described expectant management with timed delivery, intrauterine blood transfusion, and fetoscopic laser treatment. Favorable outcomes have been described in cases of uncomplicated sTAPS that underwent conservative measures. However, we believe that there may be a subgroup of high-risk or complicated sTAPS patients that may benefit from definitive treatment afforded by fetoscopic laser therapy. We describe 3 complicated cases of sTAPS successfully treated with selective laser photocoagulation of communicating vessels. In 2 of the cases, placental pathology identified thrombosed fetal vessels of the polycythemic twin.

Twin anemia-polycythemia sequence: the importance of an accurate diagnosis

Twin anemia-polycythemia sequence (TAPS), which was first described in 2007, is an atypical chronic form of twin-twin transfusion syndrome (TTTS). It presents as a large intertwin hemoglobin difference, with one twin developing anemia and the other polycythemia, without the traditional “polyhydramnios-oligohydramnios sequence” that is usually seen in TTTS. So far, ideal management of TAPS is not clear. We report here the case of a monochorionic biamniotic gestation, complicated by TAPS, detected at 30 weeks’ gestation that led to an emergent cesarean section. The recipient twin had an uneventful evolution. The donor twin was severely anemic, with a hemoglobin level of 2.5 g/dL that required immediate blood transfusion and intensive care management measures. Clinical evolution was favorable with good outcome in both twins. This case report intends to emphasize the association between hydrops fetalis and severe anemia, as well as the relevance of antenatal Doppler ultrasound investigations and the importance of an accurate management decision.

Intrauterine blood transfusion: current indications and associated risks

Fetal anemia is a serious complication in pregnancy and associated with perinatal mortality and morbidity. During 25 years of worldwide experience with intravascular intrauterine blood transfusion, a variety of indications have been described. Intrauterine transfusion (IUT) treatment is considered most successful for fetal anemia due to red cell alloimmunization. Moreover, the use of this procedure has also been reported in pregnancies with parvovirus B19 infection, fetomaternal hemorrhage and placental chorioangiomas, for example. This review focuses on the current indications of intrauterine blood transfusions. In addition, we describe the potential complications of IUT treatment.