Post-laser Twin Anemia-polycythemia Sequence Research Articles

Stage-based recipient and donor outcome in twin-to-twin transfusion syndrome treated by fetoscopic laser surgery using Solomon technique.

To evaluate twin survival stratified by Quintero stage in patients with twin-to-twin transfusion syndrome (TTTS) after Solomon laser treatment. This was a single-center study at Johns Hopkins Center for Fetal Therapy, investigating a cohort of consecutive twin pregnancies treated with the Solomon laser technique for TTTS. Preoperative Quintero stage, perioperative characteristics and obstetric factors were investigated in relation to neonatal survival of the recipient and donor twins at discharge. Determinants of twin survival were evaluated using univariate logistic regression and cumulative survival probability analyses. Of 402 pregnancies with TTTS that underwent Solomon laser treatment, 80 (19.9%) were diagnosed with Quintero Stage-I TTTS, 126 (31.3%) with Stage II, 169 (42.0%) with Stage III and 27 (6.7%) with Stage IV. Post-laser twin anemia polycythemia sequence or recurrent TTTS occurred in 19 (4.7%) patients and 11 (2.7%) required repeat laser surgery. Preterm prelabor rupture of membranes occurred in 150 (37.3%) patients and median gestational age at delivery was 32 + 1 weeks. In 303 (75.4%) patients, both twins were alive at discharge; 67/80 (83.8%) were Stage I, 101/126 (80.2%) were Stage II, 113/169 (66.9%) were Stage III and 22/27 (81.5%) were Stage IV (P = 0.062). Donor twin survival was lower than that of recipients in cases with Stage-III TTTS (118/169 (69.8%) vs 145/169 (85.8%) (χ2 = 26.076, P < 0.0001)). Higher intertwin size discordance and absent or reversed umbilical artery (UA) end-diastolic velocity (EDV) were associated with donor demise (Nagelkerke R2, 0.38; P < 0.001). Overall, spontaneous post-laser donor demise occurred in 53 (39.6%) patients, accounting for the majority of all losses. Cumulative donor survival decreased from 92% to 65% when intertwin size discordance was >30% and to 48% when UA-EDV was absent or reversed (P < 0.001). The Solomon laser technique achieves TTTS resolution and double twin survival in a high proportion of cases. Recipient and donor survival is comparable unless there is significant intertwin size discordance and placental dysfunction. This degree of unequal placental sharing, typically found in Stage-III TTTS, is the primary factor preventing double survival due to a higher rate of donor demise. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Should We Stitch-Close the Fetoscopic Percutaneous Access? A Case-Series of Laparotomy to Trans-Amniotic Membrane Suturing for Intrauterine Port Placement in Fetoscopic Surgery for Twins

Introduction: Maternal laparotomy-assisted fetoscopic surgery for in-utero myelomeningocele repair has shown that a trans-amniotic membrane suture during fetoscopic port placement can reduce postsurgical complications. Fetoscopic laser photocoagulation (FLP) for complex twins is typically performed percutaneously without a transmembrane stitch. However, in scenarios without a placental-free window, maternal laparotomy may be used for recipient sac access. Here, we present the outcomes of our series of laparotomy-assisted FLP cases, including a trans-amniotic membrane suturing of the fetoscopic port. Methods: Retrospective series of twin-twin transfusion syndrome or twin anemia-polycythemia sequence (TAPS) cases treated at 2 fetal centers that underwent maternal laparotomy to FLP from September 2017 to January 2023. We recorded preoperative and operative characteristics, as well as pregnancy and neonatal outcomes. Results: During the study period, 9 maternal laparotomy to FLP cases were performed. Two were excluded for prior percutaneous FLP in the pregnancy. The remaining seven utilized a maternal laparotomy to trans-amniotic membrane stitch with confirmation of proper suture placement under ultrasound guidance, and all surgeries were performed with a single 10 F Check-Flo® cannula. Mean gestational age (GA) at surgery was 19.1 weeks (range 16 weeks 4 days–23 weeks 3 days), with delivery occurring at a mean GA of 35.0 weeks (range 32 weeks 0 days–37 weeks 1 day), resulting in a mean latency of 15.8 weeks, significantly longer than what is reported in the literature and our own data (mean latency for percutaneous FLP 10.2, 95% CI 9.9–10.5). Furthermore, all cases underwent iatrogenic delivery before labor onset, with the lone delivery prior to 34 weeks due to concern for post-laser TAPS. Conclusion: This case series of laparotomy to FLP with trans-amniotic stitch, demonstrated no cases of spontaneous preterm birth and a longer-than-expected latency from surgery to delivery. Larger studies are warranted to investigate this approach.

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.

Twin-to-twin transfusion syndrome: Controversies in the diagnosis and management.

In twin-to-twin transfusion syndrome (TTTS) communicating placental vessels on the chorionic plate between the donor and recipient twins are responsible for the chronic imbalance of blood flow. Evidence demonstrates that fetoscopic laser ablation is superior to serial amnioreductions in terms of survival and neurological outcome for stages II-IV TTTS. However, the optimal management of stage I TTTS remains poorly understood. It is well established that all chorionic plate anastomoses should be closed by laser ablation. Compared to the selective laser method, the Solomon technique yields a significant reduction of recurrent TTTS and post-laser twin anemia polycythemia sequence (TAPS). Over the past 25 years, survival rates after fetoscopic laser surgery have significantly increased. High volume centers report up to 70% double survival and at least one survivor in >90% cases. In this review, we discuss the controversies in the diagnosis and management of TTTS, especially, the optimal management in stage I cases, very early or late diagnosis, and the optimal laser technique. Furthermore, we will discuss a stage-related outcome after laser surgery and examine whether it is necessary at all to distinguish between stages I and II. Finally, the optimal timing as well as mode of delivery after TTTS laser treatment will be discussed.

Perinatal outcomes of pregnancies with twin‐anemia polycythemia sequence complicating twin‐to‐twin transfusion syndrome using different twin‐anemia polycythemia sequence diagnostic criteria

To investigate whether the presence of twin-anemia polycythemia sequence (TAPS) with twin-to-twin transfusion syndrome (TTTS) or post-laser TAPS would change outcomes using different TAPS diagnostic criteria. TTTS cases undergoing laser surgery between 2012 and 2020 were included. Groups included pre-laser TTTS-only compared to TTTS+TAPS, and no post-laser TAPS compared to post-laser TAPS. Three prenatal TAPS diagnostic criteria were used: group A: middle cerebral artery-peak systolic velocity (MCA-PSV)>1.5 MoM in one twin and <1 MoM in the other twin, group B: inter-twin MCA-PSV difference >1 MoM, and group C: inter-twin MCA-PSV difference >0.5 MoM. Perinatal outcomes including survival and severe cerebral injury were investigated. 174 laser procedures were included. TTTS+TAPS cases were 16 in group A, 17 in group B, and 29 in group C. Post-laser TAPS cases were 11 in group A, 6 in group B, and 12 in group C. There were no differences in preoperative, operative variables and outcomes including survival and severe cerebral injury between groups using all three TAPS diagnostic criteria. The incidence of TTTS+TAPS was highest in group C (16.7%), then group B (9.8%), followed by group A (9.2%). The incidence of post-laser TAPS was highest in group C (9%), then group A (8.3%), followed by group B (4.5%). Presence of TAPS complicating TTTS and presence of post-laser TAPS do not seem to be associated with worse perinatal outcomes including postnatal-ultrasound detected cerebral injury using three different TAPS criteria. Collaborative studies are needed to investigate the validity and the performance of different TAPS criteria.

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.

Fetal and neonatal brain lesions following laser ablation for twin‐to‐twin‐transfusion‐syndrome as detected by pre‐ and post‐natal brain imaging

To determine the rate of and risk factors for fetal and neonatal brain lesions following laser ablation for twin-to-twin transfusion syndrome (TTTS). A retrospective cohort study of 83 women with monochorionic twin pregnancies who underwent ablation for TTTS at a single tertiary hospital. Post-laser survivors were followed-up with fetal neurosonogram every 2weeks and fetal brain MRI at 28-32weeks of gestation; post-natal brain imaging included neurosonogram. Cases with pre- and post-natal brain lesions were compared to those without. 153 fetuses survived the immediate post-laser period and underwent brain imaging. Of these, 17 (11.11%) exhibited brain lesions on prenatal imaging studies, and 36 (32.4%) on post-natal ultrasound. Later gestational age (GA) at the time of ablation (23.0 vs. 21.4weeks, p=0.0244), post-laser twin-anemia-polycythemia-sequence (TAPS) (29.41% vs. 9.56%, p=0.035) and birthweight discordancy (30% vs. 9%, p=0.0025) were associated with prenatal brain lesions. Earlier GA at delivery (31.0weeks vs. 32.2, p=0.0002) and post-laser TAPS (25% vs. 9.33%, p=0.038) were associated with post-natal brain lesions. Survivors of ablation for TTTS are at risk for brain lesions, which can be detected prenatally. Incorporation of neurosonogram and fetal brain MRI into the routine surveillance of such pregnancies should be considered.

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.

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.

Post-Laser Twin Anemia Polycythemia Sequence: Diagnosis, Management, and Outcome in an International Cohort of 164 Cases.

The aim of this study was to investigate the management and outcome in the post-laser twin anemia polycythemia sequence (TAPS). Data of the international TAPS Registry, collected between 2014 and 2019, were used for this study. 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 164 post-laser TAPS pregnancies were included, of which 92% (151/164) were diagnosed antenatally and 8% (13/164) postnatally. The median number of days between laser for TTTS and detection of TAPS was 14 (IQR: 7–28, range: 1–119). Antenatal management included expectant management in 43% (62/151), intrauterine transfusion with or without partial exchange transfusion in 29% (44/151), repeated laser surgery in 15% (24/151), selective feticide in 7% (11/151), delivery in 6% (9/151), and termination of pregnancy in 1% (1/151). The median gestational age (GA) at birth was 31.7 weeks (IQR: 28.6–33.7; range: 19.0–41.3). The perinatal mortality rate was 25% (83/327) for the total group, 37% (61/164) for donors, and 14% (22/163) for recipients (p < 0.001). Severe neonatal morbidity was detected in 40% (105/263) of the cohort and was similar for donors (43%; 51/118) and recipients (37%; 54/145), p = 0.568. Independent risk factors for spontaneous perinatal mortality were antenatal TAPS Stage 4 (OR = 3.4, 95%CI 1.4-26.0, p = 0.015), TAPS donor status (OR = 4.2, 95%CI 2.1–8.3, p < 0.001), and GA at birth (OR = 0.8, 95%CI 0.7–0.9, p = 0.001). Severe neonatal morbidity was significantly associated with GA at birth (OR = 1.5, 95%CI 1.3–1.7, p < 0.001). In conclusion, post-laser TAPS most often occurs within one month after laser for TTTS, but may develop up to 17 weeks after initial surgery. Management is mostly expectant, but varies greatly, highlighting the lack of consensus on the optimal treatment and heterogeneity of the condition. Perinatal outcome is poor, particularly due to the high rate of perinatal mortality in donor twins.

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.

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.

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.

Twin Anemia-Polycythemia Sequence in Monochorionic Twins: Implications for Diagnosis and Treatment

Twin anemia-polycythemia sequence (TAPS) is a recently described complication of monochorionic placentation characterized by discordance in hemoglobin (Hgb) levels in the absence of amniotic fluid abnormality characteristic of classical twin-twin transfusion syndrome (TTTS). The placental angioarchitecture that predisposes to TAPS consists of small diameter arteriovenous anastomoses and the absence of balancing arterioarterial anastomoses. This vascular pattern occurs sporadically in 3 to 5% of monochorionic twins or iatrogenically following 2 to 13% of selective fetoscopic laser surgeries for TTTS. The diagnosis is based on measurement of the middle cerebral artery peak systolic velocity (MCA-PSV) which is not part of the Quintero staging for TTTS. With mild disease increased MCA-PSV in the anemic donor twin and a decreased MCA-PSV in the recipient twin are characteristic while severe disease is associated with critical Doppler findings, hydrops or single twin demise as in TTTS. Treatment options include fetoscopic laser, fetal blood transfusion, conservative management, and often preterm delivery. The most promising approach to TAPS is its prevention since the iatrogenic form comprises the majority of cases. When the fetoscopic laser technique is modified by coagulating the chorionic plate along the vascular equator (equatorial dichorionization or "Solomon" technique) the incidence of postlaser TAPS and recurrent TTTS is significantly reduced, survival is improved, and there is no increase in complications.

Pancreatic transplantation or intensive insulin therapy?

Twin anemia-polycythemia sequence (TAPS) may occur in monochorionic twins either spontaneously or after laser surgery for twin–twin transfusion syndrome. Our aim was to analyze the placental angioarchitecture in spontaneous versus post-laser TAPS.We included all monochorionic twin placentas with spontaneous or post-laser TAPS injected at our center between 2002 and 2012. Placental angioarchitecture was evaluated using colored dye injection.A total of 600 monochorionic placentas were injected during the study period of which 43 (7.2%) with TAPS (spontaneous TAPS, n = 16; post-laser TAPS, n = 27). Almost all anastomoses (96%; 119/124) were very small (diameter <1 mm) and the majority was localized near the placental margin. The median number of anastomoses per placenta was 4 (interquartile range (IQR): 3–5) in the spontaneous TAPS group and 2 (IQR: 1–3) in the post-laser TAPS group (p = 0.003). Arterio-arterial (AA) anastomoses were detected in 14.0% (6/43) of TAPS placentas and were all minuscule (diameter <1 mm). The rate of AA anastomoses in the spontaneous TAPS group and post-laser TAPS group was 18.8% (3/16) and 11.1% (3/27), respectively (p = 0.184).Spontaneous TAPS placentas have a significantly higher total number of anastomoses compared to post-laser TAPS placentas. Most anastomoses were localized near the margins of the placenta. Minuscule AA anastomoses were detected sporadically in both groups and the rate of AA anastomoses is slightly higher in the spontaneous TAPS group than in the post-laser group.Spontaneous TAPS placentas have a different placental angioarchitecture than post-laser TAPS placentas in terms of number and type of vascular anastomoses.