Twin-to-twin transfusion syndrome: time to forget the Quintero staging system?

Consensus protocol for management of early and late twin-twin transfusion syndrome: Delphi study

OBJECTIVE

Fetoscopic laser photocoagulation (FLP) is a well-established treatment for twin-twin transfusion syndrome (TTTS) between 16 and 26 weeks' gestation. High-quality evidence and guidelines regarding the optimal clinical management of very early (prior to 16 weeks), early (between 16 and 18 weeks) and late (after 26 weeks) TTTS are lacking. The aim of this study was to construct a structured expert-based clinical consensus for the management of early and late TTTS.

METHODS

A Delphi procedure was conducted among an international panel of experts. Participants were chosen based on their clinical expertise, affiliation and relevant publications. A four-round Delphi survey was conducted using an online platform and responses were collected anonymously. In the first round, a core group of experts was asked to answer open-ended questions regarding the indications, timing and modes of treatment for early and late TTTS. In the second and third rounds, participants were asked to grade each statement on a Likert scale (1, completely disagree; 5, completely agree) and to add any suggestions or modifications. At the end of each round, the median score for each statement was calculated. Statements with a median grade of 5 without suggestions for change were accepted as the consensus. Statements with a median grade of 3 or less were excluded from the Delphi process. Statements with a median grade of 4 were modified according to suggestions and reconsidered in the next round. In the last round, participants were asked to agree or disagree with the statements, and those with more than 70% agreement without suggestions for change were considered the consensus.

RESULTS

A total of 122 experts met the inclusion criteria and were invited to participate, of whom 53 (43.4%) agreed to take part in the study. Of those, 75.5% completed all four rounds. A consensus on the optimal management of early and late TTTS was obtained. FLP can be offered as early as 15 weeks' gestation for selected cases, and can be considered up to 28 weeks. Between 16 and 18 weeks, management should be tailored according to Doppler findings.

CONCLUSIONS

A consensus-based treatment protocol for early and late TTTS was agreed upon by a panel of experts. This protocol should be modified at the discretion of the operator, according to their experience and the specific demands of each case. This should advance the quality of future studies, guide clinical practice and improve patient care. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

The High-Risk Profile of Selective Growth Restriction in Monochorionic Twin Pregnancies

The present review aims to provide a critical appraisal of the sonographic diagnosis and follow-up and to evaluate the optimal clinical management of monochorionic twin pregnancies where one of the twins is complicated by selective fetal growth restriction (sFGR). The classification is based on the umbilical artery (UA) diastolic flow reflecting the outcome. If the sFGR twin has positive diastolic flow (Type I) then the prognosis is good, and it does not require close surveillance. Biweekly or weekly sonographic and Doppler surveillance and fetal monitoring are recommended strategies to detect unpredictable complications in type II and type III forms, which are defined by persistently absent/reverse end-diastolic flow (AREDF) or cyclically intermittent absent/reverse end-diastolic flow (iAREDF) in the umbilical waveforms, respectively. The latest forms are associated with an increased risk of unexpected fetal demise of the smaller twin and 10-20% risk of neurological injury in the larger twin in addition to the overall risk of prematurity. The clinical course can be affected by elective fetal therapy ('dichorinization' of the placenta with laser or selective fetal reduction) or elective delivery in the presence of severe fetal deterioration. The prediction of the clinical outcome in complicated cases of type II and III sFGR cases remains elusive. Novel routines in fetal and placental scans in order to predict neurological impairments and unexpected fetal death to optimize the delivery time-point are needed.

Intertwin differences in umbilical artery pulsatility index are associated with infant survival in twin-to-twin transfusion syndrome

OBJECTIVES

To evaluate the association of intertwin differences in umbilical artery pulsatility index (DUAPI) and infant survival in twin-to-twin transfusion syndrome (TTTS).

METHODS

Absolute DUAPI was calculated prior to laser surgery. Receiver-operating characteristics (ROC) curve analysis provided an intertwin DUAPI cutoff of 0.4 for the prediction of double twin survival to 30 days of life. Infant survival was compared between women with an intertwin DUAPI <0.4 and ≥0.4 in the whole cohort, in TTTS cases with Quintero stages I/II and in those with Quintero stages III/IV. Regression analyses were performed to evaluate the association of intertwin DUAPI <0.4 and infant survival adjusted for confounders.

RESULTS

In total, 349 TTTS cases were included. Double twin survival to 30 days was observed in 67% (234/349) of cases. Significant differences in double twin survival was seen between intertwin DUAPI groups in the whole cohort (76.8 vs. 52.2%; p<0.001), in women with TTTS Quintero stage I or II (77.8 vs. 58.5%; p=0.015) as well as in women with TTTS Quintero stage III or IV (75 vs. 49.5%; p=0.001). Intertwin DUAPI <0.4 conferred a threefold increased chance for double twin survival.

CONCLUSIONS

Small intertwin DUAPI is associated with increased double infant survival in early and advanced TTTS stages.

Differentiation between TTTS Stages I vs II and III vs IV does not affect probability of double survival after laser therapy

OBJECTIVE

To compare the perinatal outcome of monochorionic twin pregnancies with twin-twin transfusion syndrome (TTTS), according to the disease severity, defined using Quintero staging, after treatment with fetoscopic laser surgery.

METHODS

This was a single-center study of 1020 consecutive cases with severe TTTS, which were treated with fetoscopic laser surgery. During the study period from January 1995 to March 2013, the participants were included at a mean ± SD gestational age of 20.8 ± 2.2 weeks. Perinatal survival analysis, including the rates of double survival and survival of at least one fetus, was undertaken according to the Quintero staging system. For blockwise comparisons of data, the whole population was divided into five chronologically consecutive study subgroups of 200 patients in each of the first four subgroups and 220 in the last one.

RESULTS

For the entire study population with known outcome (n = 1019), the rate of pregnancy with double fetal survival was 69.0% (127/184) in Stage-I, 71.4% (257/360) in Stage-II, 55.4% (236/426) in Stage-III and 51.0% (25/49) in Stage-IV TTTS cases. At least one twin survived in 91.3% (168/184) of pregnancies with Stage-I, 89.7% (323/360) of those with Stage-II, 83.1% (354/426) of those with Stage-III and 77.6% (38/49) of those with Stage-IV TTTS. The rates of double survival and survival of at least one fetus were both significantly higher in Stage-II TTTS compared with those in Stage-III TTTS cases (P < 0.001 and P = 0.011, respectively). Survival rates between pregnancies with Stage-I vs Stage-II TTTS and between those with Stage-III vs Stage-IV TTTS were not significantly different. Therefore, we combined pregnancies with Stage-I or Stage-II TTTS, and those with Stage-III or Stage-IV TTTS. The double survival rate was 70.6% (384/544) in combined Stage-I and Stage-II vs 54.9% (261/475) in combined Stage-III and Stage-IV TTTS cases (P < 0.001). At least one twin survived in 90.3% (491/544) of pregnancies with Stage-I or Stage-II TTTS vs 82.5% (392/475) in those with Stage-III or Stage-IV TTTS (P < 0.001). The double survival rate increased between the first and the last consecutive study subgroups from 59.8% (55/92) to 75.0% (96/128) (adjusted odds ratio (aOR)_{linear trend} , 1.26 (95% CI, 1.01-1.56); P = 0.037) in pregnancies with Stage-I or Stage-II TTTS and from 41.7% (45/108) to 62.0% (57/92) (aOR_{linear trend} , 1.21 (95% CI, 0.98-1.50); P = 0.082) in those with Stage-III or Stage-IV TTTS. Double survival rate was the lowest for Stage-III cases in which the donor twin was affected by severely abnormal Doppler findings (45.4% (64/141)).

CONCLUSIONS

Double survival and survival of at least one fetus in monochorionic twin pregnancies with TTTS were related significantly to Quintero stage. However, our data show that the differentiation between Stages I vs II and Stages III vs IV does not have any significant prognostic implication for perinatal survival. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

The Use of Sequential Integrated Screening to Stratify Risk in Monochorionic-Diamniotic Twin Pregnancies

OBJECTIVE

This study aimed to identify differences in sequential integrated screening and early ultrasound markers in monochorionic/diamniotic (MC/DA) pregnancies complicated by twin-to-twin transfusion syndrome (TTTS) and unequal placental sharing (UPS).

STUDY DESIGN

Retrospective cohort study of MC/DA pregnancies evaluated between January 2012 and July 2017 at the University of California San Francisco. MC/DA pregnancies with ultrasound surveillance up to 26 weeks who participated in the California Prenatal Screening Program (CPSP) were included. Pregnancies with structural or genetic anomalies were excluded. UPS was defined as an intertwin growth discordance ≥20%. Intertwin nuchal translucency (NT) discordance was calculated by the absolute value of the difference of the NT of cotwins. Kruskal-Wallis or ANOVA testing was performed where appropriate, and negative binomial regression models were chosen to test for differences in mean biomarker levels by outcome group.

RESULTS

A total of 191 MC/DA pregnancies were included; 85 were affected by TTTS, 35 by UPS, and 71 controls. Significant differences in intertwin NT discordance in pregnancies complicated by TTTS and UPS compared with controls (p = 0.007) were found. TTTS cases had a mean NT discordance greater than two times that of controls (p = 0.04), while UPS cases had a value more than three times greater (p = 0.003). There was a statistically significant difference in mean second trimester human chorionic gonadotropin (hCG) between the cohorts (p = 0.0002) with TTTS cases having a mean second trimester hCG value 1.5 greater than both controls (p < 0.001) and UPS cases (p = 0.001). Analysis showed a significant difference in mean second trimester inhibin between the three cohorts (p = 0.029). Pregnancies complicated by UPS had a mean second trimester inhibin 1.5 times greater than controls (p = 0.010).

CONCLUSION

Our study shows that there are unique differences in early ultrasound and sequential integrated serum markers between MC/DA gestations complicated by TTTS and UPS versus those unaffected.

KEY POINTS

· Differences exist in sequential integrated screening markers in monochorionic-diamniotic twin pregnancies.. · Early risk stratification of monochorionic-diamniotic twin pregnancies may be possible.. · Sequential integrated screening testing can provide useful information to clinicians when evaluating monochorionic-diamnitoic twin pregnancies..

Cardiac pathophysiology in twin-twin transfusion syndrome: new insights into its evolution

OBJECTIVES

In twin-twin transfusion syndrome (TTTS), unbalanced transfer of vasoactive mediators and fluid from the donor to the recipient cotwin alters their cardiovascular function. The aims of this study were to describe the impact of TTTS on fetal cardiac function in a large cohort of monochorionic-diamniotic (MCDA) pregnancies, and determine the early hemodynamic response to selective fetoscopic laser photocoagulation (SFLP).

METHODS

Echocardiography was performed in 145 MCDA pregnancies, including 26 uncomplicated MCDA, 61 TTTS Stages I+II and 58 TTTS Stages III+IV pregnancies, prior to SFLP for TTTS. Echocardiographic data after SFLP were available in a subset of 41/119 (34%) TTTS cases at a mean of 1.7 ± 1.9 days. Mitral (MAPSE) and tricuspid (TAPSE) annular systolic excursion, myocardial performance index (MPI), tissue Doppler velocities (E', A', S') and filling pressures (E/E') were measured and transformed into Z-scores. Ventricular pressure was estimated from peak atrioventricular regurgitation velocity.

RESULTS

Left ventricular hemodynamics of the recipient twin were affected in early TTTS. In all stages of TTTS, left MPI and E/E' of the recipient twin were elevated in comparison to those of the donor (all P < 0.05), with reduced recipient left S' in TTTS Stages III+IV (P < 0.001). Ventricular pressure was elevated for gestational age (median, 42 mmHg (range, 20-65 mmHg)) in 11 of 14 recipients in which this parameter was measured. Between-group difference in right ventricular E/E' was significant only in TTTS Stages III+IV recipients compared with TTTS Stages I+II (P = 0.007) and uncomplicated MCDA (P = 0.041). Recipient left and right MPI decreased while S', MAPSE and TAPSE increased after SFLP; in donors, left E/E' and cardiac output increased.

CONCLUSIONS

Cardiac function of the recipient twin in TTTS is abnormal, even in the early stages of the disease. Left ventricular filling pressures are elevated and systolic function is decreased before abnormalities in the right heart become apparent. SFLP produces rapid hemodynamic improvement. Copyright © 2017 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.

Cardiac Manifestations of Twin–to–Twin Transfusion Syndrome

This review addresses the physiology of monochorionic diamniotic (MC/DA) twins and the potential for twin–twin transfusion syndrome (TTTS). It focuses on the underlying cardiovascular pathophysiology of TTTS and the cardiovascular impact of TTTS for both the recipient and the donor twin. It explains the principles for assessment and monitoring of these cardiovascular changes and how these may be used to guide pregnancy management. Finally, it describes the effect of treatment on the altered hemodynamics and how this can influence pregnancy and perinatal management, as well as longer-term follow-up.

Monochorionic diamniotic in vitro fertilization twins have a decreased incidence of twin-to-twin transfusion syndrome

OBJECTIVE

To compare the incidence of twin-to-twin transfusion syndrome (TTTS) in spontaneous versus IVF-conceived twin pregnancies.

DESIGN

Retrospective multicenter study.

SETTING

University-affiliated tertiary medical centers.

PATIENT(S)

Women admitted for 11-14 week's scan between January 1997 and July 2013 who were diagnosed with monochorionic (MC) diamniotic twin pregnancies.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Mode of conception, TTTS.

RESULT(S)

The study cohort included 327 pregnant women with live MC diamniotic twins. Of them, 284 (86.9%) and 43 (13.1%) were spontaneous and IVF conceived, respectively. The mean maternal age was significantly higher in IVF compared with in spontaneously conceived pregnancies (33.8 ± 5.5 vs. 31.6 ± 5.4, respectively). Thirty-seven twins (11.3%) had TTTS, of whom 36/284 (12.7%) versus 1/43 (2.3%) were spontaneously and IVF conceived, respectively. The mean week of delivery was significantly lower in MC twins diagnosed with TTTS compared with those without TTTS (32.7 ± 3.3 vs. 35.5 ± 2.5, respectively). Furthermore, there was a significantly higher birthweight discordancy in twins diagnosed with TTTS compared with those without (20.6% vs. 11%, respectively).

CONCLUSION(S)

The significantly lower proportion of TTTS found in IVF-conceived twins may suggest a different embryological process that lies at the core of IVF conception of monozygotic twinning.

Twin-to-twin transfusion syndrome: perinatal outcome and recipient heart disease according to treatment strategy

AIM

The aims of the study were to compare perinatal outcome and assess recipient cardiac disease according to treatment strategy (amnioreduction (AR), laser or selective feticide).

METHODS

We retrospectively reviewed 81 consecutive cases of twin-to-twin transfusion syndrome diagnosed before 28 weeks between 1993 and 2007.

RESULTS

Although fetuses treated by laser were younger at diagnosis (median 20.4 vs. 22.4 weeks, P = 0.01), they were significantly older at birth (median 33.6 vs. 28.5 weeks, P = 0.004) than those treated by AR. Neonatal morbidity was globally lower after laser than AR, and cardiac insufficiency tended to be less frequent (31% vs. 57%, P = 0.09). There was a trend towards increased perinatal survival after laser treatment (68% vs. 49%, P = 0.1). Heart failure was the cause of death in half (23/46) of the recipients. Fetal heart failure leading to death was 2.7 times more frequent after AR than after laser (n = 11 vs. n = 4), and all four neonatal cardiac deaths occurred after AR. Compared with laser, selective feticide did not further improve the outcome.

CONCLUSIONS

Heart failure was an important cause of perinatal morbidity and death. However, laser therapy resulted in a longer diagnosis-delivery interval and lower global neonatal morbidity than AR, with a trend towards increased perinatal survival. Improved outcome after laser treatment compared with AR might be related to its impact on recipient heart disease.

Laser therapy for twin-to-twin transfusion syndrome (TTTS)

Monochorionic twins are subjected to specific complications which originate in either imbalance or abnormality of the single placenta serving two twins including twin-to-twin transfusion syndrome. The diagnosis is well established in overt clinical forms with the association of polyuric polyhydramnios and oliguric oligohydramnios. The best treatment of cases presenting before 26 weeks of gestion is fetoscopic laser ablation of the intertwin anastomoses on the chorionic plate. Although subjected to subtle variations, the core technique follows robust guidelines which could help understanding and acquiring the required skills and experience to perform this procedure. However appropriate and tailored hands-on training and appropriate perinatal set-up are critical not only for surgical management but also for the follow-up and management of related complications.

The making of fetal surgery

Fetal diagnosis prompts the question for fetal therapy in highly selected cases. Some conditions are suitable for in utero surgical intervention. This paper reviews historically important steps in the development of fetal surgery. The first invasive fetal intervention in 1963 was an intra-uterine blood transfusion. It took another 20 years to understand the pathophysiology of other candidate fetal conditions and to develop safe anaesthetic and surgical techniques before the team at the University of California at San Francisco performed its first urinary diversion through hysterotomy. This procedure would be abandoned as renal and pulmonary function could be just as effectively salvaged by ultrasound-guided insertion of a bladder shunt. Fetoscopy is another method for direct access to the feto-placental unit. It was historically used for fetal visualisation to guide biopsies or for vascular access but was also abandoned following the introduction of high-resolution ultrasound. Miniaturisation revived fetoscopy in the 1990 s, since when it has been successfully used to operate on the placenta and umbilical cord. Today, it is also used in fetuses with congenital diaphragmatic hernia (CDH), in whom lung growth is triggered by percutaneous tracheal occlusion. It can also be used to diagnose and treat urinary obstruction. Many fetal interventions remain investigational but for a number of conditions randomised trials have established the role of in utero surgery, making fetal surgery a clinical reality in a number of fetal therapy programmes. The safety of fetal surgery is such that even non-lethal conditions, such as myelomeningocoele repair, are at this moment considered a potential indication. This, as well as fetal intervention for CDH, is currently being investigated in randomised trials.

The Fetal Heart in Twin-to-Twin Transfusion Syndrome

Twin-to-twin transfusion syndrome is a severe complication occurring in 10% of monochorionic twin pregnancies. The disease is usually explained as due to an intrauterine imbalance in intertwin blood exchange, which leads to a volume depleted-donor twin and an overfilled recipient twin. The recipient has signs of cardiac dysfunction, which can be measured using echocardiography or blood and amniotic fluid derived biomarkers. Whereas cardiac dysfunction typically progresses in pregnancies treated with amniodrainage, it usually disappears within a few weeks after fetoscopic laser coagulation of the connecting intertwin anastomoses. Nevertheless, recipients remain at a increased risk of pulmonary stenosis. In this paper, we summarize the cardiac alterations in twin-to-twin transfusion syndrome, describe the changes seen after fetal therapy, list the newly proposed staging systems based on fetal cardiac function, and make recommendations about the use of fetal echocardiography in the evaluation and followup of pregnancies complicated by twin-to-twin transfusion syndrome.

Management of Stage I twin-to-twin transfusion syndrome: an international survey

OBJECTIVE

To determine practice patterns for evaluation and treatment of Stage I twin-to-twin transfusion syndrome (TTTS) among international physicians.

METHODS

An e-mail cross-sectional survey of members from the IFMSS, NAFTNet and SMFM societies and participants at a Eurofoetus-sponsored TTTS meeting was undertaken between May 2008 and November 2008. Questionnaires consisted of physician demographics and their recommendations for managing Stage I TTTS. Alternative therapies to expectant management were assessed based on the following special circumstances of the patient: residence more than 200 miles from the center, severe symptoms, or a cervical length of </= 15 mm.

RESULTS

Eighty-one surveys were returned, giving a response rate of 84%. Five surveys were excluded as a result of duplication or missing data. Of the remaining 76 surveys, 48 were from North America, 20 were from Europe and eight were from other continents. Expectant management was the predominant recommendation (78%), followed by amnioreduction (11%), laser ablation (11%) and septostomy (1%). Recommendations for amnioreduction were exclusively from North American centers. Laser centers recommended expectant management more frequently than non-laser facilities (89% vs. 59%; P < 0.01). When examples of special patient circumstances were presented, North American centers changed their recommendation from expectant management to amnioreduction more often than did European centers. However, a greater proportion of European centers recommended laser surgery for special patient circumstances.

CONCLUSION

Expectant management remains the predominant management of Stage I TTTS. In some patient circumstances, North American centers are more likely to recommend amnioreduction while European centers are more likely to recommend laser therapy. A randomized controlled trial will be necessary to evaluate the most efficacious management strategy for Stage I TTTS.

Fetal surgery is a clinical reality

An increasing number of fetal anomalies are being diagnosed prior to birth, some of them amenable to fetal surgical intervention. We discuss the current clinical status and recent advances in endoscopic and open surgical interventions. In Europe, fetoscopic interventions are widely embraced, whereas the uptake of open fetal surgery is much less. The indications for each access modality are different, hence they cannot substitute each other. Although the stage of technical experimentation is over, most interventions remain investigational. Today there is level I evidence that fetoscopic laser surgery for twin-to-twin transfusion syndrome is the preferred therapy, but this operation actually takes place on the placenta. In terms of surgery on the fetus, an increasingly frequent indication is severe congenital diaphragmatic hernia as well as myelomeningocele. Overall maternal safety is high, but rupture of the membranes and preterm delivery remain a problem. The increasing application of fetal surgery and its mediagenicity has triggered the interest to embark on fetal surgical therapy, although the complexity as well as the overall rare indications are a limitation to sufficient experience on an individual basis. We plead for increased exchange between high volume units and collaborative studies; there may also be a case for self-regulation. Inclusion of patients into trials whenever possible should be encouraged rather than building up casuistic experience.

Amniotic fluid markers of fetal cardiac dysfunction in twin-to-twin transfusion syndrome

OBJECTIVE

The objective of the study was to determine whether cardiac troponin T (cTnT) and natriuretic peptides can be isolated from the amniotic fluid (AF) of pregnancies complicated by twin-to-twin transfusion syndrome (TTTS) and whether they correlate with fetal echocardiographic findings and recipient survival.

STUDY DESIGN

AF samples from the recipient sac were obtained in 52 TTTS cases and 16 controls. Samples were assayed for cTnT and natriuretic peptides. Prior to fetoscopic laser therapy, 34 recipient twins underwent assessment of atrioventricular flow patterns, myocardial performance index (MPI), and precordial venous Dopplers. Fetal survival was assessed 48 hours postoperatively.

RESULTS

AF B-type natriuretic peptide and cTnT levels were elevated in TTTS and correlated with functional echocardiographic findings. Postoperative recipient survival was 72% when both AF-cTnT and left ventricular MPI were increased. If 1 of both markers was normal, survival was 100% (P = .046).

CONCLUSION

Combining ultrasound and AF-cTnT measurements allows the identification of fetuses at risk of postoperative demise.

Profiling fetal cardiac function in twin-twin transfusion syndrome

OBJECTIVES

Cardiomyopathy in the recipient twin is a marker of severity in twin-twin transfusion syndrome (TTTS), making it a potentially valuable tool for staging the disease. This study aimed to provide a quantitative description of cardiac function in the recipient twin.

METHODS

Consecutive monochorionic pregnancies complicated with TTTS and treated by percutaneous laser coagulation underwent fetal echocardiography before surgery. An unsupervised classification analysis was conducted to identify groups of twins with similar cardiac profiles. The predictive value of the recipient twin's preoperative cardiac function based on these profiles was assessed, using perinatal death of at least one twin as the main outcome. The cardiac function profiles that we identified were compared with the current Quintero staging.

RESULTS

A total of 107 pregnancies were included, with six of these lost to follow-up; 63/107 complete cases were available for multivariate description of the recipient's cardiac function. Three different preoperative cardiac profiles were identified with increasing right and left myocardial performance index, decreasing right and left shortening fraction, and increasing ductus venosus pulsatility index. Although the three groups represented progressive stages of the syndrome-related cardiomyopathy, no correlation was found with pregnancy outcome. Of Quintero Stage 1 cases, 55% showed significant alterations of cardiac function in the recipient twin.

CONCLUSIONS

Progressive cardiomyopathy can be assessed quantitatively in the recipient twin and does not influence pregnancy outcome when fetoscopic laser coagulation is the first-line treatment. Compared with the current staging, cardiac profiling allows discrimination of cases with significant myocardial dysfunction.

The pediatric surgeons' contribution to in utero treatment of twin-to-twin transfusion syndrome

OBJECTIVE

To evaluate the outcome of twin-to-twin transfusion syndrome (TTTS) treated using a combination of endoscopic fetal surgery-specific techniques and surgical restraint.

SUMMARY BACKGROUND DATA

TTTS is a condition of identical twins that, if progressive and left untreated, leads to 100% mortality. The best treatment option is obliteration of the intertwin placental anastomoses, but fetal surgery carries significant maternal and fetal risks. Even if successful, percutaneous endoscopic laser ablation of placental vessels (LASER) causes premature rupture of membranes (PROM) in 10% to 20% of pregnancies. Patient selection is particularly critical because the progression of the disease is unpredictable. This has prompted many to intervene early, yielding survival rates of >=1 twin of 75% to 80%.

METHODS

We developed a minimally invasive approach to fetal surgery, a unique membrane sealing technique and a conservative algorithm that reserves intervention for severe TTTS. Pregnancies with TTTS (stages I-IV) managed in the last 8 years were reviewed. LASER was offered in stage III/IV only.

RESULTS

Ninety-eight cases of TTTS were managed in a pediatric surgery/maternal-fetal medicine collaborative Fetal Treatment Program-39 were observed (40%) and 59 underwent LASER (60%). Survival of >= twin was seen in 82.7%, and overall survival was 69.4%. These survival rates are similar to, or better than, other comparable series with similar stage distribution (low:high stage ratio 1:1) in which all patients underwent LASER. PROM rate was 4%.

CONCLUSIONS

Reserving LASER treatment for severe TTTS results in outcomes similar to, or better than, LASER for all stages. Applying fetal surgery-specific endoscopic techniques, including port-site sealing, reduces postoperative complications.

Assessment of fetal cardiac function before and after therapy for twin-to-twin transfusion syndrome

OBJECTIVE

We sought to assess fetal cardiac function in monochorionic twins before and after therapy for twin-to-twin transfusion syndrome (TTTS) and compare it with control subjects.

STUDY DESIGN

We conducted prospective longitudinal assessment of fetal cardiac function in cases undergoing curative fetal therapy for TTTS (n = 39) until 4 weeks postoperatively and in uncomplicated monochorionic twins (n = 23). Fetal cardiac function was assessed by the left and right ventricular myocardial performance index, atrioventricular valve flow pattern, ductus venosus a-wave, and umbilical vein pulsations.

RESULTS

Nomograms for the myocardial performance index were constructed. Fetal cardiac function was grossly abnormal in recipient twins of TTTS when compared with control subjects (P < .001 for all indices) but normalized by 4 weeks postoperatively. The donor developed abnormal ductus venosus flow and tricuspid regurgitation postoperatively that regressed within 4 weeks.

CONCLUSION

The cardiac dysfunction in the recipient twin of TTTS normalizes within 1 month after laser. The donor develops a transient impairment of cardiac function postoperatively.