A simpler technique for umbilical-cord blockade of an acardiac twin

Twin Reversed Arterial Perfusion Sequence: Current Treatment Options

Twin reversed arterial perfusion (TRAP) sequence is a specific and severe complication of monochorionic multiple pregnancy, characterized by vascular anastomosis and partial or complete lack of cardiac development in one twin. Despite its rarity, interest in the international literature is rising, and we aimed to review its pathogenesis, prenatal diagnostic features and treatment options. Due to the parasitic hemodynamic dependence of the acardiac twin on the pump twin, the management of these pregnancies aims to maximize the pump twin's chances of survival. If treatment is needed, the best timing of intervention is still debated, although the latest studies encourage intervention in the first trimester of pregnancy. As for the technique of choice to interrupt the vascular supply to the acardiac twin, ultrasound-guided laser coagulation and radiofrequency ablation of the intrafetal vessels are usually the preferred approaches.

Fetal Sclerotherapy for Hydropic Congenital Cystic Adenomatoid Malformations of the Lung Refractory to Steroids: A Case Report and Review of the Literature

Microcystic congenital cystic adenomatoid malformations (CCAM), when associated with hydrops, carry a dismal prognosis. Options for treatment are limited and experimental, including antenatal corticosteroids, open fetal surgery, laser ablation and, more recently, sclerotherapy. We describe a case of a large, predominantly microcystic CCAM in a hydropic fetus treated successfully with direct interstitial injection of a sclerosant agent (3% sodium tetradecyl sulfate) at 23+3 weeks gestation, after multiple failed courses of steroids. Elective thoracoscopic right lower lobectomy was performed at 1 year of life and there have been no respiratory or other medical morbidities since. A literature review of fetal lung masses treated with sclerosants antenatally reveals that sclerotherapy may represent a novel treatment option for large hydropic microcystic CCAMs, which are unresponsive to corticosteroids. Further studies are required to evaluate the utility and safety of fetal sclerotherapy, as this may represent an alternative minimally invasive treatment option to fetal lobectomy.

Fetal primary pleural effusions: Prenatal diagnosis and management

Fetal pleural effusions can be associated with significant perinatal morbidity and mortality. When diagnosed antenatally, referral to a tertiary fetal medicine center is recommended for a detailed ultrasound evaluation for additional structural abnormalities or features suggestive of congenital infections or fetal anemia. The effusions should be characterized as unilateral or bilateral, and presence of hydrops and/or mediastinal shift should be documented. Additional testing should include fetal echocardiography, maternal testing for blood group and screen, hemoglobinopathies, and congenital infections. Invasive genetic testing is recommended with infectious testing on amniotic or pleural fluid. Pleuroamniotic shunting is recommended for large primary pleural effusions with significant mediastinal shift or hydrops, as several large series have demonstrated improvement in perinatal survival, particularly in hydropic fetuses. Delivery should occur in a tertiary care center with neonatal expertise, and infants should be followed up long-term for respiratory and neurodevelopmental outcomes.

Intrauterine growth restriction in monochorionic twins

Intrauterine growth restriction (IUGR) occurs in approximately 3-10% of singleton pregnancies, in 9.1% of all twins, and in 9.9% of monochorionic twins. Spontaneous demise of the IUGR twin may occur and may result in concomitant demise or severe neurological handicap of the other twin. Currently, monochorionic twins with selective IUGR (SIUGR) are managed expectantly. Alternatively, all adverse consequences resulting from the potential demise of the SIUGR twin could be averted by unlinking the circulations between the two fetuses. The latter can be achieved by laser photocoagulation of communicating vessels or by umbilical-cord occlusion. The purpose of this chapter is to review this important entity in obstetrics.

Efficacy of radiofrequency ablation for twin-reversed arterial perfusion sequence

OBJECTIVE

We report our experience in the treatment of patients with twin-reversed arterial perfusion (TRAP) sequence using radiofrequency ablation to stop perfusion to the acardiac twin and protect the pump twin.

STUDY DESIGN

An IRB approved retrospective review of all patients (n = 29) who underwent percutaneous radiofrequency ablation of an acardiac twin, using ultrasound guidance and either a 14 or 17 gauge radiofrequency needle for twin-reversed arterial perfusion sequence, from 1998 to 2005, was performed by review of hospital and outpatient medical records.

RESULTS

The outcomes of all 29 of the patients treated with radiofrequency ablation are known. Twenty-six of the patients had monochorionic-diamniotic pregnancies, whereas 2 had monochorionic-monoamniotic pregnancies. One patient had a triplet pregnancy with a monochorionic-diamniotic pair with TRAP sequence. Overall, 25 of 29 pump twins survived (86%), delivering at a mean gestational age of 34.6 weeks. Survival was 24 of 26 (92%) in monochorionic-diamniotic pregnancies with a mean gestational age of 35.6 weeks. Two women in our early experience sustained thermal injuries from the site of grounding pads.

CONCLUSION

Radiofrequency ablation of the acardiac twin effectively protects the pump twin from high-output cardiac failure and death. Greater than 90% survival can be achieved in monochorionic-diamniotic pregnancies complicated by TRAP sequence with a mean gestation age at time of delivery close to term. Our limited experience in cases of monochorionic-monoamniotic TRAP sequence does not allow the determination of efficacy in this group.

Umbilical cord occlusion of the donor versus recipient fetus in twin-twin transfusion syndrome

OBJECTIVES

To compare the technical characteristics and perinatal outcomes of selected twin-twin transfusion syndrome (TTTS) cases treated with primary umbilical cord occlusion (UCO) of the donor vs. recipient twin.

METHODS

TTTS patients who underwent primary UCO via ultrasound endoscopic-guided umbilical cord ligation (UCL) or endoscopic umbilical cord photocoagulation (UCP) were eligible for the study. Primary UCO was offered only if a discordant lethal anomaly was present or by patient choice in TTTS Stages III/IV on the cord of the fetus with abnormal Doppler studies or hydrops.

RESULTS

Primary UCO was performed in 25 TTTS cases between July 1997 and June 2002. UCO was performed in six (24%) donor twins and 19 (76%) recipient twins. UCL was performed in 23 cases and UCP in two cases. Overall, 22 (88%) patients had liveborn infants. There were no differences in cotwin survival (100% vs. 84.2%), median gestational age at delivery (34.8 vs. 33.8 weeks) and preterm premature rupture of membranes rate (16.6% vs. 15.7%) whether the donor or recipient twin, respectively, was the subject of UCO. However, two-trocar access (50% vs. 5.3%; P = 0.03) and amnioinfusion (83.3% vs. 0%; P < 0.001) were required more often in the UCO of the donor than of the recipient twin, respectively. Operating time (75 vs. 40 min) was significantly longer in UCO of the donor twin (P = 0.04). UCP was more likely to be used in occlusion of the donor's cord (33%) than of the recipient's cord (0%; P = 0.05).

CONCLUSION

Primary UCO of the donor twin is technically more demanding than that of the recipient twin, but perinatal outcomes of the cotwins are comparable.

Twin pregnancies discordant for anencephaly—management, pregnancy outcome and review of literature

AIMS AND METHODS

To examine the prognosis of conservative management in twin pregnancies discordant for anencephaly, we review the literature and report on four of our own cases, which were analyzed retrospectively.

RESULTS

In the University Hospital of Erlangen, six twin pregnancies discrepant for anencephaly were observed during an 8-year period (1992-2000). Four of these pregnancies were managed conservatively. Preterm delivery occurred in all of the cases, but the unaffected fetuses all had favorable long-term outcome. Delayed interval delivery was performed in two cases due to extreme immaturity in the healthy fetus.

CONCLUSIONS

Our data show that in twin pregnancies with early diagnosis of anencephaly in one fetus, the risk of premature delivery of the healthy fetus may be more increased than is already known in the literature. Therefore, selective fetocide of the anencephalic fetus is a management option, at least in dichorionic pregnancies, to prevent polyhydramnios and to reduce the risk of preterm delivery.

Acardiac twin: a systematic review of minimally invasive treatment modalities

This review of the literature aimed to determine pregnancy outcomes after minimally invasive treatment for occluding vascular supply to acardiac twins. A MEDLINE search was performed until 2002 using the terms 'acardiac', 'acardius', 'twin reversed arterial perfusion (TRAP) sequence' and 'chorangiopagus parasiticus' and 207 articles published in the English-language literature were identified. These articles and the corresponding cited references in English were reviewed. We identified 32 reports involving 74 cases of acardiac twin treated by minimally invasive techniques. Seventy one cases were included for analysis including 40 treated by cord occlusion and 31 by intrafetal ablation. Cord occlusion was first attempted by embolization (n = 5), cord ligation (n = 15), laser coagulation (n = 10), bipolar diathermy (n = 7) and monopolar diathermy (n = 3). Intrafetal ablation was performed by alcohol (n = 5), monopolar diathermy (n = 9), interstitial laser (n = 4) and radiofrequency (n = 13). The overall median gestational ages at treatment and delivery were 21 (range, 14-28) weeks and 36 (range, 19-42) weeks, respectively, with a median treatment-delivery interval of 13 (range, 0-25) weeks. The overall pump twin survival rate was 76% (n = 54). Intrafetal ablation was associated with later median gestational age at delivery (37 vs. 32 weeks, P = 0.04) and higher median treatment-delivery interval (16 vs. 9.5 weeks, P = 0.02) compared with cord occlusion techniques. It was also associated with a lower technical failure rate (13% vs. 35%, P = 0.03), lower rate of premature delivery or rupture of membranes before 32 weeks (23% vs. 58%, P = 0.003) and higher rate of clinical success (77% vs. 50%, P = 0.02) than cord occlusion techniques. There were no statistically significant differences in terms of outcome between the subgroups of fetoscopic- or ultrasound-guided cord occlusion techniques. This review suggests that intrafetal ablation is the treatment of choice for acardiac twins because it is simpler, safer and more effective when compared with the cord occlusion techniques.

Intrauterine treatment for an acardiac twin with alcohol injection into the umbilical artery

An acardiac twin is a unique complication of monochorionic twinning, in which a normal pump twin perfuses the acardiac twin. The mortality rate of the pump twin is greater than 50%. Herein we present the successful treatment of an acardiac twin with alcoholization as follows. An acardiac twin was diagnosed at 24 weeks gestation. Circulation interruption of the acardiac twin was successfully achieved by injection of absolute alcohol (5 mL) into the intra-abdominal umbilical artery. Serial ultrasound after the procedure revealed normal growth of the pump twin, whereas the acardiac twin was shrinking. Spontaneous premature delivery at 34 weeks gestation resulted in a normal surviving female baby weighing 2410g and an acardiac female fetus weighing 300g. This experience suggests that this simple technique may be an alternative treatment for an acardiac twin.

Interstitial laser: a new surgical technique for twin reversed arterial perfusion sequence in early pregnancy

Current treatments for twin reversed arterial perfusion sequence are associated with significant morbidity and most are not feasible in early gestation. We report the use of an interstitial laser in two pregnancies complicated by this sequence at 14 and 15 weeks, respectively. A 600 microm laser fibre was introduced via a 17 gauge needle into the abdomen of the perfused twin close to the vitelline artery and umbilical vein, which were occluded by neodymium:yttrium aluminium garnet (Nd:YAG) laser. Both pregnancies continued uneventfully and each resulted in the birth of a healthy baby at term.

Anomalies peculiar to multiple gestations

Congenital anomalies occur twice as often in twin pregnancies as in singletons. In addition to the large range of structural malformations that are described in singleton fetuses, multiple gestations are at risk for additional anomalies that are unique to the twinning process. These unique anomalies include twin-twin transfusion syndrome, twin-reversed-arterial-perfusion syndrome, and conjoined twinning. This article reviews and describes each of these unique abnormal conditions in detail.

Severe polyhydramnios in twin reversed arterial perfusion sequence: successful management with intrafetal alcohol ablation of acardiac twin and amniodrainage

We present two cases of twin reversed arterial perfusion (TRAP) sequence complicated by severe polyhydramnios during the second trimester. Both cases were successfully managed at 27 and 26 weeks with ultrasound-guided intrafetal alcohol ablation of the acardiac twin and amniodrainage. The pump twins were delivered at 35 and 37 weeks, respectively, and both had uneventful postnatal courses. These cases suggest that, in the setting of severe polyhydramnios, prenatal intervention in TRAP sequence could certainly improve the otherwise poor prognosis of the pump twin. Targeting the main intra-abdominal vessel of the acardiac twin rather than its umbilical cord seems to be a good alternative in the prenatal treatment of these cases. The option of percutaneous intrafetal alcohol injection is widely available and less invasive, simpler and easier to perform than recently advocated endoscopic techniques.

Acardiac twinning where the pump twin dies in utero due to thrombosis in the umbilical arteries

A case of acardiac twinning where the pump twin dies in utero due to massive thrombotic occlusion of umbilical arteries at a site of umbilical cord stricture of the intact twin. In acardiac twinning the morbidity and mortality of the pump twin can be reduced by some invasive or medical approaches. The authors believe that in this interesting case the death of the pump twin could not be prevented by antenatal treatment.

The consequences of monochorionic placentation

Monochorionic (MC) placentation occurs in two-thirds of monozygous twins and approximately 0.3% of all spontaneous conceptions. Vascular anastomoses within the placenta allow intertwin transfusion to occur, which is in most cases a normal event. However, imbalance in this flow may lead to the clinical sequelae observed, with acute, chronic or reverse intertwin transfusion. Acute transfusion describes the events following the death of one of an MC twin pair in utero, with an approximately 1 in 4 chance of demise or neurological damage in the co-twin. Chronic intertwin transfusion, otherwise termed feto-fetal transfusion syndrome, arises following the gradual flux of blood from one twin (the donor) to its sibling fetus (the recipient). The ensuing polyhydramnios places the pregnancy at risk of preterm amniorrhexis and/or labour, notwithstanding the specific sequelae seen in these fetuses following chronic in utero insult. Reverse transfusion describes the most bizarre form of intertwin transfusion: acardiac twinning. Retrograde perfusion of one of the twins with deoxygenated blood leads to the formation of a non-viable acardiac parasite and a 'pump twin' struggling to maintain the cardiac output required to perfuse both twins.

Acardiac twins. Two case reports

The acardius syndrome is a rare complication of monozygotic twin pregnancies, occurring in 35,000 births. Development results from arterio-arterial and veno-venous anatomoses leading to predominance of one of the twins. The acardiac twin is grossly abnormal and the outcome is invariably fatal. The normal twin provides circulation for itself as well as the acardiac and the perinatal mortality is about 50-70%, as the result of congestive heart failure. Conservative therapy may be important for congestive cardiac failure in the normal twin. Surgical therapy is direct to maintain the pump fetus by interrupting the vascular communication between the twins. We present two cases of acardiac twin prenatally diagnosed by ultrasound and successfully managed by conservative therapy.

Prenatal diagnosis and the pediatric surgeon: the impact of prenatal consultation on perinatal management

PURPOSE

Pediatric surgeons are increasingly called on by obstetrical colleagues to counsel parents about the implications of a prenatal ultrasound finding. Our understanding of the natural history of many prenatally diagnosed surgical conditions has grown significantly in recent years. Whether prenatal surgical consultation can influence perinatal course had not been investigated.

METHODS

During an 21-month period, 12,865 prenatal ultrasound studies were performed on a total of 4,551 patients, and 221 prenatal surgical consultations were obtained through a newly established fetal treatment program at a tertiary care prenatal diagnostic center. To evaluate the impact of prenatal pediatric surgical consultation on perinatal course, the authors reviewed changes in management including termination of pregnancy, in utero intervention, and altered site, mode, or timing of delivery.

RESULTS

Two hundred twenty-one fetuses were referred for consultation; their 234 congenital anomalies included genitourinary (36%), thoracic (16%), intraabdominal (14.5%), abdominal wall (10.6%), neurological (9%), skeletal (6%), and head and neck (2.5%) defects; 2.5% had tumors and 2.5% were twin pregnancies. Pregnancy was terminated in 9.5% of cases, because of patient request, chromosomal abnormality, or dismal prognosis. In 3.6%, the decision to terminate was changed as a result of consultation. Site of delivery was changed as a result of consultation in 37% to facilitate postnatal evaluation and initiate immediate treatment. Mode of delivery was changed in 6.8% to prevent dystocia, hemorrhage into a tumor, as in sacrococcygeal teratoma, or to provide an emergency airway, as in cervical teratoma. The timing of delivery was changed in 4.5% to avoid further damage to fetal organs in cases of obstructive uropathy, gastroschisis, sacrococcygeal teratoma with high-output failure, and hydrocephalus. Five percent (11) underwent treatment in utero for fetal hydrothorax, obstructive uropathy, twin-twin transfusion syndrome, or lymphangioma. The overall perinatal mortality rate was 2.5%.

CONCLUSION

Prenatal pediatric surgical consultation may have a significant impact on the perinatal management of the fetus with a surgically correctable congenital anomaly. Providing obstetric colleagues and families with valuable insight into the surgical management of anomalies allows fetal intervention when appropriate, and delivery in an appropriate setting, by the safest mode of delivery, and at the gestational age appropriate to minimize effects of the anomaly.

Syndromes in twins

There is a higher incidence of perinatal mortality and morbidity in twins than in singleton pregnancies. The main reason for this increase is the higher incidence of preterm delivery in twins. There are special conditions unique to twins that also contribute to this increased perinatal morbidity and mortality. These conditions include monoamniotic twins, congenital anomalies unique to twins, ie, conjoined twins and acardia, intrauterine fetal demise, and twin-to-twin transfusion syndrome. These conditions are the subject of this review. The prenatal determination of chorionicity is discussed first, because this assessment is key to the diagnosis and management of many of these conditions.