A new fetal therapy for chylothorax: pleurodesis with OK-432

Congenital Chylothorax of the Newborn: A Systematic Analysis of Published Cases between 1990 and 2018

BACKGROUND

Congenital chylothorax (CCT) of the newborn is a rare entity but the most common cause of pleural effusion in this age-group. We aimed to find the optimal treatment strategy.

MATERIAL AND METHODS

A PubMed search was performed according to the PRISMA criteria. All cases were analyzed according to prenatal, perinatal, and postnatal treatment modalities and follow-ups.

RESULTS

We identified 753 cases from 157 studies published between 1990 and 2018. The all-cause mortality rate was 28%. Prematurity was present in 71%, male gender dominated 57%, mean gestational age was 34 weeks, and birth weight was 2,654 g. Seventy-nine percent of newborns had bilateral CCT, the most common associated congenital anomalies with CCT were pulmonary lymphangiectasia and pulmonary hypoplasia, and the most common chromosomal aberrations were Down, Noonan, and Turner syndromes, respectively. Mechanical ventilation was reported in 381 cases for mean 17 (range 1-120) days; pleural punctuations and drainages were performed in 32% and 64%, respectively. Forty-four percent received total parenteral nutrition (TPN) for mean 21 days, 46% medium-chain triglyceride (MCT) diet for mean 37 days, 20% octreotide, and 3% somatostatin; chemical pleurodesis was performed in 116 cases, and surgery was reported in 48 cases with a success rate of 69%. In 462 cases (68%), complete restitution was reported; in 34 of 44 cases (77%), intrauterine intervention was carried out.

CONCLUSION

Respiratory support, pleural drainages, TPN, and MCT diet as octreotide remain to be the cornerstones of CCT management. Pleurodesis with OK-432 done prenatally and povidone-iodine postnatally might be discussed for use in life-threatening CCT.

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.

Treatment of Primary Fetal Hydrothorax with OK-432 (Picibanil): Outcome in 14 Fetuses and a Review of the Literature

Background: Primary fetal hydrothorax (PFHT) is an uncommon condition with an estimated prevalence of 1 in 10,000/15,000 pregnancies. Therapeutic interventions include thoracocentesis, thoraco-amniotic shunting (TAS), and pleurodesis using OK-432. Methods: A review of the literature was performed to identify all cases of PFHT treated with TAS and OK-432. All cases of PFHT referred to the Fetal Maternal Unit at Royal Prince Alfred Hospital between 2002 and 2012 were retrospectively reviewed. In the cohort of fetuses treated with OK-432, the main perinatal outcomes evaluated were termination of pregnancy, live birth, neonatal death, and fetal death in utero. Secondary outcomes included gestational age (GA) at diagnosis, GA at treatment, GA at resolution, birth weight, and GA at birth. The development of the children was screened using the Ages and Stages Questionnaires, Version 3 (ASQ-3, 2009). Results: Primary hydrothorax was diagnosed in 31 fetuses, of which 14 had treatment with OK-432. One pregnancy terminated after treatment with OK-432. Survival was 85% (11/13): 100% in fetuses treated with OK-432 without hydrops, and 78% in those treated with hydrops. This compares well to the cases of TAS in the literature with an average survival of 63%: 85% in fetuses without hydrops and 55% with hydrops. The mean GA at birth was 36+4 weeks and mean birth weight 3,007 g. Eight of the 9 children screened with ASQ-3 scored well within the normal range. Conclusion: OK-432 appears to be a valid treatment option in fetuses with PFHT, particularly in those diagnosed at early GAs.

Chylothorax and chylous ascites: management and pitfalls

Leakage of lymph from the lymphatic ducts causes chylothorax (CT) or chylous ascitis (CA). This may happen for unknown reasons during fetal life or after birth and may also be caused by trauma after thoracic surgery or by other conditions. Fetal CT and CA may be lethal particularly in cases with fetal hydrops that sometimes benefit of intra-uterine instrumentation. After birth, symptoms are related to the amount of accumulated fluid. Sometimes, severe cardio-respiratory compromise prompts active therapy. Most patients with CT or CA benefit from observation, rest, and supportive measures alone. Drainage of the fluid may be necessary, but then loss of protein, fat, and lymphoid cells introduce new risks and require careful replacement. Low-fat diets with MCT and parenteral nutrition decrease fluid production while allowing adequate nutritional input. If lymph leakage does not stop, secretion inhibitors like somatostatin or octreotide are prescribed, although there is only weak evidence of their benefits. Imaging of the lymphatic system is indicated when the leaks persist, but this is technically demanding in children. Shunting of the lymph from one body space to another by means of valved catheters, embolization of the thoracic duct, and/or ligation of the major lymphatics may occasionally be indicated in cases refractory to all other treatments.

Experimental treatment of bilateral fetal chylothorax using in-utero pleurodesis

OBJECTIVE

To assess the use and efficacy of in-utero pleurodesis for experimental treatment of bilateral fetal chylothorax.

METHODS

This was a study of 78 fetuses with bilateral pleural effusion referred to three tertiary referral centers in Taiwan between 2005 and 2009. Fetuses were karyotyped following amniocentesis and the lymphocyte ratio in the pleural effusion was determined following thoracocentesis. Forty-nine (62.8%) fetuses had a normal karyotype and were recognized to have fetal chylothorax; of these, 45 underwent intrapleural injection of 0.1KE OK-432 per side per treatment. We evaluated clinical (hydrops vs. no hydrops) and genetic (mutations in the reported lymphedema-associated loci: VEGFR3, PTPN11, FOXC2, ITGA9) parameters, as well as treatment outcome. Long-term survival was defined as survival to 1 year of age.

RESULTS

The overall long-term survival rate (LSR) was 35.6% (16/45); the LSR for non-hydropic fetuses was 66.7% (12/18) and for hydropic fetuses it was 14.8% (4/27). If we included only fetuses with onset of the condition in the second trimester, excluding those with onset in the third trimester, the LSR decreased to 29.4% (10/34). Notably, 29.6% (8/27) of hydropic fetuses had mutations in three of the four loci examined.

CONCLUSIONS

OK-432 pleurodesis appeared to be an experimental alternative to the gold-standard technique of thoracoamniotic shunting in non-hydropic fetal chylothorax. In hydropic fetuses, pleurodesis appeared less effective.

The neural and vascular effects of killed Su-Streptococcus pyogenes (OK-432) in preterm fetal sheep

Fetal exposure to inflammatory mediators is associated with a greater risk of brain injury and may cause endothelial dysfunction; however, nearly all the evidence is derived from gram-negative bacteria. Intrapleural injections of OK-432, a killed Su-strain of Streptococcus pyogenes, has been used to treat fetal chylothorax. In this study, we evaluated the neural and cardiovascular effects of OK-432 in preterm fetal sheep (104 +/- 1 days, term 147 days). OK-432 (0.1 mg, n = 6) or saline vehicle (n = 7) was infused in the fetal pleura, and fetuses were monitored for 7 days. Blood samples were taken routinely for plasma nitrite measurement. Fetal brains were taken for histological assessment at the end of the experiment. Between 3 and 7 h postinjection, OK-432 administration was associated with transient suppression of fetal body and breathing movements and electtroencephalogram activity (P < 0.05), increased carotid and femoral vascular resistance (P < 0.05), but no change in blood pressure. Brain activity and behavior then returned to normal except in one fetus that developed seizures. OK-432 fetuses showed progressive, sustained vasodilatation (P < 0.05), with lower blood pressure after 4 days (P < 0.05), but normal heart rate. There were no changes in plasma nitrite levels. Histological studies showed bilateral infarction in the dorsal limb of the hippocampus of the fetus that developed seizures, but no injury in other fetuses. We conclude that a single low-dose injection of OK-432 can be associated with risk of focal cerebral injury in the preterm fetus and chronic central and peripheral vasodilatation that does not appear to be mediated by nitric oxide.

Prenatal factors in the development of chronic lung disease

Chronic lung disease (CLD), defined as chronic oxygen dependency, is a common outcome of neonatal intensive care. It occurs most frequently in infants born very prematurely, but also in infants born at term who had severe lung disease and those with abnormal antenatal lung growth due particularly to reduction in fetal breathing movements, amniotic fluid volume or intrathoracic space. There are, however, other causes and the importance of antenatal infection/inflammation regarding impairment of antenatal lung growth is increasingly recognised. Affected infants can suffer chronic respiratory morbidity including an excess of respiratory symptoms and lung function abnormalities even in adulthood. Antenatal interventions directed at improving lung growth are available, but require testing inappropriately designed trials with pulmonary function at follow-up as an outcome.

Fetal pleural effusions

The clinical course of primary fetal hydrothorax is unpredictable. Whereas smaller unilateral effusions might remain stable or even regress, this is rarely the case with larger collections. Bilateral effusions, hydrops, preterm delivery and the lack of antenatal therapy are all associated with poor outcome. Once structural and chromosomal anomalies have been excluded, optimal management depends on gestational age, rate of progression, the development of hydrops and associated maternal symptoms. For very large effusions with mediastinal shift, hydrops and/or hydramnios, or when there is rapid enlargement of the effusion, fetal intervention is warranted. Survival can be maximized by pleuroamniotic shunting, which can reverse hydrops and hydramnios and prevent pulmonary hypoplasia. Pleuroamniotic shunting can also be used for the treatment of other large cystic lung lesions, such as a macrocystic congenital cystic adenomatoid malformation or bronchopulmonary sequestration, especially when associated with hydrops.

New Treatment of Early Fetal Chylothorax

OBJECTIVE

To evaluate OK-432, a preparation of Streptococcus pyogenes, in the treatment of early fetal chylothorax.

METHODS

A prospective study of all fetuses (n=7) with persistent early chylothorax (gestational ages 16-21 weeks) referred to the tertiary center of fetal medicine in Denmark in 2003-2005. Fetuses were injected with 0.2-1.0 mg of OK-432 into the pleural cavity. The treatment was repeated if there were persistent or increasing pleural effusions after 1-3 weeks. The main outcome measures included remission of pleural effusions and fetal and infant morbidity and mortality.

RESULTS

Total remission of pleural effusions was obtained in all fetuses after one or two intrapleural injections of OK-432. No adverse effects of the treatment were observed. No fetus developed hydrops, and all experienced an uncomplicated third trimester. All children were born healthy without pleural effusions, lung hypoplasia, or hydrops.

CONCLUSION

Persistent early chylothorax is a condition with a high mortality rate and no established treatment option. Use of OK-432 is a promising therapy for selected fetuses with persistent chylothorax early in the second trimester.

Intrathoracic Pressure in Congenital Chylothorax: Keystone for the Rationale of Thoracoamniotic Shunting?

Thoracoamniotic shunting in fetal pleural effusion has poor results, with an overall survival of less than 50% when hydrops is associated. Those cases without hydrops presented the best evolution, but the indication in these cases remains controversial. We present a dichorionic diamniotic twin pregnancy at 29 weeks' with right pleural effusion and hydrops, in which one fetus presented diaphragm inversion and mediastinal shift, both considered as ultrasonographic signs of thoracic hypertension. A thoracoamniotic shunt reversed these signs immediately. Nevertheless, 1 week after, these signs and skin edema reappeared and the effusion increased, leading to a second thoracocenthesis for drainage and intrathoracic pressure measurement. Amniotic fluid and intrathoracic pressures were found at 21 and 39 mm Hg, respectively. A cesarean section was performed and the catheter was found to be obliterated by cellular detritus of leukocytes and fibrin. Our conclusion is that ultrasonographic signs of elevated thoracic pressure are a keystone for the shunt indication, and that this could be corroborated by direct measurements. This can be an important parameter for precise indication of thoracoamniotic shunting.

Fetal pleural effusion

Fetal pleural effusion, a nonspecific accumulation of fluid in the pleural space, is an uncommon anomaly which can be associated with aneuploidy and a range of other structural malformations or genetic syndromes. Spontaneous resolution is not rare and confers a good prognosis. Perinatal outcome is better for those fetuses without hydrops than those presenting with hydrops. A detailed review of the literature indicates that, for fetuses with persistent effusions, in utero intervention (repeated thoracocentesis, intrauterine shunting and pleurodesis) may improve the chances of survival.

Proinflammatory macrophage migratory inhibition factor and interleukin-6 are concentrated in pleural effusion of human fetuses with prenatal chylothorax

OBJECTIVES

To study the role of selected cytokines and growth factors involved in the pathogenesis of fetal chylous pleural effusion.

METHODS

Seventeen fetuses with prenatal chylothorax at gestational age (GA) 17-29 weeks were enrolled as the study group during the period 2003-2005. Their pleural effusion (n = 17) and amniotic fluid (n = 17) were drawn when disease set in. Eleven fetuses received cordocentesis because of suspected fetal anemia. Forty-one normal fetuses without adverse perinatal outcome at GA 17-29 weeks received amniocentesis and were enrolled in the reference group. Levels of hepatocyte growth factor (HGF), stromal-derived factor-1(SDF-1), vascular endothelial growth factor (VEGF), interleukin-8 (IL-8), macrophage migratory inhibition factor (MIF), and interleukin-6 (IL-6) were determined in the samples from both groups (amniotic fluid, pleural fluid, and cord blood from the study group and amniotic fluid from the reference group) by enzyme-linked immunoassay (EIA).

RESULTS

No significant differences were observed in the amniotic fluids between the study group and the reference group regarding levels of IL-6, IL-8, MIF, SDF-1, HGF and VEGF. In the study group, levels of IL-8, VEGF and SDF-1 (all pro-angiogenic) showed no significant differences between the amniotic fluid, cord blood and pleural effusion. The level of HGF (proangiogenic) was significantly higher in the amniotic fluid than in the cord blood or the pleural effusion, but there were no significant differences between the levels in the pleural fluid and in the cord blood. Interestingly, the levels of MIF and IL-6 (both are proinflammatory) in the amniotic fluid and in the pleural effusion were much higher than the levels in the cord blood.

CONCLUSION

Our study demonstrated that the levels of pro-inflammatory proteins (MIF and IL-6) that we tested were higher in the fetal pleural effusion than in the fetal circulation, a phenomenon not observed in the levels of proangiogenic proteins (HGF, SDF-1, VEGF, IL-8). This result implies that inflammation-related proteins may be more relevant than the angiogenesis-related proteins in the local environment of accumulating pleural effusion, a prominent feature of prenatal chylothorax.

Outcome of fetal pleural effusions treated by thoracoamniotic shunting

OBJECTIVE

Fetal pleural effusions are uncommon, and treatment options for moderate or severe effusions include drainage and thoracoamniotic shunting. However, relatively few records of effusions treated by thoracoamniotic shunting are available in the literature, so our objective was to study the outcome after thoracoamniotic shunting in our unit.

METHODS

We searched the database of our tertiary fetal medicine unit for all cases of fetal pleural effusion treated by thoracoamniotic shunting between 1997 and 2003 inclusive, and studied the maternal and neonatal records.

RESULTS

Ninety-two cases of fetal pleural effusion were studied, of which 21 had undergone a thoracoamniotic shunt. Sixteen of these 21 fetuses (76%) had associated hydrops, of which seven (44%) survived and, of the five (24%) without associated hydrops, three (60%) survived. There were two procedure-related losses. No shunted cases were associated with abnormal karyotype or proven maternal infection, but it is probable that three cases had been caused by an underlying genetic syndrome.

CONCLUSION

The survival of fetuses with severe pleural effusions after thoracoamniotic shunting in this study was 48%.

Antenatal Treatment of Chylothorax and Cystic Hygroma with OK-432 in Nonimmune Hydrops fetalis

OBJECTIVES

To present our experience of using OK-432 in treating fetal cystic hygroma and chylothorax complicated with nonimmune hydrops fetalis.

METHODS

OK-432 (Picibanil) was injected into the fetal pleural cavity or fetal cystic hygroma.

RESULTS

Patient 1: A 23-year-old, gravida 2, para 1, was found to have a recurrent fetal chylothorax at GA 29 weeks. Serial amnioreduction and thoracocentesis was performed at GA 31, 32, 33, and 34 weeks. Intrapleural OK-432 injection was performed twice at GA 33 and 34 weeks. Cyanosis and respiratory distress were noted immediately after birth (GA 34 weeks). The baby expired despite of aggressive neonatal resuscitation. Patient 2: A 26-year-old, gravida 2, para 1, was found to have a cystic hygroma of her fetus at GA 17 weeks. Karyotype of the cystic fluid and the amniocytes were 46, XY. Fetal ascites developed at GA 22 weeks. OK-432 injection into the tumour was performed at GA 23 weeks. Stabilization of the cystic hygroma was noted throughout the pregnancy (about 3.5 cm in diameter). Serial fetal paracentesis and/or amnioreduction were performed. Karyotype of the ascites was again 46, XY. Maternal dietary modification with medium chain triglyceride was also prescribed. Chylothorax developed and the baby was born by cesareans at GA 32 weeks. Resolution of pleural effusion, ascites, and regression of cystic hygroma were noted since the 2nd day after birth. The baby had survived beyond 4 months of age at submission.

CONCLUSION

Combination of antenatal OK-432 injection, maternal dietary modification, serial thoracocentesis plus paracentesis, together with amnioreduction and tocolysis, appeared to contribute to the success of antenatal treatment. Fetal pulmonary expansion may determine the immediate neonatal survival.

Thoracoamniotic Shunts: Fetal Treatment of Pleural Effusions and Congenital Cystic Adenomatoid Malformations

OBJECTIVE

To determine whether fetuses that underwent thoracoamniotic shunt placement for treatment of pleural effusion (PE) or macrocystic congenital cystic adenomatoid malformation (CCAM) have an improved outcome as compared with an untreated population.

METHODS

A retrospective review from a single tertiary center was performed using thoracoamniotic shunt placement to treat PE or macrocystic CCAM between 1998 and 2001. Thoracoamniotic shunts were used on 26 occasions in 19 pregnancies.

RESULTS

The average gestational age at the diagnosis of PE and CCAM was 22 + 4 and 20 + 0 weeks, respectively. Shunts were offered in pregnancies complicated by hydrops or at significant risk for pulmonary hypoplasia. Shunts were placed at 26 + 2 weeks (average) and 23 + 1 weeks (average) in the PE and CCAM groups, respectively. In CCAM patients, the mean pre- and postshunting mass volumes were 50.5 and 25.7 cm(3), representing a 51% reduction in mass volume following shunt placement. In the PE group, the average delivery age was 33 + 5 weeks, with an average shunt placement to delivery time of 7 + 3 weeks. In the CCAM group, the average delivery was 33 + 3 weeks, with an average shunt placement to delivery time of 10 + 2 weeks. The postnatal survival rates were 67% (6/9) and 70% (7/10) in the PE and CCAM groups, respectively.

CONCLUSIONS

(1) Thoracoamniotic shunts should be considered as a treatment option for selected PE or macrocystic CCAM fetuses with hydrops or a significant risk for pulmonary hypoplasia; (2) the neonatal survival with shunting was similar for PE and CCAM groups and was improved as compared with literature reports, and (3) fetuses with CCAM presented earlier with hydrops than those with PE. Successful shunting resulted in a prolongation of pregnancy into the 3rd trimester in both groups.

A new successful therapy for fetal chylothorax by intrapleural injection of maternal blood

We present two cases of fetal chylothorax and hydrops diagnosed at 20 weeks' gestation, both of which underwent successful intrauterine treatment. In Case 1, a transient, near total resolution began 2 weeks after an iatrogenic hemothorax following a second thoracocentesis performed at 24 + 6 weeks. Because of pleural fluid reaccumulation, a Cesarean section was performed at 36 weeks. The 3805-g female neonate was admitted to neonatal intensive care but was discharged 50 days later in a healthy condition. In Case 2, resolution occurred after a third thoracocentesis and a second pleural injection of maternal blood, performed at 26 weeks. A 2660-g female neonate was delivered vaginally at 38 weeks. The infant remained asymptomatic and was discharged aged 4 days. Our experience suggests a possible useful role of intrapleural blood injection for the treatment of fetal chylothorax.

Treatment of severe fetal chylothorax associated with pronounced hydrops with intrapleural injection of OK-432

We describe a case of a 25-week fetus with severe bilateral pleural effusion, marked ascites, skin edema, an anterior thick (hydropic) placenta and polyhydramnios in which the most probable diagnosis was congenital chylothorax. Treatment with a pleuroamniotic shunt was planned, however the location of the fetus just below the anterior placenta made the placement of the shunt too dangerous. We therefore decided to use intrapleural injection of OK-432. From week 29, the lungs looked normal, the pleural effusion had resolved and the thoracic circumference was within normal limits. The severe ascites persisted throughout the pregnancy and a total volume of 3680 mL was removed on several occasions. A Cesarean section was performed at 38 weeks and a normal male was delivered. Continuous positive airway pressure was needed on the first 4 days but after a week the situation was stable. On day 8, an X-ray showed normally developed lungs. OK-432 appears to have prevented pulmonary hypoplasia in our patient.