Foong-Yen Lim

Congenital high airway obstruction syndrome: natural history and management

BACKGROUND Congenital high airway obstruction syndrome (CHAOS) is a life-threatening condition with a poorly understood natural history. METHODS A retrospective review of five patients with CHAOS between 1997 and 2002 was performed. RESULTS All fetuses had large echogenic lungs, dilated airways, inverted diaphragms, and massive ascites. One fetus with a laryngeal cyst was terminated at 22 weeks. A twin fetus with findings suggestive of a tracheal web had progressive hydrops, which led to fetal demise. The remaining 3 patients delivered via the ex utero intrapartum treatment (EXIT) procedure survived. The first patient tolerated progressive hydrops for 12 weeks in utero. He had tracheal atresia but underwent laryngotracheoplasty successfully. He is the first long-term CHAOS survivor and is speaking at 5 years of age. The 2 patients with relatively stable lung volumes prenatally have laryngeal atresia with a pinpoint posterior laryngeal fistula. Their postnatal clinical courses were much more benign than the first survivor. CONCLUSIONS The prenatal natural history and postnatal course of CHAOS depends on whether the airway obstruction is complete. The EXIT procedure offers the potential for salvage of this otherwise lethal condition. Hydrops may be well tolerated prenatally for weeks with potential resolution if airway fistulization is present.

Adenoviral mediated gene transfer of PDGF-B enhances wound healing in type I and type II diabetic wounds

We have shown that the genetically diabetic mouse (C57BLKS/J‐m+/+Leprdb) has a wound healing and neovascularization deficit associated with an inability to recruit endothelial precursor cells (EPCs) to the wound. This may account for a fundamental mechanism in impaired diabetic wound healing. We hypothesized that the adenoviral mediated overexpression of platelet‐derived growth factor‐B (PDGF‐B) would enhance wound healing, improve neovascularization, and recruit EPCs to the epithelial wound in three diabetic mouse models. Eight‐mm full‐thickness flank wounds were made in db/db, nonobese NOD/Ltj, streptozotocin, and C57BLKS/J mice. Wounds were treated with either 1 × 108 PFU Ad‐PDGF‐B or Ad LacZ or phosphate buffered saline solution. Wounds harvested at seven days were analyzed for epithelial gap, blood vessel density, granulation tissue area, and EPCs per high powered field. All three diabetic models have a significant wound healing and neovascularization defect compared to C57BLKS/J controls. Adenoviral‐PDGF‐B treatment significantly enhanced epithelial gap closure in db/db, streptozotocin, and nonobese NOD/Ltj mice as compared to diabetic phosphate buffered saline solution or Ad LacZ controls. A similar increase in the formation of granulation tissue and vessel density was also observed. All three models had reduced levels of GATA‐2 positive EPCs in the wound bed that was corrected by the adenoviral mediated gene transfer of PDGF. EPC recruitment was positively correlated with neovascularization and wound healing. Three different diabetic models have a wound healing impairment and a decreased ability to recruit EPCs. The vulnerary effect of adenoviral mediated gene therapy with PDGF‐B significantly enhanced wound healing and neovascularization in diabetic wounds. The PDGF‐B mediated augmentation of EPC recruitment to the wound bed may be a fundamental mechanism of these results.

Incidence of complications in twin-twin transfusion syndrome after selective fetoscopic laser photocoagulation: a single-center experience

OBJECTIVE The purpose of this study was to evaluate the incidence of complications after selective fetoscopic laser photocoagulation for twin-twin transfusion syndrome (TTTS). STUDY DESIGN One hundred fifty-two cases of TTTS were treated with selective fetoscopic laser photocoagulation from 2005-2008. Complications were TTTS recurrence, amniotic band syndrome, iatrogenic monoamnionicity, and twin anemia-polycythemia sequence. Data were placed in the following categories: no complications; early complications < or =7 days; late complications >7 days; both early and late complications. RESULTS The incidence of early, late, and both early and late complications was 31%, 39%, and 10%. Complications included 2 cases (1.3%) of monoamnionicity, 3 cases (2.0%) of recurrent TTTS, 3 cases (2.0%) of twin anemia-polycythemia sequence, and 5 cases (3.3%) of amniotic band syndrome. Cases with TTTS with early complications had a lower number of superficial arteriovenous vascular anastomoses and 1 or both fetus survival (70.2% vs 96.7%; P < .001), compared with no complications. Fetal survival was 238 of 307 cases (77.5%), with 1 or both twins surviving in 134 of 152 (88%) of pregnancies. CONCLUSION The incidence of early, late, and both early and late complications was 31%, 39%, and 10%, respectively. Close postoperative surveillance is important.

High-risk fetal congenital pulmonary airway malformations have a variable response to steroids

BACKGROUND/PURPOSE Anecdotal reports suggest that maternal steroids may arrest the growth of congenital pulmonary airway malformations (CPAMs), preventing or reversing hydrops. We reviewed our experience with CPAMs to determine the fetal response to steroid therapy. METHODS This study is a retrospective review of all fetal CPAMs from 2004 to 2008. Fetuses with high-risk CPAMs that received at least one course of steroids were identified. Fetal magnetic resonance imaging and ultrasound data were used to classify the CPAMs, identify hydrops fetalis and follow the fetuses poststeroid dosing. RESULTS Forty-four fetuses with CPAM were identified. Fifteen patients were found to have received at least one course of steroids. Thirteen were hydropic and 2 were nonhydropic. Seven of the 13 hydropic fetuses (54%) showed an initial response to steroid administration, whereas the 2 nonhydropic high-risk fetuses progressed to birth without developing hydrops. Seven of the 15 patients, however, resulted in fetal demise or early postnatal death, giving a survival rate of 53%. CONCLUSIONS High-risk CPAMs have a variable response to steroids. This variable response demonstrates the need for a placebo-controlled randomized study to more accurately determine the effect of steroids on hydrops and CPAM growth rates. Repeated steroid courses may not be helpful, and progression in CPAM volume to head circumference ratio (CVR) or hydrops should prompt open fetal surgery to prevent irreversible fetal insult.

Variants in GATA4 are a rare cause of familial and sporadic congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is characterized by incomplete formation of the diaphragm occurring as either an isolated defect or in association with other anomalies. Genetic factors including aneuploidies and copy number variants are important in the pathogenesis of many cases of CDH, but few single genes have been definitively implicated in human CDH. In this study, we used whole exome sequencing (WES) to identify a paternally inherited novel missense GATA4 variant (c.754C>T; p.R252W) in a familial case of CDH with incomplete penetrance. Phenotypic characterization of the family included magnetic resonance imaging of the chest and abdomen demonstrating asymptomatic defects in the diaphragm in the two “unaffected” missense variant carriers. Screening 96 additional CDH patients identified a de novo heterozygous GATA4 variant (c.848G>A; p.R283H) in a non-isolated CDH patient. In summary, GATA4 is implicated in both familial and sporadic CDH, and our data suggests that WES may be a powerful tool to discover rare variants for CDH.

Acute effects of selective fetoscopic laser photocoagulation on recipient cardiac function in twin-twin transfusion syndrome

OBJECTIVE This study evaluated the acute effects of selective fetoscopic laser photocoagulation (SFLP) on recipient cardiovascular function in a twin-twin transfusion syndrome (TTTS) pregnancy. STUDY DESIGN This was a retrospective chart review of echocardiographic data in TTTS including right (RV) and left (LV) ventricular Doppler myocardial performance index (MPI); LV and RV end diastolic wall thickness; and umbilical artery (UA), vein (UV), and ductus venosus (DV) Dopplers. The primary outcome measures were improved MPI defined as greater than 10% interval decrease in left and/or right MPI. Data were analyzed by Student t test and Fishers exact test. RESULTS Sixty-five patients met inclusion criteria. SFLP results in a significant improvement in UV and DV Doppler and an increase in both RV and LV wall thickness. A 10% or greater improvement in recipient LV MPI after SFLP is associated with improved recipient survival as compared with unimproved LV MPI (100% vs 86.1%, P = .05). CONCLUSION Improved recipient myocardial performance index after SFLP is associated with improvement in recipient survival.

Twin-to-Twin Transfusion Syndrome: A Comprehensive Update

Twin-to-twin transfusion syndrome (TTTS) is a serious complication in about 10% to 20% of monozygous twin gestations with an incidence of 4% to 35% in the United States. Severe TTTS is reported to occur in 5.5% to 17.5% of cases. TTTS is a progressive disease in which sudden deteriorations in clinical status can occur, leading to death of a co-twin. Up to 30% of survivors may have abnormal neurodevelopment as a result of the combination of profound antenatal insult and the complications of severe prematurity. This article presents an overview of what is known about the pathophysiology and the diagnosis of TTTS, the role of echocardiography in TTTS, treatment options available for TTTS, complications of treatment for TTTS, and short- and long-term outcomes of TTTS.

Developmental outcomes of children with congenital diaphragmatic hernia: a multicenter prospective study.

PURPOSE To determine developmental outcomes and associated factors in patients with congenital diaphragmatic hernia (CDH) at 2 years of age. METHODS This is a multicenter prospective study of a CDH birth cohort. Clinical and socioeconomic data were collected. Bayley Scales of Infant Development (BSID-III) and Vineland Adaptive Behavior Scales (VABS-II) were performed at 2 years of age. RESULTS BSID-III and VABS-II assessments were completed on 48 and 49 children, respectively. The BSID-III mean cognitive, language, and motor scores were significantly below the norm mean with average scores of 93 ± 15, 95 ± 16, and 95 ± 11. Ten percent (5/47) scored more than 2 standard deviations below the norm on one or more domains. VABS-II scores were similar to BSID-III scores with mean communication, daily living skills, social, motor, adaptive behavior scores of 97 ± 14, 94 ± 16, 93 ± 13, 97 ± 10, and 94 ± 14. For the BSID-III, supplemental oxygen at 28 days, a prenatal diagnosis, need for extracorporeal membrane oxygenation (ECMO) and exclusive tube feeds at time of discharge were associated with lower scores. At 2 years of age, history of hospital readmission and need for tube feeds were associated with lower scores. Lower socioeconomic status correlated with lower developmental scores when adjusted for significant health factors. CONCLUSION CDH patients on average have lower developmental scores at 2 years of age compared to the norm. A need for ECMO, oxygen at 28 days of life, ongoing health issues and lower socioeconomic status are factors associated with developmental delays.

Prenatal MRI Findings of Fetuses with Congenital High Airway Obstruction Sequence

Objective To define the MRI findings of congenital high airway obstruction sequence (CHAOS) in a series of fetuses. Materials and Methods Prenatal fetal MR images were reviewed in seven fetuses with CHAOS at 21 to 27 weeks of gestation. The MRI findings were reviewed. The MRI parameters evaluated included the appearance of the lungs and diaphragm, presence or absence of hydrops, amount of amniotic fluid, airway appearance, predicted level of airway obstruction, and any additional findings or suspected genetic syndromes. Results All the fetuses viewed (7 of 7) demonstrated the following MRI findings: dilated airway below the level of obstruction, increased lung signal, markedly increased lung volumes with flattened or inverted hemidiaphragms, massive ascites, centrally positioned and compressed heart, as well as placentomegaly. Other frequent findings were anasarca (6 of 7) and polyhydramnios (3 of 7). MRI identified the level of obstruction as laryngeal in five cases and tracheal in two cases. In four of the patients, surgery or autopsy confirmed the MRI predicted level of obstruction. Associated abnormalities were found in 4 of 7 (genetic syndromes in 2). Postnatal radiography (n = 3) showed markedly hyperinflated lungs with inverted or flattened hemidiaphragms, strandy perihilar opacities, pneumothoraces and tracheotomy. Two fetuses were terminated and one fetus demised in utero. Four fetuses were delivered via ex utero intrapartum treatment procedure. Conclusion MRI shows a consistent pattern of abnormalities in fetuses with CHAOS, accurately identifies the level of airway obstruction, and helps differentiate from other lung abnormalities such as bilateral congenital pulmonary airway malformation by demonstrating an abnormally dilated airway distal to the obstruction.

De novo copy number variants are associated with congenital diaphragmatic hernia

Background Congenital diaphragmatic hernia (CDH) is a common birth defect with significant morbidity and mortality. Although the aetiology of CDH remains poorly understood, studies from animal models and patients with CDH suggest that genetic factors play an important role in the development of CDH. Chromosomal anomalies have been reported in CDH. Methods In this study, the authors investigated the frequency of chromosomal anomalies and copy number variants (CNVs) in 256 parent–child trios of CDH using clinical conventional cytogenetic and microarray analysis. The authors also selected a set of CDH related training genes to prioritise the genes in those segmental aneuploidies and identified the genes and gene sets that may contribute to the aetiology of CDH. Results The authors identified chromosomal anomalies in 16 patients (6.3%) of the series including three aneuploidies, two unbalanced translocation, and 11 patients with de novo CNVs ranging in size from 95 kb to 104.6 Mb. The authors prioritised the genes in the CNV segments and identified KCNA2, LMNA, CACNA1S, MYOG, HLX, LBR, AGT, GATA4, SOX7, HYLS1, FOXC1, FOXF2, PDGFA, FGF6, COL4A1, COL4A2, HOMER2, BNC1, BID, and TBX1 as genes that may be involved in diaphragm development. Gene enrichment analysis identified the most relevant gene ontology categories as those involved in tissue development (p=4.4×10−11) or regulation of multicellular organismal processes (p=2.8×10−10) and ‘receptor binding’ (p=8.7×10−14) and ‘DNA binding transcription factor activity’ (p=4.4×10−10). Conclusions The present findings support the role of chromosomal anomalies in CDH and provide a set of candidate genes including FOXC1, FOXF2, PDGFA, FGF6, COL4A1, COL4A2, SOX7, BNC1, BID, and TBX1 for further analysis in CDH.