Recent Advances in the Genetic Pathogenesis, Diagnosis, and Management of Esophageal Atresia and Tracheoesophageal Fistula: A Review

Infants born with esophageal atresia and tracheoesophageal fistula, a complex congenital malformation occurring in 1/2500-4000 live births, may suffer threats to their cardiac, respiratory, and digestive health in addition to anomalies that may exist in the genitourinary and musculoskeletal systems. Optimal care for these patients throughout their lives is best achieved through a coordinated, multidisciplinary approach that our health care system is not always well-equipped to provide. This review, though not exhaustive, highlights the components of care that pertain to initial surgical reconstruction and subsequent diagnosis and management of the complications that are most frequently encountered. Authors from among the many specialties involved in the care of these patients summarize the current best practice with attention to the most recent advances. Assessment and improvement of quality of life and transition to adult specialists as children grow to adulthood is also reviewed.

Fibrous hamartoma of infancy: imaging findings

BACKGROUND

Fibrous hamartoma of infancy is a benign tumor that typically arises within the first 2 years of life in the subcutaneous and lower dermal layers. Diagnosis can be challenging as it is a rare tumor, and the imaging appearance is not well known.

OBJECTIVE

To describe the imaging features in 4 cases of fibrous hamartoma of infancy focusing on ultrasound (US) and magnetic resonance (MR) findings.

MATERIALS AND METHODS

In this retrospective IRB-approved study, informed consent was waived. We searched patient charts for histopathology-confirmed fibrous hamartoma of infancy diagnosis between November 2013 and November 2022. We found four cases, three boys and one girl, and the mean age was 1.4 years (5 months-3 years). The lesions were located in the axilla, posterior elbow, posterior neck, and lower back. All four patients underwent ultrasound evaluation of the lesion, and two patients also underwent MRI evaluation. The imaging findings were reviewed by consensus by two pediatric radiologists.

RESULTS

US imaging revealed subcutaneous lesions with variably defined hyperechoic regions and intervening hypoechoic bands resulting in a linear "serpentine" pattern or a "multiple semicircle" pattern. MR imaging evidenced heterogeneous soft tissue masses, localized in the subcutaneous fat, and showed hyperintense fat interspersed with hypointense septations on both T1- and T2-weighted images.

CONCLUSION

Fibrous hamartoma of infancy has a suggestive appearance on US with heterogeneous, echogenic subcutaneous lesions with intervening hypoechoic portions, in parallel or circumferential arrangement that can be seen as a serpentine or semicircular pattern. On MRI, interspersed macroscopic fatty components show high signal intensity on T1- and T2-weighted images and reduced signal on fat-suppressed inversion recovery images, with irregular peripheral enhancement.

Esophageal Surveillance Practices in Esophageal Atresia Patients: A Survey by the Eastern Pediatric Surgery Network

INTRODUCTION

Endoscopic surveillance guidelines for patients with repaired esophageal atresia (EA) rely primarily on expert opinion. Prior to embarking on a prospective EA surveillance registry, we sought to understand EA surveillance practices within the Eastern Pediatric Surgery Network (EPSN).

METHODS

An anonymous, 23-question Qualtrics survey was emailed to 181 physicians (surgeons and gastroenterologists) at 19 member institutions. Likert scale questions gauged agreement with international EA surveillance guideline-derived statements. Multiple-choice questions assessed individual and institutional practices.

RESULTS

The response rate was 77%. Most respondents (80%) strongly agree or agree that EA surveillance endoscopy should follow a set schedule, while only 36% claimed to perform routine upper GI endoscopy regardless of symptoms. Many institutions (77%) have an aerodigestive clinic, even if some lack a multi-disciplinary EA team. Most physicians (72%) expressed strong interest in helping develop evidence-based guidelines.

CONCLUSIONS

Our survey reveals physician agreement with current guidelines but weak adherence. Surveillance methods vary greatly, underscoring the lack of evidence-based data to guide EA care. Aerodigestive clinics may help implement surveillance schedules. Respondents support evidence-based protocols, which bodes well for care standardization. Results will inform the first multi-institutional EA databases in the United States (US), which will be essential for evidence-based care.

LEVEL OF EVIDENCE

This is a prognosis study with level 4 evidence.

Hybrid lung lesions in children with segmental infantile hemangiomas, a new association?

Infantile hemangiomas (IHs) are the most common tumors of infancy and, in rare instances, can present in the setting of congenital structural anomalies or as part of syndromic disorders. In this study, we present three cases of children with segmental IHs born with concurrent pulmonary anomalies: congenital pulmonary airway malformations and bronchopulmonary sequestration. To date, no known association between these entities and hemangiomas has been described.

Pediatric surgery milestones 2.0: A primer

More than twenty years ago, the Accreditation Council for Graduate Medical Education and the American Board of Medical Specialties began the conversion of graduate medical education from a structure- and process-based model to a competency-based framework. The educational outcomes assessment tool, known as the Milestones, was introduced in 2013 for seven specialties and by 2015 for the remaining specialties, including pediatric surgery. Designed to be an iterative process with improvements over time based on feedback and evidence-based literature, the Milestones started the evolution from 1.0 to 2.0 in 2016. The formation of Pediatric Surgery Milestones 2.0 began in 2019 and was finalized in 2021 for implementation in the 2022-2023 academic year. Milestones 2.0 are fewer in number and are stated in more straightforward language. It incorporated the harmonized milestones, subcompetencies for non-patient care and non-medical knowledge that are consistent across all medical and surgical specialties. There is a new Supplemental Guide that lists examples, references and links to other assessment tools and resources for each subcompetency. Milestones 2.0 represents a continuous process of feedback, literature review and revision with goals of improving patient care and maintaining public trust in graduate medical education's ability to self-regulate. LEVEL OF EVIDENCE: V.

Extracorporeal Membrane Oxygenation (ECMO) and its complications in newborns with congenital diaphragmatic hernia

BACKGROUND

Extracorporeal Membrane Oxygenation (ECMO) is offered to patients with congenital diaphragmatic hernia (CDH) who are in severe respiratory and cardiac failure. We aim to describe the types of complications among these patients and their impact on survival.

METHODS

A single-center, retrospective review of CDH patients cannulated onto ECMO between January 2005 and November 2020 was conducted. ECMO complications, as categorized by the Extracorporeal Life Support Organization (ELSO), were correlated with survival status. Descriptive statistics were used to compare observed complications between survivors and non-survivors.

RESULTS

In our cohort of CDH neonates, 21% (54/258) were supported with ECMO, of whom, 61% (33/54) survived. Survivors and non-survivors were similar in baseline characteristics except for birthweight z-score (p = 0.043). Seventy percent of CDH neonates experienced complications during their ECMO run, with the most common categories being metabolic (48.1%) and mechanical (38.9%), followed by hemorrhage (22.2%), neurological (18.5%), renal (11.1%), pulmonary (7.4%), and cardiovascular (7.4%). The median number of complications per patient was higher in the non-survivor group  (2 (IQR: 1-4) vs 1 (IQR: 0-2), p = 0.043). In addition, mechanical (57.1% vs 27.3%, p = 0.045) and renal (28.6% vs 0%, p = 0.002) complications were more common among non-survivors compared to survivors.

CONCLUSION

Complications occur frequently among ECMO-treated newborns with CDH, some of which have serious long-term consequences. Survivors had higher birth weight z-scores, shorter ECMO runs, and fewer complications per patient. Mechanical and renal complications were independently associated with mortality, emphasizing the utility of more focused strategies to target fluid balance and renal protection and to prevent circuit and cannula complications.

Identification and validation of candidate risk genes in endocytic vesicular trafficking associated with esophageal atresia and tracheoesophageal fistulas

Esophageal atresias/tracheoesophageal fistulas (EA/TEF) are rare congenital anomalies caused by aberrant development of the foregut. Previous studies indicate that rare or de novo genetic variants significantly contribute to EA/TEF risk, and most individuals with EA/TEF do not have pathogenic genetic variants in established risk genes. To identify the genetic contributions to EA/TEF, we performed whole genome sequencing of 185 trios (probands and parents) with EA/TEF, including 59 isolated and 126 complex cases with additional congenital anomalies and/or neurodevelopmental disorders. There was a significant burden of protein-altering de novo coding variants in complex cases (p = 3.3 × 10-4), especially in genes that are intolerant of loss-of-function variants in the population. We performed simulation analysis of pathway enrichment based on background mutation rate and identified a number of pathways related to endocytosis and intracellular trafficking that as a group have a significant burden of protein-altering de novo variants. We assessed 18 variants for disease causality using CRISPR-Cas9 mutagenesis in Xenopus and confirmed 13 with tracheoesophageal phenotypes. Our results implicate disruption of endosome-mediated epithelial remodeling as a potential mechanism of foregut developmental defects. Our results suggest significant genetic heterogeneity of EA/TEF and may have implications for the mechanisms of other rare congenital anomalies.

Neurologic Complications of Extracorporeal Cardiopulmonary Resuscitation in Neonates and Infants

Objective: Extracorporeal membrane oxygenation (ECMO) is a lifesaving measure for patients in cardiac or respiratory failure. Extracorporeal cardiopulmonary resuscitation (ECPR) is emergent ECMO cannulation during cardiac arrest. All ECMO patients are at high risk for neurologic complications, but the degree of risk of ECPR relative to ECMO without CPR in progress (non-ECPR ECMO) is not well documented in infants. The goal of the present study is to compare neurologic complication rates between infants who underwent ECPR and those who underwent non-ECPR ECMO. Methods: We performed a retrospective chart review on all patients admitted between 2009 and 2020 to the neonatal intensive care unit (NICU) in our quaternary children's hospital. We separated patients by ECPR vs. non-ECPR ECMO cannulation. We compared rates of death and used neuroimaging and video electroencephalogram (vEEG) to determine incidence of stroke, intracranial hemorrhage, and seizure. Chi-square and Fisher's exact tests were used to compare these categorical variables among groups.Results: A total of 181 infants were cannulated onto ECMO. Of these, 40 received ECPR, 56 received non-ECPR ECMO for a cardiac indication, and 85 received non-ECPR ECMO for a respiratory indication. After excluding patients currently admitted (n=1, ECPR), 180 patients were subjected to analysis. ECPR patients were less likely to survive to hospital discharge than patients who underwent non-ECPR ECMO for respiratory indications, and less likely to survive without any neurologic complication compared with infants who underwent non-ECPR ECMO for cardiac or respiratory indications. Interpretation: Significantly fewer ECPR patients survived without experiencing a neurologic complication, compared with non-ECPR ECMO patients.

Ethics in the Era of COVID-19

The COVID-19 pandemic has led to new ethical challenges and exposed or exacerbated others that were already present. Through the lens of pediatric surgery, this article aims to discuss issues that have been impacted by the pandemic including triage of care and allocation of scarce resources, equity and access to care, and a physician's competing responsibilities to their patients, families, and selves.

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

BACKGROUND

Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality.

METHODS

We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis.

FINDINGS

We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36-39) and median bodyweight at presentation was 2·8 kg (2·3-3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88-4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59-2·79], p<0·0001), sepsis at presentation (1·20 [1·04-1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4-5 vs ASA 1-2, 1·82 [1·40-2·35], p<0·0001; ASA 3 vs ASA 1-2, 1·58, [1·30-1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02-1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41-2·71], p=0·0001; parenteral nutrition 1·35, [1·05-1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47-0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50-0·86], p=0·0024) or percutaneous central line (0·69 [0·48-1·00], p=0·049) were associated with lower mortality.

INTERPRETATION

Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030.

FUNDING

Wellcome Trust.

Extracorporeal Membrane Oxygenation for Coronavirus Disease 2019: Crisis Standards of Care

The coronavirus disease 2019 (COVID-19) pandemic has placed extraordinary strain on global healthcare systems. Use of extracorporeal membrane oxygenation (ECMO) for patients with severe respiratory or cardiac failure attributed to COVID-19 has been debated due to uncertain survival benefit and the resources required to safely deliver ECMO support. We retrospectively investigated adult patients supported with ECMO for COVID-19 at our institution during the first 80 days following New York City's declaration of a state of emergency. The primary objective was to evaluate survival outcomes in patients supported with ECMO for COVID-19 and describe the programmatic adaptations made in response to pandemic-related crisis conditions. Twenty-two patients with COVID-19 were placed on ECMO during the study period. Median age was 52 years and 18 (81.8%) were male. Twenty-one patients (95.4%) had severe ARDS and seven (31.8%) had cardiac failure. Fifteen patients (68.1%) were managed with venovenous ECMO while 7 (31.8%) required arterial support. Twelve patients (54.5%) were transported on ECMO from external institutions. Twelve patients were discharged alive from the hospital (54.5%). Extracorporeal membrane oxygenation was used successfully in patients with respiratory and cardiac failure due to COVID-19. The continued use of ECMO, including ECMO transport, during crisis conditions was possible even at the height of the COVID-19 pandemic.

Novel candidate genes in esophageal atresia/tracheoesophageal fistula identified by exome sequencing

The various malformations of the aerodigestive tract collectively known as esophageal atresia/tracheoesophageal fistula (EA/TEF) constitute a rare group of birth defects of largely unknown etiology. Previous studies have identified a small number of rare genetic variants causing syndromes associated with EA/TEF. We performed a pilot exome sequencing study of 45 unrelated simplex trios (probands and parents) with EA/TEF. Thirteen had isolated and 32 had nonisolated EA/TEF; none had a family history of EA/TEF. We identified de novo variants in protein-coding regions, including 19 missense variants predicted to be deleterious (D-mis) and 3 likely gene-disrupting (LGD) variants. Consistent with previous studies of structural birth defects, there is a trend of increased burden of de novo D-mis in cases (1.57-fold increase over the background mutation rate), and the burden is greater in constrained genes (2.55-fold, p = 0.003). There is a frameshift de novo variant in EFTUD2, a known EA/TEF risk gene involved in mRNA splicing. Strikingly, 15 out of 19 de novo D-mis variants are located in genes that are putative target genes of EFTUD2 or SOX2 (another known EA/TEF gene), much greater than expected by chance (3.34-fold, p value = 7.20e-5). We estimated that 33% of patients can be attributed to de novo deleterious variants in known and novel genes. We identified APC2, AMER3, PCDH1, GTF3C1, POLR2B, RAB3GAP2, and ITSN1 as plausible candidate genes in the etiology of EA/TEF. We conclude that further genomic analysis to identify de novo variants will likely identify previously undescribed genetic causes of EA/TEF.

Characterization of Extracorporeal Membrane Oxygenation Support for Single Ventricle Patients

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) can provide crucial support for single ventricle (SV) patients at various stages of palliation. However, characterization of the utilization and outcomes of ECMO in these unique patients remains incompletely studied.

METHODS

We performed a single-center retrospective review of SV patients between 2010 and 2017 who underwent ECMO cannulation with primary end point of survival to discharge and secondary end point of survival to decannulation or orthotopic heart transplantation (OHT). Multivariate analysis was performed for factors predictive of survival to discharge and survival to decannulation.

RESULTS

Forty SV patients with a median age of one month (range: 3 days to 15 years) received ECMO support. The incidence of ECMO was 14% for stage I, 3% for stage II, and 4% for stage III. Twenty-seven (68%) patients survived to decannulation, and 21 (53%) patients survived to discharge, with seven survivors to discharge undergoing OHT. Complications included infection (40%), bleeding (40%), thrombosis (33%), and radiographic stroke (45%). Factors associated with survival to decannulation included pre-ECMO lactate (hazard ratio [HR]: 0.61, 95% confidence interval [CI]: 0.41-0.90, P = .013) and post-ECMO bicarbonate (HR: 1.24, 95% CI: 1.0-1.5, P = .018). Factors associated with survival to discharge included central cannulation (HR: 40.0, 95% CI: 3.1-500.0, P = .005) and lack of thrombotic complications (HR: 28.7, 95% CI: 2.1-382.9, P = .011).

CONCLUSIONS

Extracorporeal membrane oxygenation can be useful to rescue SV patients with approximately half surviving to discharge, although complications are frequent. Early recognition of the role of heart transplant is imperative. Further study is required to identify areas for improvement in this population.

Allocation of resources and development of guidelines for extracorporeal membrane oxygenation (ECMO): Experience from a pediatric center in the epicenter of the COVID-19 pandemic

The rapid spread of coronavirus disease 2019 (COVID-19) has exceeded the standard capacity of many hospital systems and led to an unprecedented scarcity of resources, including the already limited resource of extracorporeal membrane oxygenation (ECMO). With the large amount of critically ill patients and the highly contagious nature of the virus, significant consideration of ECMO candidacy is crucial for both appropriate allocation of resources as well as ensuring protection of health care personnel. As a leading pediatric ECMO program in the epicenter of the pandemic, we established new protocols and guidelines in order to continue caring for our pediatric patients while accepting adult patients to lessen the burden of our hospital system which was above capacity. This article describes our changes in consultation, cannulation, and daily care of COVID-19 positive patients requiring ECMO as well as discusses strategies for ensuring safety of our ECMO healthcare personnel and optimal allocation of resources. LEVEL OF EVIDENCE: Level V.

Neonates With Complex Cardiac Malformation and Congenital Diaphragmatic Hernia Born to SARS-CoV-2 Positive Women-A Single Center Experience

BACKGROUND

Our understanding of the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on pregnancies and perinatal outcomes is limited. The clinical course of neonates born to women who acquired coronavirus disease 2019 (COVID-19) during their pregnancy has been previously described. However, the course of neonates born with complex congenital malformations during the COVID-19 pandemic is not known.

METHODS

We report a case series of seven neonates with congenital heart and lung malformations born to women who tested positive for SARS-CoV-2 during their pregnancy at a single academic medical center in New York City.

RESULTS

Six infants had congenital heart disease and one was diagnosed with congenital diaphragmatic hernia. In all seven infants, the clinical course was as expected for the congenital lesion. None of the seven exhibited symptoms generally associated with COVID-19. None of the infants in our case series tested positive by nasopharyngeal test for SARS-CoV-2 at 24 hours of life and at multiple points during their hospital course.

CONCLUSIONS

In this case series, maternal infection with SARS-CoV-2 during pregnancy did not result in adverse outcomes in neonates with complex heart or lung malformations. Neither vertical nor horizontal transmission of SARS-CoV-2 was noted.

Development of pediatric surgical decision-making guidelines for COVID-19 in a New York City children's hospital

OBJECTIVE

During the COVID-19 pandemic, experience-based guidelines are needed in the pediatric population in order to deliver high quality care in a new way that keeps patients and healthcare workers safe and maximizes hospital resource utilization.

BACKGROUND

The COVID-19 pandemic has created an unprecedented strain on national health care resources, particularly in New York City, the epicenter of the outbreak in the United States. Prudent allocation of surgical resources during the pandemic quickly became essential, and there is an unprecedented need to weigh the risks of operating versus delaying intervention in our pediatric patients.

METHODS

Here we describe our experience in surgical decision-making in the pediatric surgical population at Morgan Stanley Children's Hospital of New York-Presbyterian (MSCHONY), which has served as a major urban catchment area for COVID-19 positive pediatric patients. We describe how we have adjusted our current treatment of multiple facets of pediatric surgery including oncology, trauma, minimally invasive procedures, and extracorporeal membrane oxygenation (ECMO).

CONCLUSIONS

Our pediatric surgery department had to creatively and expeditiously adjust our protocols, guidelines, and workforce to not only serve our pediatric population but merge ourselves with our adult hospital system during the COVID pandemic.

TYPE OF STUDY

Clinical research paper LEVEL OF EVIDENCE: Level V.

Development of pediatric surgical decision-making guidelines for COVID-19 in a New York City children's hospital

OBJECTIVE

During the COVID-19 pandemic, experience-based guidelines are needed in the pediatric population in order to deliver high quality care in a new way that keeps patients and healthcare workers safe and maximizes hospital resource utilization.

BACKGROUND

The COVID-19 pandemic has created an unprecedented strain on national health care resources, particularly in New York City, the epicenter of the outbreak in the United States. Prudent allocation of surgical resources during the pandemic quickly became essential, and there is an unprecedented need to weigh the risks of operating versus delaying intervention in our pediatric patients.

METHODS

Here we describe our experience in surgical decision-making in the pediatric surgical population at Morgan Stanley Children's Hospital of New York-Presbyterian (MSCHONY), which has served as a major urban catchment area for COVID-19 positive pediatric patients. We describe how we have adjusted our current treatment of multiple facets of pediatric surgery including oncology, trauma, minimally invasive procedures, and extracorporeal membrane oxygenation (ECMO).

CONCLUSIONS

Our pediatric surgery department had to creatively and expeditiously adjust our protocols, guidelines, and workforce to not only serve our pediatric population but merge ourselves with our adult hospital system during the COVID pandemic.

TYPE OF STUDY

Clinical research paper LEVEL OF EVIDENCE: Level V.

Extracorporeal Cardiopulmonary Resuscitation (ECPR) in Infants and Children: A Single-Center Retrospective Study

BACKGROUND

Extracorporeal cardiopulmonary resuscitation (ECPR) is increasingly used to rescue patients with cardiac arrest refractory to conventional therapy, necessitating evaluation of factors that may affect outcomes.

METHODS

A single-center retrospective review of pediatric patients (<21 years old) who underwent ECPR from January 2010 to November 2017. Comparisons between nonsurvivors and survivors, to decannulation and discharge, were made. Factors associated with survival and rate of complications were examined.

RESULTS

Seventy patients were supported with ECPR. Forty-nine (70%) patients survived to decannulation and 38 (54%) patients to discharge. There was no statistical difference between baseline characteristics of survivors and nonsurvivors, including age at cannulation, weight (kg), time to cannulation (minutes), and total time on extracorporeal membrane oxygenation (hours). Survivors to discharge had significantly higher pH prior to cannulation compared to nonsurvivors (7.11 ± 0.24 vs 6.97 ± 0.21, P = .01). Of all, 23.2% of patients received renal replacement therapy (RRT), 39.4% had significant bleeding, 22.5% had thrombotic complications, and 68.8% had neurologic injury on imaging studies. A greater number of nonsurvivors received RRT compared to survivors to discharge (35.5% vs 10.8%, P = .02). There were no differences in bleeding or thrombotic complications or radiographically established neurologic injury.

CONCLUSIONS

Although ECPR effectively increases overall survival, a better characterization of long-term outcomes is needed.

A Multilevel Analysis of Surgical Category and Individual Patient-Level Risk Factors for Postoperative Stroke

Background and Purpose

Many studies supporting the association between specific surgical procedure categories and postoperative stroke (POS) do not account for differences in patient-level characteristics between and within surgical categories. The risk of POS after high-risk procedure categories remains unknown after adjusting for such differences in patient-level characteristics.

Methods

Using inpatients in the American College of Surgeons National Surgical Quality Initiative Program database, we conducted a retrospective cohort study between January 1, 2000, and December 31, 2010. Our primary outcome was POS within 30 days of surgery. We characterized the relationship between surgical- and individual patient-level factors and POS by using multivariable, multilevel logistic regression that accounted for clustering of patient-level factors with surgical categories.

Results

We identified 729 886 patients, 2703 (0.3%) of whom developed POS. Dependent functional status (odds ratio [OR]: 4.11, 95% confidence interval [95% CI]: 3.60-4.69), history of stroke (OR: 2.35, 95%CI: 2.06-2.69) or transient ischemic attack (OR: 2.49 95%CI: 2.19-2.83), active smoking (OR: 1.20, 95%CI: 1.08-1.32), hypertension (OR: 2.11, 95%CI: 2.19-2.82), chronic obstructive pulmonary disease (OR: 1.39 95%CI: 1.21-1.59), and acute renal failure (OR: 2.35, 95%CI: 1.85-2.99) were significantly associated with POS. After adjusting for clustering, patients who underwent cardiac (OR: 11.25, 95%CI: 8.52-14.87), vascular (OR: 4.75, 95%CI: 3.88-5.82), neurological (OR: 4.60, 95%CI: 3.48-6.08), and general surgery (OR: 1.40, 95%CI: 1.15-1.70) had significantly greater odds of POS compared to patients undergoing other types of surgical procedures.

Conclusions

Vascular, cardiac, and neurological surgery remained strongly associated with POS in an analysis accounting for the association between patient-level factors and surgical categories.

Pressure ulcers in paediatric patients on extracorporeal membrane oxygenation

It has been shown that pressure ulcer formation in critically ill paediatric patients increases morbidity and mortality. We sought to identify factors associated with pressure ulcer formation in paediatric patients on extracorporeal membrane oxygenation (ECMO). From December 2014 to 2015, we identified patients at our institution who developed a pressure ulcer to create two cohorts: ulcer and no ulcer. Variables of interest included: type of ECMO, ECMO indication, hours on ECMO, location of cannulas, volume of crystalloid and blood products received during the first 7 days or during the length of the ECMO run, albumin and lactate levels on the day of cannulation, and presence of vasopressor support or steroid therapy. Of 43 patients studied, 11 (25.5%) developed a pressure ulcer. Patients that developed ulcers were older (P = 0.001) and weighed more (P = 0.006). Femoral cannulation was more frequent in the ulcer group (36.4% vs 6.3%, P = 0.029), and duration of ECMO was longer (P = 0.007). Age, weight, duration of ECMO, and femoral cannulation may contribute to the development of pressure ulcers in children who require ECMO support. Further analysis is imperative to identify specific techniques and protocols that will prevent pressure ulcers in this critically ill population.

Centrifugal pumps and hemolysis in pediatric extracorporeal membrane oxygenation (ECMO) patients: An analysis of Extracorporeal Life Support Organization (ELSO) registry data

PURPOSE

It is currently unclear whether centrifugal pumps cause more hemolysis than roller pumps in extracorporeal membrane oxygenation (ECMO) circuits. The aim of this study was to help answer that question in pediatric patients.

METHODS

A limited deidentified data set was extracted from the international multicenter Extracorporeal Life Support Organization (ELSO) registry comprising all reported ECMO runs for patients 18years or younger between 2010 and 2015. Logistic regression was used to evaluate a possible association between hemolysis and pump type, controlling for patient demographics, circuit factors, and complications.

RESULTS

14,776 ECMO runs for 14,026 patients had pump type recorded. Centrifugal pumps were employed in 60.4% of ECMO circuits. Hemolysis was a reported complication for 1272 (14%) centrifugal pump runs and for 291 (5%) roller pump runs. 1755 (20%) centrifugal pump runs reported kidney injury as compared to 797 (14%) roller pump runs. In the full logistic regression, the odds of hemolysis were significantly greater for runs using centrifugal pumps (OR 3.3, 95% CI 2.9-3.8, p<0.001).

CONCLUSIONS

In this retrospective analysis of a large international data set, the use of centrifugal pumps was associated with increased rates of hemolysis, hyperbilirubinemia, and kidney injury.

TYPE OF STUDY

Retrospective cohort study.

LEVEL OF EVIDENCE

Level III.

Routine Use of Distal Arterial Perfusion in Pediatric Femoral Venoarterial Extracorporeal Membrane Oxygenation

Lower-extremity ischemia is a significant complication in children on femoral venoarterial extracorporeal membrane oxygenation (VA ECMO). Our institution currently routinely uses distal perfusion catheters (DPCs) in all femoral arterial cannulations in attempts to reduce ischemia. We performed a single-center, retrospective review of pediatric patients supported with femoral VA ECMO from January 2005 to November 2015. The outcomes of patients with prophylactic DPC placement at cannulation (prophylactic DPC) were compared to a historical group with DPCs placed in response only to clinically evident ischemic changes (reactive DPC). Ischemic complication requiring invasive intervention (fasciotomy or amputation) was the primary outcome. Twenty-nine patients underwent a total of 31 femoral arterial cannulations, 17 with prophylactic DPC and 14 with reactive DPC. Ischemic complications requiring invasive intervention developed in 2 of 17 (12%) prophylactic DPC patients versus 4 of 14 (29%) reactive DPC. In the reactive DPC group, 7 of 14 (50%) had ischemic changes postcannulation, six underwent DPC placement, and three out of six of these patients still required invasive intervention. One of the seven patients had ischemic changes, did not undergo DPC, and required amputation. While a greater percentage of patients in the prophylactic group was cannulated during extracorporeal cardiopulmonary resuscitation (ECPR), statistical significance was not otherwise demonstrated. We demonstrate feasibility of superficial femoral artery (SFA) access in pediatric patients. We note fewer ischemic complications with prophylactic DPC placement, and observe that salvaging a limb with a reactive DPC was only successful 50% of the time. Although there was no statistical difference in the primary outcome between the two groups, limitations and confounding factors include small sample size and a greater percentage of patients in the prophylactic DPC group cannulated with ECPR in progress.

Abstract WP200: Post-operative Infection Does not Increase Risk of Post-operative Stroke: Analysis From a Nationwide Quality Initiative Program

Introduction: Infection has been described as a trigger for acute ischemic stroke, but the relationship between postoperative infection and the risk of postoperative stroke is unclear. We investigated the association between postoperative infection and stroke using the American College of Surgeons National Surgical Quality Initiative Program (NSQIP) database.

Hypothesis: Postoperative infection is associated with an increased risk of postoperative stroke.

Methods: We used the NSQIP database to identify all patients who underwent surgery between the years of 2000 and 2010 and developed a postoperative stroke within 30 days of surgery. The group was further stratified according to the presence of infection preceding stroke. Using a logistic regression model adjusted for age, race, sex, medical comorbidities, surgical type, and dichotomized functional status, we compared the risk of stroke in patients with and without preceding infections, and investigated the risk of infection following stroke.

Results: 729,886 surgical patients were identified, of whom 2,703 (0.3%) developed postoperative stroke. 848 (0.12%) patients developed both postoperative stroke and infection. Among patients who had postoperative stroke, 100 (3.7%) had developed an infection prior to developing a stroke. Patients with infection prior to stroke had a lower risk of stroke than patients who did not develop infection prior to stroke (adjusted odds ratio [OR] 0.25, 95%CI 0.20-0.32). 748 patients (0.1%) developed an infection after having a postoperative stroke. These patients had a higher risk of infection (incidence rate ratio 2.76, 95%CI 2.57-2.97) and a higher odds of infection (adjusted odds ratio [OR] 3.47, 95%CI 3.18-3.78) than patients who did not have a stroke.

Conclusions: We found that the presence of a preceding infection was associated with a low risk of postoperative stroke in a large surgical inpatient sample. Although the total number of strokes may have been under-reported, these results conflict with other studies that report that infection is a trigger for ischemic stroke. Further analyses using more granular data are needed to investigate the relationship between postoperative infection and the risk of postoperative stroke.

Abstract TP177: Preoperative Functional Status and Type of Surgery Influences Postoperative Stroke Risk: analysis from the Nationwide Surgical Quality Initiative Program

Introduction: Post-operative stroke (POS) is associated with vascular and cardiac surgery, but this finding has mainly been reported among populations receiving vascular and cardiac procedures. We investigated the association between type of surgery and risk of POS in a large, generalizable inpatient cohort from the American College of Surgeons National Surgical Quality Initiative Program (NSQIP) database.

Hypothesis: Cardiac and vascular procedures are associated with an increased risk of POS.

Methods: We identified patients that underwent surgery between the years of 2000 and 2010. Our primary outcome was POS within 30 days of surgery. Using a hierarchical model adjusted for age, race, sex, medical comorbidities and dichotomized functional status, we assessed for clustering between type of surgery and POS. We then determined risk factors for POS while adjusting for clustering. Each surgical type was compared against all other surgical types.

Results: We identified 729,886 patients, of whom 2,703 (0.3%) developed POS. In the hierarchical analysis, cardiac surgery (incidence rate ratio (IRR) 6.38, 95%CI 5.37-7.55), vascular surgery (IRR 4.41, 95%CI 4.08-4.76), and neurosurgery (IRR 2.05, 95%CI 1.69-2.48) were associated with increased risk of POS. The only patient-level factor associated with surgery type was poor preoperative functional status. Accounting for clustering, patients with poor pre-operative functional status (OR 4.11, 95%CI 3.60-4.69), history of stroke (OR 2.35 95%CI 2.06-2.69), history of transient ischemic attack (OR 2.49 95%CI 2.19-2.83), active smoking (OR 1.20, 95%CI 1.08-1.32), and COPD (OR 1.39 95%CI 1.21-1.59) were at higher risk of POS. There was no interaction between preoperative functional status and type of surgery.

Conclusions: In a large cohort of surgical inpatients, we found that the risk of POS was significantly associated with cardiac, vascular, and neurosurgical procedures. Certain patient populations, such as those with a dependent pre-operative functional status, may be at a higher risk of POS and may be more likely to undergo cardiac, vascular, or neurosurgical procedures. Further studies are needed to elucidate the relationship between pre-surgical functional status and type of surgery.

Two decades of experience with thoracoscopic lobectomy in infants and children: standardizing techniques for advanced thoracoscopic surgery

OBJECTIVES

This study evaluates the safety and efficacy of thoracoscopic lobectomy in infants and children.

MATERIALS AND METHODS

From January 1994 to November 2013, 347 patients underwent video-assisted thoracoscopic lobe resection at two institutions. All procedures were performed by or under the direct guidance of a single surgeon. Patients' ages ranged from 1 day to 18 years, and weights ranged from 2.8 to 78 kg. Preoperative diagnosis included sequestration/congenital pulmonary airway malformation (n=306), severe bronchiectasis (n=24), congenital lobar emphysema (n=13), and malignancy (n=4).

RESULTS

Of the 347 procedures, 342 were completed thoracoscopically. Operative times ranged from 35 minutes to 240 minutes (average, 115 minutes). Average operative time when a trainee was the primary surgeon was 160 minutes. There were 81 upper, 25 middle, and 241 lower lobe resections. There were four intraoperative complications (1.1%) requiring conversion to an open thoracotomy. The postoperative complication rate was 3.3%, and 3 patients required re-exploration for a prolonged air leak. Hospital length of stay (LOS) ranged from 1 to 16 days (average). In patients <5 kg and <3 months of age, the average operative time was 90 minutes, and the LOS was 2.1 days.

CONCLUSIONS

Thoracoscopic lung resection is a safe and efficacious technique. With proper mentoring it is an exportable technique, which can be performed by pediatric surgical trainees. The procedures are safe and effective even when performed in the first 3 months of life. Early resection avoids the risk of later infection and malignancy.

A comparison of bronchoalveolar lavage versus lung biopsy in pediatric recipients after stem cell transplantation

Bronchoalveolar lavage (BAL) has been a useful initial diagnostic tool in the evaluation of pulmonary complications after hematopoietic stem cell transplantation (HSCT); however, the diagnostic sensitivity, prevalence, and outcome after BAL versus lung biopsy (LB) in pediatric HSCT patients remains to be determined. We reviewed 193 pediatric HSCT recipients who underwent a total of 235 HSCTs. Sixty-five patients (34%) underwent a total of 101 BALs for fever, respiratory distress, and/or pulmonary infiltrates on chest radiograph and/or computed tomography scan. The 1-year probability of undergoing BAL was 43.0% after allogeneic stem cell transplantation (alloSCT) and 8.5% after autologous stem cell transplantation (autoSCT) (P = .001). Sixteen of the 193 patients (8%) patients underwent 19 LBs. The probability of undergoing LB at 1 year after HSCT was 9.3%. No grade III or IV adverse events related to either procedure were observed. Of the 101 BALs performed, 40% (n = 40) were diagnostic, with a majority revealing a bacterial pathogen. Among the 19 LBs performed, 94% identified an etiology. In multivariate analysis, myeloablative conditioning alloSCT conferred the highest risk of requiring a BAL (hazard ratio [HR],8.5; P = .0002). The probability of 2-year overall survival was 20.2% in patients who underwent BAL, 17.5% for patients who underwent biopsy, and 67.4% for patients who had neither procedure. In multivariate analysis, only the requirement of a BAL was independently associated with an increased risk of mortality (HR, 2.96; P < .0001). In summary, in this cohort of pediatric HSCT recipients, BAL and LB were used in approximately 35% and 8% of pediatric HSCTs with diagnostic yields of approximately 40% and 94%, respectively, and were both associated with poor long-term outcomes.

Ultrasonography/MRI versus CT for diagnosing appendicitis

BACKGROUND

Cross-sectional imaging increases accuracy in diagnosing appendicitis. We hypothesized that a radiation-free imaging pathway of ultrasonography selectively followed by MRI would not change clinical end points compared with computed tomography (CT) for diagnosis of acute appendicitis in children.

METHODS

We retrospectively reviewed children (<18 years old) who had diagnostic imaging for suspected acute appendicitis between November 2008 and October 2012. Before November 2010 CT was used as the primary imaging modality (group A); subsequently, ultrasonography was the primary imaging modality followed by MRI for equivocal findings (group B). Data collected included time from triage to imaging and treatment and results of imaging and pathology.

RESULTS

Six hundred sixty-two patients had imaging for suspected appendicitis (group A = 265; group B = 397, of which 136 [51%] and 161 [41%], respectively, had positive imaging for appendicitis). Negative appendectomy rate was 2.5% for group A and 1.4% for group B. Perforation rate was similar for both groups. Time from triage to antibiotic administration and operation did not differ between groups A and B. There was higher proportion of positive imaging and appendectomies in group A and thus more negative imaging tests in group B (ultrasonography and MRI), but diagnostic accuracy of the 2 imaging pathways was similar.

CONCLUSIONS

In children with suspected acute appendicitis, a radiation-free diagnostic imaging of ultrasonography selectively followed by MRI is feasible and comparable to CT, with no difference in time to antibiotic administration, time to appendectomy, negative appendectomy rate, perforation rate, or length of stay.

The use of recombinant tissue-type plasminogen activator in a newborn with an intracardiac thrombus developed during extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) support is often used to support infants and children with hemodynamic or respiratory failure. One of the major obstacles of safely treating a child with ECMO is balancing the risk of hemorrhage with the potential for thrombus development. Managing thrombosis in the setting of ECMO is challenging and has no defined algorithm. The use of recombinant tissue-type plasminogen activator (tPA) for thrombolysis has been previously described in cases where thrombi have developed despite adequate anticoagulation. In such situations, the risk of hemorrhage must be carefully balanced with the benefit of dissolving the clot and reestablishing flow. We present a case of an infant who required ECMO because of severe primary pulmonary hypertension and subsequently developed a right atrial thrombus adjacent to the ECMO cannula. The patient was treated with tPA with immediate improvement but had fatal intracranial hemorrhage almost 3 days after the tPA was administered. In this report, we review the current literature on tPA use during ECMO support and suggest a rational approach.

Outcomes research in pediatric surgery. Part 2: how to structure a research question

Innovative treatments and procedures are essential to the advancement of surgery. Outcomes research provides the mechanism to analyze these new treatments as they enter clinical practice and evaluate them against established therapies. Information gained through this methodology is essential because new techniques and innovations often gain rapid acceptance before clinical trials can be conducted to assess them. Increasing national emphasis is placed on comparative effectiveness as health care costs rise. Surgeons must take the lead in surgical outcomes and comparative effectiveness research, with the goal of identifying the most efficient and effective treatment for our patients. The authors show how to structure and design a research project involving pediatric surgical outcomes. The model consists of the following 3 phases: (1) study design, (2) data preparation, and (3) data analysis. The model we present provides the reader with a basic format and research structure to serve as a guide to performing high-quality surgical outcomes research.

Limb ischemia after common femoral artery cannulation for venoarterial extracorporeal membrane oxygenation: an unresolved problem

PURPOSE

Extracorporeal Life Support Organization Registry data confirm that the number of pediatric patients being supported by extracorporeal membrane oxygenation (ECMO) is increasing. To minimize the potential neurologic effects of carotid artery ligation, the common femoral artery (CFA) is frequently being used for arterial cannulation. The cannula has the potential for obstructing flow to the lower limb, thus increasing ischemia and possible limb loss. We present a single institution's experience with CFA cannulation for venoarterial (VA) ECMO and ask whether any precannulation variables correlate with the development of significant limb ischemia.

METHODS

We reviewed all pediatric patients who were supported by VA ECMO via CFA cannulation from January 2000 to February 2010. Limb ischemia was the primary variable. The ischemia group was defined as the patients requiring an intervention because of the development of lower extremity ischemia. The patients in the no-ischemia group did not develop significant ischemia. Continuous variables were reported as medians with interquartile ranges and compared using Mann-Whitney U tests. Differences in categorical variables were assessed using χ² testing (Fisher's Exact). Statistical significance was assumed at P < .05.

RESULTS

Twenty-one patients (age, 2-22 years) were cannulated via the CFA for VA ECMO. Significant ischemia requiring intervention (ischemia group) occurred in 11 (52%) of 21. In comparing the 2 groups (ischemia vs no ischemia), no clinical variables predicted the development of ischemia (Table 1). In the ischemia group, 9 (81%) of 11 had a distal perfusion catheter (DPC) placed. Complications of DPC placement included one case of compartment syndrome requiring a fasciotomy and one patient requiring interval toe amputation. Of the 2 patients in the ischemia group who did not have a DPC placed, 1 required a vascular reconstruction of an injured superficial femoral artery and 1 underwent a below-the-knee amputation. Mortality was lower in the ischemia group (27% vs 60%).

CONCLUSIONS

Limb ischemia remains a significant problem, as more than half of our patients developed it. The true incidence may not be known as a 60% mortality in the no-ischemia group could mask subsequent ischemia. Although children are at risk for developing limb ischemia/loss, no variable was predictive of the development of significant limb ischemia in our series. Because of the inability to predict who will develop limb ischemia, early routine placement of a DPC at the time of cannulation may be warranted. However, DPCs do not completely resolve issues around tissue loss and morbidity. Prevention of limb ischemia/loss because of CFA cannulation for VA ECMO continues to be a problem that could benefit from new strategies.

Laparoscopic excision of choledochal cysts with total intracorporeal reconstruction

PURPOSE

There are numerous published reports of laparoscopic resection of choledochal cysts (CDCs), but almost all involve extracorporeal reconstruction of a biliary drainage system. We describe and evaluate the technique of laparoscopic CDC resection with total intracorporeal reconstruction.

METHODS

We reviewed all patients who underwent a laparoscopic CDC resection from March 2005 to January 2010 at Rocky Mountain Children's Hospital and Children's Hospital of New York-Presbyterian. We obtained data on operative time, characteristics of reconstruction, time to initiation of diet, length of stay, complications, and outcome.

RESULTS

Thirteen patients (median age 5 years, range 1-16) underwent a laparoscopic CDC excision with total intracorporeal reconstruction. Four ports were used in all cases and no patients required conversion to an open procedure. Operative time ranged from 130 to 325 minutes (median 240 minutes). Median time to initiation of diet was 1 day (range 1-4 days). Median length of stay was 5 days (range 4-8 days). There were no cases of cholangitis; however, 1 patient developed a small bowel obstruction requiring re-operation.

CONCLUSION

Laparoscopic resection of CDCs with total intracorporeal reconstruction is a safe and effective technique. The minimal handling of the bowel appears to minimize postoperative ileus, allows for early postoperative feeding and discharge.

Percutaneous distal perfusion of the lower extremity after femoral cannulation for venoarterial extracorporeal membrane oxygenation in a small child

Femoral cannulation in pediatric patients requiring extracorporeal membrane oxygenation (ECMO) is commonly associated with distal limb ischemia. Authors have previously reported successful lower limb perfusion using various open techniques to cannulate a distal lower extremity artery at the time of initial ECMO cannulation. These procedures include open femoral artery antegrade cannulation and distal posterior tibial artery retrograde cannulation in older children and adults. Such approaches require ample vessel diameters to accommodate an arteriotomy and catheter insertion and, therefore, are of limited use in smaller children. We hypothesized that after femoral artery cannulation for ECMO, a percutaneous technique of distal limb perfusion might offer unique advantages when treating lower extremity ischemia in small pediatric patients. We report a technique for percutaneous antegrade cannulation in a 4-year-old patient shortly after her primary cannulation for venoarterial ECMO via the femoral artery.

Vascular Remodeling Marks Tumors That Recur During Chronic Suppression of Angiogenesis

The potential for avoiding acquired resistance to therapy has been proposed as one compelling theoretical advantage of antiangiogenic therapy based on the normal genetic status of the target vasculature. However, previous work has demonstrated that tumors may resume growth after initial inhibition if antiangiogenic blockade is continued for an extended period. The mechanisms of this recurrent growth are unclear. In these studies, we characterized molecular changes in vasculature during apparent resumption of xenograft growth after initial inhibition by vascular endothelial growth factor blockade, “metronome” topotecan chemotherapy, and combined agents in a xenograft murine model of human Wilms' tumor. Tumors that grew during antiangiogenic blockade developed as viable clusters surrounding strikingly remodeled vessels. These vessels displayed significant increases in diameter and active proliferation of vascular mural cells and expressed platelet-derived growth factor-B, a factor that functions to enhance vascular integrity via stromal cell recruitment. In addition, remodeled vessels were marked by expression of ephrinB2, required for proper assembly of stromal cells into vasculature. Thus, enhanced vascular stability appears to characterize tumor vessel response to chronic antiangiogenesis, features that potentially support increased perfusion and recurrent tumor growth.

Vascular remodeling marks tumors that recur during chronic suppression of angiogenesis

The potential for avoiding acquired resistance to therapy has been proposed as one compelling theoretical advantage of antiangiogenic therapy based on the normal genetic status of the target vasculature. However, previous work has demonstrated that tumors may resume growth after initial inhibition if antiangiogenic blockade is continued for an extended period. The mechanisms of this recurrent growth are unclear. In these studies, we characterized molecular changes in vasculature during apparent resumption of xenograft growth after initial inhibition by vascular endothelial growth factor blockade, "metronome" topotecan chemotherapy, and combined agents in a xenograft murine model of human Wilms' tumor. Tumors that grew during antiangiogenic blockade developed as viable clusters surrounding strikingly remodeled vessels. These vessels displayed significant increases in diameter and active proliferation of vascular mural cells and expressed platelet-derived growth factor-B, a factor that functions to enhance vascular integrity via stromal cell recruitment. In addition, remodeled vessels were marked by expression of ephrinB2, required for proper assembly of stromal cells into vasculature. Thus, enhanced vascular stability appears to characterize tumor vessel response to chronic antiangiogenesis, features that potentially support increased perfusion and recurrent tumor growth.

Duodenal atresia associated with proximal jejunal perforations: a case report and review of the literature

Duodenal atresia is associated with Down's syndrome, malrotation, and congenital cardiac defects. Idiopathic intestinal perforations in a newborn, which are not associated with necrotizing enterocolitis (NEC), have been described. The authors report on a full-term neonate who had multiple perforations of the proximal jejunum distal to duodenal atresia. To the best of the authors knowledge, the combination of idiopathic intestinal perforation and duodenal atresia has not been reported previously.

Anti-VEGF antibody in experimental hepatoblastoma: suppression of tumor growth and altered angiogenesis

BACKGROUND

Hepatoblastoma is the most common primary hepatic malignancy of childhood, frequently presenting as advanced disease. Vascular endothelial growth factor (VEGF) is an endothelial mitogen and survival factor critical to growth and angiogenesis in many human cancers. Inhibition of VEGF effectively suppresses tumorigenesis in multiple experimental models. The authors hypothesized that anti-VEGF antibody would alter vascular architecture and impede tumor growth in experimental hepatoblastoma.

METHODS

The Institutional Animal Care and Use Committee of Columbia University approved all protocols. Xenografts were established in athymic mice by intrarenal injection of cultured human hepatoblastoma cells. Anti-VEGF antibody (100 microg/dose) or vehicle was administered intraperitoneally 2 times per week for 5 weeks. At week 6, 10 control/treated mice were killed and remaining animals maintained without treatment until week 8. Tumor weights were compared by Kruskal-Wallis analysis, and vascular alterations ascertained by fluorescein angiography and specific immunostaining.

RESULTS

Anti-VEGF antibody significantly inhibited tumor growth at 6 weeks (1.85 g +/- 0.60 control, 0.05 +/- 0.03 antibody, P <.0003). In comparison with controls, treated xenografts showed decreased vascularity and dilated surviving vessels with prominent vascular smooth muscle elements.

CONCLUSIONS

Specific anti-VEGF therapy inhibits neoangiogenesis and significantly suppresses tumor growth in experimental hepatoblastoma. Surviving vasculature displays dilation and increased vascular smooth muscle. Anti-VEGF agents may represent new therapeutic alternatives for children with advanced disease.

Topotecan is anti-angiogenic in experimental hepatoblastoma

BACKGROUND

Advanced hepatoblastoma often is lethal despite current therapies, yet development of novel approaches has been hampered by the lack of biologically relevant models. One new strategy selectively targets endothelium rather than tumor cells using frequently administered, low-dose ("metronome") chemotherapy. Metronome topotecan has antiangiogenic activity in some experimental tumors. The authors developed a xenograft model of human hepatoblastoma to test the effect of metronome topotecan in this system.

METHODS

Xenografts resulted from intrarenal injection of cultured human hepatoblastoma cells in athymic mice. Topotecan (0.36 mg/kg/dose) or vehicle was injected intraperitoneally 5 times per week. At week 6, 10 control/treated mice were killed, and remaining animals were maintained without treatment until week 8. Tumor weights were compared by Kruskal-Wallis analysis, and vascular alterations were ascertained by specific immunostaining.

RESULTS

Metronome topotecan affected tumor weights in a delayed fashion: weights were diminished significantly only at 8 weeks (treated v control: 6 weeks, 0.59 g v 82 g, P value, not significant; 8 weeks, 1.13 g v 3.82; P <.02). Decreased vascularity and increased endothelial cell apoptosis were observed in treated xenografts.

CONCLUSIONS

Metronome topotecan inhibits growth and neovascularization in experimental hepatoblastoma. The durability of this effect is novel and has not been observed in other xenograft tumor models. Cytotoxic targeting of endothelial cells may hold particular promise for therapy of children with advanced hepatoblastoma. .

p53 accumulation in favorable-histology Wilms tumor is associated with angiogenesis and clinically aggressive disease

BACKGROUND/PURPOSE

Unfavorable histology (UH) in Wilms tumor has been linked to malfunction of the p53 tumor suppressor gene, which regulates (1) the endogenous angiogenesis suppressor thrombospondin-1 (TSP-1) and (2) vascular endothelial growth factor (VEGF). The authors hypothesized that clinically aggressive favorable histology Wilms tumor (FH), like UH, but distinct from standard-risk FH disease, would display altered p53/TSP-1 function and upregulated angiogenesis.

METHODS

Three Wilms tumor specimens manifesting different histology and clinical behavior were obtained: clinically aggressive UH, clinically aggressive FH, and standard-risk FH disease. Xenografts were induced intrarenally in athymic mice. P53, TSP-1, and VEGF status and neovascularity were assessed in tumor tissues. Lungs were evaluated for metastasis.

RESULTS

Clinically aggressive FH Wilms tumor displayed progressive alteration in p53/TSP-1 status and upregulation of VEGF. Such alteration was observed in the UH tumor, but was absent from the standard-risk FH tumor. Xenografts from clinically aggressive tumors displayed brisk neoangiogenesis and yielded lung metastases.

CONCLUSIONS

This is the first report of altered p53/TSP-1 function in association with clinically aggressive behavior in FH Wilms tumor. These characteristics were not observed in parallel studies of a nonaggressive FH tumor. Loss of wild-type p53 function may contribute to disease progression in FH Wilms tumor, in part by upregulation of VEGF.

Distinct response of experimental neuroblastoma to combination antiangiogenic strategies

BACKGROUND

The authors have shown previously that experimental neuroblastoma is partially inhibited (48%) by antivascular endothelial growth factor (anti-VEGF) antibody. The topoisomerase-I inhibitor, topotecan, has been shown to have antiangiogenic activity when administered in a low-dose, high-frequency regimen. We hypothesized that combining topotecan with anti-VEGF would suppress neuroblastoma more effectively than either agent alone.

METHODS

A total of 10(6) neuroblastoma cells were implanted intrarenally in athymic mice. Animals received vehicle, topotecan, anti-VEGF, or topotecan plus anti-VEGF (n = 9, 20, 20, 20, respectively). All control and half the treated mice were killed at 6 weeks. Remaining (rebound) mice were maintained without treatment for 3 more weeks. Patterns of vasculature and apoptosis were determined immunohistochemically.

RESULTS

Tumor weights at 6 weeks were reduced significantly in topotecan-only (0.07g) and combination-treated animals (0.08 g), compared with controls or anti-VEGF--treated mice (1.18 g, 0.53 g; P <.0007, all). At 9 weeks, rebound tumor weights were greatest in anti-VEGF (2.82 g), intermediate in topotecan (1.82 g), and least in combination-treated animals (1.47 g); however, the only significant difference was between anti-VEGF and combination therapy (P = 0.04). All treated tumors were vascularized sparsely in comparison with controls at 6 weeks, but exhibited brisk neoangiogenesis at 9 weeks.

CONCLUSIONS

Topotecan either with or without anti-VEGF antibody significantly suppresses neuroblastoma xenograft growth in comparison with controls or anti-VEGF antibody alone. Combining topotecan with anti-VEGF antibody significantly inhibited rebound tumor growth in comparison with anti-VEGF antibody alone. Combination therapy may improve durability of antiangiogenic inhibition of neuroblastoma.

Resistance of a VEGF-producing tumor to anti-VEGF antibody: unimpeded growth of human rhabdoid tumor xenografts

BACKGROUND/PURPOSE

Rhabdoid tumor of the kidney (RTK) is a lethal malignancy of childhood for which there currently are no effective therapies. Because vascular endothelial growth factor (VEGF) is nearly ubiquitous in human tumors, the authors hypothesized that a xenograft model of RTK would (1) express VEGF and (2) respond to anti-VEGF intervention.

METHODS

A total of 2 x 10(6) cultured RTK cells were implanted intrarenally (G-401) in athymic mice. Control/treated animals received either vehicle (phosphate-buffered saline, PBS) or anti-VEGF antibody (anti-VEGF) for 5 weeks (n = 20, 17, respectively). Vasculature was mapped by angiography and immunostaining. Apoptosis was assessed by TdT-mediated dUTP nick end labeling (TUNEL) assay, VEGF expression examined by reverse transcription polymerase chain reaction, and tumor weights compared by Kruskal-Wallis analysis.

RESULTS

Mean tumor weights were not altered significantly by anti-VEGF (0.78-g, controls v 0.56-g treated tumors; P value, not significant). Grossly, xenografts grew in a novel manner, encasing rather than invading the kidney, and did not metastasize. PECAM-1 immunostaining and fluorescein angiography showed similar vascularity in control and treated xenografts. Both apoptosis and VEGF expression were unchanged in treated specimens.

CONCLUSIONS

Unexpectedly, growth of RTK xenografts was not inhibited by specific anti-VEGF antibody, although these tumors express significant amounts of VEGF. In addition, RTK vasculature, apoptosis, and VEGF expression were not substantially altered by anti-VEGF antibody. These results suggest that tumor-derived VEGF is of highly variable importance in different malignancies.