Lymphatic interventions in congenital heart disease.

Congenital heart disease affects 1/100 live births and is one of the most common congenital abnormalities. The relationship between congenital heart disease and lymphatic abnormalities and/or dysfunction is well documented and can be grossly divided into syndromic and non-syndromic etiologies. In patients with genetic syndromes (as examples listed above), there are known primary abnormal lymphatic development leading to a large pleiotropic manifestation of lymphatic dysfunction. Non-syndromic patients, or those without clear genetic etiologies for their lymphatic dysfunction, are often thought to be secondary to physiologic abnormalities as sequelae of congenital heart disease and palliative surgeries. Patients with congenital heart disease and lymphatic dysfunction have a wide variety of clinical manifestations for which there were not many therapeutic interventions available. The development of new imaging techniques allows us to understand better the pathophysiology of these problems and to develop different percutaneous interventions aiming to restore normal lymphatic function.

Percutaneous procedures for central lymphatic conduction disorders.

Percutaneous endovascular techniques established in interventional cardiology and radiology are well-suited for managing lymphatic conduction disorders. In this article, we provide a synopsis of technical aspects of these procedures, including access of the thoracic duct, selective lymphatic embolization, and management of thoracic duct obstruction. In aggregate, these techniques have developed into an integral component of multidisciplinary management of these complex diseases.

Safety and Efficacy of Ethanol for Catheter Salvage and Central Line-Associated Bloodstream Infection Prophylaxis in Polyurethane Catheters in the PICU.

OBJECTIVES: Ethanol lock therapy (ELT) is a potential method of central catheter salvage following central line-associated bloodstream infection (CLABSI) although there is potential risk of catheter damage in polyurethane catheters. Further, there is limited efficacy data across the spectrum of common pediatric catheters, and published ELT protocols describe dwell times that are not feasible for critically ill children. We sought to evaluate the safety and efficacy of ELT in polyurethane catheters using brief (30 min to 2 hr) dwell times in our PICU. DESIGN: Investigational pilot study using historical control data. SETTING: PICU in quaternary care, free-standing children's hospital. INTERVENTIONS: ELT in polyurethane central venous catheters for catheter salvage. RESULTS: ELT with brief dwell times was used in 25 patients, 22 of whom were bacteremic. Ultimately 11 patients, comprising 14 catheters, were diagnosed with a primary CLABSI. The catheter salvage rate in primary CLABSI patients receiving ELT was 92% (13/14) and significantly higher than the salvage rate in patients receiving antibiotics alone (non-ELT) (62%, 39/64; mean difference 0.32, 95% CI [0.14-0.50], p = 0.03). The rate of catheter fracture in all patients receiving ELT was 8% (2/25) while the rate of fracture in the non-ELT group was 13% (8/64; mean difference -0.05, 95% CI [-0.18 to 0.09], p = 0.72). The rate of tissue plasminogen activator (tPA) use in the ELT group was 8% (2/25), whereas the rate of tPA use in the non-ELT group was significantly higher at 42% (26/64; mean difference -0.34, 95% CI [-0.49 to -0.17], p = 0.002). CONCLUSIONS: The use of ELT for catheter salvage and prophylaxis in the PICU is safe in a variety of polyurethane catheters. Dwell times ranging from 30 minutes to 2 hours were effective in sterilizing the catheters while allowing other therapies to continue. This approach may decrease the need for frequent line changes in a medically fragile pediatric population.

Percutaneous biopsy for the diagnosis, risk stratification, and molecular profiling of neuroblastoma: A single-center retrospective study.

PURPOSE: To determine whether percutaneous core needle biopsy (PCNB) is adequate for the diagnosis and full molecular characterization of newly diagnosed neuroblastoma. MATERIALS AND METHODS: Patients with newly diagnosed neuroblastoma who underwent PCNB in interventional radiology at a single center over a 5-year period were included. Pre-procedure imaging and procedure details were reviewed. Rates of diagnostic success and sufficiency for International Neuroblastoma Pathology Classification (INPC), risk stratification, and evaluation of genomic markers utilized in the Children's Oncology Group risk stratification, and status of the anaplastic lymphoma kinase (ALK) gene were assessed. RESULTS: Thirty-five patients (13 females, median age 2.4 years [interquartile range, IQR: 0.9-4.4] and median weight 12.4 kg [IQR: 9.6-18]) were included. Most had International Neuroblastoma Risk Group Stage M disease (n = 22, 63%). Median longest axis of tumor target was 8.8 cm [IQR: 6.1-12]. A 16-gauge biopsy instrument was most often used (n = 20, 57%), with a median of 20 cores [IQR: 13-23] obtained. Twenty-five specimens were assessed for adequacy, and 14 procedures utilized contrast-enhanced ultrasound guidance. There were two post-procedure bleeds (5.7%). Thirty-four of 35 procedures (97%) were sufficient for histopathologic diagnosis and risk stratification, 94% (n = 32) were sufficient for INPC, and 85% (n = 29) were sufficient for complete molecular characterization, including ALK testing. Biologic information was otherwise obtained from bone marrow (4/34, 12%) or surgery (1/34, 2.9%). The number of cores did not differ between patients with sufficient versus insufficient biopsies. CONCLUSION: In this study, obtaining multiple cores with PCNB resulted in a high rate of diagnosis and successful molecular profiling for neuroblastoma.

Microcystic lymphatic malformations in Turner syndrome are due to somatic mosaicism of PIK3CA.

Turner syndrome (45,X) is caused by a complete or partial absence of a single X chromosome. Vascular malformations occur due to abnormal development of blood and/or lymphatic vessels. They arise from either somatic or germline pathogenic variants in the genes regulating growth and apoptosis of vascular channels. Aortic abnormalities are a common, known vascular anomaly of Turner syndrome. However, previous studies have described other vascular malformations as a rare feature of Turner syndrome and suggested that vascular abnormalities in individuals with Turner syndrome may be more generalized. In this study, we describe two individuals with co-occurrence of Turner syndrome and vascular malformations with a lymphatic component. In these individuals, genetic testing of the lesional tissue revealed a somatic pathogenic variant in PIK3CA-a known and common cause of lymphatic malformations. Based on this finding, we conclude that the vascular malformations presented here and likely those previously in the literature are not a rare part of the clinical spectrum of Turner syndrome, but rather a separate clinical entity that may or may not co-occur in individuals with Turner syndrome.

Embolization for pediatric trauma.

BACKGROUND: The management of pediatric trauma with trans-arterial embolization is uncommon, even in level 1 trauma centers; hence, there is a dearth of literature on this subject compared to the adult experience. OBJECTIVE: To describe a single-center, level 1 trauma center experience with arterial embolization for pediatric trauma. MATERIALS AND METHODS: A retrospective review was performed to identify demographics, transfusion requirements, pre-procedure imaging, procedural details, adverse events, and arterial embolization outcomes over a 19-year period. Twenty children (age 4.5 months to 17 years, median 13.5 years; weight 3.6 to 108 kg, median 53 kg) were included. Technical success was defined as angiographic resolution of the bleeding-related abnormality on post-embolization angiography or successful empiric embolization in the absence of an angiographic finding. Clinical success was defined as not requiring additional intervention after embolization. RESULTS: Seventy-five percent (n=15/20) of patients required red blood cell transfusions prior to embolization with a mean volume replacement 64 ml/kg (range 12-166 ml/kg) and the median time from injury to intervention was 3 days (range 0-16 days). Technical success was achieved in 100% (20/20) of children while clinical success was achieved in 80% (n=16/20). For the 4 children (20%) with continued bleeding following initial embolization, 2 underwent repeat embolization, 1 underwent surgery, and 1 underwent repeat embolization and surgery. Mortality prior to discharge was 15% (n=3). A post-embolization mild adverse event included one groin hematoma, while a severe adverse event included one common iliac artery pseudoaneurysm requiring open surgical ligation. CONCLUSIONS: In this single-center experience, arterial embolization for hemorrhage control in children after trauma is feasible but can be challenging and the clinical failure rate of 20% in this series reflects this complexity. Standardization of pre-embolization trauma assessment parameters and embolic techniques may improve outcomes.

Percutaneous Nephrostomy in Neonates and Young Infants.

PURPOSE: To describe a single-center experience of placing percutaneous nephrostomy (PCN) tubes in neonates and young infants aged ≤3 months. MATERIALS AND METHODS: This retrospective study evaluated PCN placement during a 19-year period. Medical records were reviewed for patient demographics, indications, procedure details, catheter-related adverse events, and outcomes. A total of 45 primary PCN insertions were attempted in 29 children (median age, 11 days [range, first day of life to 3 months]; median weight, 3.5 kg [range, 1.4-7.0 kg]). Salvage procedures resulted in 13 secondary catheters in 6 children. The most common indication was ureteropelvic junction obstruction (40.0%), and the most common urinary tract dilation classification was P3 (88.9%). RESULTS: Technical success for primary placements was 95.6%; both technical failures were due to loss of access in the same patient. Of primary placements, 76.7% were electively removed, 6.9% were dislodged but not replaced, and the remaining 16.3% required salvage procedures. Mechanical adverse events occurred in 20.9% of primary and 53.8% of secondary catheters, including partial retraction, complete dislodgement, and occlusion. Urinary tract infections (UTIs) occurred in 18.6% of primary and 15.4% of secondary catheters. Urosepsis occurred in 2.3% of primary and 7.7% of secondary catheters. Median primary catheter dwell time was 41 days (range, 1-182 days) and median secondary catheter dwell time was 31 days (range, 10-107 days). CONCLUSION: PCN placement in neonates and young infants has a high technical success rate, although not without particular procedural and management challenges of catheter malfunction and UTI.

Genomic profiling informs diagnoses and treatment in vascular anomalies.

Vascular anomalies are malformations or tumors of the blood or lymphatic vasculature and can be life-threatening. Although molecularly targeted therapies can be life-saving, identification of the molecular etiology is often impeded by lack of accessibility to affected tissue samples, mosaicism or insufficient sequencing depth. In a cohort of 356 participants with vascular anomalies, including 104 with primary complex lymphatic anomalies (pCLAs), DNA from CD31+ cells isolated from lymphatic fluid or cell-free DNA from lymphatic fluid or plasma underwent ultra-deep sequencing thereby uncovering pathogenic somatic variants down to a variant allele fraction of 0.15%. A molecular diagnosis, including previously undescribed genetic causes, was obtained in 41% of participants with pCLAs and 72% of participants with other vascular malformations, leading to a new medical therapy for 63% (43/69) of participants and resulting in improvement in 63% (35/55) of participants on therapy. Taken together, these data support the development of liquid biopsy-based diagnostic techniques to identify previously undescribed genotype-phenotype associations and guide medical therapy in individuals with vascular anomalies.

Pathogenic variants in PIK3CA are associated with clinical phenotypes of kaposiform lymphangiomatosis, generalized lymphatic anomaly, and central conducting lymphatic anomaly.

Complex lymphatic anomalies are debilitating conditions characterized by aberrant development of the lymphatic vasculature (lymphangiogenesis). Diagnosis is typically made by history, examination, radiology, and histologic findings. However, there is significant overlap between conditions, making accurate diagnosis difficult. Recently, genetic analysis has been offered as an additional diagnostic modality. Here, we describe four cases of complex lymphatic anomalies, all with PIK3CA variants but with varying clinical phenotypes. Identification of PIK3CA resulted in transition to a targeted inhibitor, alpelisib. These cases highlight the genetic overlap between phenotypically diverse lymphatic anomalies.

Imaging of pediatric abdominal soft tissue tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper.

This paper provides imaging recommendations for pediatric abdominal tumors that arise outside of the solid viscera. These tumors are rare in children and have been categorized in two groups: abdominal wall and peritoneal tumors (desmoid tumor and desmoplastic small round cell tumor) and tumors that arise from the gastrointestinal tract (gastrointestinal stromal tumor and gastrointestinal neuroendocrine tumor). Authors offer consensus recommendations for imaging assessment of these tumors at diagnosis, during follow-up, and when off-therapy.

Characterization and treatment of thoracic duct obstruction in patients with lymphatic flow disorders.

PURPOSE: The contribution of thoracic duct obstruction to lymphatic flow disorders has not been well-characterized. We describe imaging findings, interventions, and outcomes in patients with suspected duct obstruction by imaging or a lympho-venous pressure gradient (LVPG). MATERIALS AND METHODS: Clinical, imaging, and interventional data, including the LVPG, of patients with flow disorders and imaging features of duct obstruction who underwent lymphatic intervention were retrospectively reviewed, collated, and analyzed with descriptive statistics. RESULTS: Eleven patients were found to have obstruction, median age 10.4 years (interquartile range: 8-14.9 years). Pleural effusions were seen in 8/11 (72%), ascites in 8/11 (72%), both in 5/11 (45%), and protein-losing enteropathy in 5 (45%). Eight patients (72%) had congenital heart disease. The most common site of obstruction was at the duct outlet in 7/11 patients (64%). Obstruction was secondary to extrinsic compression or ligation 4 patients (36%). Nine patients (82%) underwent interventions, with balloon dilation in 7/9 (78%), massive lymphatic malformation drainage and sclerotherapy in 1, and lympho-venous anastomosis in 1. There was resolution of symptoms in 7/9 (78% who underwent intervention, with worsening in 1 patient and no change in 1. In these patients, preprocedure mean LVPG was 7.9 ± 5.7 mmHg and postprocedure gradient was 1.6 ± 1.9 mmHg (p = 0.014). Five patients in this series underwent intervention solely to alleviate duct obstruction and in 4/5 (80%) this led to resolution of symptoms (p = 0.05). CONCLUSION: Duct obstruction may be seen in lymphatic flow disorders and can occur from intrinsic and extrinsic causes. Stenosis at the outlet was most common. Obstruction can be demonstrated by an elevated LVPG, and interventions to alleviate the obstruction can be beneficial.

Central venous access in children: Placement trends over the last decade.

PURPOSE: To evaluate central venous access placement trends for radiology and non-radiology services over the last decade. MATERIALS AND METHODS: Children who had central venous access procedures included in a large administrative database of 49 pediatric institutions in the United States between 2010 and 2020 were included. Patient demographics and patient specific factors were compared between groups. The percentage of procedures performed by interventional radiology (IR) and non-radiology services were compared over time and by region. RESULTS: A total of 483,181 vascular access encounters were recorded (45.3% female; median age 2 years (IQR 0-11 years)). Approximately one quarter of vascular access encounters were IR-led, with a slight increase of 3.8% between 2010 and 2020. Children who underwent IR-placed vascular access were older (median age of 4 years compared to 1 year in non-radiology encounters). Interventional radiology-placed access was greatest in the Midwest (33.5%) with a decrease of 5.9% over the study period; in the other three regions, IR-performed encounters increased. Patient comorbidities more prevalent in the IR encounters were technology dependence (42.4% of all radiology encounters), gastrointestinal (34.9%), respiratory (20.8%), and transplant (8.1%), while those which were more prevalent in the non-radiology encounters were nephrology/urology (21.4% of all non-radiology encounters), prematurity/neonatal (17.3%), and malignancy (17.3%). CONCLUSIONS: Interventional radiology-provided vascular access services have slightly increased over the last decade without significant service-line transfer to other specialties. Underlying comorbidities in IR-led vascular access encounters vary across institutions based on referral patterns, possibly reflecting the adoption of ultrasound guidance by other pediatric subspecialties.

Mosaic pathogenic variants in AKT3 cause capillary malformation and undergrowth.

Capillary malformations are slow-flow vascular malformations that affect the microcirculation including capillaries and post capillary venules and can be associated with growth differences. Specifically, the association of capillary malformations with undergrowth is a vastly understudied vascular syndrome with few reports of genetic causes including PIK3CA, GNAQ, and GNA11. Recently, a somatic pathogenic variant in AKT3 was identified in one child with a cutaneous vascular syndrome similar to cutis marmorata telangiectatica congenita, undergrowth, and no neurodevelopmental features. Here, we present a male patient with a capillary malformation and undergrowth due to a somatic pathogenic variant in AKT3 to confirm this association. It is essential to consider that mosaic pathogenic variants in AKT3 can cause a wide spectrum of disease. There is a need for future studies focusing on capillary malformations with undergrowth to understand the underlying mechanism.

Imaging of pediatric liver tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper.

Primary hepatic malignancies are relatively rare in the pediatric population, accounting for approximately 1%-2% of all pediatric tumors. Hepatoblastoma and hepatocellular carcinoma are the most common primary liver malignancies in children under the age of 5 years and over the age of 10 years, respectively. This paper provides consensus-based imaging recommendations for evaluation of patients with primary hepatic malignancies at diagnosis and follow-up during and after therapy.

Multicompartment Dynamic Contrast Magnetic Resonance Lymphangiography in Diagnosis of Complicated Lymphatic Anomaly.

Background: To describe the dynamic contrast magnetic resonance lymphangiography (DCMRL) findings of three patients with complicated lymphatic anomaly (CLA) and protein losing enteropathy. We further discuss the importance of a multicompartment (intrahepatic [IH], intramesenteric [IM], and intranodal [IN]) DCMRL in delineating central lymphatic flow pathologies. Methods and Results: This is a retrospective study of three patients-one adult and two children who individually underwent the three-compartment DCMRL, namely IN-DCMRL, IH-DCMRL, and IM-DCMCRL. Findings from the results of the DCMRL for these three patients were obtained from the medical records and compared. Using the multicompartment imaging modalities, chylous fluid leakage into the peritoneum was observed using IM-DCMRL and IH-DCMRL but not IN-DCMRL for one of the patients in the case series. In contrast, leakage of chyle into the mediastinum was noted using IN-DCMRL but not IH-DCMRL and IM-DCMRL on another patient in this case series. Conclusion: Owing to the variability in outlining lymphatic flow pathologies, multicompartment imaging gives a more global picture of individual conduction disorders, has the potential to improve clinical assessment, and in some cases leads to a diagnosis of the abnormality and thus provides a better understanding of lymphatic flow anomalies in patients with CLAs.

Adjunctive techniques for percutaneous enteral access in children: a pictorial review.

Primary percutaneous gastrostomy and gastrojejunostomy tube placements are fundamental procedures performed in pediatric interventional radiology, with both antegrade and retrograde techniques described. In pediatric patients, however, challenges may arise due to smaller patient size and anatomical variations. Several adjunctive techniques may facilitate safe percutaneous access in the setting of a limited percutaneous gastric access window. These include the intra-procedural use of cone beam computed tomography (CT), percutaneous needle decompression in the setting of distended air-filled bowel interposed between the stomach and abdominal wall, post-pyloric balloon occlusion to facilitate gastric distension, ultrasound-guided gastric puncture, and intra-gastric contrast-enhanced ultrasound (ceUS) to define the relationship of the gastric wall and the anterior abdominal wall. Adjunctive techniques may increase successful primary percutaneous gastroenteric tube placement and may improve operator confidence in safe placement.

Bowel perforation following percutaneous sclerotherapy of an intra-abdominal lymphatic malformation.

Mesenteric lymphatic malformations result from abnormal proliferation of disorganized mesenteric lymphatic channels. Sclerotherapy is often preferred over surgery as it is less invasive and has lower post-procedure morbidity. Sclerotherapy has been described as durable and effective with a low complication rate. We describe a serious complication from sclerotherapy of a lymphatic malformation extending from the mesentery through the bowel wall, highlighting the spectrum of this pathology and the need for multidisciplinary management of complex cases.