Background Thoracic duct obstruction can cause devastating lymphatic complications, and definitive treatments remain lacking. This investigation evaluated our initial experience and early outcomes using a surgically created thoracic duct-to-azygous vein lymphovenous anastomosis (TDA-LVA) to provide lymphatic decompression in critically ill neonates and infants with thoracic duct obstruction. Methods All children who underwent TDA-LVA creation at the Children’s Hospital of Philadelphia between December 2019 and January 2024 were retrospectively reviewed. Preoperative and postoperative clinical characteristics were compared among all patients. Primary end points of analysis included survival to discharge and at last follow-up. Results Eight children (median weight, 4.5 kg; interquartile range [IQR], 3.5-5.0 kg) underwent successful TDA-LVA creation. All procedures were tolerated very well. One patient (1 of 8 [12.5%]) required chest washout on postoperative day (POD) 7, and 1 TDA-LVA was unsuccessfully revised on POD 21. The median hospital length of stay after TDA-LVA creation was 138 days (IQR, 64-241 days). Overall, 6 of 8 patients (75.0%) survived to hospital discharge, all of which (6 of 6 [100.0%]) remained alive at a median follow-up of 165 days (IQR, 18-521 days) after discharge. Postoperative TDA-LVA patency was confirmed with conventional lymphangiography in 5 of 8 patients (62.5%), and up to POD 70. Conclusions A TDA-LVA can restore lymphatic fluid drainage into the systemic venous circulation and remain patent for >2 months in carefully selected patients with thoracic duct obstruction. Further investigations are needed to determine the long-term durability and potential impact on overall quality of life and survival in children with complex lymphatic disorders.

Background: Chylothorax is as a complex disorder of abnormal lymphatic flow. Single ventricle (SV) patients are more susceptible due to altered venous and lymphatic pressures with staged palliation. MR lymphangiography has identified pulmonary lymphatic perfusion syndrome (PLPS) as the most common etiology with favorable response to lymphatic percutaneous interventions such as nonselective TD embolization (TDE) or selective lymphatic duct embolization (SLDE). However, comparative studies between TDE and SLDE for post-operative chylothorax remain limited. We hypothesize that patients who receive SLDE have shorter time to reach chest tube output < 5 mL/kg/d (chylothorax resolution) and lower risk of developing new lymphatic abnormalities compared to those who had TDE. Methods: Single-center retrospective study of congenital heart disease (CHD) patients with post-operative chylothorax who had lymphatic imaging and intervention between 7/2012-11/2023. Those who did not undergo lymphatic intervention were excluded. Exposure was defined by first intervention type. Outcomes included resolution of chylothorax, time to resolution and new onset of other lymphatic abnormalities. Results were stratified by ventricular status Results: Out of 130 patients referred for lymphatic imaging due to chylothorax, 96 met inclusion criteria. SV circulation was present in 80%. Most patients had SLDE (55%). Baseline trends were attributable to the SV subgroup receiving SLDE, who were older and more likely to have mesenteric edema pre-intervention. PLPS was seen in 92% of patients. Rates and time to chylothorax resolution were similar (94% and median 5 days, respectively). There were 16 patients who developed new lymphatic abnormality after the initial lymphatic procedure. Of those, 10 had TDE, 4 SLDE with TD occlusion seen on follow-up imaging, and 2 had SLDE (one with hepatopulmonary connections). In follow-up, a total of 52 patients had TD occlusion (43 TDE, 6 SLDE with unintended TDE and 3 SLDE followed by TDE). In this group, 29% of patients developed new onset lymphatic abnormalities compared to 4% in the SLDE only group (p=0.002). Postprocedural complication rates were similar. Conclusion: This is the largest single-center study demonstrating an excellent response of lymphatic intervention for post-operative chylothorax. While there were no differences in short-term rates of resolution, maintaining TD patency is critical to preventing future lymphatic abnormalities and complications

Background: Lymphatic subtype (LS) 4, as identified on T2-weighted cardiac MRI (CMR), is associated with higher rates of Fontan failure. Pre-Fontan factors predictive of LS are incompletely defined. Prior analysis of our cohort revealed that demographic and clinical factors were not predictive, though moderate or greater atrioventricular valve regurgitation (AVVR) on echocardiogram was associated with higher risk LS. We aim to identify hemodynamic and CMR correlates of high risk LS. Hypothesis: Patients with high-risk lymphatic subtypes would have less favorable hemodynamic measurements by cardiac catheterization and clinical outcomes compared to lower-risk counterparts. Methods: Single-center retrospective cohort study of patients who had pre-Fontan CMR from 2017-2021. Demographic, clinical, echocardiographic, MRI, and catheterization data was collected from birth to one year after Fontan or until death or heart transplant for patients who did not undergo Fontan. Two groups were defined: standard risk (LS 1, 2, or 3 without history of chylothorax) and high risk (LS 3 with history of chylothorax, or 4). Results: There were 171 patients who had CMR within 1 year prior to Fontan, of which 23 had high risk LS. By cardiac catheterization, compared to standard risk patients, high risk patients had a higher Qp:Qs (1.2 vs 1.05, p=0.01), left pulmonary artery pressure (LPAp) (11mmHg vs 10mmHg, p=0.04), and ventricular end diastolic pressure (EDP) (8mmHg vs 7mmHg). AVVR, ejection fraction, aortopulmonary collateral burden, and pulmonary artery dimensions by MRI did not differ by groups. High risk patients had worse outcomes: lower rates of Fontan completion (75% vs 96%, p<0.01), higher rate of death pre-Fontan (9.5% vs 1.3%, p=0.02), and longer length of stay after Fontan surgery (14 days vs 9 days, p=0.01). There was no difference in days alive and out of hospital (DAOH), readmission days, or ICU readmission days 1 year post-operative between the two groups. There was no difference in death within 3 years after Fontan and one standard risk patient underwent a heart transplant within 3 years of Fontan (p=0.01). Conclusions: Pre-Fontan LPAp and EDP by cardiac catheterization were associated with high risk LS. Patients with high risk LS had worse Fontan outcomes, with lower rates of Fontan completion, longer length of stay post-Fontan, and higher rates of death pre-Fontan with no difference between DAOH, readmission or ICU readmission days.

Background There is a paucity of data regarding the impact of remoteness of residence (RoR) and socioeconomic status (SES) on access to care and outcomes for children with congenital heart disease (CHD) or acquired heart disease (AHD) in a jurisdiction of universal health and centralized cardiac care. Objectives The primary objective was to examine whether RoR, SES, and their interaction impact access to health care and outcomes for children with heart disease in Alberta, Canada. Methods This was a population-based study of children with CHD or AHD born between January 1, 2005, and December 31, 2017, in Alberta, Canada. Primary outcomes included age at diagnosis, time from diagnosis to intervention, number of annual primary care visits, annual cardiologist visits, annual emergency room visits, and survival. Multivariable Cox proportional hazards models identified independent associations. Longitudinal relationships between the number of annual physician visits and RoR and SES were assessed with multivariable Poisson models. Results We included 12,542 children (94% CHD, 6% AHD), 70.4% living <60 minutes’ drive of a cardiac center, and 10.9% residing >180 minutes away. RoR and SES were not associated with age at diagnosis, time from diagnosis to intervention, annual primary care visits, or transplant free survival for either CHD or AHD. Although SES demonstrated no impact, annual annual cardiologist visits were inversely related to RoR for CHD (60-180 minutes rate ratio [RR]: 0.83, 95% CI: 0.73-0.95; >180 minutes RR: 0.77, 95% CI: 0.67-0.88; P < 0.0001) and AHD (60-180 minutes RR: 0.63, 95% CI: 0.39-1.00; >180 minutes RR: 0.53, 95% CI: 0.34-0.84; P = 0.02). Additionally, increased annual emergency room visits were associated with further RoR (P < 0.001) in both CHD and AHD and lower SES (P < 0.001) only for those with CHD. Conclusions Age at diagnosis, time to intervention, annual primary care visits, and transplant-free all-cause survival were not impacted by RoR or SES in children with heart disease. Greater RoR and SES, however, were associated with fewer annual cardiology visits and increased annual emergency room visits, which highlights the need for novel surveillance strategies for remote pediatric patients with heart disease.

Background/Aim: Transfusion can be a life-saving intervention, however routine pre-procedural blood products frequently go unused. Recent national blood product shortages highlight the importance of blood product stewardship. In our pediatric cardiac catheterization laboratory (PCCL), packed red blood cells (pRBCs) were ordered prior to all cases. These units are rarely transfused and sometimes cannot be reallocated, resulting in waste. As a quality improvement project, we set a primary aim to reduce the percentage of monthly pRBC waste from a baseline mean of 7.4% to <5% over 12 months. Methods: Baseline data on all cardiac catheterization cases, excluding electrophysiology, lymphatic, and hybrid cases, were collected from 1/1/2022 to 2/28/2023. Interventions (Table 1) were implemented and outcomes measured from 3/1/2023 to 3/31/2024. Primary outcome measures were monthly percentage of blood wasted, and percent of unused pRBC orders. Emergency blood product activation was measured as a balancing metric. Statistical process control charts were used to display and analyze data. Results: During the intervention period 1,318 cases were performed of which 32% met low-risk criteria for pRBC order de-implementation. The percent of blood that was subsequently wasted was reduced from 7.4% to 5.5% (Figure 1A), primarily driven by the reduction in the anecdotal practice of pRBC unit splitting in patients <1 year old (Figure 1B). The percent of unused pRBC orders was reduced from 97% to 79% with sustained improvement following two cycles of routine blood order de-implementation for low-risk cases. No emergency blood activation occurred (0%, 97.5% CI: 0-0.28%). Conclusion: De-implementation of default pRBC orders for low-risk catheterization procedures and reduction in unit splitting reduced the percent of blood wasted in our PCCL, saving time and cost without compromising patient safety. A data-driven approach to blood stewardship may be broadly applicable across procedural areas.

The development of new imaging techniques for the study of the central lymphatic system allows us to understand the anatomy and pathophysiology of all the disorders of the thoracic duct. With the help of catheters placed percutaneously in the thoracic duct, we can do now complex operations on the thoracic duct to restore its functionality. Advance imaging, expert percutaneous skills, and expert microsurgical skills are critical to the success of these interventions.

Patients with central lymphatic conduction disorders commonly have recalcitrant pleural effusions and or ascites. These conditions cause a profound deterioration in the patient's quality of life. Support measures such as low-fat diet and diuretics alone hardly ever provide meaningful improvement. New understanding of the pathophysiology of these disorders has opened the door in recent years to the development of several surgical procedures that have remarkable success rates. However, these patients must be managed by expert multidisciplinary teams.

Patients with lymphatic disorders are remarkably complex and require a wide variety of medical and surgical services. Establishing a multidisciplinary program improves the efficiency of the patients’ hospital experience minimizing the compartmentalization of their care. Offering a clear intake process guarantees that patients will be seen promptly by all the required teams. Additionally, having regular multidisciplinary meetings allows all participating teams to learn from each other and gain experience in the care of a population that is extraordinarily heterogeneous. Additionally, establishing a solid program allows for long-term data collection, research and education.

Magnetic resonance imaging (MRI) is now an indispensable diagnostic tool in medicine due to its outstanding contrast resolution and absence of radiation exposure, enabling detailed tissue characterization and three-dimensional anatomical representation. This is especially important when evaluating individuals with congenital heart disease (CHD) who frequently require cardiac implantable electrical devices (CIEDs). While MRI safety issues have previously limited its use in patients with CIEDs, new advances have called these limitations into question. However, difficulties persist in the pediatric population due to the continued lack of specific safety data both related to imaging young children and the specific CIED devices they often require. This paper discusses MRI safety considerations related to imaging patients with CIEDs, investigates pediatric-specific problems, and describes thorough methods for safe MRI access, highlighting the significance of specialized institutional guidelines.

Lymphatic failure is a broad term that describes the lymphatic circulation's inability to adequately transport fluid and solutes out of the interstitium and into the systemic venous circulation, which can result in dysfunction and dysregulation of immune responses, dietary fat absorption, and fluid balance maintenance. Several investigations have recently elucidated the nexus between lymphatic failure and congenital heart disease, and the associated morbidity and mortality is now well-recognized. However, the precise pathophysiology and pathogenesis of lymphatic failure remains poorly understood and relatively understudied, and there are no targeted therapeutics or interventions to reliably prevent its development and progression. Thus, there is growing enthusiasm towards the development and application of novel percutaneous and surgical lymphatic interventions. Moreover, there is consensus that further investigations are needed to delineate the underlying mechanisms of lymphatic failure, which could help identify novel therapeutic targets and develop innovative procedures to improve the overall quality of life and survival of these patients. With these considerations, this review aims to provide an overview of the lymphatic circulation and its vasculature as it relates to current understandings into the pathophysiology and pathogenesis of lymphatic failure in patients with congenital heart disease, while also summarizing strategies for evaluating and managing lymphatic complications, as well as specific areas of interest for future translational and clinical research efforts.

ObjectiveThe thoracic duct is the largest lymphatic vessel in the body, and carries fluid and nutrients absorbed in abdominal organs to the central venous circulation. Thoracic duct obstruction can cause significant failure of the lymphatic circulation (i.e., protein-losing enteropathy, plastic bronchitis, etc.). Surgical anastomosis between the thoracic duct and central venous circulation has been used to treat thoracic duct obstruction but cannot provide lymphatic decompression in patients with superior vena cava obstruction or chronically elevated central venous pressures (e.g., right heart failure, single ventricle physiology, etc.). Therefore, this preclinical feasibility study sought to develop a novel and optimal surgical technique for creating a thoracic duct-to-pulmonary vein lymphovenous anastomosis (LVA) in swine that could remain patent and preserve unidirectional lymphatic fluid flow into the systemic venous circulation to provide therapeutic decompression of the lymphatic circulation even at high central venous pressures.MethodsA thoracic duct-to-pulmonary vein LVA was attempted in 10 piglets (median age 80 [IQR 80-83] days; weight 22.5 [IQR 21.4-26.8] kg). After a right thoracotomy, the thoracic duct was mobilized, transected, and anastomosed to the right inferior pulmonary vein. Animals were systemically anticoagulated on post-operative day 1. Lymphangiography was used to evaluate LVA patency up to post-operative day 7.ResultsA thoracic duct-to-pulmonary vein LVA was successfully completed in 8/10 (80.0%) piglets, of which 6/8 (75.0%) survived to the intended study endpoint without any complication (median 6 [IQR 4-7] days). Initially, 2/10 (20.0%) LVAs were aborted intraoperatively, and 2/10 (20.0%) animals were euthanized early due to post-operative complications. However, using an optimized surgical technique, the success rate for creating a thoracic duct-to-pulmonary vein LVA in six animals was 100%, all of which survived to their intended study endpoint without any complications (median 6 [IQR 4-7] days). LVAs remained patent for up to seven days.ConclusionA thoracic duct-to-pulmonary vein LVA can be completed safely and remain patent for at least one week with systemic anticoagulation, which provides an important proof-of-concept that this novel intervention could effectively offload the lymphatic circulation in patients with lymphatic failure and elevated central venous pressures.

Central lymphatic obstructions are associated with anasarca and high mortality. We hypothesized that opening dilated cutaneous lymphatic channels by creating a lymphocutaneous fistula (LCF) would decompress the lymphatic circulation and improve anasarca. We reviewed all patients that had at least one LCF created between 9/2019 and 12/2022. LCF efficacy was determined by changes in weight, urine/diuresis, ventilation, and clinical status. We created eleven LCFs in four infants. LCFs initially drained 108 cc/kg/d (IQR68–265 cc/kg/d). Weights significantly decreased after LCF creation (6.9 [IQR6.1–8.1] kg vs. 6.1 [IQR 4.9–7.6] kg, P = 0.042). Ventilatory support decreased significantly in all patients after at least one LCF was created, and 3/4 patients (75

Introduction: Lymphatic subtype as determined by T2-weighted MRI (T2-CMR) after superior cavopulmonary connection (SCPC) is known to predict clinical outcome after Fontan. Factors related to lymphatic subtype development are not well understood. This study aims to identify early predictors of high-risk lymphatic subtypes. Methods: Retrospective cohort study of consecutive patients with pre-Fontan T2-CMR from 2017 to 2021. Patients divided into two groups based on lymphatic subtype: Group 1 - subtypes 1, 2, and 3; Group 2 - subtypes 3+ (defined as type 3 with history of chylothorax) and 4. Pearson’s chi square, Fisher’s exact, Wilcoxon rank sum, univariate and multivariate logistic regression analysis were performed. Results: We identified 171 patients. The groups differed significantly in total hospital, ICU, and chest tube days, number of catheterizations and number of cardiac surgeries (Table 1). Moderate or greater atrioventricular valve regurgitation (Mod+ AVVR), increased catheterizations and increased chest tube days were associated with high-risk lymphatic subtype. Maintenance of antegrade pulmonary blood flow at the time of SCPC was not significant (Table 2). In multivariate analysis, Mod+ AVVR and number of chest tube days remained in the model after adjusting for other covariates. Overall model significance was 0.007 with an area under the curve of 0.777. Conclusions: Mod+ AVVR and increased chest tube days are predictive of high-risk lymphatic subtype. Further study is needed to determine if lymphatic subtype is acquired via clinical exposure or whether native lymphatic subtype may be predictive of clinical course even prior to cavopulmonary connection.

Background Congestive heart failure is a leading cause of morbidity and mortality worldwide. One of the signs of congestive heart failure is fluid overload including pulmonary edema, peripheral edema, and ascites. The cause of fluid overload remains incompletely understood, and management of these patients continues to be a challenge. The role of lymphatic circulation abnormalities in the cause and pathophysiology of fluid overload also remains unclear. Here we report on a study in a large animal model of right heart failure caused by severe tricuspid regurgitation comparing cardiovascular and lymphatic findings in a group of animals that did not develop ascites with a group of animals that developed ascites. Methods and Results Thirteen Yorkshire pigs were included in this study divided into 2 groups. Group 1 included 6 animals that did not develop ascites, and Group 2 included 7 animals that had developed ascites. The groups were compared on hemodynamic parameters as well as comparison of the animal's lymphatic anatomy and function. There was no difference between the groups in degree of tricuspid regurgitation and central venous pressure, with inferior vena cava pressure measuring 11.6±1.6 versus 13.2±3.7 ( P =0.534) and superior vena cava pressure measuring 12.0±2.3 versus 13.7±3.2 ( P =0.366). There was also no difference between the groups in all measured hemodynamic parameters, including right ventricular pressure, pulmonary artery pressure, and left ventricular function. The weighted liver size in the ascites group was significantly larger than in the nonascites group (30.3±12.4 versus 63.3±14.0 mL/kg, respectively; P =0.001). The 2 groups also differed in the number of animals with regurgitant thoracic duct flow (Group 1: 1/6,17% versus Group 2: 6/7, 86%; P =0.029) and the minimal thoracic duct diameter (Group 1: 2.3±0.3 versus Group 2: 4.2±2.2; P =0.035). Conclusions In animals with right heart failure caused by severe tricuspid regurgitation, fluid overload did not correlate with hemodynamic parameters but rather with changes in the lymphatic system, including regurgitant lymphatic flow, minimal thoracic duct diameter, and liver size. This study is consistent with lymphatic dysfunction and not cardiovascular function playing a significant role in the cause of fluid overload. Further studies are needed to confirm these findings.

Introduction: Superior cavopulmonary anastomosis (SCPC) inevitably exposes the thoracic duct to higher venous pressure, potentially triggering disordered lymphatic perfusion manifesting as chylothorax (CT) and/or plastic bronchitis (PB) . Though outcomes following lymphatic interventions after Fontan completion (FC) are well described, they are not well described in patients after SCPC. Methods: A single-center retrospective study of patients who underwent lymphatic intervention for PB or CT following SCPC 1/1/2011-12/31/2021 was performed, excluding those with planned two ventricle or 1.5 ventricle repair, patients who underwent thoracic duct ligation, and those in whom interventions were performed either prior to SCPC or following FC. Results: In total, 27 patients (56% male) were studied, of which 22% had PB and 78% with CT, 7% with Noonan’s syndrome and 19% with heterotaxy syndrome. Median age at intervention was 11.3 months (IQR 7.4 - 33.5). Median time following SCPC was 3.5 months (IQR 2.1 - 24.2). In terms of interventions, 41% (n=11) underwent selective lymphatic channel embolization. Of these 36% (4/11) underwent subsequent thoracic duct embolization (TDE). The remaining 59% (n=16) patients underwent TDE. The thoracic duct was able to be accessed in 23 patients (85.2%). Twenty-four patients (19/21 with CT, 5/6 with PB) had resolution of symptoms following transcatheter intervention at our center. Following intervention, seven patients (all of whom were of the type IV lymphatic subtype) were successfully referred for FC, ten are currently awaiting FC, five are not Fontan candidates and five passed away from non-procedural comorbidities. Median duration of post-operative chest tubes following FC was 7 days (IQR 6-8) and median follow up is 39.1 months (IQR 15.1 - 45.1). Conclusions: Selective lymphatic embolization and TDE are feasible in SCPC recipients with CT and PB, with most patients experiencing symptomatic improvement. Subsequent FC has been achieved in some patients with type IV lymphatic abnormalities, suggesting that these interventions may alter the unnatural history of lymphatic dysfunction in single ventricle patients. Future research is needed to define longer term outcomes of this high-risk cohort.

Several studies have suggested an inverse relationship between lower socioeconomic status (SES) and the incidence of congenital heart disease (CHD) among live births. We sought to examine this relationship further in a Canada-wide population study, exploring CHD subtypes, trends, and associated noncardiac abnormalities. Infants born in Canada (less Quebec) from 2008 to 2018 with CHD requiring intervention in the first year were identified using ICD-10 codes through the Canadian Institute for Health Information Discharge Abstract Database. Births of CHD patients were stratified by SES (census-based income quintiles) and compared against national birth proportions using X 2 tests. Proportions with extracardiac defects (ED) and nonlethal genetic syndromes (GS) were also explored. From 2008 to 2018, 7711 infants born with CHD were included. The proportions of major CHD distributed across SES quintiles were 27.1%, 20.1%, 19.2%, 18.6%, and 15.0% from lowest to highest, with significant differences relative to national birth proportions (22.0%, 20.0%, 20.6%, 20.7%, and 16.7% from lowest (1) to highest (5)) ( p < 0.0001). No temporal trends in the CHD proportions across SES categories were observed over the study period. The distribution across SES quintiles was different only for specific CHD subtypes (double-outlet right ventricle ( n = 485, p = 0.03), hypoplastic left heart syndrome ( n = 547, p = 0.006), heterotaxy ( n = 224, p = 0.03), tetralogy of Fallot ( n = 1007, p = 0.008), truncus arteriosus ( n = 126, p < 0.0001), and ventricular septal defect ( n = 1916, p < 0.0001)), with highest proportions observed in the lowest quintile. The proportion of the total population with ED but not GS was highest in lower SES quintiles (< 0.0001) commensurate with increased proportion of CHD. Our study suggests a negative association between SES and certain CHD lesions and ED.

Aim Recent advances in lymphatic imaging allow understanding the pathophysiology of lymphatic central conduction disorders with great accuracy. This new imaging data is leading to a wide range of novel surgical interventions. We present here the state-of-the-art imaging technology and current spectrum of surgical procedures available for patients with these conditions. Method Descriptive report of the newest lymphatic imaging technology and surgical procedures and retrospective review of outcome data. Results There are currently two high-resolution imaging modalities for the central lymphatic system: multi-access dynamic contrast-enhanced MR lymphangiogram (DCMRL) and central lymphangiography (CL). DCMRL is done by accessing percutaneously inguinal and mesenteric lymph nodes and periportal lymphatics vessels. DCMRL provides accurate anatomical and dynamic data on the progression, or lack thereof, of the lymphatic fluid throughout the central lymphatic system. CL is done by placing a catheter percutaneously in the thoracic duct (TD). Pleural effusions are managed by pleurectomy and intraoperative lymphatic glue embolization guided by CL. Anomalies of the TD are managed by TD-to-vein anastomosis and/or ligation of aberrant TD branches. Chylous ascites and organ-specific chylous leaks are managed by intraoperative glue embolization, surgical lymphocutaneous fistulas, and ligation of aberrant peripheral lymphatic channels, among several other procedures. Conclusion The surgical management of lymphatic conduction disorders is a new growing field within pediatric general surgery. Pediatric surgeons should be familiar with the newest imaging modalities of the lymphatic system and with the surgical options available for patients with these complex surgical conditions to provide prompt treatment or referral. Level of Evidence V.