Chylothorax after Surgery for Congenital Cardiac Disease: A Prevention and Management Protocol

Chylothorax: a rare postoperative complication in paediatric cardiac surgery patients - a 15-year retrospective study from a tertiary care centre in a developing country

Chylothorax, a postoperative complication of CHD surgery, involves chyle accumulation in the pleural cavity, posing challenges in diagnosis and management. This retrospective study investigates the prevalence, aetiology, management, and outcomes of postoperative chylothorax in paediatric patients undergoing cardiac corrective surgery at a tertiary care centre over 15 years. Medical records of paediatric patients who underwent cardiothoracic surgery at the Children's Heart Center at the American University of Beirut Medical Center between 2007 and 2022 were retrospectively reviewed. Data collection included demographic characteristics, blood parameters, chylous fluid characteristics, diagnostic criteria, treatment modalities, and hospitalisation details. Ethical approval was obtained, and descriptive statistics were employed using SAS 9.4. Among 2,997 children who underwent cardiothoracic surgery, nineteen cases of postoperative chylothorax were identified. The majority were females (63.2%) with a median age of 9 months. Glenn, Fontan, and Blalock-Taussig shunt-related surgeries were the most common operations associated with chylothorax. Single ventricle physiology was the predominant CHD observed (58%). Diagnosis relied primarily on clinical presentation, imaging studies, and triglyceride levels in pleural fluid. Treatment options included conservative dietary modifications, medical therapy such as octreotide, and surgical intervention if necessary. No mortalities were reported, and patients were adequately followed up. This study sheds light on postoperative chylothorax in paediatric cardiac patients, offering insights into its epidemiology, aetiology, clinical features, and treatment outcomes. While conservative and medical approaches effectively managed chylothorax in this group, larger studies are needed to develop standardised diagnostic and treatment protocols, improving outcomes in paediatric patients with postoperative chylothorax.

Chylothorax in Infants and Children After Congenital Heart Surgery: Approach and Review

Chylothorax in infants after surgery for congenital heart disease is associated with significant morbidity and mortality. Numerous management modalities applied alone or in various combinations have been utilized but definitive guidelines have not yet been established. We present two infants who developed refractory chylothorax after congenital heart surgery. We also reviewed evidence for the use of available treatment modalities. In our experience, the use of lymphangiography followed by pleurodesis by povidone-iodine was safe and our impression was that it may have played a decisive role in controlling the lymph leak.

Efficacy of nil per oral, total parenteral nutrition, milrinone and non-suction chest tube drainage-based management for chylothorax following pediatric cardiac surgery

OBJECTIVE

A single centre experience with chylothorax in post cardiac surgical patients.

METHODS

Retrospective review.

RESULTS

Chylothorax developed in 55 out of 873 operated patients (6.3%). Median age of the chylothorax cohort was 95 days (range 1-995). Neonates constituted 36% and 49% were infants. Group-1(35 patients-treated during the years 2011-2015) included those who were managed with low fat diet initially with other standard measures including steroid, octreotide, pleurodesis, lymphangiogram or thoracic duct ligation whenever required.Group-2 (20 patients, treated between year 2016-2018) were managed with nil per oral, total parenteral nutrition, extended use of milrinone and no use of chest tube suction with other above standard measures when required.Group-1 and group-2 were comparable in terms of their age and weight (p > 0.05).We observed lower volume of chest drainage, shorter intubation time, length of intensive care stay and hospital stay in group-2 compared to group-1 though they were statistically not significant (p > 0.05). Occurrence of massive chylothorax (>20 ml/kg/day) in group-1 was significantly higher [18 patients (51%) in group-1 vs 4 patients in group-2 (20%) (Chi-square 5.25, p = 0.02)]. In hospital mortality in group-1 was higher compared to group-2 (5/35 = 14.5% vs 1/20 = 5%), however, it was statistically not significant [risk ratio 2.86; 95% CI 0.36, 22.77; p = 0.59)]. Acute kidney injury was observed in about 25% of patients who had chylothorax. A higher mortality was observed in patients with chylothorax who had acute kidney injury [5/14 (35%)] compared to those who did not have acute kidney injury [1/41 (2.4%)] (Chi-square 11.89, p = 0.001)].

SUMMARY

In a heterogenous cohort of post-cardiac surgical patients who developed chylothorax, our suggested new regime (nil per oral, parenteral nutrition, extended use of milrinone and no suction applied to the chest drains) contributed to reduce the frequency of massive chylothorax occurrence significantly.

Chylothorax After Heart Surgery in Children

Chylothorax is a consequence of a thoracic duct injury that can occur during surgical procedures in patients with congenital heart disease. It is associated with high rates of morbimortality and increased use of clinical and hospital resources. The aim of this study was to evaluate the risk factors, distribution, manifestations, complications, and treatments for chylothorax in patients undergoing cardiac surgery in a tertiary pediatric hospital in southern Brazil. This is a retrospective, quantitative study, in which all medical records (n = 166) of patients with chylothorax after pediatric cardiac surgery between January 2014 and December of 2020 and a matched control group (n = 166) were analyzed. Over the study period, there was an increase in incidence of chylothorax from 4.5% in 2014 to 7.6% in 2020, a trend that has been reported in the literature. After multivariate analysis, the following were identified as risk factors for the diagnosis of chylothorax: genetic syndrome (OR 2.298); prolonged cardiopulmonary bypass time (greater than 120 min) (OR 2.410); fluid overload in the immediate postoperative period (OR 1.110); and SIRS (OR 2.527). Mortality was two times greater (p = 0.021) and there was a higher rate (34.4%) of infection (p < 0.001) in patients who developed chylothorax. In addition, a sensitivity analysis was performed comparing patients with low- and high-output chylothorax (> 20 mL/kg), which confirmed unfavorable outcomes for the latter group. Herein, we show that hemodynamic alterations were important factors for diagnosis. Understanding the risk factors, outcomes, and complications helps early identification and enables the reduction of morbidity and mortality.

Nutrition for critically ill children with congenital heart disease

Children with congenital heart disease often require admission to the cardiac intensive care unit at some point in their lives, either after elective surgical or catheter-based procedures or during times of acute critical illness. Meeting both the macronutrient and micronutrient needs of children in the cardiac intensive care unit requires complex decision-making when considering gastrointestinal perfusion, vasoactive support, and fluid balance goals. Although nutrition guidelines exist for critically ill children, these cannot always be extrapolated to children with congenital heart disease. Children with congenital heart disease may also suffer unique circumstances, such as chylothoraces, heart failure, and the need for mechanical circulatory support, which greatly impact nutrition delivery. Guidelines for neonates and children with heart disease continue to be developed. We provide a synthesized narrative review of current literature and considerations for nutrition evaluation and management of critically ill children with congenital heart disease.

Nutritional management of postoperative chylothorax in children with CHD

INTRODUCTION

Chylothorax after congenital cardiac surgery is associated with increased risk of malnutrition. Nutritional management following chylothorax diagnosis varies across sites and patient populations, and a standardised approach has not been disseminated. The aim of this review article is to provide contemporary recommendations related to nutritional management of chylothorax to minimise risk of malnutrition.

METHODS

The management guidelines were developed by consensus across four dietitians, one nurse practitioner, and two physicians with a cumulative 52 years of experience caring for children with CHD. A PubMed database search for relevant literature included the terms chylothorax, paediatric, postoperative, CHD, chylothorax management, growth failure, and malnutrition.

RESULTS

Fat-modified diets and nil per os therapies for all paediatric patients (<18 years of age) following cardiac surgery are highlighted in this review. Specific emphasis on strategies for treatment, duration of therapies, optimisation of nutrition including nutrition-focused lab monitoring, and supplementation strategies are provided.

CONCLUSIONS

Our deliverable is a clinically useful guide for the nutritional management of chylothorax following paediatric cardiac surgery.

Incidence, Risk Factors and Effective Treatment Strategies for Chylothorax After Pediatric Heart Surgeries: Retrospective Analysis of Large Database in Single Institution

Background

Risk factors for postoperative chylothorax in children who had cardiothoracic procedures are not always clear. Due to complex course in post-operative care, It's always challenging to find the risk factors, and their management.

Objective

The aim of our study was to identify the incidence, risk factors and effective treatment approaches for chylothorax after pediatric heart surgery.

Methods

Children who had the cardiac surgery and subsequently developed chylothorax were included in the study. The ratio of the experimental group to the control group was 1:2. Decannulations of extracorporeal membrane oxygenation (ECMO) were not included in the analysis of patient outcomes. For each patient, we keep track of their age, weight, gender, syndrome, RACH-1 scoring, fluid balance, bypass time, clamp time, redo operations, open or close heart surgeries, and rhythm difficulties. Care logs were kept for every single therapy that was administered. Primary outcome was chylothorax, with secondary outcomes included time in the intensive care unit (ICU), length of hospital stay (LOS), and death.

Results

5210 surgeries were performed in six years. 96 patients developed the chylothorax with incidence of 1.8%. In chylothorax group, mean weight was 6.7 ± 4.2, while mean age was 11.7 ± 15.2. Clamp time was 74.5 ± 53.5 versus 39.9 ± 13.7. Mean bypass time was 128.34(76.25) versus 84.3 ± 25.1 with an odds ratio 1.02 (Z test 0.0001). Six (6.3%) children with chylothorax had redo cardiac surgeries in the same admission (p-value 0.01) while none in other. Five (5.2%) cases got operated by thoracotomy, three from left side. Mean Chest tube duration was 10±7.8 days versus 3.8±2.4 in control group. (p-value 0.02). chylothorax resolved (mean resolving time = 4 days) in 76 (79.2%) children with monogen formula. Two patients receive midodrine with no significant effect. Four children underwent surgical repair for chylothorax.

Conclusion

Bypass time linearly increases incidence of chylothorax. Younger age, low weight, syndromic children, redo operations, non-open-heart surgeries, and arrhythmias also contribute to this. Gender, fluid balance, and RACHS-1 Scoring were not significant. While further research and testing are required for the use of midodrine. However, the low-fat formula of Monogen has proven to be an effective treatment.

Prediction Model with External Validation for Early Detection of Postoperative Pediatric Chylothorax

Earlier diagnosis of chylothorax following pediatric cardiac surgery is associated with decreased duration of chylothorax. Pleural fluid testing is used to diagnosis chylothorax which may delay detection in patients who are not enterally fed at time of chylothorax onset. Our aim was to develop and externally validate a prediction model to detect chylothorax earlier than pleural fluid testing in pediatric patients following cardiac surgery. A multivariable logistic regression model was developed to detect chylothorax using a stepwise approach. The model was developed using data from patients < 18 years following cardiac surgery from Primary Children's Hospital, a tertiary-care academic center, between 2017 and 2020. External validation used a contemporary cohort (n = 171) from Lucille Packard Children's Hospital. A total of 763 encounters (735 patients) were analyzed, of which 72 had chylothorax. The final variables selected were chest tube output (CTO) the day after sternal closure (dichotomized at 15.6 mL/kg/day, and as a continuous variable) and delayed sternal closure. The highest odds of chylothorax were associated with CTO on post-sternal closure day 1 > 15.6 mL/kg/day (odds ratio 11.3, 95% CI 6,3, 21.3). The c-statistic for the internal and external validation datasets using the dichotomized CTO variable were 0.78 (95% CI 0.73, 0.82) and 0.84 (95% CI, 0.78, 0.9) and performance improved when using CTO as a continuous variable (OR 0.84, CI: 95% CI 0.80, 0.87). Using the models described, chylothorax after pediatric cardiac surgery may be detected earlier and without reliance on enteral feeds.

Development of consensus recommendations for the management of post-operative chylothorax in paediatric CHD

OBJECTIVE

A standardised multi-site approach to manage paediatric post-operative chylothorax does not exist and leads to unnecessary practice variation. The Chylothorax Work Group utilised the Pediatric Critical Care Consortium infrastructure to address this gap.

METHODS

Over 60 multi-disciplinary providers representing 22 centres convened virtually as a quality initiative to develop an algorithm to manage paediatric post-operative chylothorax. Agreement was objectively quantified for each recommendation in the algorithm by utilising an anonymous survey. "Consensus" was defined as ≥ 80% of responses as "agree" or "strongly agree" to a recommendation. In order to determine if the algorithm recommendations would be correctly interpreted in the clinical environment, we developed ex vivo simulations and surveyed patients who developed the algorithm and patients who did not.

RESULTS

The algorithm is intended for all children (<18 years of age) within 30 days of cardiac surgery. It contains rationale for 11 central chylothorax management recommendations; diagnostic criteria and evaluation, trial of fat-modified diet, stratification by volume of daily output, timing of first-line medical therapy for "low" and "high" volume patients, and timing and duration of fat-modified diet. All recommendations achieved "consensus" (agreement >80%) by the workgroup (range 81-100%). Ex vivo simulations demonstrated good understanding by developers (range 94-100%) and non-developers (73%-100%).

CONCLUSIONS

The quality improvement effort represents the first multi-site algorithm for the management of paediatric post-operative chylothorax. The algorithm includes transparent and objective measures of agreement and understanding. Agreement to the algorithm recommendations was >80%, and overall understanding was 94%.

Postoperative Chylothorax in Neonates and Infants after Congenital Heart Disease Surgery-Current Aspects in Diagnosis and Treatment

Postoperative chylothorax is a rare complication following cardiac surgery for congenital heart disease (CHD) in the pediatric population, including neonates and infants. Multiple mechanisms are involved in the development of postoperative chylous effusions, mainly the traumatic injury of lymphatic vessels, systemic venous obstruction and dysfunction of the right ventricle. In this review, we focus on the existing evidence regarding the definition and diagnosis of postoperative chylothorax in children with CHD, as well as current therapeutic approaches, both nutritional and interventional, for the management of these patients. As part of nutritional management, we specifically comment on the use of defatted human milk and its effect on both chylothorax resolution and patient growth. A consensus with regard to several key aspects of this potentially significant complication is warranted given its impact on the cost, morbidity and mortality of children with CHD.

Lymphatic Endothelial Cell Defects in Congenital Cardiac Patients With Postoperative Chylothorax

Objectives

Chylothorax following cardiac surgery for congenital cardiac anomalies is a complication associated with severe morbidities and mortality. We hypothesize that there are intrinsic defects in the lymphatics of congenital cardiac patients.

Methods

Postsurgical chylothorax lymphatic endothelial cells (pcLECs) (n = 10) were isolated from the chylous fluid from congenital cardiac defect patients, and characterized by fluorescent-activated cell sorting, immunofluorescent staining, and quantitative RT-PCR. Results were compared to normal human dermal lymphatic endothelial cells (HdLECs). pcLECs (n = 3) and HdLECs were xenografted into immunocompromised mice. Implants and postoperative chylothorax patient's pulmonary tissues were characterized by immunostaining for lymphatic endothelial proteins.

Results

pcLECs expressed endothelial markers VECADHERIN, CD31, VEGFR2, lymphatic endothelial markers PROX1, podoplanin, VEGFR3, and progenitor endothelial markers CD90 and CD146. However, pcLECs had key differences relative to HdLECs, including altered expression and mislocalization of junctional proteins (VECADHERIN and CD31), and essential endothelial proteins, VEGFR2, VEGFR3, and PROX1. When xenografted in mice, pcLECs formed dilated lymphatic channels with poor cell-cell association. Similar to congenital lymphatic anomalies, the pulmonary lymphatics were dilated in a patient who developed postoperative chylothorax after cardiac surgery.

Conclusions

Recent studies have shown that some postoperative chylothoraces in congenital cardiac anomalies are associated with anatomical lymphatic defects. We found that pcLECs have defects in expression and localization of proteins necessary to maintain lymphatic specification and function. This pcLEC phenotype is similar to that observed in lymphatic endothelial cells from congenital lymphatic anomalies. Co-existence of lymphatic anomalies should be considered as a feature of congenital cardiac anomalies.

Management of visceral vascular anomalies

Visceral vascular anomalies are common in patients with vascular malformations in other parts of the body and can include lymphatic, venous, and arteriovenous malformations. Depending on the organ or organs involved they may present differently and pose different treatment challenges. Defining the malformation and understanding its extent is paramount in devising management regimens. Medical, interventional, and surgical therapies are often required in combination to treat these complex lesions. There are new and promising advances in the development of therapeutic agents targeting the PI3K/AKT/mTOR pathway. Due to the complex nature of these lesions a coordinated, multi-disciplinary approach is necessary to manage and mitigate symptoms and complications of this diverse group of vascular malformations.