Chylothorax following paediatric cardiac surgery: a case-control study

POBS-Card, a new score of severe bleeding after cardiac surgery: Construction and external validation

Objective

Bleeding after cardiac surgery leads to poor outcomes. The objective of the study was to build the PeriOperative Bleeding Score in Cardiac surgery (POBS-Card) to predict bleeding after cardiac surgery.

Methods

We conducted a retrospective cohort study in 2 academic hospitals (2016-2019). Inclusion criteria were adult patients after cardiac surgery under cardiopulmonary bypass. Exclusion criteria were heart transplantation, assistance, aortic dissection, and preoperative hemostasis diseases. Bleeding was defined by the universal definition for perioperative bleeding score ≥2. POBS-Card score was built using multivariate regression (derivation cohort, one center). The performance diagnosis was assessed using the area under the curve in a validation cohort (2 centers) and compared with other scores.

Results

In total, 1704 patients were included in the derivation cohort, 344 (20%) with bleeding. Preoperative factors were body mass index <25 kg/m2 (odds ratio [OR], 1.48 [1.14-1.93]), type of surgery (redo: OR, 1.76 [1.07-2.82]; combined: OR, 1.81 [1.19-2.74]; ascendant aorta: OR, 1.56 [1.02-2.38]), ongoing antiplatelet therapy (single: OR, 1.50 [1.09-2.05]; double: OR, 2.00 [1.15-3.37]), activated thromboplastin time ratio >1.2 (OR, 1.44 [1.03-1.99]), prothrombin ratio <60% (OR, 1.91 [1.21-2.97]), platelet count <150 g/L (OR, 1.74 [1.17-2.57]), and fibrinogen <3 g/L (OR, 1.33 [1.02-1.73]). In the validation cohort of 597 patients, the area under the curve was 0.645 [0.605-0.683] and was superior to other scores (WILL-BLEED, Papworth, TRUST, TRACK). A threshold >14 predicted bleeding with a sensitivity of 50% and a specificity of 73%.

Conclusions

POBS-Card score was superior to other scores in predicting severe bleeding after cardiac surgery. Performances remained modest, questioning the place of these scores in the perioperative strategy of bleeding-sparing.

Incidence, risk factors, and outcomes of chylothorax after cardiac procedure in the United States

Background

To examine the epidemiology and risk factors of chylothorax after cardiac procedure in the United States using a contemporary nationally representative database.

Methods

We identified postoperative chylothorax events through National Inpatient Sample database (2016-2019) and compared baseline demographics, comorbidities, and in-hospital outcomes between hospitalizations with and without postoperative chylothorax. The Cochrane-Armitage test was used to analyze trends in incidence rates. Multivariable Poisson regression models were used to identify potential risk factors for postoperative chylothorax after cardiac procedure.

Results

A total of 819 (0.24%) admissions were associated with postoperative chylothorax. The crude and standardized incidence rates of chylothorax were 23.7 (95%CI, 22.1-25.4) and 61.5 per 10,000 cardiac procedure-related admissions, respectively, with no significant temporal change in incidence rate over the study period (Ptrend = 0.5249). Infants [adjusted rate ratio (aRR), 117.3, 95% confidence interval (CI), 94.5-145.5] and children (aRR, 60.2, 95%CI, 48.0-75.5) were more likely to develop chylothorax compared to adults. Heart and great vessel procedures (aRR, 4.36, 95%CI, 3.61-5.26), septal repair (aRR, 1.91, 95%CI, 1.58-2.29), heart transplant (aRR, 5.68, 95%CI, 4.55-7.10) and pericardial procedures (aRR, 4.04, 95%CI, 3.32-4.91) were associated with elevated risk for chylothorax. Admissions with chylothorax were associated with higher inpatient mortality (4.9% vs. 3.0%, p<0.0001), longer inpatient stay, higher costs and greater perioperative complication burden.

Conclusions

Following cardiac procedures, chylothorax is an uncommon but serious complication that affects the prognosis. The analysis reveals varying incidence rates across age groups and specific surgical procedures, with infants at elevated risk.

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.

Risk factors and early outcomes of chylothorax following congenital cardiac surgery: A single-center experience

Background

This study aims to investigate the incidence and risk factors for chylothorax and to evaluate the effect of chylothorax on the early postoperative outcomes following congenital cardiac surgery.

Methods

A total of 1,053 patients (606 males, 447 females; median age: 12 months; range, 3 days to 48 years) who underwent surgery for congenital heart disease at our institute between January 2018 and December 2019 were retrospectively analyzed. Patients with chylothorax were identified and the data of this cohort was compared with the entire study population. Following the diagnosis of chylothorax, a standardized management protocol was applied to all patients.

Results

Of 1,053 patients operated, 78 (7.4%) were diagnosed with chylothorax. In the univariate analysis, younger age, peritoneal dialysis, preoperative need for mechanical ventilation, surgical complexity, delayed sternal closure, high vasoactive inotrope score in the first 24 h after operation, residual or additional cardiac lesions which required reoperations were found to be the risk factors for chylothorax (p<0.05). In the multivariate analysis, the correlation persisted with only younger age, infections, and peritoneal dialysis requirement (p<0.05). In the chylothorax group, ventilation times were longer, and re-intubation and infection rates were higher (p<0.05). Although the length of intensive care unit and hospital stay was significantly longer in this patient group, there was no significant association between the development of chylothorax and in-hospital mortality (p>0.05).

Conclusion

Chylothorax following congenital cardiac surgery is a significant problem which prolongs the length of hospital stay and increases the infection rates. Complex cardiac pathologies which require surgery at early ages and re-operations are risk factors for chylothorax. Although there is no consensus on the most optimal therapeutic strategy, standardizing the management protocol may improve the results.

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.

Chylothorax in newborns after cardiac surgery: a rare complication?

The aim of this study was to analyze patients diagnosed with chylothorax after congenital heart disease surgery among a cohort of neonatal patients, comparing the evolution, complications, and prognosis after surgery of patients who were and were not diagnosed with chylothorax, and to analyze possible risk factors that may predict the appearance of chylothorax in this population. Retrospective and observational study included all neonates (less than 30 days since birth) who underwent congenital heart disease surgery in a level III neonatal intensive care department. We included infants born between January 2014 and December 2019. We excluded those infants who were born before 34 weeks of gestational age or whose birth weight was less than 1800 g. We also excluded catheter lab procedures and patent ductus arteriosus closure surgeries. Included patients were divided into two groups depending on whether they were diagnosed with chylothorax or not after surgery, and both groups were compared in terms of perinatal-obstetrical information, surgical data, and NICU course after surgery. We included 149 neonates with congenital heart disease surgery. Thirty-one patients (20.8%) developed chylothorax, and in ten patients (32.3%), it was considered large volume chylothorax. Regarding the evolution of these patients, 22 infants responded to general dietetic measures, a catheter procedure was performed in 9, and 5 of them finally required pleurodesis. Cardiopulmonary bypass, median sternotomy, and delayed sternal closure were the surgical variables associated with higher risks of chylothorax. Patients with chylothorax had a longer duration of inotropic support and mechanical ventilation and took longer to reach full enteral feeds. As complications, they had higher rates of cholestasis, catheter-related sepsis, and venous thrombosis. Although there were no differences in neonatal mortality, patients with chylothorax had a higher rate of mortality after the neonatal period. In a multiple linear regression model, thrombosis and cardiopulmonary bypass multiplied by 10.0 and 5.1, respectively, the risk of chylothorax and have an umbilical vein catheter decreases risk.

CONCLUSION

We have found a high incidence of chylothorax after neonatal cardiac surgery, which prolongs the average stay and causes significant morbidity and mortality. We suggested that chylothorax could be an underestimated complication of congenital heart disease surgery during the neonatal period.

WHAT IS KNOWN

• Acquired chylothorax in the neonatal period usually appears as a complication of congenital heart disease surgery, being the incidence quite variable among the different patient series (2.5-16.8%). The appearance of chylothorax as a complication of a cardiac surgery increases both mortality and morbidity in these patients, which makes it a quality improvement target in the postsurgical management of this population.

WHAT IS NEW

•Most of the published studies include pediatric patients of all ages, from newborns to teenagers, and there is a lack of studies focusing on neonatal populations. The main strength of our study is that it reports, to the best of our knowledge, one of the largest series of neonatal patients receiving surgery for congenital heart disease in the first 30 days after birth. We have found a high incidence of chylothorax after cardiac surgery during the neonatal period compared to other studies. We suggested that chylothorax could be an underestimated complication of congenital heart disease surgery during this period of life.

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.

Post-operative Chylothorax in Patients with Repaired Transposition of the Great Arteries

Patients with dextro-transposition of the great arteries (d-TGA) require surgical repair as neonates. These patients are at risk for post-operative chylothorax. We sought to describe the presentation, imaging, and outcomes after intervention for patients with d-TGA with post-operative chylothorax. A retrospective chart review was performed in patients with repaired d-TGA who were referred from 1/1/2013 to 4/1/2020 for evaluation of chylothorax. Patient history, lymphatic imaging, and interventional data were collected. Impact of intervention on lymphatic drainage was evaluated with a student's t-test. Eight patients met inclusion criteria for this study. Five patients had a history of central venous thrombus leading to thoracic duct outlet occlusion. Five patients underwent intervention, two were managed conservatively, and one was not a candidate for intervention. Chylothorax resolved in six patients. There was a significant difference in output from 7 days prior to first intervention (114 mL/kg/day) compared to 28 days following final intervention (27 mL/kg/day, p = 0.034). There were no procedural complications. Chylothorax in patients with repaired transposition of the great arteries is often amenable to intervention. Early surveillance and management of central venous thrombosis may reduce the burden of lymphatic disease in these patients.

Beyond the Syndrome: Extensive Congenital Abnormalities in an Infant With Trisomy 21

Herein we discuss the clinical course and subsequent autopsy of a female infant with trisomy 21 with balanced Rastelli Type "C" complete atrioventricular septal defect (AVSD), tetralogy of Fallot and right aortic arch with mirror image branching pattern who underwent a palliative right modified Blalock-Taussig-Thomas shunt (mBTTS) for hypoxemia from progressive right ventricular outflow tract obstruction. The baby was found to have multiple concomitant pathologic findings not typically seen with this constellation of cardiac anatomy. Autopsy revealed significant abdominal adhesions with near-complete stenosis of the transverse colon. In addition, the infant was found to have significantly elongated villi within the small and large bowel and a relatively large collagenous polyp in the small bowel. The decedent also had an abnormal tracheal bronchus, characterized by an additional superior right-sided bronchus, which is an extremely rare abnormality. Her clinical course was complicated by severe pulmonary hypertensive arteriolar changes out of proportion to what would be typical for her age, trisomy 21 status, and degree of left to right intracardiac shunting. Furthermore, she had refractory anasarca and recurrent chylous pleural effusions without gross lymphatic abnormalities that may have been secondary to systemic capillary leak syndrome (SCLS) versus severe pulmonary hypertension. Due to the aforementioned findings, the family elected for comfort care and the baby expired shortly after extubation. Overall, the infant had multiple, rare coexisting congenital abnormalities that likely represents an extreme phenotype of trisomy 21 that has not been described in the literature to date.

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

Background

Chylothorax after congenital heart surgery is not an uncommon complication, and it is associated with significant morbidity. However, consensus treatment guidelines are lacking. To improve the treatment outcomes of patients with postoperative chylothorax, we implemented a standardized management protocol at Severance Hospital in September 2014.

Methods

A retrospective review of patients treated at a single center was done. All corrective and palliative operations for congenital heart disease performed at our institution between January 2008 and April 2018 were reviewed. The incidence and treatment outcomes of postoperative chylothorax were analyzed.

Results

The incidence of chylothorax was 1.9%. Sixty-one percent of the patients could be managed with a low-fat diet, while 28% of the patients required complete restriction of enteral feeding. Thoracic duct embolization was performed in 2 patients and chest tube drainage decreased immediately after the procedure. No patient required thoracic duct ligation or pleurodesis. After implementation of the institutional management protocol, the number of chest tube drainage days decreased (median, 24 vs. 14 days; p=0.45).

Conclusion

Implementing a strategy to reduce postoperative chylothorax resulted in an acceptable incidence of postoperative chylothorax. Instituting a clinical practice protocol helped to curtail the treatment duration and to decrease the requirement for surgical treatment. Image-guided embolization of the thoracic duct is an effective treatment for postoperative chylothorax.

Non-surgical Risk Factors for the Development of Chylothorax in Children after Cardiac Surgery-Does Fluid Matter?

We hypothesize that there are post-operative, non-surgical risk factors that could be modified to prevent the occurrence of chylothorax, and we seek to determine those factors. Retrospective chart review of 285 consecutive patients < 18 years who underwent cardiac surgery from 2015 to 2017 at a single institution pediatric intensive care unit. Data was collected on patient demographics, cardiac lesion, surgical and post-operative characteristics. Primary outcome was development of chylothorax. Of 285 patients, median age was 189 days, median weight was 6.6 kg, 48% were female, and 10% had trisomy 21. 3.5% of patients developed upper extremity DVTs, and 8% developed chylothorax. At 24 h following surgery, a majority were in the 0-10% fluid overload category or had a negative fluid balance (63% and 34%, respectively), and a positive fluid balance was rare at 72 h (16%). In univariate analysis, age, weight, bypass time, DVT, arrhythmia, and trisomy 21 were significantly associated with chylothorax and adjusted for in logistic regression. Presence of an upper extremity DVT (OR 49.8, p < 0.001) and trisomy 21 (OR 5.8, p < 0.001) remained associated with chylothorax on regression modeling. The presence of an upper extremity DVT and trisomy 21 were associated with the development of chylothorax. Fluid overload was rare in our population. The presence of positive fluid balance, fluid overload, elevated central venous pressure, and early initiation of fat containing feeds were not associated with chylothorax.