Risks of venous thrombosis and bleeding in critically ill adolescents after trauma or major surgery

Derivation and Validation of a Machine Learning Algorithm for Predicting Venous Thromboembolism in Injured Children

BACKGROUND

Venous thromboembolism (VTE) causes significant morbidity in pediatric trauma patients. We applied machine learning algorithms to the Trauma Quality Improvement Program (TQIP) database to develop and validate a risk prediction model for VTE in injured children.

METHODS

Patients ≤18 years were identified from TQIP (2017-2019, n = 383,814). Those administered VTE prophylaxis ≤24 h and missing the outcome (VTE) were removed (n = 347,576). Feature selection identified 15 predictors: intubation, need for supplemental oxygen, spinal injury, pelvic fractures, multiple long bone fractures, major surgery (neurosurgery, thoracic, orthopedic, vascular), age, transfusion requirement, intracranial pressure monitor or external ventricular drain placement, and low Glasgow Coma Scale score. Data was split into training (n = 251,409) and testing (n = 118,175) subsets. Machine learning algorithms were trained, tested, and compared.

RESULTS

Low-risk prediction: For the testing subset, all models outperformed the baseline rate of VTE (0.15%) with a predicted rate of 0.01-0.02% (p < 2.2e^-16). 88.4-89.4% of patients were classified as low risk by the models.

HIGH-RISK PREDICTION

All models outperformed baseline with a predicted rate of VTE ranging from 1.13 to 1.32% (p < 2.2e^-16). The performance of the 3 models was not significantly different.

CONCLUSION

We developed a predictive model that differentiates injured children for development of VTE with high discrimination and can guide prophylaxis use.

LEVEL OF EVIDENCE

Prognostic, Level II.

TYPE OF STUDY

Retrospective, Cross-sectional.

Thrombosis and hemorrhage experienced by hospitalized children with SARS-CoV-2 infection or MIS-C: Results of the PICNIC registry

INTRODUCTION

Coagulopathy and thrombosis associated with SARS-CoV-2 infection are well defined in hospitalized adults and leads to adverse outcomes. Pediatric studies are limited.

METHODS

An international multicentered (n = 15) retrospective registry collected information on the clinical manifestations of SARS-CoV-2 and multisystem inflammatory syndrome (MIS-C) in hospitalized children from February 1, 2020 through May 31, 2021. This sub-study focused on coagulopathy. Study variables included patient demographics, comorbidities, clinical presentation, hospital course, laboratory parameters, management, and outcomes.

RESULTS

Nine hundred eighty-five children were enrolled, of which 915 (93%) had clinical information available; 385 (42%) had symptomatic SARS-CoV-2 infection, 288 had MIS-C (31.4%), and 242 (26.4%) had SARS-CoV-2 identified incidentally. Ten children (1%) experienced thrombosis, 16 (1.7%) experienced hemorrhage, and two (0.2%) experienced both thrombosis and hemorrhage. Significantly prevalent prothrombotic comorbidities included congenital heart disease (p-value .007), respiratory support (p-value .006), central venous catheter (CVC) (p = .04) in children with primary SARS-CoV-2 and in those with MIS-C included respiratory support (p-value .03), obesity (p-value .002), and cytokine storm (p = .012). Comorbidities prevalent in children with hemorrhage included age >10 years (p = .04), CVC (p = .03) in children with primary SARS-CoV-2 infection and in those with MIS-C encompassed thrombocytopenia (p = .001) and cytokine storm (p = .02). Eleven patients died (1.2%), with no deaths attributed to thrombosis or hemorrhage.

CONCLUSION

Thrombosis and hemorrhage are uncommon events in children with SARS-CoV-2; largely experienced by those with pre-existing comorbidities. Understanding the complete spectrum of coagulopathy in children with SARS-CoV-2 infection requires ongoing research.

Central venous catheter-associated deep vein thrombosis in critically ill pediatric patients: risk factors, prevention, and treatment

PURPOSE OF REVIEW

Central venous catheter (CVC) placement and ICU admission are the two most important risk factors for pediatric deep vein thrombosis. The optimal prevention and treatment strategies for CVC-associated deep vein thrombosis (CADVT) are unclear, but recently, seminal studies have been published. This review aims to summarize the recent literature on CADVT in critically ill children.

RECENT FINDINGS

Recent publications focused on three themes: risk factors, prevention, and treatment of CADVT. Newly identified risk factors for CADVT relate to Virchow's triad of hemostasis, blood vessel injury, and hypercoagulability. New risk prediction models have moderately good accuracy in predicting CADVT. Though previous data on pharmacologic CADVT prophylaxis was equivocal, recent studies indicate that low-molecular-weight heparin may be effective in preventing CADVT, particularly in critically ill children. Finally, new studies suggest that direct oral anticoagulants and shorter treatment times are noninferior to traditional agents and treatment durations in the treatment of CADVT.

SUMMARY

Recent research suggests new ways to accurately identify children at high risk of CADVT, effectively prevent CADVT, and optimize CADVT treatment. Future research should focus on understanding the pathobiology of CADVT formation, prevention, and treatment in critically ill children.

Use of Pharmacologic Prophylaxis Against Venous Thromboembolism in Hospitalized Injured Children

Despite a practice management guideline and risk prediction model for venous thromboembolism (VTE), pediatric-specific evidence on pharmacologic prophylaxis is lacking. In a retrospective study, we characterized receipt of prophylaxis and explored its effectiveness in hospitalized injured patients below 18 years old using data from the Trauma Quality Improvement Program. Concordance of receipt of prophylaxis with guideline and predicted risk of VTE was estimated using κ statistic. Effectiveness was explored using cohorts matched based on the risk prediction model. A total of 11,165 (6.2%) of 180,932 patients received prophylaxis. Those who received prophylaxis were more commonly post-pubertal and more severely injured. Receipt of prophylaxis was fairly concordant with the guideline (κ=0.32) and predicted risk of VTE (κ=0.29). Receipt of prophylaxis was associated with higher rates of VTE likely due to confounding by indication. Low molecular weight heparin seemed more effective against VTE than unfractionated heparin (incidence rate ratio: 0.52; 95% confidence interval: 0.36, 0.75), but less effective when received ≥72 hours after admission to the hospital. We showed that hospitalized injured children did not commonly receive prophylaxis. We also showed that prophylaxis may be effective in hospitalized injured children, but it needs to be proven definitively in a randomized clinical trial.

Venous thromboembolism prophylaxis after pediatric trauma

In recent years, there has been an increased focus on developing and validating venous thromboprophylaxis guidelines in the pediatric trauma population. We review the current literature regarding the incidence of and risk factors for venous thromboembolism (VTE) and the use of prophylaxis in the pediatric trauma population. Risk factors such as age, injury severity, central venous catheters, mental status, injury type, surgery, and comorbidities can lead to a higher incidence of VTE. Risk stratification tools have been developed to determine whether mechanical and/or pharmacologic prophylaxis should be implemented depending on the degree of VTE risk. When VTE risk is high, pharmacologic prophylaxis, such as with low molecular weight heparin, is often initiated. However, the timing and duration of VTE prophylaxis is dependent on patient factors including ambulatory status and contraindications such as bleeding. In addition, the utility of screening ultrasound for VTE surveillance has been evaluated and though they are not widely recommended, no formal guidelines exist. While more research has been done in recent years to assess the most appropriate type, timing, and duration of VTE prophylaxis, further studies are warranted to create optimal guidelines for decreasing the risk of VTE after pediatric trauma.