Validation of a venous thromboembolism prediction algorithm for pediatric trauma: A national trauma data bank (NTDB) analysis

Pediatric Orthopaedic Venous Thromboembolism: A Systematic Review Investigating Incidence, Risk Factors, and Outcome

Background

There is growing evidence of increased venous thromboembolism (VTE) incidence in children with trauma or infection. The purpose of this study was to conduct a systematic review of existing literature related to VTE in the pediatric orthopaedic population, to estimate the overall incidence of VTE and identify risk factors associated with this condition.

Methods

A systematic review of the available literature was performed to identify articles that described VTE in pediatric orthopaedic surgery or admission. Literature queries were performed to identify articles published from 1980 to 2021 that included patients ≤21 years of age. A stepwise search strategy of 5 electronic databases yielded 1,426 articles, which were filtered by 2 reviewers to identify 30 articles for full-text review. The primary aim was to determine the rate of VTE, and the secondary aim was to identify risk factors for VTE. The pooled incidence of VTE was estimated and reported in cases per 10,000. Studies were stratified by study size, by trauma versus elective surgery, and by orthopaedic subspecialty.

Results

The 30 articles reported 3,113 VTE events in 2,467,764 pediatric patients (including those with non-orthopaedic conditions), for a pooled VTE incidence of 20 events (95% confidence interval [CI] = 10.8 to 37.2) per 10,000. Four of the studies were excluded for incomplete data or high heterogeneity. The remaining 26 studies had 850,268 orthopaedic patients with 1,108 cases of VTE, for a pooled VTE incidence of 16.6 events (95% CI = 9.1 to 30.5) per 10,000. Studies with <10,000 patients and those involving a diagnosis of trauma had the highest VTE incidence when stratification was performed. The most frequently analyzed risk factors in 15 available studies included age, sex, obesity/body mass index, type of surgery, and use of a central venous catheter.

Conclusions

This systematic review indicated that the risk of VTE associated with pediatric orthopaedic surgery or admission remains low, at <17 events per 10,000 cases. However, orthopaedic surgeons should be aware of the most common risk factors associated with pediatric orthopaedic VTE and should pay special attention to traumatic etiologies, as these yielded the highest incidence.

Levels of Evidence

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Impact of institutional prophylaxis guidelines on rates of pediatric venous thromboembolism following trauma-A multicenter study from the pediatric trauma society research committee

BACKGROUND

A paucity of data exists with regard to the incidence, management, and outcomes of venous thromboembolism (VTE) in injured children. We sought to determine the impact of institutional chemoprophylaxis guidelines on VTE rates in a pediatric trauma population.

METHODS

A retrospective review of injured children (≤15 years) admitted between 2009 and 2018 at 10 pediatric trauma centers was performed. Data were gathered from institutional trauma registries and dedicated chart review. The institutions were surveyed as to whether they had chemoprophylaxis guidelines in place for high-risk pediatric trauma patients, and outcomes were compared based on the presence of guidelines using χ 2 analysis ( p < 0.05).

RESULTS

There were 45,202 patients evaluated during the study period. Three institutions (28,359 patients, 63%) had established chemoprophylaxis policies during the study period ("Guidelines"); the other seven centers (16,843 patients, 37%) had no such guidelines ("Standard"). There were significantly lower rates of VTE in the Guidelines group, but these patients also had significantly fewer risk factors. Among critically injured children with similar clinical presentations, there was no difference in VTE rate. Specifically within the Guidelines group, 30 children developed VTE. The majority (17/30) were actually not indicated for chemoprophylaxis based on institutional guidelines. Still, despite protocols only one VTE patient in the guidelines group who was indicated for intervention ended up receiving chemoprophylaxis prior to diagnosis. No consistent ultrasound screening protocol was in place at any institution during the study.

CONCLUSION

The presence of an institutional policy to guide chemoprophylaxis for injured children is associated with a decreased overall frequency of VTE, but this disappears when controlling for patient factors. However, the overall efficacy is impacted by a combination of deficits in guideline compliance and structure. Further prospective data are needed to help determine the ideal role for chemoprophylaxis and protocols in pediatric trauma.

LEVEL OF EVIDENCE

Therapeutic/Care Management; Level IV.

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.

Venous thromboembolic screening in pediatric trauma: A prospective cohort study of risk-stratified ultrasonography

BACKGROUND

This prospective observational cohort study evaluates risk-stratified venous thromboembolism (VTE) screening in injured children. While the reported incidence of VTE is 6% to 10% among critically injured children, there is no standard for screening. Venous thromboembolism may have long-term sequelae in children, including postthrombotic syndrome.

METHODS

Patients admitted to a level 1 pediatric trauma center were risk stratified for VTE using a validated prediction algorithm. Children at high risk (risk scores ≥523; i.e., ≥1% risk) received screening duplex ultrasonography. Children at moderate risk (risk scores 410-522; i.e., 0.3-0.99% risk) were screened as a comparison/control.

RESULTS

Three-hundred fifty-five children were consecutively risk stratified from October 2019 to May 2021. Forty-seven children received screening duplex ultrasounds: 21 from a high-risk cohort and 26 from a moderate-risk cohort. Four children were diagnosed with VTE in the high-risk cohort compared with seven in the moderate-risk cohort ( p = 0.53). Total incidence of VTE among screened children was 23.4% (11 of 47). Asymptomatic VTE accounted for 81.8% of all events (9 of 11). Fifty-four percent (6 of 11) of VTE were central venous catheter associated. Venous thromboembolism in surviving children resolved by 3 to 6 months with no symptoms of postthrombotic syndrome after 1 year. No cases of VTE were identified in unscreened children, yielding an institutional VTE incidence of 3.1% (11 of 355).

DISCUSSION

Risk-stratified screening demonstrates a significant incidence of asymptomatic VTE in injured children. These results may guide reevaluation of prediction algorithms developed from symptomatic VTE risk and longitudinal study of the sequelae of asymptomatic VTE.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level III.

Venous thromboembolic risk stratification in pediatric trauma: A Pediatric Trauma Society Research Committee multicenter analysis

BACKGROUND

Venous thromboembolism (VTE) in injured children is rare, but its consequences are significant. Several risk stratification algorithms for VTE in pediatric trauma exist with little consensus, and all are hindered in development by relying on registry data with known inaccuracies. We performed a multicenter review to evaluate trauma registry fidelity and confirm the effectiveness of one established algorithm across diverse centers.

METHODS

Local trauma registries at 10 institutions were queried for all patients younger than 18 years admitted between 2009 and 2018. Additional chart review was performed on all "VTE" cases and random non-VTE controls to assess registry errors. Corrected data were then applied to our prediction algorithm using 10 real-time variables (Glasgow Coma Scale, age, sex, intensive care unit admission, transfusion, central line placement, lower extremity/pelvic fracture, major surgery) to calculate VTE risk scores. Contingency table classifiers and the area under a receiver operator characteristic curve were calculated.

RESULTS

Registries identified 52,524 pediatric trauma patients with 99 episodes of VTE; however, chart review found that 13 cases were misclassified for a corrected total of 86 cases (0.16%). After correction, the algorithm still displayed strong performance in discriminating VTE-fated encounters (sensitivity, 69%; area under the receiver operating characteristic curve, 0.96). Furthermore, despite wide institutional variability in VTE rates (0.04-1.7%), the algorithm maintained a specificity of >91% and a negative predictive value of >99.7% across centers. Chart review also revealed that 54% (n = 45) of VTEs were directly associated with a central line, usually femoral (n = 34, p < 0.001 compared with upper extremity), and that prophylaxis rates were underreported in the registries by about 50%; still, only 19% of the VTE cases had been on prophylaxis before diagnosis.

CONCLUSION

The VTE prediction algorithm performed well when applied retrospectively across 10 diverse pediatric centers using corrected registry data. These findings can advance initiatives for VTE screening/prophylaxis guidance following pediatric trauma and warrant prospective study.

LEVEL OF EVIDENCE

Clinical decision rule evaluated in a single population, level III.

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.

Significant practice variability exists in the prevention of venous thromboembolism in injured children: results from a joint survey of the Pediatric Trauma Society and the Trauma Center Association of America

BACKGROUND/PURPOSE

The purpose of this study was to characterize current practices to prevent venous thromboembolism (VTE) in children and measure adherence to recent joint consensus guidelines from the Pediatric Trauma Society and Eastern Association for the Surgery of Trauma (PTS/EAST).

METHODS

An 18-question survey was sent to the membership of PTS and the Trauma Center Association of American. Responses were compared with Chi-square test.

RESULTS

One hundred twenty-nine members completed the survey. Most respondents were from academic (84.5%), Level 1 pediatric (62.0%) trauma centers. Criteria for VTE prophylaxis varied between hospitals with freestanding pediatric trauma centers significantly more likely to stratify children by risk factors than adult trauma centers (p = 0.020). While awareness of PTS/EAST guidelines (58.7% overall) was not statistically different between hospital types (44% freestanding adult, 52% freestanding pediatric, 71% combined adult pediatric, p = 0.131), self-reported adherence to these guidelines was uniformly low at 37.2% for all respondents. Lastly, in three clinical scenarios, respondents chose VTE screening and prophylaxis plans in accordance with a prospective application of PTS/EAST guidelines 55.0% correctly.

CONCLUSION

Currently no consensus regarding the prevention of VTE in pediatric trauma exists. Prospective application of PTS/EAST guidelines has been limited, likely due to poor quality of evidence and a reliance on post-injury metrics. Results of this survey suggest that further investigation is needed to more clearly define the risk of VTE in children, evaluate, and prospectively validate alternative scoring systems for VTE prevention in injured children.

LEVEL OF EVIDENCE

N/A-Survey.