Post-thrombotic syndrome in children

Management options for pediatric venous thromboembolic disease: Beyond anticoagulation with endovascular therapies

Venous thromboembolism (VTE) in pediatric patients is an uncommon but serious diagnosis that has an array of therapeutic options and challenges. An assessment of the existing literature on management of pediatric patients with VTE was conducted. The interventions reviewed include anticoagulation, thrombolysis, thrombectomy, inferior vena cava (IVC) filters, and venous stenting. For each intervention, a discussion of mechanism of action, indications, contraindications, and potential complications was performed. While anticoagulants are considered the first-line pediatric VTE treatment, many drugs remain investigational in this patient population and treatment recommendations are extrapolated from adult practice. Thrombolysis may be indicated in cases of acute thrombosis requiring more rapid clot resolution but presents a greater bleeding risk than anticoagulation. Similarly, thrombectomy also provides rapid clot resolution and offers a larger therapeutic window and usage in more mature thrombi than thrombolysis. In select patient groups, IVC filters may be indicated in the prevention of PE but present with inherent thrombogenicity and risk of migration. The data regarding pediatric VTE treatment options, monitoring, and long term outcomes is limited compared to the adult population. The relatively few clinical trials including pediatric patients have a relatively small sample size and are heterogenous with regards to predisposing factors that further exacerbate generalizability. Additional research is needed to help construct and evaluate a robust treatment algorithm for pediatric patients with VTE.

Current Diagnostic and Therapeutic Approaches in May-Thurner Syndrome in Children, Adolescents, and Young Adults: A Survey among Thrombosis Experts of the German Society of Thrombosis and Haemostasis

May-Thurner syndrome (MTS) is a pelvic venous disorder involving compression of the left common iliac vein by the right common iliac artery, which results in predisposition for deep vein thrombosis. Although MTS is increasingly recognized in young patients, specific guidelines on diagnosis and management for children, adolescents, and young adults do not exist so far. The aim of this study was to assess current diagnostic and therapeutic practice in Germany, Austria, and Switzerland in children and young adults with thrombosis and MTS.We designed an online survey with 11 questions, which we sent via a mailing list to all members of the German, Austrian, and Swiss Society of Thrombosis and Haemostasis Research. Between July and October 2022, 33 specialists answered the questionnaire. Most participating specialists worked at pediatric hospitals (61%). Numbers of annually treated thromboses ranged from <5 (26%) to >30 (13%). Most specialists used venous ultrasound to diagnose deep vein thrombosis, 53% magnetic resonance imaging. Only 25% of specialists systematically screened for MTS in deep vein thrombosis. MTS was managed with anticoagulation (65%), iliac vein stent placement (32%), or balloon angioplasty (13%). In total, 31% of specialists reported to use more than one therapeutic method. Diagnostic and therapeutic approaches for MTS differed between specialists. Lack of standardization resulted in individualized and highly diverse management. Prospective observational clinical studies investigating the outcome of different management strategies including long-term follow-up on outcome and incidence of postthrombotic syndrome will help in defining patient groups who benefit most from revascularizing interventional strategies and developing standardized guidelines.

Unraveling the pathophysiology of lower-limb postthrombotic syndrome in adolescents: a proof-of-concept study

A better understanding of the pathophysiology of pediatric postthrombotic syndrome (PTS) is needed to develop strategies to treat this condition. We investigated calf pump function, exercise capacity, balance in power output, and changes in limb muscle oxygen saturation (SmO2) and fluid content during exercise in 10 pediatric patients with unilateral lower-limb PTS, and in age- and sex-matched controls (1:1-1:2 ratio). Outcomes were investigated using bioimpedance spectroscopy, torque-sensing pedals, and near-infrared spectroscopy during incremental- and constant-load cycling tests. The median age at participation was 17 years (25th-75th percentile, 15-18 years); 68% of participants were females. The median CAPTSure score in the affected leg of affected participants was 35 points (25th-75th percentile, 24-46 points), indicating moderate/severe PTS; 20% of patients had a history of central venous catheter-related thrombosis. Increasing PTS severity was associated with higher calf pump venous volume and higher ejection volume, leading to compensated calf pump performance. We found no evidence of PTS impact on exercise capacity. Leg contribution to power output was similar in affected and unaffected legs. However, the PTS-affected legs showed lower SmO2 during active cycling and recovery with increasing PTS severity, indicating impaired microvascular function in the muscle. These findings suggest that PTS severity is associated with impaired blood flow, presumably from elevated venous pressure during and after exercise. The fact that microvascular function is impaired in young patients with PTS underscores the relevance of developing strategies to mitigate the effects of this chronic vascular disease to minimize its deleterious effects as children grow older.

Risk of venous thromboembolism in pediatric hospitalized patients undergoing noncardiac surgery: A report from the Children's Hospital-Acquired Thrombosis consortium

Background

Surgery is a known risk factor for hospital-acquired venous thromboembolism (HA-VTE) in children.

Objectives

To assess whether the odds of HA-VTE differs across six anatomic sites of noncardiac surgery and to identify risk factors for HA-VTE in these children.

Methods

This was a multicenter, case-control study. Anatomic sites of surgery and risk factors for HA-VTE were collected on hospitalized pediatric patients who had undergone a single noncardiac surgery and developed HA-VTE (cases), and those who did not develop HA-VTE (controls), via the Children's Hospital-Acquired Thrombosis (CHAT) Registry. Logistic regression estimated the odds ratio (OR) and 95% confidence intervals (CIs) between six anatomic sites of surgery and 16 putative HA-VTE risk factors. Variables with a p value of 0.10 or less in unadjusted analyses were included in adjusted models for further evaluation. The final model used backward selection, with a significance level of 0.05.

Results

From January 2012 to March 2020, 163 cases (median age, 5.7 years; interquartile range [IQR], 0.3-14.2) and 208 controls (median age of 7.5 years; IQR, 3.7-12.9) met our criteria. There was no statistically significant increased odds of VTE among the types of noncardiac surgery. In the final adjusted model, central venous catheter (CVC; OR, 14.69; 95% CI, 7.06-30.55), intensive care unit (ICU) stay (OR, 5.31; 95% CI, 2.53-11.16), and hospitalization in the month preceding surgery (OR, 2.75; 95% CI, 1.24-6.13) were each independently significant risk factors for HA-VTE.

Conclusion

In children undergoing noncardiac surgery, placement of CVCs, admission/transfer to the ICU, or hospitalization in the month prior to surgery were positively associated with HA-VTE.

Direct oral anticoagulants versus standard anticoagulation in children treated for acute venous thromboembolism

Direct oral anticoagulants (DOACs) are widely used to treat venous thromboembolism (VTE) in adults. Little attention is given to pediatric VTE (PVTE). The objective of this study is to study the efficacy and safety of DOACs in published PVTE randomized control trials (RCTs). PubMed, Embase, China National Knowledge Infrastructure, the Cochrane Library, SinoMed, and ClinicalTrials.gov were searched until 2021, to identify RCTs that enrolled patients with VTE <18 years of age who received DOACs versus standard anticoagulation. Outcomes were evaluated using the Mantel-Haenszel method of random-effects model. Our study evaluated seven RCTs that included 1139 cases of PVTE, which had a low risk of publication and assessment bias. Compared with standard anticoagulation, patients receiving DOACs presented a lower rate of recurrent VTE (relative risk [RR], 0.42 [confidence interval {CI}, 0.20 to 0.89]), similar mortality rate (RR, 0.50 [CI, 0.07 to 3.57]), major bleeding (RR, 0.46 [CI, 0.14 to 1.57]), and higher clinically relevant nonmajor bleeding (RR, 2.71 [CI, 1.05 to 7.02]) with low heterogeneity. Limiting to subgroups, dabigatran and rivaroxaban yielded similar findings, except for a higher incidence of nonmajor bleeding during rivaroxaban use. DOACs could be an alternative to standard anticoagulation in PVTE. Dabigatran and rivaroxaban have similar effects. IMPACT: In venous thromboembolism (VTE), direct oral anticoagulants (DOACs) are widely used as a substitution for standard anticoagulation in most situations for adults; however, little attention is paid to the pediatric population. For pediatric VTE, previous meta-analyses have emphasized the epidemiology, risk factors, and the use of traditional anticoagulants, and seldom reported the use of novel oral anticoagulants. This is the first meta-analysis of randomized controlled trials that focuses on the efficacy outcomes and safety endpoints of DOACs compared with standard anticoagulation in pediatric VTE.

Central venous catheter-associated complications in pediatric patients diagnosed with Hodgkin lymphoma: implications for catheter choice

Purpose

The purpose of this study was to determine the most optimal central venous catheter (CVC) for pediatric patients with Hodgkin lymphoma (HL) in terms of complications.

Methods

A retrospective study including patients diagnosed with HL from 2015 to 2021 at the Princess Máxima Center was performed. Patients were followed from CVC insertion until removal or 06–2021, whichever came first. The primary outcome was the CVC-related complication incidence rate (IR) per 1000 CVC-days. Furthermore, the incidence rate ratio (IRR) was calculated by comparing complication IRs between peripherally inserted central catheters (PICC) and totally implantable venous access ports (TIVAP). Additionally, risk factors for central venous thrombosis (CVT) were identified.

Results

A total of 98 patients were included. The most frequently observed complications were local irritation/infections (18%; IR 0.93), malfunctions (15%; IR 0.88), and CVC-related CVTs (10%; IR 0.52). Single lumen PICCs were associated with a higher risk of complications (49% vs. 26%; IRR 5.12, CI95% 2.76–9.50), severe complications (19% vs. 7%; IRR 11.96, CI95% 2.68–53.42), and early removal (18% vs. 7%; IRR 9.96, CI95% 2.18–45.47). A single lumen PICC was identified as a risk factor for CVC-related CVT when compared to TIVAPs (12% vs. 7%, IRR 6.98, CI95% 1.45–33.57).

Conclusion

The insertion of a TIVAP rather than a PICC should be recommended for pediatric patients with HL, especially in the presence of CVT-related risk factors. Future trials should evaluate the efficacy and safety of direct oral anticoagulants for the primary prevention of CVT in pediatric patients with a PICC and other CVT-related risk factors.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00520-022-07256-3.

Thrombosis in Children: Approach to Anatomic Risks, Thrombophilia, Prevention, and Treatment

Pediatric venous thromboembolism (VTE) is increasing in incidence but minimal data exist for best practices regarding therapy, use of thrombophilia testing, and management of long-term complications. Classification schema use anatomic location and presence of clinical or thrombophilic inciting factors. There are a small number of risk-assessment and risk-modeling systems for incident VTE, but all suffer from low numbers, single-institution design, and lack of prospective validation. Acute treatment is limited to heparin products and thrombolysis may be indicated in specific situations. In addition, chronic postthrombotic comorbidities are expected to increase in incidence and lack evidence-based treatment paradigms.