Real-world practices in the management of pediatric iliofemoral deep vein thrombosis, results of the elite-kids survey from the CHAT consortium Free

Background Deep vein thrombosis (DVT) of the extremities is the most common presentation of venous thromboembolism (VTE) in children. While anticoagulation remains a mainstay of management, DVT location and severity may warrant multimodal therapy, including the use of endovascular intervention (e.g. mechanical thrombectomy [MT] or catheter-directed thrombolysis [CDT]), particularly in pediatric patients with severe iliofemoral DVT (IF-DVT) with/without May-Thurner Syndrome (MTS). Nevertheless, there is a paucity of evidence on endovascular interventions in this patient population, with a lack of evidence on the safety and efficacy of different modalities in pediatric patients, leading to the absence of management consensus and heterogeneity of clinical practice.

Aim To characterize the management practices, including the use of endovascular interventions, in pediatric patients presenting with severe IF-DVT, with/without MTS. We hypothesize that there is substantial variability in the use of endovascular interventions and modality preferences.

Methods As part of the ELITE-Kids study (Endovascular Limb Intervention for Thrombosis, Evaluation in Kids), a Qualtrics survey was emailed to pediatric hematologists practicing at 65 institutions, part of the Children's Healthcare Advancements in Thrombosis (CHAT) consortium (May 5^th to June 30^th, 2025). The survey was approved by the Johns Hopkins All Children's Hospital IRB. Descriptive statistics were used to summarize results.

Results The response rate was 58% (69 emailed surveys, 40 total responses, 35 complete responses analyzed). Amongst responders, 77% had ≥6 years of experience, with 86% practicing in academic children's hospitals. All the responders had the resources to provide endovascular interventions for the management of pediatric VTE, and most (97%) reported its use for select patients with severe IF-DVT. Most common clinical factors considered for the use of endovascular management were presence of severe symptoms (24%) and concern for either limb ischemia or MTS (both at 20%).

For patients with IF-DVT without MTS, pharmacomechanical CDT (PCDT) was the most commonly recommended endovascular modality (44%), followed by CDT (35%), and 12% for MT alone (without the use of thrombolytic agents). Similarly, for patients with MTS, PCDT was most frequently recommended (41%), followed by CDT (29%), and MT alone (18%). In all cases of MTS, endovascular approaches included balloon angioplasty with/without iliac stent placement.

When assessing the use of MT alone as first-line therapy, 45% of respondents recommend this modality always or sometimes, 27% rarely, and 21% never. Amongst those who reported the use of MT alone in the past, 61% reported acceptable outcomes with rare DVT recurrences.

Regarding the use of iliac stents for patients with IF-DVT and MTS, 45% would recommend upfront placement only for select patients, 12% do not/very rarely recommend it, and 6% recommend it for all patients. Amongst those recommending iliac stent placement in select patients, the most common clinical factors considered were age/size of the patient (60%) and degree of iliac vein compression (47%), with most deferring the decision to the interventionalist (80%). Timing of iliac stent placement was also deferred to the interventionist by 69% of responders.

Concomitant anticoagulation (AC) with unfractionated heparin at prophylactic dosing during endovascular intervention was reported by 63%. Preferred outpatient therapy included direct oral anticoagulants (53%) and low molecular weight heparin (23%). For patients without an iliac stent, most common duration of therapeutic AC was 6-12 weeks (47%), with 37% reporting longer durations. Amongst those with an iliac stent, 53% reported AC for at least 6 months, and 45% would recommend the use of concurrent antiplatelets during and/or after the course of AC therapy.

Conclusion This survey of pediatric hematologists revealed heterogeneity in endovascular management practices and use of conventional AC therapy in pediatric patients with IF-DVT, with/without MTS. These findings highlight the need for collaborative multicenter cohort studies and registries evaluating the safety and efficacy of endovascular interventions in pediatric IF-DVT that can inform future treatment guidelines.