Treatment of VTE with rivaroxaban in adolescents – long-term results from the prospective Dresden NOAC Registry (NCT01588119)

Introduction The effectiveness and safety of acute venous thromboembolism (VTE) treatment with rivaroxaban in adolescents, demonstrated in phase-III trials, needs to be confirmed in daily care.

Method Since 2012 (even before rivaroxaban was approved for under-aged patients), a prospective cohort of adolescent VTE patients treated with rivaroxaban was enrolled into the Dresden NOAC Registry. All patients and their legal representatives provided informed consent to participate in the registry and for off-label treatment with rivaroxaban. In our registry, all patients receive quarterly phone visits by the registry office. All suspected outcome events are centrally adjudicated using standard scientific definitions.

Results Until 31st August 2022, 29 adolescents receiving rivaroxaban for VTE were enrolled (23 female, 6 male, mean age 15.6±1.1 years, mean BMI 22.3±3.7 kg/m²). None of the patients reported a previous VTE. 11 patients (37.9%) had a family history for VTE. 22 of 23 female patients received hormonal contraception at time of VTE. 16 patients were carriers of thrombophilia, 8 were tested negative and the remaining 5 patients were not tested so far.

Fig. 1  Time-frequency-plot of anticoagulation status; Time-frequency-plot of anticoagulation status, recurrent VTE, ISTH major and clinically relevant non-major bleeding

Median time between VTE diagnosis and initiation of rivaroxaban was 12 d (inter-quartile range [IQR] 6/35 d); a total of 9 patients started rivaroxaban within the first week after VTE diagnosis.

Median rivaroxaban exposure was 18 months (range 6.2-39.8 months). During follow-up (median 82.4 months; IQR 48.7/100.5 months), 8 recurrent VTE occurred in 5 patients ([Fig. 1]). Patient 13 experienced a late VTE recurrence (no anticoagulation) as distal DVT. Patient 18 experienced a late recurrence of an iliac DVT (due to incompliance) in the context of May-Turner syndrome and Type I protein C deficiency. Patient 19 experienced two early thrombotic stent occlusions after scheduled May-Turner Stenting 18d after index event (both events occurred during heparin bridging following catheter thrombolysis). Patient 21 experienced 2 recurrent thrombotic iliac vein stent occlusions (due to incompliance) and a late distal DVT (no anticoagulation). Patient 25 experienced a late VTE recurrence (popliteal vein DVT; no anticoagulation).

19 patients reported a total of 54 bleeding events. Of these 37 were ISTH minor and 16 were ISTH non-major clinically relevant bleeding. One major bleeding occurred (enteral bleeding with haemoglobin drop in acute ulcerative colitis).

Conclusion Rivaroxaban treatment for VTE seems feasible and effective also in adolescent patients, in whom the prevalence of thrombophilia and a positive family history for VTE is high. However, bleeding complications are common with rivaroxaban exposure and recurrent VTE events are predominantly ssen in complex iliac vein thrombosis, in incompliant patients and after stopping anticoagulation, indicating a complex patient selection. As a consequence, VTE treatment of under-aged patients should ideally be performed in specialized anticoagulation clinics.

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Artikel online veröffentlicht:
20. Februar 2023