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Venous thromboembolism [TE] is a multifactorial disease and antithrombin deficiency [ATD] constitutes a major risk factor. In the present study the prevalence of ATD and the clinical presentation at TE onset in a cohort of paediatric index cases are reported. In 319 unselected paediatric patients (0.1-18 years) from 313 families, recruited between July 1996 and December 2013, a comprehensive thrombophilia screening was performed along with recording of anamnestic data. 21 of 319 paediatric patients (6.6%), corresponding to 16 of 313 families (5.1%), were AT-deficient with confirmed underlying AT gene mutations. Mean age at first TE onset was 14 years (range 0.1 to 17). Thrombotic locations were renal veins (n=2), cerebral veins (n=5), deep veins (DVT) of the leg (n=9), DVT & pulmonary embolism (n=4) and pelvic veins (n=1). ATD co-occurred with the factor-V-Leiden mutation in one and the prothrombin G20210A mutation in two children. In 57.2% of patients a concomitant risk factor for TE was identified, whereas 42.8% of patients developed TE spontaneously. A second TE event within primarily healthy siblings occurred in three of 313 families and a third event among siblings was observed in one family. In an unselected cohort of paediatric patients with symptomatic TE, the prevalence of ATD adjusted for family status was 5.1%. Given its clinical implication for patients and family members, thrombophilia testing should be performed and the benefit of medical or educational interventions should be evaluated in this high risk population.

Within the last two decades low molecular weight heparins (LMWH) have gained increasing widespread use as anticoagulants in children. The use of LMWH has been implemented into clinical care even though there is a lack of firm evidence on the efficacy and safety of LMWH in this population due to the absence of sufficiently powered randomized controlled trials. In the absence of clinical trials, we performed a meta-analysis of available single-arm studies using LMWH in children. A systematic search of electronic databases (Medline, EMBASE, OVID, Web of Science, The Cochrane Library) for studies published from 1980 to 2010 was conducted using keywords in combination both as MeSH terms and text words. Two authors independently screened citations and those meeting a priori defined inclusion criteria were retained. Data on year of publication, study design, country of origin, number of patients, ethnicity, venous thromboembolic events type, and frequency of recurrence and major bleedings were abstracted. Pooled incidence rates (IR) including 95% confidence intervals (95% CIs) on efficacy and safety data of LMWH administration on primary prophylaxis, as well as on secondary prophylaxis in children following symptomatic thromboembolism (TE) were shown. We included 2251 pediatric patients derived from 35 single-arm studies from 12 study countries who were eligible for analysis in the present systematic review. Pooled incidence rates (95% CI) to develop first TE on primary prophylaxis, further TE event on LMWH secondary prophylaxis, or a major bleeding event on LMWH were 0.047 (0.023 to 0.091), 0.052 (0.037 to 0.073) for efficacy, and 0.054 (0.039 to 0.074) for safety (treatment data only), respectively. Efficacy and safety data are comparable with adult data. The present systematic review suggests that use of LMWH in children as primary prophylaxis and in treatment of symptomatic thrombosis is effective and safe. However, properly designed randomized controlled trials are needed., (© Thieme Medical Publishers.)

In patients with von Willebrand disease (VWD) replacement therapy with factor VIII/von Willebrand (VWF) concentrates is increasingly applied as prophylactic regimen. Since 2000, 82 consecutively enrolled patients with clinically relevant bleeding episodes (spontaneous, peri- or postoperative) were diagnosed with VWD [type 1: 42/82; type 2: 24/82; type 3: 13/82; acquired: 3/82]. In all patients, decision for initiating prophylaxis was based on a bleeding score > 2 prior to diagnosis, concomitant with recurrent bleeds associated with anaemia in patients with on-demand VWD therapy. We report results on secondary prophylactic VWF replacement therapy applied in 32 patients [children n=13; adolescents n=7; adults n=12] with VWD [type 1: 4; type 2: 15; type 3: 13], 15 of which were females, and nine of these at the reproductive period. Eight patients were treated with Humate P® or Wilate® (n=24). Median [min-max] dose [vWF:RCo] was 40 [20-47] IU/kg, 23 patients were given substitution therapy twice weekly, seven patients three times a week, and two children four times per week. Within a 12-month-period haemoglobin concentrations returned to normal values. Median duration of prophylaxis was three years. Recurrent bleeding episodes stopped in 31 of 32 patients, whereas inhibitors developed in one. Following a 12-month observation period the monthly bleeding frequency and the bleeding score was significantly reduced [3 vs. 0.07; 3 vs. 0: p< 0.001], compared to the pre-prophylaxis/pre-diagnostic values. The use of secondary prophylactic VWF replacement therapy is an effective tolerated treatment modality, highly beneficial for patients with VWD, who present with recurrent bleeding events during on-demand therapy.