There is a lack of epidemiological data regarding pediatric venous thromboembolism (VTE) in Brazil.

A registry to evaluate the incidence of VTE in hospitalized children (0 to 16 years) in a southeastern Brazilian city.

A prospective multicenter study initially involving two tertiary hospitals, a pediatric cancer (Boldrini) and a nursery with ICU (Clinical Hospital, UNICAMP), in Campinas, SP-Brazil. All hospitalized patients were evaluated daily, through access to each patient's electronic medical record and those with a diagnosis of VTE by an objective method were included. All patients with a central venous catheter (CVC) were carefully observed and should undergo doppler ultrasound (US) with any sign of VTE. There was no search for asymptomatic VTE.

During Sept2018 to Feb2021, 971 children were hospitalized and 21 cases of VTE were diagnosed, an incidence of 2.1/100 hospital admissions. Demographic and risk factors associated with VTE in children with and without VTE were: bed immobilization 64.4% in non VTE versus 57.1% in VTE patients; The majority of patients with VTE did not make surgery during hospitalization (19% vs. 36.9% in no VTE patients). The VTE patients did not suffer trauma. In relation to CVC 38.1% of patients with VTE presents CVC vs. 27.6% of non VTE patients. The hospitalization time was higher in the group of non VTE mean of 33 days in comparison to 12 days for VTE group. The VTE group presented a higher the necessity of intensive care unit (ICU) 66.7% vs. 32.3% for non VTE group. VTE was located in the upper (n = 8/38.1%) or lower limbs (n = 10/47.6%), portal vein (n = 1/4.8%), and pulmonary embolism (n = 1/4.8%). Regarding presentation, 6 (28.6%) were incidental, 2 (9.5%) malfunctioning CVC and 13 (61.9%) with common signs of VTE. VTE was associated with CVC in 10 (47.6%) cases. The time between CVC insertion and VTE diagnosis was 22.1 days (±43.2). The time between symptoms/diagnosis was 2.5 (±2.5) days. Risk factors for VTE were found in 95% of the children, represented by immobilization (42.8%), infection (66.7%), surgery or intravascular procedure (38.1%), ICU (61.9%) and CVC (47.6%). Corticosteroids and asparaginase were more commonly used in VTE patients (33.3% and 4.8% vs. 22.1% and 0.1%, respectively). Therapeutic anticoagulation was used only in 13 (61.9%) patients, because of thrombocytopenia in those with cancer.

Preliminary data from the first Brazilian VTE pediatric registry indicate it is prevalent among hospitalized children, and largely associated to CVC. Approved by Ethics Research Committee of Unicamp.