PB0050 - Heparin concentrations in pediatric patients with Paediatric Inflammatory Multisystem Syndrome associated with COVID-19. The measurement importance in the inflammatory state.

Background: In December 2019, the presence of a virus (SARS-COV2) with a high transmission rate was announced. Despite the global spread, epidemiological and clinical patterns of COVID-19 remain largely unclear, particularly among children. COVID-19-associated multisystem pediatric syndrome (PIMS) is a serious complication presented rarely in childhood. The Pediatric/Neonatal Subcommittee of the International Society of Thrombosis and Haemostasis suggests the initiation of thromboprophylaxis in patients severely affected by COVID-19.

Aims: Verify the heparin plasma concentration in the patient with PIMS in which a thromboprophylaxis heparin dose is administered.

Methods: An observational, descriptive study was carried out at the National Institute of Pediatrics, from April to September 2020.
Patients under 18 years old with a Multisystem Inflammatory Syndrome (PIMS) secondary to COVID-19 according to the WHO definition were included and received heparin as the international recommendations.

Results: A total sample of 61 pediatric patients diagnosed with COVID-19 was obtained, 20 patients (32.8%) were diagnosticated with PIMS, 18 received thromboprophylaxis, 16 pt (80%) LWMH, the remaining two patients received unfractionated heparin due to kidney damage.
The heparin plasma levels were performed in 93.7%, obtaining levels at 4 hrs, prophylactic in 62.5% of patients, requiring a dose adjustment in the rest of patients with an average dose of 1.97mgkgdo. Required a high dose of LMWH to achieve prophylactic levels.

Conclusion(s): PIMS affects children at a low rate.
Thromboprophylaxis in adults suggests usefulness in children
Doses should be monitored with anti-Xa factor, in this report there is a proportion of patients who required a higher dose of heparin to achieve prophylactic concentrations, reaching doses above the therapeutic dose.
The measurement of heparin levels is even more essential in acute inflammatory states where probably the high concentrations of fibrinogen, factor VIII, and the decrease in ATIII described in the patient with COVID-19 become important in the final plasma concentrations of heparin.