ObjectivesDescribe clinical characteristics and outcomes including transfusion requirements of pediatric patients with congenital heart disease undergoing aspiration thrombectomy DesignRetrospective chart review SettingQuaternary academic children's hospital ParticipantsPatients < 18yrs with congenital heart disease undergoing aspiration thrombectomy from November 2017-February 2022. Measurements and main results13 patients underwent mechanical thrombectomy with the Penumbra Indigo System®. Median age was 3.8 years and median weight was 15.2kg. Seven patients had palliated single ventricle and 6 had biventricular circulation. Nine patients were receiving ICU care pre-procedure and 12 required ICU care post-procedure. Indications for thrombectomy included systemic venous thrombus (n=7), pulmonary arterial thrombus (n=3), systemic arterial thrombus (n=2), and systemic to pulmonary shunt occlusion (n=1). Median estimated blood loss was 7.7ml/kg (interquartile range 1.4ml/kg-15.8ml/kg, range 0.5ml/kg-51.5ml/kg). Seven patients required intraoperative transfusion of pRBCs (n=4), FFP (n=2), platelets (n=3), and/or cryoprecipitate (n=1). In those requiring transfusion, median transfusion volume was 22ml/kg (interquartile range 15.5ml/kg-76.5ml/kg, range 9.3ml/kg-132.8ml/kg). Thrombectomy was successful in 8 of 13 patients, although 3 experienced recurrent thrombosis. ConclusionsMechanical aspiration thrombectomy is increasingly used to treat critically ill pediatric patients and presents unique anesthetic considerations particularly related to the need for volume and blood product resuscitation