Prevalence and outcomes of thrombotic and hemorrhagic complications in pediatric acute promyelocytic leukemia in a tertiary Brazilian center

INTRODUCTION: Little attention is given to thrombosis associated with pediatric acute promyelocytic leukemia (APL). This study describes the thrombotic and hemorrhagic manifestations of APL in pediatric patients and evaluates their hemostasis, based on coagulation tests. METHODS: Inclusion criteria were age 0–18 years and APL diagnosis between April 2005 and November 2017. Patients who had received blood transfusion prior to coagulation tests were excluded. Baseline coagulation tests, hematologic counts, and hemorrhagic/thrombotic manifestations were evaluated. RESULTS: Median age was 10.7 years (1–15 years). The initial coagulation tests revealed a median Hgb of 8.3 g/dL (4.7–12.9 g/dL), median leucocyte count of 10.9 × 10⁹/L (1.1–95.8 × 10⁹/L), median platelet count of 31.8 × 10⁹/L (2.0–109.0 × 10⁹/L), median activated partial thromboplastin time (aPTT) of 31.7 s (23.0–50.4 s), median aPTT ratio of 1.0 (0.78–1.6), median thromboplastin time (PT) of 17.5 s (13.8–27.7 s), median PT activity of 62% (25–95 %), and median fibrinogen of 157.7 mg/dL (60.0–281.0 mg/dL). Three patients (13%) had thrombosis. At diagnosis, 21 patients (91.3%) had bruising, one patient (4.3%) had splenic vein and artery thrombosis and one patient (4.3%) presented without thrombohemorrhagic manifestations. During treatment, two patients (8.6%) had thrombosis. CONCLUSION: Knowledge of thrombosis in pediatric APL is important to determine its risk factors and the best way to treat and prevent this complication.