PF286 EARLY ADMISSION IN INTENSIVE CARE UNIT IS ASSOCIATED WITH LOWER MORBIDITY AND MORTALITY IN ACUTE MYELOID LEUKEMIA WITH HYPERLEUKOCYTOSIS: A RETROSPECTIVE ANALYSIS

Background: Patients presenting with acute myeloid leukemia (AML) at diagnosis are at high risk of severe complications and death, particularly with high white blood cell (WBC) count. Intimate collaboration between hematologists and intensive care unit (ICU) specialists is crucial. Late admission to ICU in critical situation is associated with poor prognosis 1 . Aims: The primary purpose of this study was to evaluate interest of early support in ICU in terms of morbidity (use of life‐sustained therapy) and mortality. The secondary purpose was to highlight the risk factors of secondary transfer in ICU. Methods: All patients aged >18 years who received intensive chemotherapy for AML with hyperleukocytosis (HL) (Defined by WBC > 50000/mm3) in our department between 2008 and 2016 were included. Since 2012, the most of patients presenting with HL AML are primary referred in ICU for the diagnostic work‐up and the induction chemotherapy. They are transferred later in Hematology department for the following support. These patients are designated as “Primary ICU”. Before 2012, patients with suspicion of HL AML were referred in Hematology department to engage chemotherapy. This group of patients has been allocated into two subgroups, depending on necessity of a secondary transfer in ICU for complication during induction (“Secondary ICU”) or not (“No ICU”). To avoid bias related to very‐early mortality in the most serious patients, those admitted in ICU for initial organ failure before diagnosis and initiation of chemotherapy were excluded. Results: One hundred fifty‐four patients were included: 77 (50%) were allocated to the group “No ICU”, 18 (12%) to “Secondary ICU” and 59 (38%) to “Primary ICU”. The group “Primary ICU” showed a higher WBC than the other groups (140 G/L vs 74 in the group “No ICU” and 68 in “Secondary ICU”, p   =   0.038 ). Early mortality was higher in the group “Secondary ICU” than in the groups “Primary ICU” and “No ICU”, with mortality at day 7 of 16.6%; 10.2% and 1.3% respectively and mortality at day 30 of 27.8%; 16.9% and 2.6% respectively. Only 6 of 59 (10.2%) patients in the “Primary ICU” group needed to be re‐transferred in ICU for complications linked to aplasia (transfers occurred from day 6 to day 31). Three of them (50%) were dead at day 30. One of the 18 patients (5.5%) in the group “Secondary ICU” needed a second transfer in ICU, at day 27 and was alive at day 30. The group “Secondary ICU” required more frequently life‐sustained therapy than the group “Primary ICU”: There was an increased use of mechanical ventilation (MV) (44.4% vs 18.6%, p   =   0.027 ), vasopressive therapy (33.3% vs 11.9%, p   =   0.035 ) and renal replacement therapy (RRT) (11.1% vs 5.1%, p   =   0.37 ). When we compare “Secondary ICU” group and “No ICU” group, the risk factors of ICU transfer were leukostasis (33% vs 6%, p   =   0.001 ) and biological disseminated intravascular coagulation (DIC) (38.9% vs 11.7%, p   =   0.006 ). The use of Hydroxyurea for reduction of tumor burden previous to chemotherapy seems to be protector of ICU transfer (46.7% in “No ICU” group vs 22.2% in “Secondary ICU” group, p   =   0.059 ). Summary/Conclusion: Early referral to ICU seems an effective strategy to reduce early morbidity and mortality for HL AML at diagnosis in this study. A drastically shortened length of support of hemopathy‐related complications in ICU was observed. Patients with AML 4/5 according to FAB with leukostasis or DIVC seem to benefit the most of this strategy.