Risk of venous thromboembolism after discontinuing prophylactic or therapeutic anticoagulation in patients with haematologic malignancies because of thrombocytopenia.

Although the rates of thrombocytopenia in patients with hematologic malignancies are well known, clinical reports of patients with haematological malignancies presenting with thrombocytopenia who developed venous thromboembolism (VTE) are rare. Defining the risk of VTE in patients with hematologic malignancies in whom anticoagulation is discontinued could help to individualize concepts of anticoagulation. We performed a retrospective analysis of medical records of patients with hematologic malignancies and thrombocytopenia grade 3 (25 × 10⁹/L to < 50 × 10⁹/L) or more severe in 2019-2022 in the Department of Haemato-Oncology at HELIOS Klinikum Krefeld. Data from 67 patients (34 (51%) males, 33 (49%) females) aged between 22 and 82 years (38 leukaemia, 23 lymphoma, 6 other) were included. Prophylactic anticoagulation was performed in 59 (88%) patients and therapeutic due to atrial fibrillation in 8 (12%). Anticoagulation was discontinued in 37 (55%) patients due to thrombocytopenia. Thrombotic events occurred in eight (12%) and minor bleeding in two (3%) patients. Seven patients developed a deep vein thrombosis (DVT) or superficial vein thrombosis (SVT) of the upper limbs, only one patient had a thrombosis of the femoral veins. Thrombotic event were much more frequent in patients suffering from leukaemia compared to lymphoma. Two thrombotic events occurred despite continued prophylaxis (2 of 30, 6.6%), the other six after discontinuing of anticoagulation (6 of 37, 16.2%). Both bleedings occurred in the group with continued anticoagulation. Five of the six patients with a thrombotic event, but without anticoagulation, received anticoagulation again despite a low platelet count and no bleeding was observed. Only one patient with jugular vein thrombosis and a platelet count around 4 × 10⁹/L remained without anticoagulation and no thrombus formation was observed. Risk of VTE in our patients with haematologic malignancies in whom anticoagulation is discontinued due to thrombocytopenia grade 3 is about 2.5 times higher than in patients in whom anticoagulation is continued and predominantly affects patients with leukaemia and upper extremity.