Platelet transfusion and anticoagulation in hematological cancer-associated thrombosis and thrombocytopenia: The CAVEaT multicenter prospective cohort

Background Venous thromboembolism (VTE) in patients with thrombocytopenia represents a complex management challenge. Objectives To describe practice, document outcomes, and compare management to national guidelines. Methods We present a prospective multicenter cohort of 105 patients with hematological cancer, VTE within 28 days, and platelets <50 x 10(9)/L from May 14, 2019 to April 24, 2021 from 20 sites. Results Median age was 64 and median initial platelet count 28 x 10(9)/L. Thromboses were: 46% catheter-associated, 11% lower limb, 33% pulmonary emboli (PE), and 10% other sites. Management was according to International Society on Thrombosis and Haemostasis (ISTH) guidance in 30 (47%) of 64 patients with high-risk thrombosis and 2 (5%) of low-risk thrombosis (catheter-associated or asymptomatic subsegmental PE). Twelve patients (11%) received no anticoagulation. At 28 days mortality was 15%, 8% experienced VTE progression, 7% experienced major bleeding, and 25% experienced clinically relevant non-major bleeding. Four inferior vena cava filters were placed, two were later removed. The median number of platelet units transfused was 5 (range 0-53). Twenty-seven percent of patients had a change of management strategy by 28 days. There was no clear relationship among platelet transfusion threshold, anticoagulant dose reduction threshold, and risk of thrombosis progression or major bleeding. Conclusions This data set demonstrates the heterogeneity of approaches used in patients presenting with severe thrombocytopenia and acute thrombosis and confirms the high rates of bleeding in this cohort with thrombosis progression rates similar to the wider cancer-associated thrombosis population. Randomized data is required to inform the optimal management.

Automated summary

This study describes the practice and outcomes of patients with hematological cancer, venous thromboembolism (VTE), and thrombocytopenia. The results demonstrate the heterogeneity of management approaches and high rates of bleeding in this patient population. Randomized data is needed to inform optimal management strategies.