Background: History of venous thromboembolism (VTE) is common in patients undergoing hematopoietic cell transplantation (HCT). Management of VTE and anticoagulation during conditioning-induced thrombocytopenia remains challenging due to concerns about increased risks for bleeding.
Aims: Assess impact of continuing versus temporarily withholding anticoagulation during thrombocytopenia on short-term VTE recurrence and bleeding.
Methods: Patients undergoing first autologous or allogenic HCT 2006-2015 were selected from our institutional database. Patients included in this retrospective study had confirmed VTE prior to HCT and were receiving therapeutic anticoagulation upon arrival for HCT. Patients were allocated to two cohorts based on anticoagulation strategy at the onset of thrombocytopenia, defined as platelets ≤50 x109/L or first platelet transfusion after conditioning. Those who continued on therapeutic anticoagulation received platelet transfusions to maintain threshold of 50×109/L for ≥ 3 days, while those who temporarily held did so until platelet recovery. Inverse probability of weighting (IPW) using propensity score was used to account for potential confounders and estimate the causal effect associated with differential management. Primary outcomes included VTE recurrence, PE/DVT recurrence, major bleeding (WHO grade 3-4), and overall bleeding (WHO grade 1-4) at 30 days after HCT.
Results: Of 3,722 HCT patients over 10 years, 340 patients met inclusion criteria, of which 227 continued anticoagulation and 113 temporarily withheld (Figure 1). Median duration of thrombocytopenia was 14 days. Adequate balance with standardized difference <0.10 was achieved on all covariates after IPW. In IPW-weighted analysis, continuing versus holding anticoagulation was not significantly associated with decreased risk of VTE recurrence within the first 30 days (3% vs 4%), however trended toward higher risk of both major bleeding (7% vs 5%) and overall bleeding (41% vs 32%) (Table 1).
|Pre-IPW Weighting (n=340)||Post-IPW Weighting (n=340)|
|Outcome at 30d||Continue||Hold||p-value||Continue||Hold||ATEa||p-value|
|All VTE recurrence||3%||2%||1.00||3%||4%||-1.5%||0.61|
|aAverage treatment effect (ATE) is the anticipated benefit or adverse outcome if all the patients in the HOLD group were instead continued on anticoagulation.
Abbreviations: IPW, inverse-probability weighting; ATE = average treatment effect; VTE, venous thromboembolism; PE, pulmonary embolism; DVT, deep venous thrombosis
Conclusions: In patients taking anticoagulant medication for prior VTE, temporarily withholding anticoagulant therapy may reduce bleeding without significantly increasing risk of recurrent VTE within the first 30 days following HCT.
To cite this abstract in AMA style:Martens K, Amos C, Rojas Hernandez C, Kebriaei P, Basom R, Davis C, Kesten M, Carrier M, Garcia D, Lee S, Li A. Anticoagulation Strategies during Conditioning-induced Thrombocytopenia in Hematopoietic Cell Transplant Patients with Venous Thromboembolism [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/anticoagulation-strategies-during-conditioning-induced-thrombocytopenia-in-hematopoietic-cell-transplant-patients-with-venous-thromboembolism/. Accessed December 8, 2021.
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