Management and Prevention of Histotripsy-Induced Acute Bland Portal Vein Thrombosis in Histotripsy-Treated Liver Tumors

PURPOSE: To evaluate the incidence and management of histotripsy-induced portal vein thrombosis (PVT) during treatment of primary and metastatic liver tumors located near main portal vein branches and assess strategies for thrombus mitigation. MATERIALS AND METHODS: In this institutional review board (IRB)-approved, Health Insurance Portability and Accountability Act (HIPAA)-compliant retrospective study, 48 patients with 73 hepatic tumors treated with histotripsy between February 2024 and October 2025 were identified. Twenty-one patients with 21 tumors in which the expected treatment zones abut or encase a large portal or hepatic vein branch met inclusion criteria. Pretreatment, immediate posttreatment, and 1-month posttreatment contrast-enhanced computed tomography (CT) or magnetic resonance (MR) imaging scans were reviewed for PVT development and/or resolution. Anticoagulation strategies were modified sequentially during the study period to mitigate thrombus formation. RESULTS: Bland, occlusive or nonocclusive PVT occurred in 38% (8/21) of patients treated with histotripsy. The first 2 patients received no periprocedural anticoagulation and developed occlusive thrombus; subsequent consecutive adjustments to periprocedural anticoagulation resulted in nonocclusive thrombus in 6 of the remaining 19 patients. Logistic regression analysis revealed no association between PVT development and mean histotripsy voltage, tumor size, or tumor type. All cases of PVT resolved or improved with short-term anticoagulation, without chronic liver changes. CONCLUSIONS: Histotripsy can induce bland PVT, which may be mitigated by appropriate anticoagulation during the procedure.