The Expanding Role of Endovascular Therapy in Cerebral Venous Sinus Thrombosis

Anticoagulation is the primary treatment of Cerebral Venous Sinus Thrombosis (CVST). However, methods of managing CVST have been changing as a result of the increased use of endovascular therapy (EVT) (1-4). The use of systemic anticoagulation showed efficacy and safety in therapy, with a large percentage of patients achieving clinical stability as a result of therapy. It is important to note that despite the use of therapeutic doses of heparin, CVST with malignant findings may lead to venous congestive encephalopathy, herniation and worse outcomes (1,5). Malignant CVST occurs most frequently when there is no drainage of cerebrospinal fluid (CSF) because of major dural venous sinus occlusion, which most commonly affects the superior sagittal sinus. When no longer able to be absorbed into the bloodstream, excessive amounts of CSF would be produced and consequently raise ICP dramatically. (5).

Recent research showed the efficacy of using endovascular therapy (EVT) to reduce intracranial pressure (ICP) through removing clots from the vessel lumen. Anticoagulation may stop additional clot aggregation but does not affect ICP immediately. Thus, using EVT provides immediate mechanical decompression to allow for a stable pressure gradient. Although the TO-ACT study led to doubts regarding efficacy, advances in the understanding of venous circulation pathophysiology have changed EVT from an individual experimental rescue therapy to a directed therapy for high-risk patients (2,10).

Early EVT methods involved using catheter-directed thrombolysis were commonly accompanied by complications such as intracranial haemorrhage (5,7). Modern EVT techniques reduced this risk by acquiring adaptations from acute ischemic stroke EVT (10). Recent modifications apply rapid mechanical debulking using large-bore aspiration thrombectomy and stent retriever microsynergy (4,5). The combined approach elevates the stent retriever by anchoring and sectioning the stubborn thrombus, whilst a high-flow aspiration catheter interlocks with the clot. This method, adapted from the large-bore aspiration and mechanical clot-softening techniques, maximises the extraction of dense, organised venous clots (4,5). This mechanism minimises endothelial denudation, thus protecting venous architecture and minimising the risk of systemic lytic complications. Using mechanical thrombectomy in addition to local thrombolysis reduced the risk by physically aspirating the thrombosis (1,4).

The clinical focus subsequently shifted from determining how to intervene to identifying which patients would derive the greatest benefit from intervention. To eliminate the subjective application of clinical scoring systems, the field is undergoing an imaging-driven evolution, selecting patients by adapting neuroimaging biomarkers (3,10).

Arterial perfusion maps identify ischemic penumbra, whilst venous perfusion maps quantify the venous penumbra, characterised by elevated venous pressure and severe microvascular congestion, preserving cerebral blood volume. This implies a critical, reversible threshold where tissues are affected by severe congestion and imminent venous infarction, whilst remaining structurally robust due to collateral vasculature. Identifying this mismatch established the need for an objective framework for intervention (3,10).

Primary predictors to consider for early EVT include those with anatomical risk such as an occluded deep venous system (straight sinus or internal cerebral veins), those presenting with pre-treatment coma, altered mental capacity and/or progressive neurological deficits, and those deteriorating within 24-48 hours after receiving therapeutic anticoagulation (1,8). This ensures that mechanical interventions target patients before venous congestion progresses into irreversible hemorrhagic intervention.

As we move forward, endovascular therapy in CVST is better understood as a salvage method, rather than a replacement for anticoagulation (2,10). The main obstacle for venous EVT is a low patient volume, consecutively leading to a low level of interventionalist training and scarce data on short- and long-term outcomes. These issues undermine the need for large-scale, controlled trial data, which will be necessary to establish guideline-level evidence (2,9). Therefore, there is an urgent need for multicentre study collaboration to assess the predictors of benefit of EVT in CVST patients to reduce the burden of immediate complications and to enhance patient outcomes.

References:

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