Dural arteriovenous fistulas (dAVFs) often lead to dural venous sinus stenosis due to turbulent flow from increased blood flow, which has been recognized as leading to additional stenosis in the transverse sinus. This condition can result in venous hypertension and retrograde flow, worsening the dAVF. Approximately 60% of dAVFs in the transverse-sigmoid sinus exhibit this phenomenon. Treatment options include open surgery, endovascular embolization, or stereotactic radiosurgery. Endovascular treatments are minimally invasive and aim to address stenosis and restore normal cortical venous drainage, effectively managing the dAVF.

Here, we present a case of severe dAVF causing right transverse sinus stenosis and occlusion, retrograde flow through the superior sagittal sinus (SSS), and significant cortical venous congestion, leading to reversible pseudodementia in a 66-year-old male. On physical exam, he exhibited mild bilateral paraparesis, a wide-based gait with instability, and mild bilateral upper extremity dysmetria on finger-to-nose testing. Pre-treatment cerebral angiography revealed a Borden Type II, Cognard II a+b dAVF with right transverse sinus and chronic left sigmoid sinus occlusion (figure 1A). Intervention involved arterial embolization and subsequent venous deconstruction with occlusion of the left transverse sinus. A burr hole was used to gain direct puncture access into the SSS using a 4 French sheath since neither sinus system was accessible from the neck. After this, coil embolization was used to achieve occlusion of the left transverse sinus to close the majority of the dAVF. 4 months after embolization, the patient‘s neurocognitive deficits improved remarkably. Follow-up angiography confirmed restored patency of the right transverse sinus and resolution of retrograde flow in the superior sagittal and straight sinuses (figure 1B).

This case highlights a specific example of the pathophysiology of venous sinus stenosis in altered hemodynamics. A left-sided dAVF was associated with ipsilateral transverse-sigmoid sinus occlusion and contralateral transverse sinus occlusion. Post-embolization, the dAVF improved significantly, and the contralateral sinus was recanalized. The modification of inlet flow from the dAVF by treatment suggests a relationship between inlet flow into the sinus and venous sinus stenosis and occlusion. At 5-year follow-up, the fistula is Borden type I, Cognard type I and the patient is still symptom-free.

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Abstract E-155 Figure 1

A. L ECA injection, L dAVF with connections into the left transverse-sigmoid junction with retrograde flow through the SSS. B. Residual Borden type 1, Cognard type 1 L dAVF seen connecting to venous sinuses with drainage into dural sinuses with anterograde flow and no cortical venous reflux.

Disclosures S. Sriraman: None. J. Sims: None. M. Zamora: None. C. Nickele: None.