O-026 Persistent venous pressure gradient after venous sinus stenting with resolution after second stent placement: a technical note

Object Although venous sinus stenting is an established treatment for medically refractory idiopathic intracranial hypertension (IIH), a subset of patients do not sustain improvement in symptoms post-procedurally. While many physicians perform post-stent manometry, this is not universal and there is no accepted practice regarding where pressures should be measured when pursued. In this report, two patients are described who had resolution of their pressure gradient across the stented region after venous sinus stenting, yet had a persistent physiologic venous pressure gradient elsewhere. After placement of a second stent during the same procedure, subsequent resolution of the gradient was achieved. Methods This retrospective chart review evaluated patients at a single institution who underwent venous sinus stenting and had follow-up of at least one-year. Results Two patients (41F and 42F) with medically refractory IIH underwent angiography with venous manometry. In the first patient, stenosis was observed at the transverse-sigmoid sinus junctions bilaterally. The maximum venous pressure was 40 mmHg, and a gradient of 30 mmHg was present across the right transverse-sigmoid junction, where a unilateral venous sinus stent (Zilver, Cook Medical, Bloomington IN) was placed. Post-stent pressure measurements showed there was no longer a gradient from the transverse to sigmoid sinus. However, manometry in the superior sagittal sinus revealed that a significant pressure gradient persisted, which resolved after an additional stent was placed in the contralateral transverse sinus. The second patient had unilateral venous stenosis and a maximum pressure of 50 mmHg. Following placement of a right transverse-sigmoid sinus stent, the gradient was eliminated and pressures normalized in the transverse sinus. Upon measuring pressures in the superior sagittal sinus, the maximum venous pressures had only decreased to 30 mmHg, with a persistent gradient of 20 mmHg between the superior sagittal sinus and the right transverse sinus. An additional stent was placed across this location, and the pressure gradient resolved completely. Both patients had improvement in their symptoms, which has been sustained at one-year follow-up. Conclusions In some patients with IIH and venous sinus stenosis, placement of a single stent may eliminate the pressure gradient across the transverse-sigmoid sinus junction, yet may not sufficiently normalize pressures throughout the venous system. This may account for some patients who ‘fail’ venous sinus stenting. Additionally, manometry on both sides of the stent alone would not have detected a persistent pressure gradient, which was only detected with measurement in the superior sagittal sinus. We therefore advocate for measuring pressures in the superior sagittal sinus following stent placement, regardless of the location of the stent, which may detect the presence of a second clinically relevant stenosis, and an additional stent may be needed. Disclosures H. Dasenbrock: None. A. Beer-Furlan: None. M. Chen: 2; C; Genentech, Pneumbra, Stryker, Medtronic. R. Crowley: None.