Dural Venous Stenting for Idiopathic Intracranial Hypertension- Our experiences and literature review. S Saipriya 1, C Miranda 2, S Chettri 2, H Sonwalker 2, S Wuppalapatti Central Manchester University Hospitals, Manchester, United Kingdom 2- Royal Preston Hospital, Preston, United Kingdom EP-33

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Background and Purpose Idiopathic intracranial hypertension (IIH) is a rare condition which can lead to visual loss due to chronic papilledema and secondary optic atrophy if left untreated. Most of these patients are treated medically but nearly 20% eventually require surgery 1. A sizeable subset of patients have been shown to have abnormalities in the venous sinuses, when compared to control subjects in a study by Farb et al 2.

Background and Purpose Hypotheses have been put forth suggesting that the stenoses lead to alterations in the pressure gradient required for normal CSF absorption, and derangements in the feedback loop mechanism resulting in increasing CSF production, decreased absorption and raised intracranial pressure 3,4. Venous Sinus Stenosis Altered Pressure Gradient Reduced CSF Absorption Increased CSF Pressure

There remains continuous debate over whether the association of venous stenoses is a cause of BIH or is merely a consequence. Background and Purpose Venous Sinus Stenosis Altered Pressure Gradient Reduced CSF Absorption Increased CSF Pressure

Background and Purpose Venous sinus stenting (VSS) is a new, albeit controversial treatment option which aims to reduce the pressure gradient across the stenosis. A few case series so far have shown promising results with significant clinical improvement in a majority of the patients. Complications of VSS include perforation of the vessels, stent migration, increased risk of thrombus formation, and restenosis. 5,6 This report outlines our experience with venous sinus stenting in a cohort of patients chosen via a strict selection criteria.

Methods Patients were selected using a patient selection pathway based on current evidence as of Jan 2012, after peer review at a departmental level.

Selection criteria Patients had to meet all the below criteria to proceed to diagnostic intracranial venography. -Progressive headache as defined by the International headache society (version 1) Section Raised intracranial pressure (ICP)> 250 mmH20 -Normal cerebro-spinal fluid chemistry -No intracranial disease -Temporal relation of the headache to raised ICP -Improvement of symptoms following therapeutic lumbar puncture -Papilledema/ visual defect/ 6 th nerve palsy

Methods Selected patients underwent angiography. If a significant focal venous stenosis was identified, a stent was placed across the focal venous sinus stenosis. Patients were followed up at 3 and 12 month intervals. Post treatment visual fields were compared to pre treatment figures to assess for improvement.

Results A total of 28 patients were referred to our hospital with IIH. 27 of these were female with an average age of 42.5 and average BMI of patients met the criteria and proceeded to have direct retrograde cerebral venography (DRCV).

Procedure Following vascular access under general anesthesia, pre-stenosis and post-stenosis pressures were measured. The above images depict intravenous catheter tip (arrowed) measuring pre- (Image A) and post- (Image B) stenotic pressures. A A B B

Procedure Following a road map of the stenosis, an intravascular stent was placed (EV3 Protégé or Cordis Precis) was placed. A A B B Image A- Oblique view showing the stenosis, involving the right transverse sinus. Image B- Catheter and guidewire in place for placement of stent.

Procedure The pressures are reassessed to confirm the absence of a pressure gradient. A A B B Image A shows a digital subtraction images showing a deployed stent. Image B is an oblique view taken post stenting, with a normal caliber of the transverse sinus.

Results The patients were followed up at 3, 6 and 12 months. ConditionSignificance Gradient across stenosis (Pre- and Post- stent) 12 (1-62) 3 (0-16) <0.05 Proceeded for stenting19 No stenosis identified1 Post procedure complications within 24 hours 1 Symptom improvement at 3 months17 Symptom improvement at 6 months14 Symptom improvement at 12 months14

Results All but 1 of our patients had demonstrable venous sinus stenoses. All of the stenoses involved the transverse sinus, with 11 patients having bilateral transverse sinus stenoses. 1 of our patients who was stented had a serious complication- hemorrhagic stroke with post procedural disability.

Results 14/18 patients (78%) had sustained symptomatic improvement of visual acuity even 12 months after the procedure. 12/ 18 patients (67%) also noted relief of headache. 6 patients needed further CSF drainage to relieve headache and 3 of these went on to require a lumbar peritoneal CSF shunt

Results Of the remaining 10 patients who did not qualify for DRCV: –4 underwent lumbar peritoneal CSF shunt insertion –1 continues to be treated by intermittent CSF drainage –5 were lost to follow up

Conclusion The pathophysiology of BIH is still not fully understood. There is a strong association between the presence of venous stenoses, esp. transverse sinus stenosis, and BIH. There is continued debate over whether this causes BIH or is merely a consequence of BIH. Recent studies have shown cerebral venous sinus stenting (VSS) to be a treatment modality in some patients with BIH.

Conclusion A review article published in the Lancet analyzed a total of 31 patients, and documented similar outcomes 8. In our study, 78% of the patients who were stented showed sustained symptomatic improvement at 12 months. Further controlled prospective studies are required to evaluate this new treatment option.

References 1. Burgett RA, Purvin VA, Kawasaki A: Lumboperitoneal shunting for pseudotumor cerebri. Neurology 1997;49:734– Farb R, Vanek I, Scott J, Mikulis D, Willinsky R, Tomlinson G, Brugge K. Idiopathic intracranial hypertension: the prevalence and morphology of sinovenous stenosis. Neurology. 2003;60:1418–24 3. Bateman GA. Idiopathic intracranial hypertension: priaprism of the brain? Medical Hypotheses. 2004;63:549–52 4. Davson H, Hollingworth G, Segai M. The mechanism of drainage of the cerebrospinal fluid. Brain. 1970;93:665– Thrombus formation- Malek AM, Higashida RT, Balousek PA, Phatouros CC, Smith WS, Dowd CF: Endovascular recanalization with balloon angioplasty and stenting of an occluded occipital sinus for treatment of intracranial venous hypertension: technical case report. Neurosurgery 1999;44:896– Tsumoto T, Miyamoto T, Shimizu M, Inui Y, Nakakita K, Hayashi S, et al: Restenosis of the sigmoid sinus after stenting for treatment of intracranial venous hypertension: case report. Neuroradiology 2003;45:911– Headache classification committee of the International Headache Society (HIS) Version Higgins JN, Owler BK, Cousins C, Pickard JD. Venous sinus stenting for refractory benign intracranial hypertension.Lancet Jan 2002;19;359(9302):228-30