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Case report
Concomitant intracranial pressure monitoring during venous sinus stenting for intracranial hypertension secondary to venous sinus stenosis
  1. Kyle M Fargen1,
  2. Gregory J Velat1,
  3. Stephen B Lewis1,
  4. Brian L Hoh1,
  5. J Mocco2,
  6. Matthew F Lawson3
  1. 1Department of Neurosurgery, University of Florida, Gainesville, Florida, USA
  2. 2Department of Neurosurgery, Vanderbilt University, Nashville, Tennessee, USA
  3. 3Department of Neurosurgery, Tallahassee Neurological Clinic, Tallahassee, Florida, USA
  1. Correspondence to Dr M F Lawson, Department of Neurosurgery, Tallahassee Neurological Clinic, 1401 Centerville Road, Suite 300, Tallahassee, FL 32308, USA; mflpublications{at}yahoo.com

Abstract

Background There is a growing body of literature supporting venous sinus stenosis as a causative etiology for many patients diagnosed with idiopathic intracranial hypertension. Recent series have documented improvement in the pre- and post-stenosis venous pressure gradient as well as clinical symptoms after stenting. Concomitant real time intracranial pressure (ICP) monitoring has not been previously described during venous sinus stenting.

Case report A woman in her twenties presented with rapidly progressive visual loss and cranial neuropathies with an MRI revealing high grade right transverse sinus stenosis. Lumbar puncture demonstrated an opening pressure >55 cm H2O. Her vision and cranial neuropathies continued to worsen despite ventriculoperitoneal shunting. A parenchymal ICP monitoring wire was placed, revealing ICP persistently >70 cm H2O. She underwent venography and a pre- to post-stenosis pressure gradient of 55 mm Hg was measured. The patient underwent sinus stenting resulting in a near immediate reduction in her ICP from 70 to 20 cm H2O within 30 s after deployment. Her ICP completely normalized within 24 h of stenting.

Conclusions A case is presented of severe intracranial hypertension with rapidly progressive neurologic decline despite CSF diversion secondary to venous sinus stenosis that resolved following venous sinus stenting. This is the first report of real time ICP monitoring during venous sinus stenting.

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Introduction

There is increasing evidence implicating venous sinus stenosis as a causative etiology for many patients diagnosed with idiopathic intracranial hypertension (IIH). First reported as a treatment in 2001 by Hunt and colleagues1 for venous sinus thrombosis and then by Higgins and colleagues2 in 2002 for IIH, venous sinus stenosis stenting has gained popularity as a definitive treatment for those patients with IIH and associated venous sinus stenosis.3–11 In recent series,7 ,10 candidacy for stenting has been assessed by measuring the venous pressure gradient from pre- to post-stenosis. Patients with an elevated gradient (≥8–12 mm Hg) have shown clinical improvement following stenting. In nearly all reported patients, the pressure gradient is relieved after stenting, with venous pressure assumed to be a surrogate metric for intracranial pressure (ICP). To date, concomitant measurement of ICP during venous sinus stenting has not been described. We report a case of a young woman with refractory intracranial hypertension and rapidly progressive neurologic decline who underwent stenting of high grade venous sinus stenosis with real time measurement of ICP using a parenchymal monitor.

Case report

An obese African–American woman in her mid-20s with no significant past medical history presented to the emergency room with a 1 week history of progressive headaches and visual loss. Initial examination revealed bilateral papilledema, poor visual acuity and mild bilateral abducens palsies. On initial evaluation by ophthalmology, she was noted to have acuity of 20/400 in the left eye and could only count fingers at 1 foot in the right eye. She underwent brain MRI and MR venography, revealing a suspected transverse sinus thrombosis with partial recanalization, small ventricles and absence of any mass lesion (figure 1). Lumbar puncture was attempted in the emergency department but could not be performed due to her body habitus. She was initiated on a heparin infusion for her suspected venous sinus thrombosis and was admitted to the hospital. A hypercoagulability workup was initiated, and other than a normal pregnancy 5 months previously and current oral contraceptive use, was unrevealing.

Figure 1

(A) MR venogram demonstrating a filling defect of the right transverse sigmoid sinus junction (arrow). (B) Coronal MR venogram showing the relationship of the sagittal and transverse sinuses. (C) T2 weighted MR demonstrating small ventricles without evidence of mass lesion.

Shortly after admission the patient complained of worsening vision. Repeat ophthalmologic evaluation showed further visual deterioration with the patient being restricted to counting fingers in each eye. The neurosurgical team was consulted and a lumbar puncture was performed after holding the heparin drip for several hours, demonstrating an elevated opening pressure >55 cm H2O. A high volume tap was performed (70 ml). During the lumbar puncture, the patient became agitated and suffered a generalized tonic–clonic seizure. A post-lumbar puncture head CT demonstrated loss of cortical sulci suggestive of cerebral edema without evidence of hemorrhage. After improving to her baseline neurologic examination over the ensuing few hours, she underwent stereotactic computer navigated ventriculoperitoneal shunt placement.

After surgery, the patient developed bilateral oculomotor palsies with mild confusion, but was still awake, alert and following commands. However, she had further decline in her visual acuity and was noted to have light detection only on clinical examination. She underwent a repeat head CT that showed satisfactory placement of the ventricular catheter within the right lateral ventricle (figure 2). A shunt tap was performed that demonstrated proximal flow. Due to concern for increasing ICP, she underwent placement of a Codman Microsensor parenchymal ICP monitoring wire (Codman, Raynham, Massachusetts, USA), revealing a pressure >70 cm H2O with a good waveform. During the ensuing hours, her ICP remained above 70 cm H2O, with a mean arterial pressure of 100–110 mm Hg, yet she was still able to follow commands with only mild confusion but had bilateral sixth and third nerve palsies. Due to her rapidly progressive symptoms, deteriorating neurologic examination and markedly elevated ICP despite CSF diversion, she was taken to the interventional radiology suite for possible endovascular intervention.

Figure 2

Non-contrast CT after shunt placement, revealing the catheter within the frontal horn of the small right lateral ventricle.

Endovascular technique

Under general anesthesia, the right femoral artery was accessed in a standard fashion and a cerebral arteriogram was performed, revealing a high grade stenosis of the right transverse sigmoid sinus junction with markedly delayed venous outflow (figure 3A). The vast majority of the cortical venous drainage was via the sagittal sinus to the right transverse sinus, sigmoid sinus and jugular vein. The left transverse sinus appeared to drain the deep venous structures only and was of normal caliber.

Figure 3

(A) Oblique view of the venous phase during cerebral arteriography demonstrating a high grade stenosis of the right transverse sigmoid sinus junction (arrow). (B) Unsubtracted lateral view after stent placement. (C) Oblique view of the venous phase during cerebral arteriography after stent placement, demonstrating significant improvement in flow through the right sigmoid sinus.

Her right femoral vein was then accessed and a 6 F guide catheter was positioned into the jugular bulb. High volume contrast venography was attempted but no contrast could be seen passing rostral to the jugular bulb due to the high venous pressures. An SL-10 microcatheter (Stryker, Kalamazoo, Michigan, USA) was subsequently positioned in the sigmoid sinus and pressure was measured as 20–25 mm Hg. Next, the microcatheter was navigated through the tight stenosis, and pressure was measured to be 80–85 mm Hg (a pre–post stenosis pressure gradient of approximately 55–60 mm Hg). At this point, ICP was approximately 60–70 cm H2O, with a good waveform and a mean arterial pressure of approximately 100–110 mm Hg. Next, the guide catheter was exchanged for a shuttle sheath that was placed with its distal tip in the sigmoid sinus, just proximal to the stenosis. An 8×40 mm Precise carotid stent (Cordis, Bridgewater, New Jersey, USA) was then deployed across the stenotic segment (figure 3B), resulting in an immediate ICP drop over the ensuing 30 s to 20–25 cm H2O. Arteriography was once again performed, revealing marked improvement in cerebral filling, with a patent right transverse and sigmoid sinus, and a significant reduction in cortical venous congestion (figure 3C). She was given an aspirin suppository and was continued on a heparin infusion.

Outcome

Immediately following the procedure the patient was able to follow complex commands bilaterally. Her ICP remained stable in the 10–30 cm H2O range overnight, but by post-procedure day 2, her ICP recordings were in the single digits and the ICP wire was removed. She was initiated on clopidogrel and her heparin infusion was stopped. A CT venogram performed during her hospital stay demonstrated stent patency. She was discharged to inpatient rehabilitation 1 week after the procedure, with improving bilateral partial oculomotor palsies, able to count fingers in both eyes, and with normal mental status and motor examinations. Ophthalmology evaluation 3 weeks following the procedure revealed resolution of her papilledema. At her 1 month follow-up visit, the patient was neurologically intact except for persistent stable visual loss.

Discussion

Only a subset of patients carrying a diagnosis of IIH have documented venous sinus stenosis with elevated pre–post stenosis pressure gradients, and there are currently no widely accepted guidelines as to patient screening, patient selection for endovascular treatment or gradient thresholds for stenting in this patient population. To date, the largest series of venous sinus stenting in IIH is by Ahmed and colleagues10 who stented 52 patients over a 10 year period. The average ICP based on lumbar puncture was 32 cm H2O, with an average pre–post transverse sinus pressure gradient of 20 mm Hg. In all patients, placement of a transverse sinus stent immediately ameliorated the pre–post stenosis pressure gradient with rapid improvement of symptoms, although six patients did relapse. Forty-nine of the 52 patients were improved at the last follow-up. Other groups have reported similarly promising results,2–9 ,11 with the majority of patients with documented elevated pre–post stenosis pressure gradients showing symptomatic improvement after sinus stenting. In almost all cases where it was measured, the pressure gradient immediately decreased following stenting.

This case represents the first report where real time ICP monitoring was used simultaneously during venous sinus stent placement for intracranial hypertension associated with venous sinus stenosis. A near instantaneous improvement in ICP from >70 cm H2O to approximately 20 cm H2O was noted following stent deployment. As expected, arteriography demonstrated normalization of cerebral perfusion with improvement in venous outflow. This rapid reduction in ICP after stenting confirmed venous sinus outflow obstruction as the etiology of her elevated cerebral venous pressures and elevated ICP.

The presented case is certainly not representative of most patients with elevated ICP from documented sinus stenosis, but this case is particularly interesting as it illustrates the relationship between venous outflow obstruction and parenchymal ICPs. It is unclear why this patient had such a rapid progression of symptoms with neurologic decline over 1 week, a feature uncharacteristic of ‘benign’ IIH. Although the posterior circulation was not studied, cortical venous drainage was predominantly via the sagittal sinus to the right transverse and sigmoid sinuses on carotid injections. Stenosis of this major cortical outflow tract is the likely explanation for the patient's malignant elevation of ICPs, and the reason that pressures normalized following stenting. It is this extraordinary course (rapid neurologic decline even after CSF diversion) that resulted in the need for ICP monitoring, allowing for ICP to be documented before, during and after her procedure.

Conclusions

We have presented a case of severe intracranial hypertension with rapidly progressive neurologic decline, despite CSF diversion, secondary to venous outflow obstruction from sinus stenosis that improved after venous sinus stenting. This is the first report of real time ICP normalization following venous sinus stenting.

References

Footnotes

  • Contributors All authors (KMF, GJV, SBL, BLH, JM, MFL) contributed to this manuscript through patient care, article composition and/or critical review.

  • Competing interests None.

  • Patient consent Not obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.