Predictors of dural venous sinus pressure gradient in patients with idiopathic intracranial hypertension.

OBJECTIVE

Growing evidence suggests that venous outflow obstruction from venous sinus stenosis (VSS) may lead to increased intracranial pressure (ICP) in patients with idiopathic intracranial hypertension (IIH). There is a paucity of evidence examining clinical predictors of elevated cerebral venous pressure gradient (CVPG) from VSS in patients with IIH. In this study, the authors examined predictors of elevated CVPG, determined the sensitivity and specificity of common presenting symptoms of IIH, and identified the optimal opening pressure threshold on lumbar puncture (LP) to determine which patients should undergo venous manometry (VM).

METHODS

Patient demographics, presenting symptoms, complications, and opening pressure on LP were collected. Venous pressure gradient across a stenotic dural venous sinus and maximum venous pressure values were recorded from cerebral venograms. VM was considered positive when the CVPG was ≥ 8 mm Hg between two contiguous segments of a dural venous sinus. Sensitivity, specificity, and multivariable logistic regression analysis was performed.

RESULTS

The predominant patient population was young (mean age 38.9 years), obese (BMI ≥ 30; 83.8%), and female (95.0%). Sensitivity and specificity for papilledema were 74% and 70% (area under the curve [AUC] 0.71, 95% CI 0.63-0.80), and 70% and 63% (AUC 0.66, 95% CI 0.57-0.75) for pulsatile tinnitus. Vision changes demonstrated a sensitivity of 80% and specificity of 50% (AUC 0.63, 95% CI 0.54-0.72). VSS seen on magnetic resonance venography (MRV) demonstrated a sensitivity of 90% and specificity of 53% (AUC 0.71, 95% CI 0.63-0.79). Youden's index analysis identified an opening pressure ≥ 25 cm H2O on LP (AUC 0.72, 95% CI 0.60-0.83) as an optimal threshold for predicting elevated CVPG.

CONCLUSIONS

Predictors of elevated CVPG on VM include childbearing age, African American race, papilledema, pulsatile tinnitus, obesity (BMI ≥ 30), focal VSS with unilateral dominance in venous drainage seen on MRV, or an opening pressure on LP ≥ 25 cm H2O.