Characteristics and Outcomes of the Idiopathic Intracranial Hypertension Treatment in Intrinsic and Extrinsic Stenosis: A Single-Center Experience in China

Real time intravascular ultrasound evaluation and stent selection for cerebral venous sinus stenosis associated with idiopathic intracranial hypertension

The value of intravascular ultrasound (IVUS) in the diagnosis and treatment of the venous system is not well established. Introducing a novel approach to utilizing IVUS to evaluate cerebral venous sinus (CVS) stenosis and select stent. Idiopathic intracranial hypertension (IIH) patients with CVS stenosis who underwent IVUS-guided stenting were included in the data analysis from January 2014 to February 2022. The degree of maximum stenosis was determined based on the cross-sectional area (CSA) measured by IVUS, and a stent selection method was applied in the study. Follow-up evaluations were conducted at 6 months to 1 year after endovascular treatment to assess symptom improvement. Additionally, repeated digital subtraction angiography (DSA) or Magnetic resonance venography (MRV) / CT venography（CTV） was performed to evaluate the stent patency at 6 months to 1 year post-procedure. The study included 61 patients. IVUS indicated a lower degree of stenosis compared to conventional DSA measurements when evaluating the degree of stenotic segments preprocedure (74.84 ± 10.12% vs. 78.48 ± 8.72%, p = 0.035). Post-procedural CSA of the most severe stenotic segments showed significant improvement (36.44 ± 8.07 mm2 vs. 7.42 ± 3.28 mm2, p < 0.001). The stent achieved complete expansion (mean stent expansion index, 0.93 ± 0.20) with no significant change in the structure of the reference segment. The trans-stenotic mean pressure gradients (MPGs) across 61 patients significantly decreased from 11.00 ± 6.23 mmHg to 2.09 ± 2.34 mmHg. 47 out of 61 patients received imaging follow-up; among them, 44 (93.6%) demonstrated stent patency in the follow-up imaging. IVUS has great potential to evaluate the degree and extent of CVS stenosis, assist stent selection, and optimize stent position during the interventional procedure in conjunction with DSA.

The Effects of Pressure Gradient on Papilledema Improvement After Venous Sinus Stenting in Idiopathic Intracranial Hypertension

PURPOSE

This study aimed to evaluate the impact of the pressure gradient on papilledema after stenting in patients with idiopathic intracranial hypertension (IIH) patients and venous sinus stenosis (VSS).

MATERIALS AND METHODS

In this prospective cohort study, we examined 121 patients with IIH and VSS who underwent stenting. The papilledema Frisen grade at the 1-month follow-up was used as a grouping factor (favorable outcome: 0-1; unfavorable outcome: 2-5). We used multivariable logistic regression modeling to determine independent predictors of favorable outcome. The performance of the prediction model was evaluated using a receiver operating characteristic (ROC) analysis.

RESULTS

A total of 96 patients had papilledema grades 0 to 1, and 25 patients had papilledema grades 2 to 5. Patients with the first group had significantly lower gradient pressures preoperatively (15.2 mmHg vs. 21.4 mmHg, p=0.001) and postoperatively (2 mmHg vs. 3.3 mmHg, p=0.002) relative to those in the second group. Multivariate analysis indicated that preoperative pressure gradient (odds ratio [OR] = 1.119; 95% confidence interval [CI] = 1.034-1.211]) and postoperative pressure gradient (OR = 1.498; 95% CI = 1.147-1.957) were independent predictors of favorable outcome. In the ROC analysis, the cut-off pressure gradient for the highest sensitivity (0.44) and specificity (0.874) was 22.75 mmHg, with a Youden's index of 0.314. Survival analysis demonstrated that patients with a preoperative pressure gradient <22.75 mmHg had more rapid improvement of papilledema than did those with a pressure gradient >22.75 mmHg (mean+SD: 2.639+0.382 [95% CI: 1.890-3.388] versus mean+SD: 3.882+0.884 [95% CI: 2.149-5.616]; p=0.004).

CONCLUSION

A significant reduction in the pressure gradient appears to be strongly correlated with the success of VSS in patients with IIH. A higher preoperative pressure gradient may reduce stenting efficacy in patients with IIH.Clinical ImpactVenous sinus stenting has the potential to yield substantial clinical advantages in individuals diagnosed with idiopathic intracranial hypertension with venous sinus stenosis. Nevertheless, a heightened preoperative pressure gradient could lead to less favorable results. Thus, the early adoption of venous sinus stenting is advised to avert additional irreversible clinical deterioration among idiopathic intracranial hypertension patients with venous sinus stenosis.

Clinical outcomes after stenting treatment in patients with idiopathic intracranial hypertension and intrinsic versus extrinsic venous sinus stenosis

BACKGROUND

Endovascular stenting is a promising treatment for patients with idiopathic intracranial hypertension (IIH) and venous sinus stenosis (VSS). However, data on the impact of stenosis type on clinical outcomes of patients undergoing stenting treatment remain limited. This prospective cohort study aimed to compare post-stenting outcomes in patients with IIH and intrinsic versus extrinsic VSS.

METHODS

Patients with IIH and VSS undergoing stenting at a tertiary hospital in China were enrolled consecutively from 2017 to 2023. Based on digital subtraction angiography, high-resolution MRI, and intravascular ultrasound findings, patients were categorized into two groups: intrinsic or extrinsic stenosis. At 6 months post-stenting, clinical outcomes including cerebrospinal fluid (CSF) pressure, headache, visual impairment, and papilledema were recorded. Multivariable regression models were used to explore the relationship between stenosis type and clinical outcomes.

RESULTS

In total, 92 patients were included, 60 with intrinsic stenosis and 32 with extrinsic stenosis. At 6 months, the intrinsic group had lower CSF pressure (median 180 vs 210 mmH2O, β coefficient -31.8, 95% CI -54.0 to -9.6) and a higher rate of complete symptom resolution (81.7% vs 40.6%, OR 8.88, 95% CI 2.60 to 30.30) than the extrinsic group. Additionally, 36.8% (95% CI 10.5% to 77.2%) of the effect of stenosis type on complete symptom resolution at 6 months was mediated through reduction in CSF pressure.

CONCLUSION

This single-center study suggested that patients with IIH and intrinsic VSS had lower CSF pressure and better symptom recovery compared with those with extrinsic VSS at 6 months post-stenting. Further validation in other centers and populations is needed.

TRIAL REGISTRATION NUMBER

ChiCTR.org.cn, ChiCTR-ONN-17010421.

Stenting versus medical treatment for idiopathic intracranial hypertension based on a propensity score matching method

Background

In recent years, stenting has been widely used to treat patients with idiopathic intracranial hypertension (IIH) and venous sinus stenosis (VSS); however, research comparing stenting and medical treatment (MT) remains scarce. This study aimed to evaluate the effectiveness of stenting and MT in treating patients with IIH and VSS.

Methods

In this single-center, retrospective, cohort study, the clinical data of patients diagnosed with IIH and VSS at The First Affiliated Hospital of Zhengzhou University from January 2018 to June 2023 were collected for analysis. Based on the treatment approaches, the patients were divided into the following two groups: the stenting group (Group S), and the MT group (Group M). The patients underwent 1:1 propensity score matching (PSM) to compare the improvement in papilledema Frisén grade, lumbar puncture opening pressure (LPOP), and clinical symptoms after treatment.

Results

In total, 128 participants were included in the study. The participants had an average age of 40.0±11.1 years (range, 18-61 years) and a body mass index (BMI) of 27.5±3.3 kg/m2 (range, 20.0-40.0 kg/m2), and 73.43% were female (68 in Group S and 60 in Group M). Compared with the patients in Group M, those in Group S had a longer median time from onset to treatment (2 vs. 1 month, P=0.026), a higher proportion of papilledema (85.3% vs. 68.3%, P=0.033), a higher median pretreatment stenosis rate (80% vs. 70%, P=0.005), and a larger median pretreatment trans-stenotic pressure gradient (15.5 vs. 11.0 mmHg, P=0.001), and a larger median pretreatment LPOP (391.1 vs. 350.5 mmH2O, P=0.006). Following 1:1 PSM, both groups comprised 28 patients each, and there were no statistically significant differences between the two groups in terms of the covariates (all P>0.05). Compared with the patients in Group M, those in Group S had a lower median papilledema Frisén grade (1 vs. 2, P=0.002) and average LPOP (213.0 vs. 259.8 mmHg, P=0.003) at discharge, and showed more pronounced symptom improvement at the time of discharge (P=0.019), and at 6 months (P=0.011) and 12 months (P<0.001) post-discharge.

Conclusions

The research indicated that stenting was quicker and more effective in alleviating papilledema, LPOP, and corresponding symptoms and signs than MT.

Progress and recognition of idiopathic intracranial hypertension: A narrative review

BACKGROUND

Idiopathic intracranial hypertension (IIH) mainly affects obese young women, causing elevated intracranial pressure, headaches, and papilledema, risking vision loss and severe headaches. Despite weight loss as the primary treatment, the underlying mechanisms remain unclear. Recent research explores novel therapeutic targets.

AIMS

This review aimed to provide a comprehensive understanding of IIH's pathophysiology and clinical features to inform pathogenesis and improve treatment strategies.

METHODS

Recent publications on IIH were searched and summarized using PubMed, Web of Science, and MEDLINE.

RESULTS

The review highlights potential pathomechanisms and therapeutic advances in IIH.

CONCLUSION

IIH incidence is rising, with growing evidence linking it to metabolic and hormonal disturbances. Early diagnosis and treatment remain challenging.

Differentiation Between the Low and High Trans-Stenotic Pressure Gradient in Patients With Idiopathic Intracranial Hypertension Using 4D Flow MRI-Derived Hemodynamic Parameters

BACKGROUND

Trans-stenotic pressure gradient (TPG) measurement is essential for idiopathic intracranial hypertension (IIH) patients with transverse sinus (TS) stenosis. Four-D flow MRI may provide a noninvasive imaging method for differentiation of IIH patients with different TPG.

PURPOSE

To investigate the associations between 4D flow parameters and TPG, and to evaluate the diagnostic performance of 4D flow parameters in differentiating patients with high TPG (GroupHP) from low TPG (GroupLP).

STUDY TYPE

Prospective.

POPULATION

31 IIH patients with TS stenosis (age, 38 ± 12 years; 23 females) and 5 healthy volunteers (age, 25 ± 1 years; 2 females).

FIELD STRENGTH/SEQUENCE

3T, 3D phase contrast MR venography, and gradient recalled echo 4D flow sequences.

ASSESSMENT

Scan-rescan reproducibility of 4D flow parameters were performed. The correlation between TPG and flow parameters was analyzed. The netflow and velocity difference between inflow plane, outflow plane, and the stenosis plane were calculated and compared between GroupHP and GroupLP.

STATISTICAL TESTS

Pearson's correlation or Spearman's rank correlation coefficient, Independent samples t-test or Wilcoxon rank-sum test, Intra-class correlation coefficient (ICC), Bland-Altman analyses, Receiver operating characteristic curves. A P value <0.05 was considered significant.

RESULTS

Significant correlations were found between TPG and netflow parameters including Favg,out-s, Favg,in-s, Fmax,out-s, and Fmax,in-s (r = 0.525-0.565). Significant differences were found in Favg,out-s, Fmax,out-s, Favg,in-s, and Fmax,in-s between GroupHP and GroupLP. Using the cut-off value of 2.19 mL/sec, the Favg,out-s showed good estimate performance in distinguishing GroupHP from GroupLP (AUC = 0.856). The ICC (ranged 0.905-0.948) and Bland-Altman plots indicated good scan-rescan reproducibility.

DATA CONCLUSIONS

4D flow MRI derived flow parameters showed good correlations with TPG in IIH patients with TS stenosis. Netflow difference between outflow and stenosis location at TS shows the good performance in differentiating GroupHP and GroupLP cases.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 2.

Prediction of Venous Trans-Stenotic Pressure Gradient Using Shape Features Derived From Magnetic Resonance Venography in Idiopathic Intracranial Hypertension Patients

OBJECTIVE

Idiopathic intracranial hypertension (IIH) is a condition of unknown etiology associated with venous sinus stenosis. This study aimed to develop a magnetic resonance venography (MRV)-based radiomics model for predicting a high trans-stenotic pressure gradient (TPG) in IIH patients diagnosed with venous sinus stenosis.

MATERIALS AND METHODS

This retrospective study included 105 IIH patients (median age [interquartile range], 35 years [27-42 years]; female:male, 82:23) who underwent MRV and catheter venography complemented by venous manometry. Contrast enhanced-MRV was conducted under 1.5 Tesla system, and the images were reconstructed using a standard algorithm. Shape features were derived from MRV images via the PyRadiomics package and selected by utilizing the least absolute shrinkage and selection operator (LASSO) method. A radiomics score for predicting high TPG (≥ 8 mmHg) in IIH patients was formulated using multivariable logistic regression; its discrimination performance was assessed using the area under the receiver operating characteristic curve (AUROC). A nomogram was constructed by incorporating the radiomics scores and clinical features.

RESULTS

Data from 105 patients were randomly divided into two distinct datasets for model training (n = 73; 50 and 23 with and without high TPG, respectively) and testing (n = 32; 22 and 10 with and without high TPG, respectively). Three informative shape features were identified in the training datasets: least axis length, sphericity, and maximum three-dimensional diameter. The radiomics score for predicting high TPG in IIH patients demonstrated an AUROC of 0.906 (95% confidence interval, 0.836-0.976) in the training dataset and 0.877 (95% confidence interval, 0.755-0.999) in the test dataset. The nomogram showed good calibration.

CONCLUSION

Our study presents the feasibility of a novel model for predicting high TPG in IIH patients using radiomics analysis of noninvasive MRV-based shape features. This information may aid clinicians in identifying patients who may benefit from stenting.

Idiopathic Intracranial Venous Hypertension: Toward a Better Understanding of Venous Stenosis and the Role of Stenting in Idiopathic Intracranial Hypertension

BACKGROUND

Venous sinus stenosis, typically at the junction of the transverse and sigmoid sinus, is increasingly recognized as a contributor to the pathophysiology of idiopathic intracranial hypertension (IIH), whether it be the intrinsic type that does not reverse with normalization of intracranial pressure or the extrinsic type, which does. Efforts to treat the stenosis and reduce the associated transstenotic gradient through placement of a stent at the site of stenosis have been studied over the past 2 decades, primarily through retrospective studies, with variable emphasis on formal visual testing and direct assessment of poststent opening pressure. Most studies have presented evidence for utilization of stenting as an alternative to cerebrospinal fluid shunting or optic nerve sheath fenestration in patients with IIH who harbor the stenosis and are refractory to or intolerant of intracranial pressure-lowering medications, but an assessment of the current data is needed to better understand the role of stenting for this patient population.

EVIDENCE ACQUISITION

A search in PubMed was made for "IIH," "papilledema," and "venous stenting." Data pre and post stenting, including symptoms attributable to IIH, intracranial pressure, papilledema, retinal nerve fiber layer thickening on optical coherence tomography, and visual field assessment (mean deviation), were collected. Need for retreatment and complications were assessed among all studies. Studies using stenting for special circumstances, such as cerebrospinal leaks or for stenosis along anomalous vessels, were reviewed.

RESULTS

In total, 49 studies (45 retrospective and 4 prospective) and 18 case reports (with 3 or less patients) were found and included in the analysis, for a total of 1,626 patients. In 250 patients in whom poststent intracranial pressure was measured, the mean value was 19.7 cm H 2 O, reduced from a mean of 33 cm H 2 O. Transient visual obscurations resolved in 79.6% of 201 patients who complained of it, pulsatile tinnitus resolved in 84.7% of 515, diplopia resolved in 93% of 86 patients, and nonspecific visual symptoms such as "blurry vision" improved in 76.2% of 537 patients. Headaches resolved in 36% and improved in a further 40.7% of 1,105 patients in whom they were documented before stenting. Of 1,116 with papilledema, 40.8% demonstrated resolution and 38.2% improvement. The mean retinal nerve fiber layer thickness improved from 170.2 µm to 89.2 µm among 402 eyes in which optical coherence tomography was used to measure it. Among 135 eyes in which formal visual fields were performed pre and post stenting, the prestent average mean deviation of -7.35 dB improved to -4.72 dB after stenting. Complications associated with stenting included in-stent stenosis or thrombosis, subdural hematoma, intracerebral hematoma, cerebral edema, stent migration, and death. A recurrence of symptoms requiring a follow-up surgical intervention occurred in 9%.

CONCLUSIONS

A growing body of evidence supports the use of venous sinus stenting as a viable option for medically refractory IIH, especially when papilledema threatens visual function. Complication and failure rates seem to be similar to alternative surgical approaches, although serious neurological sequalae can rarely occur. Emerging studies evaluating stent type, including novel stents designed for use in the venous system, may help improve ease of the procedure and long-term success rates. Prospective head-to-head studies are needed to better understand the performance of stenting compared with other interventions.

Estimation of venous sinus pressure drop in patients with idiopathic intracranial hypertension using 4D-flow MRI

OBJECTIVE

We aimed to explore a non-invasive estimate of pressure drop in patients who undergo venous sinus stenting to treat idiopathic intracranial hypertension (IIH).

METHODS

This prospective study included 28 IIH patients scheduled for venous stenting. 4D-flow MRI was acquired 24-48 h before venous manometry. Manometry-obtained pressure drop (Mp) was dichotomized into low (Lp: 0-8 mmHg) and high (Hp: 8-30 mmHg) groups. Hemodynamic indices were compared between Lp and Hp. Trans-stenotic pressure drop was estimated by work-energy equation, simplified Bernoulli equation, vorticity magnitude, and velocity difference between inlet and outlet and was compared with Mp. Measurement agreement, correlation, and accuracy were evaluated using the κ coefficient, Pearson's r, and confusion matrix-derived accuracy.

RESULTS

Among 28 patients (mean age 38.8 ± 12.7), 19 (67.9%) were female. Work-energy equation-estimated pressure drop (WEp) had strong correlation (r = 0.91, 95% confidence interval [CI]: 0.81-0.96, p < 0.001) and high agreement (intraclass correlation coefficient = 0.90, 95% CI: 0.78-0.95, p < 0.001) with Mp. WEp classified Lp and Hp with an accuracy of 0.96. The κ value between WEp and Mp was 0.92 (95% CI: 0.78-1.00). In the work-energy equation, the viscosity energy term (V_e) had the largest weights, and the ratio of V_e to the summation of the three energy terms was 0.93 ± 0.07. V_e had strong correlation with mVort (r = 0.93, 95% CI: 0.85-0.97, p < 0.001), and mean vorticity magnitude was significantly elevated in Hp compared to that in Lp (259.8 vs. 174.9 mL/s, p < 0.001).

CONCLUSION

Trans-stenotic pressure drop in IIH can be estimated using the work-energy equation with favorable accuracy.

KEY POINTS

• Trans-stenotic pressure drop in patients with idiopathic intracranial hypertension can be estimated accurately with the work-energy equation using the 4D-flow MRI full velocity field. • Compared with traditional venous sinus manometry, the 4D-flow MRI-derived pressure drop is totally non-invasive and cost-saving. • 4D-flow MRI may help neurointerventionalist to select IIH patients suitable for venous sinus stenting.

Prediction of the trans-stenotic pressure gradient with arteriography-derived hemodynamic features in patients with idiopathic intracranial hypertension

The pathogenesis of idiopathic intracranial hypertension (IIH) is attributed to segmental stenosis of the venous sinus. The current treatment paradigm requires a trans-stenotic pressure gradient of ≥8 mmHg or ≥6 mmHg threshold. This study aimed to develop a machine learning screening method to identify patients with IIH using hemodynamic features. A total of 204 venous manometry instances (n = 142, training and validation; n = 62, test) from 135 patients were included. Radiomic features extracted from five arteriography perfusion parameter maps were selected using least absolute shrinkage and selection operator and then entered into support vector machine (SVM) classifiers. The Thr8-23-SVM classifier was created with 23 radiomic features to predict if the pressure gradient was ≥8 mmHg. On an independent test dataset, prediction sensitivity, specificity, accuracy, and AUC were 0.972, 0.846, 0.919, and 0.980, respectively (95% confidence interval: 0.980-1.000). For the 6 mmHg threshold, thr6-28-SVM incorporated 28 features, and its sensitivity, specificity, accuracy, and AUC were 0.923, 0.956, 0.935, and 0.969, respectively (95% confidence interval: 0.927-1.000). The trans-stenotic pressure gradient result was associated with perfusion pattern changes, and SVM classifiers trained with arteriography perfusion map-derived radiomic features could predict the 8 mmHg and 6 mmHg dichotomized trans-stenotic pressure gradients with favorable accuracy.