Stenting versus balloon angioplasty alone for idiopathic intracranial hypertension

Introduction

Idiopathic intracranial hypertension (IIH) manifests as increased intracranial pressure (ICP) without any observable intracranial mass, hydrocephalus, or venous sinus thrombosis (1). The underlying pathophysiology of IIH remains elusive; however, recent advancements in venography have revealed the presence of structural abnormalities in the cerebral venous sinuses of most patients with IIH (2,3).

Stenting for venous sinus stenosis (VSS) can effectively resolve stenotic lesions with strong and continuous radial force (4). Recent studies have repeatedly demonstrated the safety and effectiveness of stenting in the treatment of IIH and VSS (5-7), which have been evaluated by systematic reviews and meta-analyses (8,9). Although the effectiveness of balloon angioplasty alone for stenosis in the intracranial arterial system has been shown (10), comparisons between balloon angioplasty alone and stenting for treating IIH and VSS are limited. This study sought to determine whether the therapeutic efficacy of balloon angioplasty alone is comparable to that of stenting, thereby providing a treatment alternative for patients with concerns about the risks associated with stenting. We present this article in accordance with the STROCSS reporting checklist (available at https://qims.amegroups.com/article/view/10.21037/qims-24-1272/rc).

Methods

Study design and participants

We retrospectively analyzed the data of patients who were diagnosed with IIH and VSS at the First Affiliated Hospital of Zhengzhou University between January 2018 and June 2023. The diagnostic criteria for IIH were as follows (11): (I) papilledema; (II) normal neurological examination results except for cranial nerve abnormalities; (III) normal brain parenchyma without hydrocephalus, masses, or structural lesions on neuroimaging, and no abnormal meningeal enhancement or venous sinus thrombosis on magnetic resonance imaging (MRI) or magnetic resonance venography (MRV); or if MRI was unavailable, contrast-enhanced computed tomography (CT); (IV) a normal cerebrospinal fluid (CSF) composition; and (V) a raised lumbar puncture (LP) opening pressure (OP) (>25 cmH₂O in the lateral decubitus position). A diagnosis of IIH without papilledema was made if sixth nerve palsy was present and all the other features (criteria 2–5) were met. Additionally, IIH could also be diagnosed based on the following neuroimaging findings (7): (I) an empty sella; (II) flattening of the posterior aspect of the globe; and (III) dilation of the peri-optic arachnoid space with or without a tortuous optic nerve.

To be eligible for inclusion in this study, the patients had to meet the following inclusion criteria: (I) meet the IIH diagnostic criteria; (II) have a pressure variance exceeding 8 mmHg in the stenotic area; and (III) be aged ≥18 years. Patients were excluded from the study if they met any of the following exclusion criteria: (I) had undergone medical treatment alone; (II) had concomitant venous sinus thrombosis; (III) had a change in their treatment regimen during therapy; and/or (IV) had incomplete clinical information. The flow chart for patient selection is shown in Figure 1.

Figure 1 Flow chart of patient selection. IIH, idiopathic intracranial hypertension.

The data collected included demographics, clinical manifestations, risk factors, imaging data, surgical records, follow-up information, and complications. (The clinical data were mainly obtained from the First Affiliated Hospital of Zhengzhou University database, and the data collection was mainly performed by Z.X.). Lateral sinus stenosis was classified as intrinsic, extrinsic, or mixed based on digital subtraction angiography (DSA) and MRI (12). The type of stenosis was determined by two experienced neurointerventional radiologists (S.S. and L.Y. with 30 and 15 years of experience, respectively) based on imaging data. The presence of intraluminal lesions, such as arachnoid granulation (a rounded endosinusal image) and septations, was considered intrinsic stenosis; the presence of long sinus stenosis without an endoluminal image caused by compression of the venous sinus from the brain parenchyma was considered extrinsic stenosis; and the presence of both types of stenosis was considered mixed stenosis. Depending on the treatment modality, the patients were classified into the following two groups: Group S, which comprised patients who underwent stenting with or without balloon angioplasty; and Group B, which comprised patients who underwent balloon angioplasty alone. Some patients chose balloon angioplasty because they were concerned about the risks associated with stenting procedures and the occurrence of bleeding resulting from prolonged antiplatelet use.

This study was performed in accordance with the Declaration of Helsinki (as revised in 2013) and approved by the Ethics Committee of the First Affiliated Hospital of Zhengzhou University (No. 2024-KY-0605). The requirement for informed consent was waived due to the retrospective nature of the study.

Preoperative preparation

Every patient exhibited VSS on non-invasive imaging (MRV/CT venography) and consented to the procedure. Standard medications, such as antiplatelets (aspirin 100 mg/d and clopidogrel 75 mg/d) and anticoagulant (rivaroxaban 15 mg/dose, twice daily), were administered 3–5 days before surgery. All patients underwent funduscopic examination by an ophthalmologist to assess the degree of papilledema, which was evaluated based on the Frisén optic papillary edema grade criteria (13). The LP procedure was performed to measure OP.

Venography, manometry, and treatment strategies

The patients fasted from food and water for 6 h before surgery. The patient was first placed in the supine position, the inguinal and perineal areas were then routinely disinfected, and finally a sterile surgical sheet was applied. A 5F arterial sheath and 8F venous sheath (Merit Medical Systems, Inc., USA) were inserted after right femoral artery and femoral vein puncture under local anesthesia, with subsequent systemic heparinization. Initial cerebral angiography was conducted to determine the extent and degree of VSS. An 8F MACH 1 guiding catheter (Boston Scientific, Marlborough, MA, USA) or Navien^™ intracranial support catheter (ev3/Covidien, Irvine, California, USA) was then introduced into the corresponding internal jugular vein, and a Rebar-27 ev3 microcatheter (Neurovascular, Irvine, CA, USA) connected to a manometry device was used to measure intracranial venous sinus pressures distal and proximal to the stenotic segment and to determine the gradients. The pressure gradient was defined as the difference in the pressure between the distal and proximal stenotic segments, which is the key factor in determining patient candidacy for endovascular treatment (14,15). Previous studies have shown the safety and efficacy of stenting in cases where the pressure gradient of stenosis is ≥8 mmHg (14-16). All surgeries were performed after obtaining signed consent from the patient or family.

Stenting

A suitable size Wallstent (Boston Scientific Corp., Natick, MA, USA) or Protégé stent (eV3, Neurovascular, Irvine, CA, USA) was introduced along the Synchro-14 300 cm microguidewire (Boston Scientific Inc.) and released with the narrowing area as the center. Adjuvant balloon angioplasty was performed at the discretion of the neurointerventional radiologist to ensure optimal stent expansion. The success of the stenting procedure was assessed by repeat venography, which demonstrated a significant decrease in the degree of stenosis. Subsequently, the pressure at both ends of the stenosis was re-assessed and documented to evaluate the efficacy of the stent.

Balloon angioplasty alone

Both the Synchro-14 300 cm microguidewire (Boston Scientific Inc.) and balloon catheter (Sterling, Boston Scientific Inc.; Aviator Plus, Cordis, FL, USA) were used to navigate toward the center of the stenosis, and the balloon was inflated to dilate the venous sinus and held for approximately 10–20 s before being deflated. Following the deflation and removal of the balloon, angiography was repeated to examine radiographic improvement. Pressure was measured immediately postoperatively and documented.

After Dyna CT scanning to exclude intracranial hemorrhage, all patients received a subcutaneous injection of 3,000–5,000 units of low molecular weight heparin. Patients’ vital signs were closely monitored for 24 hours postoperatively. LP was repeated three days after surgery, and a funduscopic examination was performed prior to discharge. Within 3 months of surgery, the patients in Group S were administered oral dual antiplatelet agents (aspirin 100 mg/d and clopidogrel 75 mg/d), while the patients in Group B were administered oral anticoagulant drugs (rivaroxaban 15 mg/dose, twice daily on days 1–21, adjusted to 20 mg/d from day 22). Subsequent adjustments to the medication regimen were made based on imaging review.

Outcome measures

Patients were closely monitored through outpatient or inpatient follow-up to evaluate the effectiveness of the treatment. The main symptoms assessed at follow-up were headache, papilledema, visual impairment, sixth nerve palsy, and tinnitus. The primary outcome was defined as the changes in symptoms observed at 3, 6, and 12 months after the surgical intervention. Based on these changes, the patients were classified as: (I) asymptomatic: all clinical symptoms returned to normal; (II) improved: significantly improved compared with pretreatment, requiring no further intervention; and (III) unchanged or worsened: unchanged or worsened compared with pretreatment, requiring further intervention (17). The secondary outcomes were defined as an improvement in LP-OP and papilledema Frisén grade at 3 days postoperatively, and an improvement in trans-stenotic pressure gradient in the immediate postoperative period. The safety outcomes were defined as any procedural complication.

Statistical analysis

The clinical data were analyzed using SPSS version 26.0 (IBM, Armonk, NY, USA). The continuous variables are presented as the mean ± standard deviation (SD), and were compared between the two groups using the Student’s t-test. The ordinal variables are presented as the median [interquartile range (IQR)], and were compared using the Wilcoxon rank-sum test. The categorical variables are expressed as the number (percentage), and were compared using either the Pearson’s chi-square test or Fisher’s exact test. Statistical significance was defined as a P value <0.05.

Results

A total of 122 patients were enrolled in the study, including 64 patients in Group S and 58 patients in Group B. The patients had an average age of 39.95 years. The baseline data from the two groups were analyzed and compared (Tables 1,2). The patients in Group S had a longer median time from onset to treatment (2 vs. 1, P=0.013), a greater preoperative stenosis rate (80% vs. 70%, P=0.045), and a longer stenosis length (25 vs. 20, P=0.005). There were no statistically significant differences between the two groups in terms of age, sex, blood pressure, signs and symptoms, obesity or metabolic aspects (body mass index, hypertension, diabetes, hyperlipidemia, hyperhomocysteinemia, or thyroid-related diseases), female-related factors (anemia, uterine fibroids, polycystic ovary syndrome, history of oral contraceptive use, or pregnancy/miscarriage), other factors (a history of smoking, anxiety or depression, liver function abnormalities, or autoimmune-related diseases), stenosis site, type, or transverse sinus dominance (all P>0.05). The patients underwent standardized follow-up visits after the procedure, and changes in clinical symptoms were compared as the primary endpoints at discharge, and at 3, 6, and 12 months postoperatively (Figure 2). Both groups showed an improvement in symptoms, with an increasing number of patients experiencing symptom resolution over time. The proportions of patients whose symptoms (i.e., headache, sixth nerve palsy, and tinnitus at discharge) disappeared did not differ significantly between the two groups (all P>0.05). However, during the follow-up period, a significantly greater proportion of patients experienced symptom resolution in Group S than Group B (all P<0.05, Table 3).

Figure 2 Bar graphs showing symptom changes at discharge (A), 3 months (B), 6 months (C), and 12 months (D) in both groups.

The secondary outcomes were compared between the two groups based on the preoperative and postoperative papilledema Frisén grade (Figure 3), LP-OP, and stenosis pressure gradient (Figure 4). No statistically significant difference was observed between the two patient groups before surgery (all P>0.05), but the patients in Group S had a significantly lower median Frisén grade of papilledema at discharge (1 vs. 2, P<0.001), a lower mean LP-OP at 3 days postoperatively (210.86 vs. 241.12 mmH₂O, P=0.006), and a smaller mean stenosis pressure gradient measured in the immediate postoperative period (1.98 vs. 3.72 mmHg, P=0.004) than those in Group B following surgery (3).

Figure 3 Distribution of preoperative and postoperative papilledema Frisén grade in the two groups of patients. (A) Proportion of papilledema Frisén grade patients in Group S. (B) Proportion of papilledema Frisén grade patients in Group B. op, operation.

Figure 4 Graphs of individual patients preoperative and postoperative results for LP-OP and trans-stenotic pressure gradient. Changes in LP-OP in Group S and Group B (A,B). Changes in trans-stenotic pressure gradient in Group S and Group B (C,D). ***, P<0.001. LP-OP, lumbar puncture opening pressure; op, operation.

In Group S, 5 (7.8%) patients experienced complications during the follow-up period. Among these patients, 1 patient developed in-stent thrombosis but showed improvement after receiving thrombolytic therapy; 1 patient exhibited in-stent occlusion, limited stenosis relief following balloon angioplasty but showed improvement after the reimplantation of a single stent; 1 patient experienced thrombosis at the distal end of the stent but showed improvement after balloon dilatation and thrombolysis (Figure 5); and 2 patients developed stenosis distal to the stent but showed improvement after the reimplantation of 1 stent each, one of whom is shown in Figure 6. In Group B, 6 patients (10.3%) experienced complications. Among these patients, 1 patient presented with hematoma at the puncture site but showed improvement following symptomatic treatment; 4 patients exhibited in situ recurrent stenosis that was successfully managed through balloon vasodilatation; and 1 patient had mild stenosis without any accompanying symptoms and received conservative treatment. There was no statistically significant difference in the complication rates between the two groups (P>0.05). No complications related to guidewire perforation, intracranial hemorrhage, or stent displacement occurred (Table 3).

Figure 5 A 47-year-old female presented with chronic headache and blurred vision that persisted for more than 2 months, along with thrombosis that occurred 6 days after stenting. (A) Preoperative MRV: stenosis at the junction of the right transverse-sigmoid sinus. (B) Preoperative DSA: stenosis at the same location, ∆P=15 mmHg. (C) Stenosis improved after the implantation of the 7 mm × 40 mm Protege stent, ∆P=2 mmHg. (D) On the sixth postoperative day, the patient experienced another episode of headache, prompting a review of the DSA, which confirmed thrombosis at the distal end of the stent. (E) Dilatation with a 6 mm × 30 mm balloon was performed at the site of thrombus formation. (F) The postoperative result was poor, and the microcatheter was left in place to perform thrombolysis (urokinase 1,000,000 UI/d), and the patient’s coagulation ability was monitored during this period. (G) After 4 consecutive days of thrombolysis, follow-up DSA demonstrated recanalization of the vessel. (H) At six months postoperatively, repeat DSA revealed smooth blood flow through the stented segment, ∆P=1 mmHg. MRV, magnetic resonance venography; DSA, digital subtraction angiography.

Figure 6 A 52-year-old male presented with binocular diplopia for more than 2 months and was diagnosed with severe stenosis at the distal end of the stent 9 months after stent implantation. (A) Preoperative MRV: stenosis in the posterior one-third of the SSS. (B) Preoperative DSA: stenosis in the posterior one-third of SSS, ∆P=20 mmHg. (C) Dilatation with a 6*40 mm balloon was performed to address the stenosis. (D) A 7 mm × 50 mm Wallstent was implanted in the stenosis. (E) The degree of stenosis decreased compared with before, ∆P=2 mmHg. (F) Nine months after initial stenting: severe restenosis was observed distal to the previously placed stent, ∆P=9 mmHg. (G) The stenosis retracted after dilatation with a 6 mm × 40 mm balloon, and a 7 mm × 40 mm Wallstent stent was implanted again. (H) The three-month follow-up post-stenting review revealed that blood flow in the stent was smooth, ∆P=1 mmHg. MRV, magnetic resonance venography; SSS, superior sagittal sinus; DSA, digital subtraction angiography.

Discussion

In patients with drug-refractory IIH and VSS, treatment by CSF diversion surgery or optic nerve sheath fenestration (ONSF) has been shown to be effective. However, the results of a meta-analysis showed that approximately 43% of patients required additional surgical intervention after CSF shunting, and only 44% of patients experienced headache relief after ONSF (18); such results are considered unsatisfactory.

Cardona et al. (19) divided VSS into the intrinsic and extrinsic morphological types, and these types are widely thought to be involved in the physiology of IIH. For example, angulation, as an intrinsic cause, could have a significant effect on VSS and IIH development. Stent implantation is a pivotal approach in the treatment of IIH and VSS that modifies either endogenous stenosis resulting from structural obstruction in the venous sinus lumen, or exogenous stenosis caused by the compression of the venous sinus walls due to elevated ICP (20,21). The prevailing theory underlying this therapeutic approach is that the stent-assisted restoration of venous sinus outflow enhances CSF clearance (4). Raynald et al. (7) showed that the percentage of patients with complete resolution of symptoms was 58.3% at 3 months after stenting, and 80.6% at 6 months after surgery. Similarly, we found that the rates at which various symptoms disappeared at 3, 6, and 12 months after surgical stenting ranged from 48.1–63.6%, 72.7–80.8%, and 80.0–92.3%, respectively (Table 3).

The complication rate for stenting was low; however, the potential for serious complications exists. The potential complications of restenosis and thrombosis, as well as bleeding associated with prolonged antiplatelet drug usage following stent placement, should not be ignored (22). Studies have reported a restenosis rate as high as 17.7% after stenting (23), and an in-stent thrombosis rate of between 2.3–15.4% (24). Therefore, this study was conducted to determine whether the therapeutic efficacy of balloon angioplasty alone was comparable to that of stenting in patients with IIH and VSS. It was hoped that the findings would provide data in support of the use of balloon angioplasty in VSS.

Research has shown that balloon angioplasty has therapeutic outcomes comparable to those of stenting in the treatment of arterial stenosis (25); however, few studies have investigated its efficacy in the management of IIH and VSS. Consistent with our findings, Carlos et al. (4) concluded that compared with stenting, balloon angioplasty may be a short-term salvage option for patients with IIH and VSS but it should not be used as a first-line therapy. However, their study included only 62 patients and spanned a decade. The treatment of patients over such a long period and the rapid evolution of neurointerventional techniques during this period somewhat reduced the comparability of their results. Moreover, in their study, the complication rate of balloon angioplasty (11.11%) was similar to ours (10.3%), but the stent group had a lower complication rate (3.8%) than ours (7.8%).

Our study is the largest analysis to date to examine the efficacy of balloon angioplasty compared to stenting in the treatment of IIH and VSS. We found that angioplasty alone demonstrated clinical efficacy in terms of the objective and subjective clinical parameters; however, just in terms of headache, sixth nerve palsy, and tinnitus at discharge, the efficacy of angioplasty was comparable to that of stenting. During the subsequent follow-up period, the degree of improvement in the clinical symptoms of the patients treated with angioplasty was not as significant as that of the patients treated with stenting, and the proportion of asymptomatic patients remained low and increased slowly with the follow-up time, indicating that its long-term efficacy was unsatisfactory. Further, the efficacy of secondary outcomes of angioplasty were also less significant than those of stenting, and patients in Group S exhibited a significantly lower median Frisén grade of papilledema at discharge, a lower mean LP-OP at 3 days postoperatively, and a smaller mean stenosis pressure gradient measured in the immediate postoperative period than those in Group B following surgery. Notably the change in the postoperative trans-stenotic pressure gradient is an important criterion for assessing the efficacy of the intervention. Kumpe et al. (26) suggested that the postoperative trans-stenotic pressure gradient should ideally be no higher than 5 mmHg, and in our study, the median value was 1 mmHg in Group S and 2 mmHg in Group B, both of which were satisfactory. Future high-quality studies need to be conducted to determine the optimal criteria for postoperative trans-stenotic pressure gradients.

Therefore, we contend that balloon angioplasty alone should be employed as a transient therapeutic option exclusively for patients with contraindications to stenting or as an adjunct to stenting. The strict perioperative management and meticulous intraoperative management, and the selection of the right size stent for each individual patient also ensured the efficacy of stenting in this study. We prefer to use slightly longer stents to completely cover the stenotic segment, and two stents can be implanted if necessary to reduce the probability of restenosis.

No deaths were observed in our study. At the end of the follow-up period, 5 (7.8%) complications were observed in Group S, which is lower than the 13.7% treatment failure and complication rate after stenting reported in a recent meta-analysis (8). In addition to advancements in neurointerventional devices and techniques, the operator’s personal experience and meticulous attention to procedural details play a crucial role in ensuring the success rate of surgery. The majority of stenosis occurs at the junction of the transverse and sigmoid sinuses, which are characterized by a substantial angle of curvature. Due to its superior balance between support and in-place properties, the Navien™ intracranial support catheter can enhance procedural success in cases in which stent delivery poses a challenge. To reduce the incidence of restenosis, we prefer slightly larger and longer carotid stents to ensure comprehensive coverage of the stenotic site. Additionally, double stenting can be used for lesions with long stenotic segments. Although the majority of patients showed satisfactory outcomes, the challenges associated with restenosis and thrombosis must be acknowledged. Enhanced postoperative management and the regular administration of antiplatelet medication are key to reducing the incidence of complications. In Group B, there were 6 (10.3%) complications, 5 of which were in situ recurrent stenosis. This may be linked to the thinner intima-media musculature and greater elastic retraction force of the venous sinus, and may be one reason for the limited efficacy of balloon angioplasty.

Limitations

This study had several limitations. First, in patients in Group S, the period from disease onset to treatment was prolonged, and the degree and length of preoperative stenosis were more severe, which might have masked the efficacy of the stenting procedure to some extent. Second, the assessment of clinical symptom improvement primarily relied on subjective measures and did not include objective evaluation indicators or scales, which might have led to bias. Finally, this was a single-center retrospective study conducted in China with limited long-term follow-up data, which restricts the generalizability of its findings to the overall population. Therefore, in the future, multicenter, large-scale randomized controlled trials should be conducted to validate the reliability of our results.

Conclusions

We found that stenting was significantly superior to balloon angioplasty alone in the treatment of IIH and VSS. Balloon angioplasty showed short-term clinical efficacy, but as its long-term results were unsatisfactory, it cannot be recommended as a first-line treatment; instead, it can be used as a complementary or adjunctive therapy to stenting.

Acknowledgments

Funding: None.

Footnote

Reporting Checklist: The authors have completed the STROCSS reporting checklist. Available at https://qims.amegroups.com/article/view/10.21037/qims-24-1272/rc

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-24-1272/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. This study was performed in accordance with the Declaration of Helsinki (as revised in 2013) and approved by the Ethics Committee of the First Affiliated Hospital of Zhengzhou University (No. 2024-KY-0605). The requirement for informed consent was waived due to the retrospective nature of the study.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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