Abstract
Introduction
Venous sinus stenting is a well established alternative to cerebrospinal fluid diversion for the treatment of idiopathic intracranial hypertension (IIH) with associated venous sinus stenosis. During this procedure, distal guide catheter placement within the venous sinuses may be desirable to facilitate stent delivery. We report our initial experience using the TracStar LDP™ (Imperative Care, Campbell, USA, 0.088-inch inner diameter) as the guide catheter for intracranial access during venous sinus stenting.
Methods
A multi-institutional retrospective chart review of a prospectively maintained IRB-approved database was performed. Consecutive patients who underwent venous sinus stenting from 1/1/2020-9/6/2021 for IIH were included. Patient characteristics, procedural details, TracStar distal reach, outcomes, and complications were collected and analyzed.
Results
Fifty-eight patients were included. The mean age was 33.8 years and 93.1% of patients were female. Visual changes prompted evaluation in 86.2% of patients. Stent placement was successful in all patients. The TracStar LDP catheter was advanced to the location of stent placement in 97.9% of cases in which it was attempted. The large 0.088-inch inner diameter lumen enabled compatibility with all desired stent sizes ranging from six to 10 millimeters. Gradient pressure across transverse sinus stenosis dropped from an average of 19.5 mmHg pre-procedure to 1.7 mmHg post-stent placement (p < 0.001). Clinical improvement was achieved in 87.9% (51/58) of patients. There were no catheter-related complications.
Conclusion
The TracStar LDP is a safe and effective access platform for reaching treatment locations in patients who present with idiopathic intracranial hypertension and who are candidates for venous sinus stent placement.
Keywords: Idiopathic intracranial hypertension, venous sinus stenosis, venous stenting, endovascular, neurosurgery
Introduction
Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, is a disease that is characterized by headaches, visual disturbances, papilledema, tinnitus, and elevated intracranial pressures as measured by opening pressures on lumbar puncture. 1 Initial management of IIH is typically medical, however, surgical intervention is required in cases refractory to medical management or when medical management is not well tolerated. Surgical options have classically included temporizing lumbar punctures, permanent cerebrospinal diversion, and optic nerve sheath fenestration. More recently, venous sinus stenting for the treatment of IIH cases with associated venous sinus stenosis and a significant pressure gradient across the stenosis has emerged as an effective treatment for these patients.2–6 The hypothesis to explain the efficacy of this treatment option is that venous sinus stenosis causes cerebral venous outflow obstruction and resultant intracranial pressure elevation. Several studies have already demonstrated safety and efficacy of venous sinus stenting for symptomatic relief and reduction of elevated intracranial pressure.2,3,5,6 Previously published techniques for venous sinus stent placement already exist and typically utilize a guide catheter that is positioned in the internal jugular (IJ) vein, such as a 6-French NeuronMax catheter (Penumbra™, Alameda, California), 7-French shuttle sheath (Cook, Bloomington, Indiana), or Envoy catheter (Codman, Raynham, Massachusetts).3,4,6 However, tortuosity across the sigmoid sinus-internal jugular vein or transverse sinus-sigmoid sinus junction can make crossing a severe stenosis for stent deployment a challenge for the interventionalist, even when using an intermediate catheter for additional support. More distal guide catheter support within the venous sinuses themselves facilitates stent placement by requiring less forward force to advance the stent across the stenosis and also by protecting the venous sinus from the stent delivery system itself.
The Tracstar™ catheter (Imperative Care, Campbell, CA, USA) is a large bore catheter with an 0.088-inch inner diameter that has been described for intracranial access for ischemic and hemorrhagic stroke treatment.7,8 Its flexible distal segment is intended for optimum trackability to the site of an intracranial target while its stiffer proximal end provides a stable platform for interventions. While promising for the use in venous sinus stenting procedures, its use for this purpose has not been reported.
We report our initial experience using a technique in which the distal guide catheter achieves intracranial access for delivery of the venous sinus stent, with the main objective being to report the results on the safety and efficacy of the Tracstar™ catheter for this use.
Methods
After obtaining approval from each institution's institutional review board, a retrospective chart review was performed of all cases that have been performed at the study institutions from 1/1/2020-9/6/2021 of intracranial venous sinus stenting utilizing the Tracstar 088 catheter. While other techniques may have been utilized for venous sinus stenting procedures during the study period, only cases utilizing the Tracstar guide catheter were included in the study. Informed consent for the procedure and use of de-identified information for research purposes had been obtained from all individuals included in the study. Data collection was performed onto a de-identified standardized worksheet that included relevant clinical history, procedural details, clinical outcomes, and complications. Statistical analysis was performed using Microsoft Excel Version 16.52 and SPSS Version 28.0.0. Patient data and outcomes were analyzed and reported. Data are presented as mean (standard deviation) and percentage (counts). The paired t-test and was used to determine if there is a significant difference between the gradient pressure across transverse sinus before and after procedure. P value <0.05 was the threshold for statistically significance.
The venous stenting techniques varied according to the each neuro-interventionalist's preferences and practice patterns, however, the following steps were generally taken. Transfemoral arterial and venous access was obtained using a 5-French and 8-French 10-centimeter sheath, respectively. Peri-procedural anticoagulant and antiplatelet therapy was administered according to the standard practice of each neurointerventionalist Diagnostic angiography was performed through the 5-French catheter and the catheter was left positioned in the internal carotid artery on the side that produced the clearest visualization of the targeted venous anatomy. The diagnostic catheter was connected to a continuous heparinized saline flush and remained in place for the duration of the procedure. A roadmap view of the venous phase through the arterial catheter, centered over the chest (anteroposterior view) and neck (lateral view), was used to navigate the venous catheters.
The Tracstar 088 catheter was advanced under roadmap guidance over a 0.35 inch glidewire and 5-French Berenstein Select catheter (Penumbra, Almeda, California) to the jugular bulb. A new arteriogram was performed, which was centered over the intracranial circulation with the distal tip of the Tracstar catheter included in the field of view. The venous phase was then used as a new roadmap to advance the Tracstar catheter to the intended venous target and often across the area of stenosis. This was often performed over a microcatheter and microwire combination, such as an Echelon™ (Medtronic, Minneapolis, Minnesota) and Synchro2 Soft microwire (Stryker Neurovascular, Fremont, California), though exact choice of wire and catheter combinations for crossing the stenosis was at the discretion of each interventionalist Once the Tracstar catheter reached its intended target, the stent chosen for that procedure was advanced across the venous sinus stenosis and deployed in a manner suitable for that type of stent. The Tracstar was withdrawn as needed, while maintaining the position of the distal wire and stent delivery system, to make room immediately prior to or during stent deployment. After stent deployment, venous sinus manometry and a final angiographic run assessing venous phase was performed prior to removal of the Tracstar guide catheter.
Results
There were a total of 58 patients included in the study. Patient characteristics are demonstrated in Table 1. The mean age was 33.8 (10.8) years, and the vast majority of patients were female (93.1%, 54/58). Visual changes prompted evaluation in 86.2% (50/58) of patients and 82.7% (48/58) had papilledema. The other presenting symptoms included headaches (96.6%, 56/58), tinnitus (60.3%, 35/58), and vertigo (13.7%, 8/58). The mean opening pressure on lumbar puncture was 34.7 millimeters of mercury (mmHg). Of the 56 patients who had non-invasive vascular imaging prior to undergoing cerebral angiography, 36 patients (64.3%) had venous sinus stenosis. Fourteen patients (24.1%) had previously undergone cerebrospinal fluid (CSF) shunting and 38 patients (66.7%) had failed a trial of medical management.
Table 1.
Patient characteristics.
| Female, n/n (%) | 54/58 (93.1) |
| Age, average (SD) | 33.8 (10.8) |
| BMI, average (SD) | 38.0 (9.4) |
| History of smoking, n/n (%) | 24/57 (42.1) |
| Oral contraceptive use, n/n (%) | 8/58 (13.8) |
| Symptoms | |
| Headache, n/n (%) | 56/58 (96.6) |
| Visual Symptoms, n/n (%) | 50/58 (86.2) |
| Papilledema, n/n (%) | 48/58 (82.7) |
| Tinnitus, n/n (%) | 35/58 (60.3) |
| Vertigo/Nausea/Dizziness, n/n (%) | 8/58 (13.7) |
| Hearing loss, n/n (%) | 2/58 (3.6) |
| Lumbar puncture opening pressure (mmHg), average (SD) | 34.7 (11.4) |
| Stenosis on non-invasive imaging, n/n (%) | 36/56 (64.3) |
| Previously Placed CSF Shunt, n/n (%) | 14/58 (24.1) |
| Failed medical therapy, n/n (%) | 38/57 (66.7) |
| Location of Stenosis | |
| Transverse sinus, n/n (%) | 38/58 (65.5%) |
| Transverse/sigmoid junction, n/n (%) | 20/58 (34.5%) |
| Sigmoid sinus, n/n/ (%) | 3/58 (5.2%) |
| Laterality of Stenosis | |
| Right Stenosis, n/n (%) | 43/58 (74.1) |
| Left Stenosis, n/n (%) | 14/58 (24.1) |
| Bilateral Stenosis, n/n (%) | 1/58 (1.7) |
*BMI: body mass index.
Table 2 demonstrates procedural details and outcomes. Right sided venous sinus stent placement was performed in 74.1% (43/58) of patients, while 24.1% of cases were performed on the left side. There was only one case of bilateral stent placement. Slightly less than half of the procedures were performed under general anesthesia. The system was typically advanced initially to the jugular bulb over an 0.035-inch Glidewire® (Terumo, Somerset, New Jersey). Some proceduralists then used a microcatheter and microwire co-axially with the Tracstar to cross the venous stenosis, while others used a relatively stiff wire such as the Platinum Plus™ guidewire (Boston Scientific, Malborough, MA, USA). A microcatheter and microwire were used to cross the venous sinus stenosis in 65.5% of cases. The guide catheter was able to be advanced to the distal location of planned stent placement in all but one case in which it was attempted (97.9%) (Figure 1). The location of Tracstar placement prior to stent deployment was the superior sagittal sinus in eight cases, torcula in 12 cases, transverse sinus in 29 cases, sigmoid sinus in eight cases, and IJ vein in four cases. In 54 cases, a single venous stent was placed. A second stent was placed in four cases. The gradient across the area of stenosis measured an average of 19.5 millimeters of mercury prior to stent placement and 1.7 millimeters of mercury after stent placement.
Table 2.
Procedural characteristics and outcomes.
| General Anesthesia, n/n (%) | 27/58 (46.6) |
|---|---|
| Mac, n/n (%) | 31/58 (53.4) |
| Laterality of Stenting | |
| Right, n/n (%) | 43/58 (74.1) |
| Left, n/n (%) | 14/58 (24.1) |
| Bilateral, n/n (%) | 1/58 (1.7) |
| TracStar Landing Zone, n/n (%) | |
| SSS, n/n (%) | 8/58 (13.8) |
| Tor, n/n (%) | 7/58 (12.1) |
| TS, n/n (%) | 29/58 (50) |
| Sig, n/n (%) | 8/58 (13.8) |
| IJ, n/n (%) | 4/58 (6.9) |
| Location of Proximal Stent Placement Reached by TracStar | |
| Yes, n/n (%) | 46/58 (79.3) |
| No, n/n (%) | 1/58 (1.7) |
| Not attempted, n/n (%) | 11/58 (19.0) |
| Successful stent placement using TracStar, n/n (%) | 58/58 (100) |
| Microcatheter/Microwire Used for Access to Venous Target, n/n (%) | 38/58 (65.5%) |
| Procedure Time (min), average (SD) | 49.1 (37.8) |
| Fluoro Time (min), average (SD) | 23.4 (16.7) |
| Fluoro Dose (mGy), average (SD) | 896.1 (657.6) |
| Number of Stents Placed | |
| One stent placed | 54/58 (93.1) |
| Two stents placed | 4/58 (6.9) |
| Gradient Pre-Stent (mmHg), average (SD) | 19.5 (11.2) |
| Gradient Post-Stent (mmHg), average (SD), n = 45 | 1.7 (1.7) |
| Clinical Improvement | 51/58 (87.9) |
| Complications | |
| Stent Re-stenosis, n/n (%) | 2/58 (3.6) |
| Stent Thrombosis, n/n (%) | 1/58 (1.7) |
| Retreatment with Shunt or Stent, n/n (%) | 2/58 (3.6) |
| Groin hematoma requiring surgical intervention, n/n (%) | 1/58 (1.7) |
*min: minutes; mmHg: millimeters of mercury.
Figure 1.
Distal placement of Tracstar large distal platform catheter facilitates venous sinus stent placement. A. Anterior-posterior and B. Lateral x-ray demonstrates 088 Tracstar catheter in transverse sinus. The Zilver stent delivery system was advanced through the Tracstar. C. Anterior-posterior and D. Lateral x-ray demonstrates stent deployment.
In all 58 cases, venous sinus stent placement was able to be successfully performed using the Tracstar catheter. The stents utilized in this series included the Zilver® (Cook Medical, Bloomington, Indiana, USA), Precise™ (Cordis, Miami Lakes, FL, USA), Acculink™ (Abbott, Chicago, IL, USA), and Wallstent™ (Boston Scientific, Malborough, MA). The diameter of the stents ranged from six to 10 millimeters. The average procedural time was 49.1 min and the average fluoroscopy time was 23.4 min. Post-operatively, clinical improvement was seen in 87.9% (51/58) of patients. Gradient pressure across the transverse sinus stenosis dropped significantly from 19.5 (11.2) mmHg pre-procedurally to 1.7 (1.7) mmHg post-stent placement. The overall complication rate was 10.3% (6/58). The complications that were seen peri-procedurally or at follow up were stent re-stenosis in two patients, stent thrombosis in one patient, retreatment with CSF diversion or an additional stent in two cases, and one groin hematoma that required surgical intervention.
Discussion
Venous sinus stenting has become accepted as a viable option for the treatment of IIH associated with venous sinus stenosis and a significant pressure gradient of greater than or equal to 8 mmHg. 2 Adequate catheter support and an atraumatic delivery system facilitates safely crossing the venous stenosis and deliver the stent. As mentioned previously, the Tracstar catheter has previously been reported for intracranial use during mechanical thrombectomies. 3 While the stiffer proximal segment provides support as a guide catheter, the flexibility of the distal segment and beveled tip improves trackability and safety to reach intracranial targets. Distal access to the venous sinus provides significant support to both deliver the stent and protect the vein from injury as the rigid delivery systems are passed through them before the TracStar is withdrawn for stent delivery (Figure 1).
Our series demonstrated a 100% success rate in ability to perform venous sinus stenting using this technique. The Tracstar catheter was able to reach the location of stent placement in all but one case in which it was attempted, which demonstrates its ability to track to an intracranial venous sinus target in most cases. The neuro-interventionalists performing this procedure did not always attempt to access beyond the venous stenosis with the Tracstar catheter, as a more proximal location was at times thought to be sufficient for stent deployment. In nearly all cases in which they chose to do so, however, they were successful. In the one case in which the Tracstar catheter did not reach the venous stenosis despite an attempt to do so, it remained at the jugular bulb as proximal support while a Zilver stent was successfully deployed over a Platinum Plus wire across a focal stenosis at the transverse-sigmoid junction.
There were no instances of having to switch to an alternative catheter system for stent placement or ovalizing of the system requiring replacement of the Tracstar catheter. Our complication rate was 10.3%, as described above, though none of these events were found to be related to the use of the guide catheter itself. The clinical outcomes and adverse event rates in our series are similar to those reported elsewhere.3,6 Previous techniques for performing venous sinus stenting for idiopathic intracranial hypertension successfully have all ready been reported elsewhere.3,4,6 However, to our knowledge, this is the first multi-institutional series that describes intracranial placement of an 0.088 inch inner diameter guide catheter beyond the sigmoid sinus for venous stent deployment. Based on our aforementioned technical success of stent placement and low complication rate using this catheter, we propose that it is a reasonable option for interventionalists performing this procedure, especially for the purpose of more distal guide catheter support and protection of the venous sinuses during delivery of the stent system.
Limitations of this study include retrospective nature and lack of comparison cohort. While it is our opinion that advancing the Tracstar catheter in the intracranial venous sinuses over a microcatheter and microwire, over a Glidewire, or by itself is safe and effective, the present study does not provide a cohort for direct comparison using other systems. Comparative analysis could be considered for future studies, which could evaluate for any potential cost benefit, decrease in fluoroscopy doses, or shortened procedure times with one technique over another. However, all cases in the present series were successful in achieving the goal of the procedure. The strengths of the study include being a multi-center experience, with multiple operators of varying experience levels and institutional practices. While larger and comparative studies could be performed to validate our findings, this preliminary experience suggests that it is safe and effective to perform venous sinus stenting using the Tracstar catheter for venous sinus access.
Conclusion
The TracStar LDP is a safe and effective access platform for reaching treatment locations in patients who present with idiopathic intracranial hypertension and who are candidates for stent placement. The high rate of technical success in accessing the pathology may be attributed to the unique design of the TracStar LDP.
Footnotes
Author contribution statement: All contributing authors met criteria for authorship and made a substantial contribution to the design of the work, data acquisition, data analysis, data interpretation, drafting and/or revisions of the manuscript.
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Ethical disclosure: This study was approved by the Institutional Review Board. IRB approval number: 2021E0963.
ORCID iD: Stephanie Zyck https://orcid.org/0000-0002-1743-1056
Funding: The author(s) received no financial support for the research, authorship, and/or publication of this article
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