Case Report: Mechanical thrombectomy of cerebral venous sinuses using the NeVa stent retriever

1 Introduction

Cerebral venous sinus thrombosis (CVST) is an uncommon condition accounting for less than 1% of cerebrovascular events worldwide, yet potentially reversible when detected and treated promptly. Although it can occur at any age, it is more prevalent in women of reproductive age due to risk factors such as oral contraceptive use, hormone replacement therapy, pregnancy, and the postpartum period; nevertheless, up to 20% of cases are idiopathic (1).

Diagnosis is challenging owing to the heterogeneity of clinical manifestations, which range from isolated headache to seizures, focal neurological deficits, and altered consciousness, necessitating a high index of clinical suspicion (2, 3). Magnetic resonance venography (MRV) is the diagnostic modality of choice (4, 5), although in clinical practice the initial study is usually non-contrast head computed tomography (CT), whose sensitivity for venous sinus thrombosis signs remains limited (6).

Initial treatment consists of anticoagulation with low-molecular-weight or unfractionated heparin, followed by oral vitamin K antagonists; evidence supporting direct oral anticoagulants remains insufficient (2, 4). In the most severe cases or those with inadequate response to medical therapy, mechanical thrombectomy is considered, a technique whose indications, device selection, and optimal protocol still lack established consensus (7, 8).

The aim of this article is to present the case of a patient with extensive CVST treated by mechanical thrombectomy using a NeVa stent retriever — a device whose application in the cerebral venous system constitutes an off-label use, as it is approved for mechanical thrombectomy in acute ischemic stroke — and to discuss the potential rationale for its application in this context.

2 Case presentation

A 32-year-old woman with a history of migraine headaches and oral contraceptive use presented to the emergency department with a five-hour history of severe headache that began on awakening, associated with disorientation and right hemiparesis. She had no surgical history, no family history of thrombophilia, and no known coagulation disorders. On physical examination, she was alert, oriented in person and place but with intermittent disorientation to time. Pupils were isochoric and normoreactive, and the Glasgow Coma Scale score was 14/15. Neurological examination revealed right hemiparesis with Medical Research Council (MRC) grade 3/5 strength, mild dysarthria, and no dysmetria or meningeal signs. Vital signs on admission were as follows: blood pressure 146/89 mmHg, heart rate 77 bpm, respiratory rate 19 breaths/min, SpO₂ 98%, and temperature 36.0 °C.

The initial NIHSS score was 3 and progressed to 7 within two hours, accompanied by focal seizures; a stroke code was activated given the clinical suspicion of a wake-up cerebrovascular event.

Urgent brain magnetic resonance imaging (MRI) revealed paramagnetic artifact in supratentorial sulci consistent with convexity subarachnoid hemorrhage secondary to venous congestion, a recognized manifestation of CVST. Magnetic resonance venography demonstrated absent flow signal in nearly the entire superior sagittal sinus, the torcular herophili, bilateral transverse and sigmoid sinuses, the proximal left internal jugular vein, and the right basal vein of Rosenthal, with cortical venous dilatation and leptomeningeal enhancement (Figure 1).

These findings established the diagnosis of extensive CVST involving the superficial and deep venous systems, with no evidence of herniation or active parenchymal hemorrhage. Intravenous unfractionated heparin was initiated immediately. Given progressive neurological deterioration despite anticoagulation, the interventional radiology service was consulted for mechanical thrombectomy. The full clinical timeline from symptom onset through follow-up is summarized in Table 1.

Table 1. Clinical timeline.

On hospital day 1, cerebral angiography with mechanical thrombectomy was performed using a combined aspiration and stent retriever technique. The materials employed included a Neuron MAX guide catheter, a Red 73 aspiration catheter, a Phenom 21 microcatheter, a NeVa stent retriever (5.5 × 37 mm), and continuous flush systems with hemostatic valves.

Via femoral access, cerebral angiography confirmed occlusion of the superior sagittal sinus and bilateral transverse sinuses; the arterial system was normal (Figure 2). For the therapeutic phase, right jugular venous access was obtained, and the guide catheter was advanced to the proximal internal jugular vein. The Red 73 aspiration catheter was navigated to the right transverse sinus under fluoroscopic roadmap guidance. The Phenom 21 microcatheter was advanced coaxially to navigate the thrombosed superior sagittal sinus and to deliver the NeVa stent retriever, which was deployed with a 6-second integration time and retrieved under continuous aspiration, extracting organized thrombus fragments with each pass (Figures 3A,B). After six passes, near-complete recanalization of the superior sagittal sinus was achieved with restoration of antegrade venous drainage and no intraprocedural complications (Figures 3C,D).

Post-procedural CT showed a residual filling defect in the superior sagittal sinus with no hemorrhage or herniation. The patient demonstrated improvement in hemiparesis (MRC 4/5), although moderate-to-severe headache persisted.

On hospital day 11, the patient developed secondary intracranial hypertension documented by lumbar puncture, with an opening pressure of 33 cmH₂O. Cerebrospinal fluid analysis revealed a white blood cell count of 3/mm³ (34% segmented neutrophils, 66% lymphocytes), glucose 64.1 mg/dL, protein 49.7 mg/dL, and a negative Gram stain. The neurology service prescribed topiramate 50 mg every 12 h for headache control and apixaban 5 mg every 12 h as oral anticoagulation. The patient showed progressive symptomatic improvement and was discharged after 12 days of hospitalization, with instructions for outpatient follow-up by neurology and ophthalmology.

At the neurology follow-up visit 34 days after discharge, the patient demonstrated favorable clinical evolution with a modified Rankin Scale (mRS) score of 0, without new seizure episodes or neurological deterioration. Paresthesias attributed to topiramate prompted gradual discontinuation and transition to lacosamide 100 mg every 12 h, with no other changes in the pharmacological regimen.

3 Patient perspective

The patient initially attributed her symptoms to a migraine attack and did not seek care until limb weakness developed. After the procedure, she noticed rapid neurological improvement and expressed relief. At the 34-day follow-up visit she reported having returned to work without functional limitations. Her primary concerns were the duration of anticoagulation therapy and antiepileptic medication. She provided written consent for publication and expressed her hope that this case might benefit others in a similar situation.

4 Discussion

The simultaneous involvement of the superior sagittal, transverse, and sigmoid sinuses in our patient represents a particularly extensive thrombotic pattern. Although the superior sagittal sinus is the most frequently affected site (up to 84.6% in Latin American cohorts) (1), multisinus thrombosis of this magnitude is uncommon and carries a higher risk of clinical deterioration (1, 2). In this context, the patient's migraine history likely delayed initial diagnostic suspicion, as headache — the most frequent symptom of CVST — presented in a pattern indistinguishable from her baseline episodes (1–3). Imaging confirmed both the cord sign and the empty delta sign, classic but variably present indicators of venous sinus thrombosis whose sensitivity on non-contrast CT ranges from 25% to 56% (6).

The hemodynamic and anatomical differences between the arterial and venous systems have important implications for device selection in mechanical thrombectomy. Cerebral venous sinuses are large-caliber, thin-walled, valveless structures with luminal diameters ranging from 8 to 12 mm for the superior sagittal sinus and 5 to 10 mm for the transverse sinuses — considerably larger than the 2–4 mm caliber of typical arterial targets in acute ischemic stroke. These structures operate under low-flow, low-pressure conditions, which substantially reduce the mechanical support that arterial blood flow normally provides during stent retriever withdrawal. Furthermore, histological analysis of EVT-retrieved CVST thrombi has shown predominantly erythrocyte-rich composition with lower fibrin content compared with arterial thrombi, and variable signs of early structural organization (17); beyond what this exploratory study demonstrates, thrombus composition in CVST is known to be heterogeneous and time-dependent, and progressive fibrin deposition with advancing thrombus age may increase adherence to the sinus wall — all features potentially distinct from the softer, more homogeneous composition of acute arterial thrombi. The combination of large vessel caliber and this evolving thrombus biology suggests that devices with high mesh density may theoretically improve thrombus engagement in venous structures. These hemodynamic differences may partially explain the greater number of passes typically required in CVST compared with arterial occlusions: while the average for the NeVa in arterial studies is close to a single pass (12), our patient required six passes, reflecting the greater thrombus burden associated with extensive multisinus CVST. These considerations are summarized conceptually in Figure 4.

Given the severity of the clinical presentation and progressive neurological deterioration despite therapeutic anticoagulation with intravenous unfractionated heparin, mechanical thrombectomy was indicated. A recent technique-based meta-analysis of endovascular treatment for CVST found that aspiration alone was the most commonly employed modality (29.3%), followed by combined aspiration-plus-stent-retriever (19%) and stent retriever alone (12.5%) (8). The direct aspiration first-pass technique (ADAPT) has been described as the initial approach, with stent retrievers as the secondary alternative (9). Overall, systematic reviews report successful recanalization rates of 70%–95%, with hemorrhagic complication rates of 5%–15% (7, 8).

The NeVa stent retriever (Vesalio, Nashville, TN, United States) features a self-expanding nitinol mesh with 35 μm filaments and 115 μm pores, conferring superior mesh density compared with conventional stent retrievers. It is important to note that its use in the cerebral venous system constitutes an off-label application, as the device is approved for mechanical thrombectomy in acute ischemic stroke; this decision was individualized based on the severity of clinical presentation, progressive neurological deterioration despite therapeutic anticoagulation, and a careful risk-benefit analysis (10, 11). The CLEAR study demonstrated that its drop-zone technology enhances capture of organized thrombi in anterior circulation occlusions (10), and a meta-analysis confirmed its safety and efficacy in acute ischemic stroke (11). In real-world practice, the NeVa NET achieved recanalization in 94% of cases with an average of a single pass (12), and favorable outcomes have been reported in ST-elevation myocardial infarction (13).

To contextualize the choice of the NeVa over other commercially available stent retrievers, Table 2 summarizes the key characteristics of devices that have been used or considered for CVST. The Solitaire (Medtronic) and Trevo (Stryker) feature open-cell cylindrical mesh designs optimized for soft, erythrocyte-rich arterial thrombi in small-caliber vessels; their lower mesh density may limit thrombus engagement in large venous structures with organized clot. The Embotrap (Johnson & Johnson) incorporates a dual-layer design that improves thrombus integration but is sized for arterial targets (≤5.5 mm). In contrast, the NeVa's closed-cell architecture with higher mesh density and the availability of a 5.5 × 37 mm configuration provide greater longitudinal thrombus contact surface, which may be advantageous in the wide-diameter, organized thrombus encountered in multisinus CVST. While comparative studies in the venous setting are absent and no device has received regulatory approval for this indication, the NeVa's structural design properties provided a rational basis for its selection in our patient.

Table 2. Stent retriever design features and theoretical considerations for cerebral venous sinus thrombectomy.

Venous suitability assessments are theoretical, based solely on device design specifications and engineering principles; no head-to-head comparative data in the venous setting exist for any of these devices. J&J, Johnson & Johnson. This table is intended to illustrate design differences, not to establish superiority of any device.

Regarding integration time, the 6-second protocol applied in our patient was selected based on the manufacturer's recommendation for the NeVa stent retriever in acute ischemic stroke (Vesalio, Nashville, TN), as no dedicated venous thrombectomy protocol exists for this device. In standard arterial thrombectomy with conventional stent retrievers, integration times typically range from 3 to 5 min to allow passive thrombus ingrowth into the device interstices. The NeVa's drop-zone capture mechanism, however, is designed for mechanical thrombus engagement rather than passive ingrowth, enabling shorter integration times of 3–6 s as evaluated in the CLEAR study (10). We conservatively selected the upper limit of this range (6 s) to maximize thrombus integration within the denser mesh given the organized and fibrin-rich nature of the venous clot; in the venous context, where flow conditions are less favorable for passive thrombus capture, a slightly prolonged integration time may intuitively facilitate clot engagement, although this remains speculative. It must be acknowledged that this decision was empirical and extrapolated from arterial data; dedicated studies comparing integration times in the venous setting are needed to optimize future protocols.

Although the NeVa stent has been deployed in the venous sinus for endovascular biopsy (14), to our knowledge there are no prior reports of its use for venous thrombectomy. The landscape is actively evolving: a pilot randomized trial of a dedicated venous thrombectomy device demonstrated complete recanalization in 76.7% versus 20% in controls (15), and venous sinus stenting has been used for idiopathic intracranial hypertension and dural arteriovenous fistulas (16). Although other arterial stent retrievers have been used in CVST (7, 8), the distinctive feature of our case is the use of the NeVa, whose higher mesh density may provide a plausible biomechanical advantage for organized venous thrombi in large-caliber sinuses.

The secondary intracranial hypertension (opening pressure 33 cmH₂O) documented in our patient is a recognized complication of CVST that may occur regardless of the therapeutic modality employed and requires specific follow-up and management (4, 5).

This case suggests that the NeVa stent may constitute a viable off-label therapeutic alternative in extensive CVST, particularly when: aspiration alone is insufficient or not feasible; the thrombus is predominantly organized; multisinus involvement is present; or there is progressive neurological deterioration despite anticoagulation. Nevertheless, this report carries the inherent limitations of a single case, which precludes generalization of results or establishment of comparative efficacy. The follow-up period of 34 days is insufficient to assess long-term functional outcomes or thrombotic recurrence; thrombophilia screening results were not available; and no standardized neurocognitive tests were performed to objectively document functional recovery. Larger case series, comparative studies with other thrombectomy techniques, standardized device selection protocols, and cost-effectiveness analyses are needed (4, 5).

5 Conclusion

Mechanical thrombectomy using a NeVa stent retriever was successfully performed in an off-label fashion in a patient with extensive CVST and progressive neurological deterioration. The device achieved near-complete recanalization of the superior sagittal sinus with restoration of antegrade venous drainage and no intraprocedural complications. At 34-day follow-up, the patient had an mRS score of 0. The NeVa's higher mesh density and closed-cell design, when compared with conventional open-cell retrievers, provide a plausible biomechanical rationale for further investigation in the venous setting — though superiority cannot be established from a single case. This report expands the therapeutic options considered for severe CVST and underscores the need for larger studies evaluating the safety, efficacy, device selection criteria, integration time optimization, and cost-effectiveness of endovascular approaches in the cerebral venous system.

Generative AI statement

The author(s) declared that generative AI was not used in the creation of this manuscript.

Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us.

Publisher's note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Footnotes

Edited by: Francesco Tiralongo, A.O.U. Policlinico San Marco, P.O. "G.Rodolico", Italy

Reviewed by: Shail Thanki, Ochsner Lafayette General Hospital, United States

Fatma Shakarchi, University of Arkansas for Medical Sciences, United States