El Hajj, Gerard

Background: Pulsatile tinnitus (PT) is frequently caused by venous sinus stenosis and may be associated with idiopathic intracranial hypertension (IIH). Venous sinus stenting (VSS) directly addresses venous outflow obstruction and has emerged as a therapeutic option; however, outcome data remain heterogeneous. We performed an updated systematic review and meta-analysis to evaluate the efficacy and durability of VSS for PT and to compare outcomes between IIH-associated and isolated PT. Methods: MEDLINE, Scopus, and Web of Science were searched from inception through December 2025 following PRISMA guidelines. Clinical studies reporting PT outcomes after VSS were included. Random-effects meta-analyses of proportions were conducted to estimate pooled rates of overall improvement, complete resolution, and recurrence. Prespecified subgroup analyses compared IIH versus isolated PT. Results: Thirty-two studies comprising 850 patients were included (641 with IIH; 209 with isolated PT). Venous sinus stenosis accounted for 90.3% of treated etiologies. The pooled rate of overall PT improvement was 89.8% (95% CI, 85.5-92.9). Complete resolution occurred in 87.1% (95% CI, 82.5-90.6). Recurrence at last follow-up was 10.9% (95% CI, 8.3-14.2). Improvement and complete resolution rates did not differ significantly between IIH and isolated PT. Recurrence was higher in IIH (12.0%) than in isolated PT (5.7%), without reaching statistical significance. Conclusions: VSS is associated with high rates of PT improvement and complete resolution with low recurrence. Recurrence trends appear higher in IIH, suggesting underlying pathophysiology may influence durability.

Background Animal models are essential for evaluating endovascular device safety and efficacy. Rats offer advantages, such as genetic manipulability, lower cost, and shorter healing and breeding cycles, compared to large animals. These features support studying aneurysm healing mechanisms and enable high-throughput testing. We developed an optimal rat aneurysm model for device evaluation. Methods Saccular aneurysms were created at the origins of the left renal artery (LRA) with acetylsalicylic acid (ASA) (LRA/ASA group, n = 7); the right common iliac artery (RCIA) with ASA alone (RCIA/ASA group, n = 6) or ASA plus clopidogrel (CLP) (RCIA/ASA + CLP group, n = 7); and the left common iliac artery (LCIA) with ASA + CLP (LCIA/ASA + CLP group, n = 7). The origins of these arteries were surgically exposed. During temporary ligation of the vessel origin, the vessel was bisected and endoluminal elastase was incubated in the proximal stump for 10 min, followed by release of the proximal ligation and permanent ligation of the stump. Angiographical and histological analysis were performed 4 weeks post-procedure. Results Follow-up digital subtraction angiography revealed mean ± standard deviation aneurysm height/neck dimensions of 1.2 ± 0.4/1.2 ± 0.1, 2.9/3.1, 2.3 ± 0.6/1.9 ± 0.3, and 2.1 ± 0.6/2.0 ± 0.4 mm for the LRA/ASA, RCIA/ASA, RCIA/ASA + CLP, and LCIA/ASA + CLP groups, respectively. The survival rate was 29%, 17%, 71%, and 86% in the LRA/ASA, RCIA/ASA, RCIA/ASA + CLP, and LCIA/ASA + CLP groups, respectively. Histopathological analysis of these aneurysms confirmed the absence of the internal elastic lamina and revealed aneurysmal changes in the arterial wall, resembling the pathological findings observed in human aneurysm specimens. Conclusions Common iliac aneurysm models with ASA + CLP can be used to evaluate the safety and efficacy of endovascular devices.

Purpose Large aneurysms have a higher rupture risk, yet no available in vivo animal model consistently produces large aneurysms for testing endovascular therapies. Recent research suggests that adding calcium chloride (CaCl 2 ) to elastase yields larger aneurysms in a surgical rabbit model. We evaluated whether this effect translates to an endovascular approach by comparing aneurysm sizes created using elastase alone versus a CaCl 2 –elastase combination. Methods Aneurysms were created in the right common carotid artery of New Zealand rabbits. One group received 1 mL porcine elastase; the other received elastase plus 0.055 g CaCl 2 (0.5 M). After four weeks, patency was confirmed via digital subtraction angiography. Two blinded co-authors measured the neck, width, and height of the aneurysms. Aneurysm volumes were estimated using AngioCalc.com. Statistical analyses were performed using either the Mann–Whitney U -test or t -test based on data distribution. Results Twenty-nine (29) New Zealand rabbits were included in the study: six in the CaCl 2 and elastase groups, 23 in the elastase-alone group. All induced aneurysms remained patent at follow-up. Mean neck size was significantly larger in the CaCl 2 + elastase group than in the elastase-alone group (4.4 ± 1.1 mm vs 3.5 ± 0.95 mm; respectively, p = 0.02). Differences in width (4.1 ± 0.92 mm vs 3.4 ± 0.36 mm; p = 0.06), height (9.0 ± 1.1 mm vs 9.1 ± 2.1 mm; p = 0.46), and volume (83.5 ± 38.35 mm ³ vs 53.0 ± 16.94 mm³; p = 0.11) were not significant between CaCl 2 + elastase and elastase-alone, respectively. Conclusions CaCl 2 modestly increased neck size but did not significantly enlarge overall aneurysm dimensions. Further studies are needed to assess its utility in endovascular aneurysm models.

Background/Objectives: Idiopathic intracranial hypertension (IIH) often features dural venous sinus stenosis; venous sinus stenting (VSS) improves venous outflow and intracranial pressure, but most stents are off-label, and few are engineered for intracranial venous anatomy. The aim was to synthesize animal models relevant to IIH/VSS, catalogue stents used clinically for VSS and summarize corresponding animal data, appraise current preclinical VSS research, and propose a pragmatic preclinical evaluation framework. Methods: We performed a targeted search (PubMed, Web of Science, Scopus; through to May 2025), dual-screened the records in Nested Knowledge, and extracted the model/device characteristics and outcomes as per the predefined criteria. Results: We identified 65 clinical VSS studies; most were retrospective and used off-label carotid/peripheral/biliary stents (Precise, Zilver, and Wallstent were the most frequent). Recent dedicated systems (River, BosStent) have limited animal evidence; VIVA has GLP porcine venous peripheral data demonstrating its patency, structural integrity, and benign healing outcomes. Rodent models reproduce obesity/androgen drivers with modest, sustained ICP elevation; large animal models show the technical feasibility of in sinus implantation, but no chronic focal venous stenosis model fully mirrors the IIH condition. Conclusions: Despite broad clinical uptake, the translational underpinnings of VSS in IIH remain incomplete: most devices lack intracranial venous-specific preclinical validation, and there is no existing animal model that recapitulates both IIH biology and focal sinus stenosis.

Cerebrospinal fluid venous fistulas (CSFVF) can lead to spontaneous intracranial hypotension, causing debilitating symptoms in patients. The transvenous embolization technique has been developed to occlude leakage sites via an endovascular approach. However, the spinal venous anatomy remains relatively unfamiliar to many neurointerventionalists. This technical video presents a swine model designed to train physicians in navigating the spinal venous system, performing embolization injections, observing their spread, and testing new embolization systems for treating CSFVF. Although there are slight anatomical differences, the spinal venous system in swine closely resembles that of humans, including its navigability and employing liquid embolic agents. We successfully embolized multilevel spinal vasculature that can potentially drain into a fistula formation, without any complications.

We have developed a cost-effective method to study the fate of stents, particularly flow diverter stents placed in the abdominal aorta, in a rat model. This technique utilizes (caudal) tail artery access,1–5 thereby avoiding the need for surgical exposure of the femoral or carotid arteries and reducing procedural invasiveness,6 7 aligning with the principles of refinement and reduction in animal research.7 This approach may be particularly beneficial for studies requiring multiple or iterative vascular access. The use of ultrasound guidance further reduces costs and infrastructure requirements by eliminating the need for specialized angiography suites.8 This makes this technique accessible to a broader range of research settings, promoting wider adoption and collaboration in the field of endovascular research. A detailed demonstration of this method is provided in the accompanying educational video (video 1). Video 1 -Technical video describing the tail artery access and flow diverter deployment using ultrasound guidance.