Maple Grove, Minn., July 22, 2026
Serenity Medical announced new four- to five-year clinical data demonstrating the long-term effectiveness of its River Stent™ System for treating Idiopathic Intracranial Hypertension (IIH) during a late-breaking presentation at the Society of Neurointerventional Surgery (SNIS) 23rd Annual Meeting. The findings from the multicenter River Study, the first evaluation of the purpose-built venous sinus stent for IIH, showed durable clinical, radiological, and patient-reported improvements across headache burden, vision, quality of life, and imaging outcomes. Researchers reported that the benefits observed during the first year of treatment remained stable or continued to improve through five years of follow-up, with no evidence of in-stent stenosis or thrombosis. The results further strengthen the evidence supporting the FDA-approved River Stent™ as a long-term treatment option for adults with severe, refractory IIH who do not respond adequately to medical therapy.
River Study Demonstrates Sustained Clinical Improvements
The long-term follow-up confirmed that patients receiving the River Stent™ experienced lasting symptom relief and continued neurological improvement years after treatment. Investigators reported that 90% of patients achieved clinically meaningful improvement in headache burden by the fifth year, with no rebound increase in headache severity during follow-up. In addition, papilledema, the swelling of the optic nerve associated with elevated intracranial pressure, resolved in 95.7% of participants by the second year and reached 100% resolution during years four and five. Significant gains in quality of life were also maintained throughout the study period without evidence of long-term decline. Importantly, these favorable outcomes were observed regardless of patient weight loss, suggesting that venous sinus stenting provided independent therapeutic benefits for carefully selected IIH patients. Investigators highlighted the purpose-engineered design of the River Stent™ as a key factor supporting its durable long-term performance.
FDA Approval Marks Major Advancement for IIH Treatment
Idiopathic Intracranial Hypertension is a serious neurological disorder characterized by elevated intracranial pressure, often leading to chronic headaches, progressive vision loss, cognitive impairment, and reduced quality of life. The disease disproportionately affects overweight women between 20 and 50 years of age, and its prevalence continues to rise. Until recently, treatment options for patients with severe disease remained limited. In March 2026, the U.S. Food and Drug Administration (FDA) granted Humanitarian Device Exemption (HDE) approval to the River Stent™, making it the first FDA-approved cerebral venous sinus stent specifically indicated for adults with severe, refractory IIH who are resistant or intolerant to medical therapy. The approval covers patients with significant venous sinus stenosis who continue to experience severe headaches or vision-threatening symptoms despite at least six months of conservative treatment, including weight-loss efforts where appropriate.
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Serenity Medical Expands Neurovascular Innovation Portfolio
Beyond the success of the River Stent™, Serenity Medical continues to expand its position in neurovascular medical technology through strategic product development and commercialization initiatives. The company recently established a partnership with Radical Catheter Technologies to accelerate commercialization of the River Stent™ while combining advanced neurovascular access and delivery catheter technologies to broaden patient access. Serenity is also advancing its Shepherd Stent™ System, which received FDA Breakthrough Device Designation in June 2026 for the treatment of severe pulsatile tinnitus, further strengthening its portfolio of innovative venous sinus technologies. With encouraging long-term evidence demonstrating sustained symptom relief, improved vision, enhanced quality of life, and durable device performance, the River Stent™ continues to establish itself as an important FDA-approved medical device for patients living with severe Idiopathic Intracranial Hypertension.
Source: Serenity Medical press release
