The River study: the first prospective multicenter trial of a novel venous sinus stent for the treatment of idiopathic intracranial hypertension

The River stent is the first stent specifically designed for intracranial venous sinuses. We report the 1-year results of the River trial, performed to obtain Humanitarian Device Exemption approval of the River stent in the United States (US). The River trial was a prospective, open-label, multicenter, single-arm trial which enrolled 39 subjects at 5 US centers. Eligible patients had clinical diagnosis of idiopathic intracranial hypertension (IIH) with severe headaches or visual field loss and had failed medical therapy. The primary safety endpoint was the 1-year rate of major adverse events compared with cerebrospinal fluid (CSF) shunting using historical controls. The primary benefit endpoint was a composite at 1 year of clinical improvement and absence of venous sinus stenosis. Secondary endpoints included improvement in pulsatile tinnitus, visual symptoms, quality of life (QOL) scores, and medications. All procedures were technically successful. There was one serious adverse event, a gastrointestinal hemorrhage observed 2 months after the procedure while the patient was still on dual antiplatelet therapy. The primary safety endpoint was met with a rate of major adverse event of 5.4% versus 51.7% for CSF shunts. The primary benefit endpoint was achieved in 60% of trial participants. Additional improvements were also observed in opening CSF pressure, headaches, papilledema, pulsatile tinnitus, visual symptoms, and QOL scores. Post hoc analysis demonstrated that subjects with minimal or absent papilledema at baseline showed similar improvement compared with subjects with papilledema at baseline, in terms of headaches, pulsatile tinnitus, and QOL. The River study 1- year results establish safety and suggest efficacy for venous sinus stenting in IIH subjects who have failed medical therapy.