A retrospective longitudinal analysis of risk factors, treatment outcomes and imaging parameters of ventricular collapse in idiopathic intracranial hypertension

Ventricular collapse is a prevalent yet poorly understood complication of ventriculo-peritoneal shunting (VPS) in idiopathic intracranial hypertension (IIH). By identifying the risk factors of ventricular collapse (VC), this study aims to characterize the clinical progression and treatment of IIH and its complications. The relationships between ventricular area, symptoms and treatments were assessed longitudinally with ventricular segmentation on MRI/CT imaging, and correlated with other risk factors of IIH and VC. We retrospectively reviewed 147 patients who underwent VPS for IIH at our Institution, and identified 73 shunt-naïve subjects. Manual segmentation of CT/MRI scans was performed at each clinical stage (baseline, post-shunting, post-collapse and after each intervention). Variables collected included valve type and opening-pressure, shunt revisions, use of anti-siphoning devices (ASD), comorbidities, venous sinus hypoplasia/stenosis, stenting, general demographics. Linear univariate regression models were used to determine the association between individual risk factors and VC, and quantitatively assess the effect of treatment. Two multivariate models were tested, including Pre-Shunting and Post-Shunting variables, to quantify their association with VC. Of 73 IIH patients with new shunts, 32 experienced collapse (uni- or bilateral, 26.5% of the total). In shunt-naïve patients, collapse was associated with pre-shunting (rho = −0.36; p = 0.001) and post-shunting ventricular area (rho = 0.62; p = 0.0002). Both collapse and ventricular area were correlated with shunt-related symptoms at 6 months (rho = −0.29; p = 0.01). Shunt adjustment, addition of ASDs, valve replacement proved to be effective strategies to re-expand the ventricles and reduce symptoms. Nonetheless, a significant fraction of patients remained symptomatic after multiple treatments, suggesting a complex etiology for VC. On univariate analysis, catheter revisions were more common in the VC group, while the multivariate model with Post-Shunting factors was significantly associated with VC. In newly VP-shunted IIH patients, small ventricular area predisposes to collapse and headaches, while higher valve settings and ASDs may reduce the risk of collapse and promote symptomatic improvement. Within the restraints of a retrospective analysis, this study is the first to analyze the risk factors of VC in IIH patients, longitudinally integrating the clinical progression with ventricular imaging. Further studies are warranted to better understand the clinical progression of collapse.