A Retrospective Longitudinal Analysis of Risk Factors, Treatment Outcomes and Imaging Parameters of Ventricular Collapse in Idiopathic Intracranial Hypertension

Abstract ObjectiveVentricular collapse is a prevalent yet poorly understood complication of ventriculo-peritoneal shunting (VPS) in patients with idiopathic intracranial hypertension (IIH). By identifying and describing the risk factors of ventricular collapse (VC), this study aims to characterize the clinical progression, etiopathogenesis and treatment of IIH and its complications. The relationships between ventricular size, symptoms and treatments were also assessed longitudinally with ventricular segmentation on MRI/CT imaging, and correlated with other risk factors of IIH and VC. MethodsWe retrospectively reviewed records of 147 patients who underwent VPS for IIH at our Institution, and identified 73 shunt-naïve subjects included in the final analysis. Manual segmentation of CT/MRI scans was performed longitudinally 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 and stenting, and general demographics. Linear univariate regression models were used to determine the association between individual risk factors and VC, and to quantitatively assess the effect of treatment. Two multivariate models were also tested, including Pre-Shunting and Post-Shunting variables, to quantify their association with VC. ResultsOf 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 size (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, and valve replacement proved to be the most effective strategies to re-expand the ventricles and reduce symptoms. Nonetheless, a significant fraction of patients remained symptomatic after multiple treatments, suggesting a complex and multifactorial etiology for VC. On univariate analysis, catheter revisions were more common in the VC group, while the multivariate model with Post-Shunting risk factors proved to be significantly associated with VC. ConclusionsIn newly VP-shunted IIH patients, small ventricular size predisposed to collapse and headaches, while higher valve OPs 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 prospective studies are warranted to better understand the etiopathogenesis and clinical progression of collapse.