A New Insight in Nonaneurysmal Subarachnoid Hemorrhage: The Potential Role of the Internal Jugular Veins.

Abstract

Causes of the nonaneurysmal subarachnoid hemorrhage (na-SAH) are still debated. Many studies confirmed the possible involvement of the intracranial venous system, in particular variants of the basal vein of Rosenthal. The aim of this study is to investigate the role of extracranial venous system, in particular the jugular drainage, in the na-SAH pathophysiology. This is a multicenter retrospective study including patients suffering from na-SAH who were radiologically screened to exclude vascular malformations. The course of the internal jugular veins was evaluated to reveal any stenosis (caliber reduction >80%). Particular attention was paid at the passage between the styloid process and the arch of C1 to detect possible compression. As a control group, we enrolled patients who underwent CT angiograms and/or cerebral DSAs in the past 2 years. We included 194 patients. The na-SAH group consisted of 94 patients, whereas the control group consisted of 100 patients. Fifty patients of the control group underwent a CT angiography for an ischemic cerebrovascular disease or trauma and 50 patients for an SAH due to a ruptured aneurysm. A significant jugular stenosis was found in 49 (52.1%) patients in the na-SAH group and in 18 (18%) patients in the control group. At univariate and multivariate analysis, the difference was statistically significant (p < 0.0001). This is the first study investigating the correlation between jugular stenosis and the occurrence of na-SAH. The impaired venous outflow due to reduced venous caliber could result in an engorgement of the upstream intracranial veins with transient hypertensive phases facilitating ruptures. Further larger prospective studies are necessary to confirm these data.