Extracranial venous stenosis is an unlikely cause of multiple sclerosis

Abstract

Background: Extracranial venous stenosis (EVS) has recently been implicated as the primary cause of multiple sclerosis (MS).

Objective: The aim of this study was to determine the presence of EVS in MS patients.

Methods: We performed selective extracranial venography on 42 patients with early MS (EMS): clinically isolated syndrome (CIS) or relapsing-remitting MS (RRMS) of less than 5 years duration, and late MS (LMS): RRMS of more than 10 years duration. Magnetic resonance imaging (MRI) and clinical relapse data were reviewed for all patients with EVS.

Results: EVS was present in 7/29 patients with EMS and 12/13 patients with LMS, a highly significant statistical difference (p< 0.001). Only 3/42 patients (all in the LMS group) had two vessel stenoses, while the rest had only one vessel involved. EVS was seen in 1/11 patients with CIS compared with 6/18 RRMS patients of less than 5 years duration. Disease duration was greater in patients with EVS overall (p < 0.005). LMS remained an independent predictor of EVS following multivariate adjustment for gender, age at disease onset and Expanded Disability Status Scale (EDSS) (Adjusted Odds Ratio = 29 (3-298); p = 0.005]. Within the EMS group, patients with (n = 7) and without (n = 22) EVS had similar EDSS and disease duration, suggesting similar disease severity. No clear correlation could be found between site of EVS and anatomic localization of either clinical relapses or MRI gadolinium-enhancing lesions.

Conclusions: We conclude that EVS is an unlikely cause of MS since it is not present in most patients early in the disease and rarely involves more than one extracranial vein. It is likely to be a late secondary phenomenon.