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Objective
Chronic cerebrospinal venous insufficiency (CCSVI) has been implicated in the etiology of multiple sclerosis (MS), with truncular venous malformations leading to stenosis of the jugular (IJV) and azygous veins and result in insufficient drainage of the cerebrospinal venous circulation. Consistent with this theory is an increased mean transit time in MRI perfusion studies and histology showing hemosiderin deposits and pericapillary fibrin cuffs. This study prospectively evaluated patients with MS for the presence of CCSVI using duplex ultrasound (US), venography, and intravascular ultrasound (IVUS).
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Methods
This prospective analysis was performed under IRB approval (IRB# 2010-186, August 2010). One hundred consecutive patients with MS were screened by US using parameters of flow direction (reflux), B-mode abnormalities (stenosis, webs, septum), obstructed flow, and decreased venous area below 0.4 cm2 (no widening in the supine position). CCSVI was positive if two or more of these criteria were found with those patients undergoing venography with IVUS. Venous angioplasty was performed in patients with IJV or azygous stenosis by venography confirmed by IVUS. Balloon size was guided by IVUS measurements using low-pressure balloons and prolonged inflation times. Post-treatment venography and IVUS were performed in all treated patients. No stents were deployed.
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Results
US findings were positive for CCSVI in 57% of patients screened. The most common finding was abnormal flow direction with unilateral reflux in 52% and bilateral reflux in 43%; right IJV in 57% (reflux time, 0.55-1.70 seconds) and left IJV in 62% (reflux time, 0.68-2.25 seconds). Venograms were performed in 48 patients, with abnormalities in 35 (73%); right IJV stenosis (29%), left IJV stenosis (33%), and azygous stenosis (10%). IVUS imaging confirmed sclerotic, hyperplastic areas of stenosis, but also identified venographic “pseudostenosis” of the proximal IJV valve in various states of closure. In 32 patients (67%), angioplasty was performed; right IJV in 9 (28%), left IJV in 13 (41%) and the azygous vein in 4 (12.5%). Venography and IVUS were performed after angioplasty.
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Conclusions
This study describes initial observations of imaging the cervical venous circulation in patients with MS. There were a substantial number of patients with venous abnormalities; however, there was no comparative normal group. IVUS was critical in differentiating true abnormalities from venous valvular phenomena, which may prove essential in guiding intervention if a causal relationship is proven.