Incompetence of internal jugular vein valve in patients with transient global amnesia

Abstract

Transient global amnesia (TGA) could be related to acute ischemic disturbances in mesial parts of temporal lobes, which are important for memory. Incompetence of internal jugular vein (IJV) valve with venous congestion causes venous microthrombosis of hippocampus. The aim of this study was to investigate the frequency of IJV valve incompetence, as well as other hemodynamic and structural properties of cerebral circulation in TGA patients. IJV valve competence was investigated in 40 TGA patients and 30 persons of the control group (matched by age and sex), as well as detection of microembolic signals and detection of right to left cardiopulmonal shunt, cerebral vasomotor reactivity and echocardiography by color triplex ultrasonography and transcranial doppler. A significant difference in frequency of IJV valve incompetence was found between the TGA patients and the control persons (55% TGA vs. 30% controls; p < 0.001). We did not find a significant structural (plaques frequency) or hemodynamic (flow velocity, pulsatility index) differences on arteries of the neck and cerebral arteries between the TGA patients and the controls, except for the increased pulsatility index on the basilar artery (40% TGA vs. 16.6% controls; p < 0.01) and decreased vasomotor reactivity in TGA patients (50% TGA vs 26.6% controls;p < 0.001). Microembolic signals were detected very rarely (17.5% TGA patients vs. 13.3% controls; p > 0.05), as well as right to left cardiopulmonal shunt (15% TGA vs. 16.6% controls; p > 0.05), indicating that embolism was not important for pathogenesis of TGA. Transesophageal echocardiography confirmed it, because only one TGA patient had a potent foramen ovale. We found a significantly increased frequency of IJV incompetence in the TGA patients, which confirmed the role of vein drainage disturbances in pathogenesis of TGA.