Ultrasound Proof of Pre-Reflux Stages of Venous Insufficiency

Abstract

There are several attempts to explain the origin of venous insufficiency, like hereditary or acquired modifications of receptors and transmitters by wall extension or shear stress. With use of novel high-resolution ultrasound systems (12-40 MHz), valvular structures and low-flow microaggregates may be depicted. This study examined associations between the appearance of microaggregates, changes of valve cusps, valve function, and variations of vein flow (B-flow) in patients with different patterns of vein stress. There were 33 patients (21 women, 11 men; 32-58 years), including professions with >6 hours of sitting (n = 22) or standing (n = 12), with inconspicuous findings of the great saphenous vein (GSV) during routine ultrasonography (5-10 MHz) who underwent ultrasound examination with high-resolution systems (8-16 MHz, peak up to 40 MHz). A total of 120 well-depicted GSV vein valves were selected for this study. Criteria were shape, thickness, mobility, and closure mechanism of vein valves but in particular the appearance of microaggregates and the ability of the patients to resolve these aggregates by movements, simulating their daily life. Furthermore, the effects of newly worn medical compression stockings (class II) and additional daily walking distances (+3 miles) were investigated. The higher the resolution of the chosen ultrasound mode, the more intense is the appearance of low-flow pseudoaggregates, which is the basis for B-flow mode. The definition is that pseudoaggregates are always resolvable by flow increase. True microaggregates, characterized by failing dissolution or mobilization, were found within the sinus of 47 of 120 “healthy” vein valves (39.1%). Pathologic findings were more frequent in valves of subjects with sitting or standing professions (87/96; 90.6%). Focal thickenings of valve cusps could be detected only in slim patients (depth of GSV <2.5 cm; n = 11); all of them were associated with local microaggregates. Measurements after 4 weeks with medical compression stockings or increased daily walking distances did not detect relevant changes. The observations seem to support a thesis of inflammation-induced changes of vein valves; inflammation is generated by local accumulation of blood particles. Long periods with decreased or stagnant flow, typically in individuals with lack of movement or exercise, seem to promote the formation of such aggregates. However, to eliminate microaggregates or the underlying impaired venous flow, 4 weeks of medical compression stockings or walking exercise seem to be too short. As the study is continued, updates will be presented.