Possibilities of the Use of Standard Duplex Ultrasound Scanning in Diagnostics of the Microcirculatory Disorders in Patients with Varicose Disease

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Introduction - duplex ultrasound scanning (DUS) is a standard examining procedure in patients with varicose disease (VD). DUS gives sufficient information on the anatomy and function of the superficial, deep, and perforator (PV) veins. A complete examination should include assessment of microcirculatory bed as a key parameter in the pathogenesis of trophic disorders. Capillaroscopy, percutaneous oximetry, and laser Doppler imaging are traditionally used for the evaluation of microcirculation. New generation ultrasound scanners provide a possibility of imaging the microcirculatory bed by using Superb Micro-Vascular Ultrasound Imaging (or SMI mode) with high accuracy, but still indirectly. However, all these methods require additional equipment. Microcirculatory bed may be assessed with the help of a standard DUS device. PVs of the distal part of the medial surface of the lower leg are the main draining vessels of the superficial tissues in this region. Right next to a PV there is an arterial branch (perforator artery, PA), which feeds the vascular wall of the PV on the epiphasic level, fascia, hypoderma, and dermis in this region; altogether these vessels form the microcirculatory bed. Therefore, assessment of the hemodynamic parameters of the perforator vessels can provide important information about microcirculation. Methods - the study included 195 subjects with VD. Patients with concomitant arterial pathology were not included in the study. Distribution of the patients according to the CEAP clinical classification of chronic venous disorders was as follows: 78 subjects – class C2, 39 - C3, 52 - C4, 26 – C5/C6. The study was performed using a Medison SonoaceX8 scanner. Anatomy and function of the superficial, deep, and perforator veins were determined. Blood flow velocity and resistive indexes were assessed in the perforator arteries. Results - the most frequently encountered PVs were those localized on the medial surface in the distal part of the lower leg (Table № 1). Interestingly, low resistive indexes were accompanied by normal systolic peak and high diastolic velocities. In addition, pseudopulsating flow was detected in 50% of PVs. According to the DUS criteria, these are direct signs of arteriolo-venular shunting (AVS). Statistical analysis showed significant differences in this parameter between the patients with CEAP classes C2 and C3, C3 and C4 (P <0.05), and classes C4 and C5/C6, despite the fact that the values varied (C4 - 0.83, C 5/C6 - 0.81). Our study confirmed the presence of a perforator vascular bundle. Analysis of the characteristics of the blood flow through the perforator vessels has revealed that there were ultrasound signs of the presence of AVS in areas of trophic changes, which requires appropriate therapies. Moreover, initial signs of AVS were detected in patients with edema, i.e. no trophic changes. Changes in the microcirculation begin at clinical class C3. Conclusion - Standard duplex ultrasound scanners may be useful in assessing microcirculation in patients with trophic changes due to varicose disease.