The use of ultrasound in the evaluation of the efficacy of calf muscle pump function in primary chronic venous disease

Objectives: To evaluate popliteal vein blood flow during calf muscle contraction in chronic venous disease (CVD) patients and healthy controls using ultrasound imaging and to investigate the relationship between venous blood flow and gastrocnemius muscle (GM) morphology. Methods: Thirty-one subjects participated in this study (mean age: 40.3 [11.8] years), 15 healthy controls and 16 with CVD (clinical classification: C1-4). Popliteal vein cross-sectional area and venous blood flow velocity (FV) were evaluated by Doppler ultrasound at baseline and during three sets of 10 tip-toe movement repetitions. Muscle thickness, muscle fascicle length and pennation angle of both medial and lateral GM were measured by ultrasound. Measures were repeated a week later in 17 participants in order to assess reproducibility with intraclass correlation coefficient (ICC) and Bland-Altman analysis. Results: Peak FV was lower in CDV group compared with Control group for both first (40.6 [11.8] versus 62.4 (22.1) cm(2)/second; P = 0.021) and last (30.4 [9.1] versus 49.5 (22.7) cm(2)/second; P = 0.024) contraction. In CVD group, peak FV during first contraction increased with GM's muscle fascicle length (r = 0.63; P = 0.041). Popliteal FV also increased with rising range of muscle fascicles pennation change between ankle dorsiflexion and plantar flexion (r = 0.70; P = 0.025). No associations were found between haemodynamics and medial or lateral GM thickness. Calf muscular architecture was similar in both CVD and control participants. Test-retest reliability of FV measured in the same session was high (ICC approximate to 0.70) for measures taken in the first contraction of the set but lowered when using the last contraction (ICC<0.50). Reproducibility of ultrasound evaluation of calf pump is acceptable within the same session but is unsatisfactory when testing in separate days. Conclusion: Patients with moderate CVD have lower FV during calf muscles contraction but similar muscle anatomical characteristics compared with healthy controls. Changes in calf muscles flexibility and fatigue resistance may be investigated as possible causes of calf pump dysfunction.