Last modified: 2012-02-18
Abstract
Purpose:
The aim of this study was create a reliable protocol to assess the hemodynamic response and muscular strength of calf venous pump function, once, despite the muscular issues underlying chronic venous disorders (CVD), there are no instruments that measure simultaneously these parameters.
Relevance:
Assess muscular function of the gastrocnemius is needed, in order to create effective structured rehabilitation protocols targeted to improve the function of venous pump in CVD.
Subjects:
The sample was convenience and non-probabilistic, and it was composed by 37 subjects separated in two groups: 19 in control group (healthy subjects) with 44,33 (±10,76) years old; 18 in the experimental group (CVD subjects) classified as C0-4 according toCEAP classification, with 38,63(±12,39) years old. All subjects signed informed consent and all of them were assessed twice (with one week interval).
Methods:
On this pilot comparative study was used a protocol of 10 ankle movements of plantar flexion/dorsiflexion with an isokinetic dynamometer (60º/s) – Biodex System 3 in order to assess the muscular strength. Popliteal vein hemodynamics (cross sectional area and mean velocity to calculate the mean flow volume) were measured by Doppler ultrasonography, before (T0), after (T1) and 5 minutes after (T2) the isokinetic protocol. The clinical severity was assessed with CEAP classification and VCSS.
Analysis:
The Intraclass Correlation Coefficient (ICC) was used to calculate the test-retest reliability of this protocol; the differences between the three moments and between groups were calculated and the muscular strength and popliteal vein hemodynamics were correlated with clinical severity of CVD.
Results:
Flow volume in popliteal vein showed a poor reliability with ICC=0.41 in T0 and ICC=0.41 in T1. However, T2 revealed moderated reliability with ICC=0.54. The clinical severity wasn’t related to the hemodynamic parameters of popliteal vein and muscle strength. The baseline values and the muscular strength parameters weren’t statistically different between groups (p>0,05). Regarding the mean’s difference, there were a significant increase of the mean venous flow from T0 to T1 and decrease from T1 to T2, in both groups (p<0,05). Mean flow volume was significantly increased past five minutes (T2=11,924 (±5,498)) compared to baseline values (T0=4,213 (±2,242)) (p=0,02) for control group, however in the experimental group it doesn’t happen (T0=4,272 (±1,808); T2= 12,519 (±5,382) (p=0,52). No other differences were found in muscular strength or popliteal vein hemodynamics between groups.
Conclusions:
Five minutes after ankle movements, mean flow volume in popliteal vein, compared with baseline, keep increased in healthy subjects but not in CVD subjects, even in the first stages of CVD. This evaluation-protocol appeared to be moderated reliable measuring venous flow volume of the popliteal vein after ankle movements. We concluded that in these subjects the calf pump force is less efficient than in non-CVD subjects, and this protocol could be used to measure it. However, refinements of such protocols are needed in order to develop the significance of the results.