Diminished Sphenous Compartment Connective Tissue Elasticity has Little Impact on Low Grade Venous Insufficiency: An Ultrasound Shearwave Elastography Study

Abstract

Background: Greater Saphenous Vein (GSV) courses within saphenous compartment, an adipose-filled space bound by fasciae provides structural support. Ultrasound Shear-Wave Elastography (SWE) provides objective and quantitative data on tissue shear elasticity modulus.

Objective: This study aims to analyze possible associations between early stage GSV insufficiency and saphenous intracompartmental SWE measurements.

Methods: Two-hundred consecutive patients, ages 22 to 81 (mean=44.3) years, with venous insufficiency symptoms underwent Doppler and SWE examinations. Patients had no visible or palpable sign of venous disease or had telangiectasia and reticular veins only. Analyses regarding patient age, gender, presence of venous insufficiency of GSV proper and intracompartmental connective tissue elasticity were performed.

Results: Ninety-six patients had Doppler evidence for either bilateral or unilateral insufficiency of GSV proper at mid-thigh level. Intracompartmental elasticity of patients with venous insufficiency (mean=4.36±2.24 kilopascals; range 1.55 to 10.44 kPa) did not differ significantly from those with normal veins (mean=4.82±2.61 kPa; range 2.20 to 12.65 kPa) (p=0.231). No threshold for predicting the presence of venous insufficiency could be determined. Neither were there any correlations between age, gender and intracompartmental elasticity. In patients with unilateral insufficiency, however, elastography values around insufficient veins were significantly lower compared to contralateral normal GSV (p<0.001).

Conclusion: Many intrinsic and patient factors affect intracompartmental connective tissue elastography measurements; thus, cut-off values obtained from specific populations have limited generalizability. Nevertheless, statistically significant intrapatient differences of intracompartmental elasticity among diseased and normal saphenous veins indicate that lack of elastic support from surrounding connective tissues contributes to venous insufficiency in early stages.

Keywords: Chronic venous disease; saphenous compartment; saphenous vein; shear wave elastography; ultrasound.; venous insufficiency.

Fig. (1)

Transverse scan of medial mid-thigh level visualizes GSV within saphenous compartment. Real-time B mode scan (left) and SWE measurement (right) side by side on the screen. Circular ROI of 2 millimeters diameter is used. Elasticity values, in kilopascals, are denoted on left lower corner of screen. (A higher resolution / colour version of this figure is available in the electronic copy of the article).

Fig. (2)

Box-plot chart of compartment elasticity versus GSV insufficiency. Both groups have wide ranges with large overlap of elasticity values, precluding calculation of an elasticity threshold for venous insufficiency.

Fig. (3)

Box-plot chart of compartment elasticity versus gender. Both groups have wide ranges of elasticity values and considerable overlap in between.

Fig. (4)

Linear plot of compartment elasticity versus patient age. There is no statistically significant correlation between two parameters (Spearman’s rho=0.044; p=0.154).

Fig. (5)

Box-plot chart of intracompartmental elasticity comparing refluxing with non-refluxing contralateral saphenous veins. Though there is overlap of elasticity values, a significant difference is present when refluxing and normal veins are compared within each patient.

Fig. (6)

Real-time B mode scan (left) and SWE measurement (right) of intracompartmental tissue surrounding (a) unilateral refluxing GSV and (b) contralateral non-refluxing GSV. As expected refluxing saphenous vein has a larger diameter compared to normal contralateral GSV. (A higher resolution / colour version of this figure is available in the electronic copy of the article).