Acute effects of graduated and progressive compression stockings on leg vein cross-sectional area and viscoelasticity in patients with chronic venous disease.

OBJECTIVE: To determine the effects of graduated and progressive elastic compression stockings (ECS) on postural diameter changes and viscoelasticity of leg veins in healthy controls and in limbs with chronic venous disease (CVD). METHODS: In 57 patients whose legs presented with C1s, C3, or C5 CEAP classes of chronic venous disease and were treated primarily with compression, and 54 healthy controls matched for age and body mass index, we recorded interface pressures (IFP) at 9 reference leg levels. Cross-sectional areas of the small saphenous vein (SSV) and a deep calf vein (DCV) were measured with B-mode ultrasound with patients supine and standing, recording the force (PF) applied on the ultrasound probe to collapse each vein with progressive ECS, and with and without graduated 15 to 20 mm Hg and 20 to 36 mm Hg elastic stockings. We chose these veins because they were free of detectable lesion and could be investigated at the same level (mid-height of the calf), and their compression by the ultrasound probe was not hampered by bone structures. RESULTS: IFP decreased from ankle to knee with graduated 15 to 20 and 20 to 36 mm Hg, but increased with progressive ECS, and were 8.4 to 13.8 mm Hg lower for C1s than for control or C3 and C5 limbs. Without ECS, the SSV median [lower-upper quartile] cross-sectional area was 4.9 mm2 [3.6-7.1 mm2] and 7.1 mm2 [3.0-9.9 mm2] in C3 and C5 limbs versus 2.9 mm2 [1.8-5.2 mm2] and 3.8 mm2 [2.1-5.4 mm2] in controls (P < .01), respectively, while supine and standing. It remained greater in C3 and C5 than in C1s and control limbs wearing any ESC. Wearing compression, especially with progressive ECS, decreased the SSV and DCV cross-sectional area only with patients supine, thus decreasing postural changes, which remained highly diverse between individuals. The SSV cross-sectional area versus PF function traced a hysteresis loop of which the area, related to viscosity, was greater in C3 and C5 limbs than controls, even with graduated 15 to 20 or 20 to 36 mm Hg ECS. Progressive ECS decreased vein viscosity in the supine position, whereas 20 to 36 mm Hg and progressive ECS increased distensibility in the standing position. CONCLUSIONS: ECS decrease the cross-sectional area of SSV and DCV with patients supine, but not upright. C1s limbs show distinctive features, especially regarding IFP. Graduated 20 to 36 mm Hg and progressive stockings lower viscosity and increase distensibility of the SSV.

Noninvasive measurement of venous wall deformation induced by changes in transmural pressure shows altered viscoelasticity in patients with chronic venous disease.

OBJECTIVE: The noninvasive measurement of venous wall deformation induced by changes in transmural pressure could allow for the assessment of viscoelasticity and differentiating normal from diseased veins. METHODS: In 57 patients with limbs in the C1s (telangiectasia or reticular veins and symptoms), C3 (edema), or C5 (healed venous ulcer) CEAP (clinical, etiologic, anatomic, pathophysiologic) category of chronic venous disease and 54 matched healthy controls, we measured the changes in the cross-sectional area of the small saphenous vein and a deep calf vein in the supine and standing positions and under compression with an ultrasound probe using ultrasonography. RESULTS: The small saphenous vein, but not the deep calf vein, cross-sectional area was smaller in the limbs of the controls than in the limbs with C3 or C5 disease but was not different from that in C1s limbs. When changing from the supine to the standing position, a greater force was required to collapse the leg veins. Their cross-sectional area increased in most subjects but decreased in 31.5% of them as for the small saphenous veins and 40.5% for the deep calf vein. The small saphenous vein area vs compression force function followed a hysteresis loop, demonstrating viscoelastic features. Its area, which represents the viscosity component, was greater (P < .001) in the pooled C3 and C5 limbs (median, 2.40 N⋅mm2; lower quartile [Q1] to upper quartile [Q3], 1.65-3.88 N⋅mm2) than in the controls (median, 1.24 N⋅mm2; Q1-Q3, 0.64-2.14 N⋅mm2) and C1s limbs (median, 1.15 N⋅mm2; Q1-Q3, 0.71-2.97 N⋅mm2). The area increased (P < .0001) in the standing position in all groups. CONCLUSIONS: Postural changes in the cross-sectional area of the leg veins were highly diverse among patients with chronic venous disease and among healthy subjects and appear unsuitable for pathophysiologic characterization. In contrast, small saphenous vein viscoelasticity increased consistently in the standing position and the viscosity was greater in limbs with C3 and C5 CEAP disease than in controls.

An ultrasound look at Korotkoff sounds: the role of pulse wave velocity and flow turbulence.

AIMS: The aim of this study was to analyze the temporal relationships between pressure, flow, and Korotkoff sounds, providing clues for their comprehensive interpretation. MATERIALS AND METHODS: When measuring blood pressure in a group of 23 volunteers, we used duplex Doppler ultrasonography to assess, under the arm-cuff, the brachial artery flow, diameter changes, and local pulse wave velocity (PWV), while recording Korotkoff sounds 10 cm downstream together with cuff pressure and ECG. RESULTS: The systolic (SBP) and diastolic (DBP) blood pressures were 118.8±17.7 and 65.4±10.4 mmHg, respectively (n=23). The brachial artery lumen started opening when cuff pressure decreased below the SBP and opened for an increasing length of time until cuff pressure reached the DBP, and then remained open but pulsatile. A high-energy low-frequency Doppler signal, starting a few milliseconds before flow, appeared and disappeared together with Korotkoff sounds at the SBP and DBP, respectively. Its median duration was 42.7 versus 41.1 ms for Korotkoff sounds (P=0.54; n=17). There was a 2.20±1.54 ms/mmHg decrement in the time delay between the ECG R-wave and the Korotkoff sounds during cuff deflation (n=18). The PWV was 10±4.48 m/s at null cuff pressure and showed a 0.62% decrement per mmHg when cuff pressure increased (n=13). CONCLUSION: Korotkoff sounds are associated with a high-energy low-frequency Doppler signal of identical duration, typically resulting from wall vibrations, followed by flow turbulence. Local arterial PWV decreases when cuff pressure increases. Exploiting these changes may help improve SBP assessment, which remains a challenge for oscillometric techniques.

Evaluation of lower limb vein biomechanical properties and the effects of compression stockings, with an instrumented ultrasound probe.

We present a new approach for the evaluation of the biomechanical properties of lower limb veins based on the simultaneous measurements of the vein cross-sectional area with B-mode ultrasound imaging and of the force exerted on the skin by the ultrasound probe. Ongoing clinical trials allowed us to identify a behavioral model of lower limb veins without and with compression stockings.

Validation of lower limb segmental volumetry with hand-held, self-positioning three-dimensional laser scanner against water displacement.

BACKGROUND: Measurement of limb volume is helpful for the evaluation and follow-up of edema, especially in patients with chronic venous insufficiency (CVI) or lymphedema. Water displacement (WD) is the reference method for limb volumetry but is not really suitable for clinical routine. Indirect volumetry based on circumference measurements as well as the more expansive but automatic optoelectronic techniques do not allow detailed measurement at the extremity of the limb. METHODS: We used a self-positioning laser scanner with dynamic referencing for acquisition and real-time three-dimensional (3D) reconstruction of the lower limb volume in 30 patients with CVI, 30 patients with lymphedema, and 30 healthy controls. Two independent observers performed either one or two laser scans, whose results were tested for intra- and interobserver reproducibility and compared with WD volumetry by Lin's concordance correlation coefficient and Bland and Altman graphic analysis. RESULTS: Automatic volume calculation from 3D laser scanning data failed in one patient with major lymphedema. Lin's concordance correlation coefficient was 0.99 and 0.98, respectively, for intraobserver no. 1 and no. 2, 0.98 for interobserver reproducibility, and 0.98 and 0.96, respectively, for observer no. 1 and observer no. 2 vs WD comparison. The 3D laser scanning yielded 1.99% precision. Accuracy was 3.12% for observer no. 1 and 2.71% for observer no. 2, laser scanning values being 90 mL higher than WD, which could be attributed to the different posture during measurement. CONCLUSIONS: Three-dimensional laser scanning is accurate and reproducible, and appears suitable for the evaluation of limb volume in patients with CVI or lymphedema.