Effects of Continuous Graduated Pneumatic Compression and Intermittent Pneumatic Compression on Lower Limb Hemodynamics for VTE Prophylaxis in Arthroplasty

OBJECTIVE

Intermittent pneumatic compression (IPC) is considered the standard of care for preventing venous thromboembolism (VTE) in the hospital setting. However, its widespread adoption after hospitalization has been limited due to its shortcomings in obstruction of venous valves and blood reflux. The objective of this study is to compare the effects of continuous graduated pneumatic compression (CGPC), a new device with a novel mechanism, and IPC on lower hemodynamics and the incidence of VTE in patients undergoing arthroplasty.

METHODS

We randomized 123 participants undergoing knee arthroplasty to receive either IPC or CGPC from June 2022 through August 2023. An experienced sonographer used a Doppler ultrasound scanner to obtain hemodynamic indicators of venous blood. The primary outcome was the blood velocity of the femoral vein measured by a Doppler scanner. Secondary outcomes included the hemodynamic of the femoral vein and popliteal vein, quality of life at discharge and 30 days after surgery, symptomatic and asymptomatic VTE up to 30 days, and adverse events related to the IPC and CGPC device. For statistical analyses, Student's t-test, analysis of covariance, and the Mann-Whitney U test were used. Statistical significance was indicated with p < 0.05.

RESULTS

There was no significant difference in femoral vein velocity between the IPC and CGPC groups. However, CGPC demonstrated a significant increase in femoral vein flow compared to the IPC group, with a median (interquartile) increasing from 158.9 (122.9, 204.3) to 265.6 (203.3, 326.8) mL/min in the CGPC group and from 139.0 (103.3, 175.9) to 189.6 (161.4, 270.8) mL/min in the IPC group (p < 0.001). Similar trends were observed in popliteal vein measurements. The differences between the two groups were similar in terms of quality of life, incidence of VTE, and adverse events.

CONCLUSION

The CGPC device provides a substantial increase in blood flow compared to the IPC device. Its safety and effectiveness have been preliminarily validated. The CGPC device presents a promising alternative for VTE prophylaxis in arthroplasty.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (registration number: ChiCTR2300078201).

Evaluating the Impact of Active Footwear Systems on Vascular Health and Static Balance: An Exploratory Study

Work-related musculoskeletal disorders are prevalent in occupations requiring prolonged standing and repetitive movements, often leading to vascular issues and reduced static balance. Innovations in wearable technology, such as smart footwear integrating active systems, aim to mitigate these challenges. This exploratory study assessed the effects of a novel active footwear system, incorporating compression and vibration, on vascular blood flow and static balance in healthy adults. Sixteen healthy participants (seven men and nine women) were randomized into active and placebo phases, each involving repetitive tasks. Outcomes included reflection photoplethysmography, postural sway, and foot volumetry. Data were analyzed pre- and post-intervention, with statistical significance set at p < 0.05. For men, significant improvements in reflection photoplethysmography median values were observed post-active phase (p = 0.031), while women showed no change. Enhanced static balance, reflected in decreased total sway (p = 0.025), was noted in women. No significant changes occurred during the placebo phase. The active system improved vascular function in men and static balance in women, highlighting its potential for ergonomic interventions in industrial settings. Future studies should explore long-term effects and applications in diverse populations, including those with work-related musculoskeletal disorders.

Effect of active and passive techniques used in thromboembolic prophylaxis on venous flow velocity in the post-procedure period

Introduction

Studies have shown that using mechanical thromboembolic prophylaxis methods speeds up venous flow and decreases stasis. These studies examine the post-intervention period of 1-10 min. The length of the effect of procedures to raise venous flow velocity cannot be determined by clinical trials. To apply mathematical techniques to estimate how long mechanical thromboembolism prophylaxis procedures will increase venous flow rate.

Methods

In the survey, we examined 25 persons (poststroke patients), with an average age of 57.2 ± 6.3 years. Regarding the proportion of genders, 13 (52%) participants were male and 12 (48%) female. The peak venous blood flow velocity was measured with a HADECO BIDOP ES-100V II type Doppler ultrasound device, using an 8 MHz head, in the femoral vein, at the level of the hip joint. We estimated the change of the venous blood flow velocity from the available sampled data using the method of least squares. For the calculations, we used Microsoft Excel, version Mac Excel 2019.

Results

The decrease in peak venous flow velocity can be approximated by a logarithm function. Mathematical calculations show that after active thromboembolic prophylaxis interventions, resting venous flow velocity is restored at 26.8 min on the intact limb and 85.1 min on the hemiparetic side. Resting flow velocity is restored in 131.9 min after passive mobilization of the hemiparetic side and in 137.7 min after the consensual effect.

Discussion

An elementary mathematical function can be used to estimate the time to recovery of peak venous flow velocity to resting state from measurements taken 15 min after the intervention. Active and passive mechanical thromboembolic prophylaxis after the intervention has a longer-term effect on venous flow velocity.

The changes of the calf-vein deformation and femoral vein peak velocity during ankle pump exercise with or without graduated compression stockings

Objectives

To analyze the changes of lower limb hemodynamics parameters before and after wearing graduated compression stockings (GCS) during ankle pump exercise in patients preparing for arthroplastic surgery.

Method

The leg veins of 16 patients awaiting arthroplasty were analyzed using a Sonosite M-Turbo ultrasound system during ankle pump exercise with or without GCS. The age of them was 70 ± 7 years (mean ± SD) (range 56—82 years) and body mass index was 25.8 ± 3.0 kg/m2 (range 18.0—30.5 kg/m2). Measured data including the cross-sectional area (CSA), anteroposterior (AP) diameter and lateromedial (LM) diameter of the soleus vein (SV), posterior tibial vein (PTV) and great saphenous vein (GSV). Additionally, the peak velocities of femoral vein (FV) were also measured.

Results

GCS could significantly decrease the cross-sectional area of SV, PTV and GSV in supine position at rest and maximum ankle plantar flexion. But the compression effect of GCS to SV and GSV was not observed during maximum ankle dorsiflexion. It was found that GCS application reduced the peak flow velocity of the femoral vein from 61.85 cm/s (95% CI = 50.94–72.75 cm/s) to 38.01 cm/s (95% CI = 28.42–47.59 cm/s) (P < 0.001) during ankle plantar flexion and decreased the femoral vein in these patients from 80.65 cm/s (95% CI = 70.37–90.92 cm/s) to 51.15 cm/s (95% CI = 42.58–59.73 cm/s) (P < 0.001) during ankle dorsiflexion. But this effect was not significant in supine position at rest.

Conclusions

GCS could significantly reduce the peak flow velocity of the femoral vein during ankle pump exercise in the patients preparing for arthroplastic surgery.

The impact of graduated compression stockings on calf-vein deformation and blood velocity in patients awaiting total knee arthroplasty

Objectives

This study was designed to explore venous deformation of the lower extremities and the changes in venous hemodynamics in supine position before and after wearing graduated elastic stockings in patients awaiting total knee arthroplasty (TKA).

Method

The leg veins of 21 elderly patients awaiting TKA were imaged in the supine position with and without knee-length graduated compression stockings (GCS) according to a fixed protocol. Measured parameters including the lateromedial (LM) diameter, anteroposterior (AP) diameter, and cross-sectional area (CSA) of the great saphenous vein (GSV), gastrocnemius vein (GV), soleus vein (SV), posterior tibial vein (PTV), fibular vein (FV), and anterior tibial vein (ATV). In addition, the mean and maximum velocities of the popliteal vein (PV) and superficial femoral vein (FSV) were measured.

Results

GCS-related compression was observed for all the measured veins. Maximal reduction was observed for the GV and SV, whereas the GSV exhibited the lowest degree of GCS-related compression. The mean cross-sectional area reduction values associated with GCS were 33.1 ± 41.2 % for the GSV, 94.8 ± 11.1 % for the GV, and 85.6 ± 20.3 % for the SV, while the mean reduction of anteroposterior diameter was 18.1 ± 34.5 % for the GSV, 89.0 ± 22.5 % for the GV, and 72.9 ± 35.1 % for the SV, and the mean reduction of the lateromedial diameter was 25.9 ± 36.4 % for the GSV, 89.6 ± 19.6 % for the GV, 78.2 ± 28.3 % for the SV. No significant GCS-related changes in blood velocity in the superficial femoral veins or popliteal veins were detected.

Conclusions

For elderly patients awaiting TKA, knee-length GCS can significantly reduce calf vein dilation while at rest in the supine position, with the greatest reductions being observed for the soleus and gastrocnemius veins. These data might help provide a theoretical basis for the GCS in reducing incidence of deep vein thrombosis in patients undergoing TKA.

Novel Evidence Concerning Lacrimal Sac Movement Using Ultra-High-Frequency Ultrasound Examinations of Lacrimal Drainage Systems

PURPOSE

Current hypothesis regarding the mechanism of active tear drainage is based on studies performed ex vivo or under nonphysiological conditions. Novel ultra-high-frequency ultrasound has the advantage of generating images with superior resolution, enabling measurements of low flow in small vessels, and the tracking of tissue motion in real time. The purpose of this study was to investigate the lacrimal drainage system and active drainage using this modality.

METHODS

The upper lacrimal drainage system was investigated with 40-70 MHz ultrasound in 22 eyes in 13 patients. Irrigation confirmed a lacrimal obstruction in 10 eyes. Motion tracking was used to map movement of the lateral lacrimal sac wall and to measure flow when possible.

RESULTS

The anatomy of the upper lacrimal drainage system was mapped in vivo, including the proximal canaliculi, which have not previously been imaged. The lacrimal sac lumen is slit shaped in its resting state but is distended when irrigated or if a nasolacrimal duct obstruction is present. Thus, the healthy lacrimal sac is not a cavity, and the medial retinaculum does not act against a stretched structure. Motion tracking visualized the "lacrimal pump," showing that the direction of motion of the lateral lacrimal sac wall is mainly in the sagittal plane during blinking.

CONCLUSIONS

Ultra-high-frequency ultrasound allows detailed physiological monitoring of the upper lacrimal drainage system in vivo. Our findings suggest that current theories of active tear drainage need to be reappraised.