Evidence-based compression: prevention of stasis and deep vein thrombosis

Interventional treatment for post-thrombotic chronic venous obstruction: Progress and challenges

Chronic venous obstruction, including nonthrombotic iliac vein lesions and post-thrombotic syndrome, presents a significant burden on patients' quality of life and health care systems. Venous recanalization and stenting have emerged as promising minimally invasive approaches, yet challenges in patient selection, procedural techniques, and long-term outcomes persist. This review synthesizes current knowledge on the interventional treatment of post-thrombotic syndrome, focusing on the evolution of endovascular techniques and stenting. Patient selection criteria, procedural details, and the characteristics of dedicated venous stents are discussed. Particular emphasis is given to the role of inflow and other anatomical considerations, along with postoperative management protocols for an optimal long-term outcome.

Should intermittent pneumatic compression devices be standard therapy for the prevention of venous thromboembolic events in major surgery? Protocol for a randomised clinical trial (IMPOSTERS)

INTRODUCTION

Venous thromboembolism (VTE) is a recognised postsurgical risk. Current prevention methods involve low molecular weight heparin (LMWH), graduated compression stockings (GCS), and intermittent pneumatic compression devices (IPCDs). Australian guidelines, commonly adopted by surgeons, recommend LMWH with GCS and/or IPCDs. IPCDs pose clinical risks, increase care burden, are poorly tolerated, and are costly single-use plastic items. Utilising only LMWH and GCS, without IPCDs, could be more practical, patient-friendly, and cost-effective, with added environmental benefits.

METHODS

This is a multicentre, prospective, two-arm randomised controlled non-inferiority trial at five New South Wales (NSW) hospitals, in Australia. We propose to randomise 4130 participants in a 1:1 ratio between arm A: LMWH+GCS+IPCDs (n=2065) or arm B: LMWH+GCS (n=2065). The primary outcome of interest is symptomatic VTE (deep vein thrombosis/pulmonary embolism) identified at the day 30 phone follow-up (FU), confirmed by ultrasound or imaging. Radiologists interpreting the lower-extremity ultrasonography will be blinded to intervention allocation. Secondary outcomes are quality of life at baseline, days 30 and 90 FU using the 5-level European Quality of Life Score, compliance and adverse events with IPCDs, GCS, and LMWH, as well as healthcare costs (from the perspective of the patient and the hospital), and all-cause mortality. The trial has 90% power to detect a 2% non-inferiority margin to detect a reduction rate of VTE from 4% to 2%.

ETHICS AND DISSEMINATION

This study has been approved by the Hunter New England Human Research Ethics Committee (2022/ETH02276) protocol V.10, 13 July 2023. Study findings will be presented at local and national conferences and in scientific research journals.

TRIAL REGISTRATION NUMBER

ANZCTR12622001527752.

Application Areas of Intermittent Pneumatic Compression in the Prevention of Deep Vein Thrombosis During Dixon Surgery: A Randomized, Controlled Trial

PURPOSE

Deep vein thrombosis (DVT) is common in the lithotomy position after laparoscopic surgery. Intermittent pneumatic compression (IPC) plays an important role in DVT prevention. However, few studies have compared the different compression areas of IPC application. It was hypothesized that the location of the compression sleeves could have an impact on the effects of thromboprophylaxis.

METHODS

In this randomized, controlled trial performed from August 2020 to March 2021, 164 patients scheduled to undergo laparoscopic Dixon surgery were randomly assigned to one of four groups, based on the bilateral placement of compression sleeves during surgery: feet, calves, thighs, or control (no IPC). Both lower extremities were monitored for DVT on days 1 and 7 after surgery, using ultrasonographic assessment of mean blood velocity, blood flow volume, and diameter of the common femoral veins. Thrombosis-related hematologic analysis was performed.

FINDINGS

On day 1 after surgery, IPC of the feet or calves was associated with a reduced prevalence of DVT compared with controls (both: P = 0.024; OR = 0.09; 95% CI, 0.01-0.72), while IPC of the thighs had no significant benefit (P = 0.781; OR = 0.86; 95% CI, 0.29-2.55). The prevalence of DVT in the left extremity was lower with IPC of the feet and calves compared with controls (both, P = 0.048). The mean blood velocity in the common femoral vein was significantly increased after surgery with IPC of the left and right feet (P = 0.006 and 0.007, respectively) and calves (P = 0.011 and P = 0.026, respectively) compared with controls. Similarly, the volume of blood flow in the left common femoral vein was greater with IPC of the feet and calves (P = 0.03 and 0.027, respectively). However, on day 7 after surgery, the between-group differences in the prevalences of DVT and hematologic indicators of thrombosis were not significant.

IMPLICATIONS

On day 1 after surgery, IPC application at the feet or calves facilitated venous return and, hence, reduced the prevalence of DVT, especially in the left extremities. However, there were no significant differences in the prevalences of DVT or thrombosis-related hematologic indicators among the four groups on the day 7 after surgery. Chinese Clinical Trial Registration identifier: ChiCTR2000035325.

Postoperative intermittent pneumatic compression for preventing venous thromboembolism in Chinese lung cancer patients: a randomized clinical trial

BACKGROUND

Postoperative lung cancer patients belong to the high-risk group for venous thromboembolism (VTE). The standardized preventive measures for perioperative VTE in lung cancer are not perfect, especially for the prevention and treatment of catheter-related thrombosis (CRT) caused by carried central venous catheters (CVCs) in lung cancer surgery.

PATIENTS AND METHODS

This study included 460 patients with lung cancer undergoing video-assisted thoracic surgery (VATS) in our center from July 2020 to June 2021. Patients were randomized into two groups, and intraoperatively-placed CVCs would be carried to discharge. During hospitalization, the control group was treated with low-molecular-weight heparin (LMWH), and the experimental group with LMWH + intermittent pneumatic compression (IPC). Vascular ultrasound was performed at three time points which included before surgery, before discharge, and one month after discharge. The incidence of VTE between the two groups was studied by the Log-binomial regression model.

RESULTS

CRT occurred in 71.7% of the experimental group and 79.7% of the control group. The multivariate regression showed that the risk of developing CRT in the experimental group was lower than in the control group (Adjusted RR = 0.889 [95%CI0.799-0.989], p = 0.031), with no heterogeneity in subgroups (P for Interaction > 0.05). Moreover, the fibrinogen of patients in the experimental group was lower than control group at follow-up (P = 0.019).

CONCLUSION

IPC reduced the incidence of CRT during hospitalization in lung cancer patients after surgery.

TRIAL REGISTRATION

No. ChiCTR2000034511.

Vascular impulse technology versus elevation for reducing the swelling of upper and lower extremity joint fractures

Soft-tissue conditioning due to posttraumatic oedema after complicated joint fractures is a central therapeutic aspect both pre- and postoperatively. On average, 6-10 days pass until the patient is suitable for surgery. This study compares the decongestant effect of vascular impulse technology (VIT) with that of conventional elevation. In this monocentric RCT, 68 patients with joint fractures of the upper (n = 36) and lower (n = 32) extremity were included and randomized after consent in a 1:1 ratio. Variables were evaluated for all fractures together and additionally subdivided into upper or lower extremity for better clinical comparability. Primary endpoint was the time in days from hospital admission to operability. Secondary endpoints were total length of stay, oedema reduction, pain intensity, complications, and revisions. The time from admission until operability was reduced by 1.4 (95% CI - 0.4; 3.1) days in the mITT analysis (p = 0.120) and was statistically significant with 1.7 (95% CI 0.1; 3.3) days in the as-treated sensitivity analysis (p_AT = 0.038). Significantly less pain and a faster oedema reduction were found in the intervention group. Due to rare occurrences, nothing can be concluded regarding complications and revisions. Administration of VIT therapy did not lead to a significant reduction in time until operability in the whole population but was superior to elevation for soft-tissue conditioning and pain reduction. However, there was a significant reduction by 2.5 days (95% CI 0.7; 4.3) in the subgroup of lower extremity fractures. VIT therapy therefore seems to be a helpful tool in the treatment of posttraumatic oedema after complex joint fractures of the lower and upper extremity, especially in tibial head and lower leg fractures.

Sway and Acceleration Changes of the Center of Mass during Walking Stance Phase before and after Total Knee Arthroplasty

Elucidating the sway and changes in the acceleration of center of mass (COM) during walking is important for effective gait training and rehabilitation. The objective of this study was to verify the improvement in gait before and after total knee arthroplasty (TKA) from COM sway and the changes in the acceleration of COM during the stance phase of walking. This study included 13 patients (1 male and 12 females) with medial knee osteoarthritis who were hospitalized for TKA. The COM sway during the stance phase of walking was evaluated using root mean square (RMS) normalized by walking speed, and the changes in acceleration were further verified. Lateral and vertical RMS showed significant differences between preoperative and postoperative states and demonstrated low values after TKA. The lateral acceleration at the latter part of the early stance phase demonstrated a significant difference between preoperative and postoperative states. A significant difference was also observed in the lateral acceleration in the late stance phase between the two groups. Improvement in pain and alignment after TKA reduced the lateral sway of COM and the changes in acceleration during the gait stance phase, which is speculated to lead to improvement in gait and prevention of falls.

Obesity and the Risk of Venous Thromboembolism after Major Lower Limb Orthopaedic Surgery: A Literature Review

The risk of venous thromboembolism following total joint arthroplasty is significantly greater than those of other types of elective orthopaedic procedures. This risk is increased in obesity due to the associated prothrombotic physiological and hematological changes that predispose to embolic events. The prevalence of obesity is increasing in the aging population, which contributes to a further increase in the risk of postoperative thrombosis in the older patients. There is a lack of clear evidence regarding dosing information for thromboprophylaxis medications in patients with obesity. As a result, the currently available thromboprophylaxis guidelines do not provide specific recommendations for this group. Suboptimal dosing regimens for these medications can place these patients at a risk of bleeding or clotting complications postsurgery. Hence any increase in dosage may require intensive surveillance for the residual anticoagulant effects and careful balancing of risks and benefits on an individual basis. Our review discusses the basis for increased thrombotic risk in obesity, the evidence supporting dosage recommendations, and the implications of the current guidelines for pharmacological thromboprophylaxis in patients with obesity undergoing lower limb arthroplasty.

Efficacy of intermittent compression devices for thromboembolic prophylaxis in major abdominal surgery: a systematic review and meta-analysis

BACKGROUND

The benefits of mechanical prophylaxis for the prevention of venous thromboembolism (VTE) in abdominal and pelvic surgery are uncertain, with different guidelines stating that graduated compression stockings (GCS) and intermittent pneumatic compression devices (IPCDs) can be used either alone or in combination. To review the efficacy of IPCDs in preventing VTE following abdominal and pelvic surgery.

METHODS

A systematic review was conducted, identifying relevant literature reporting clinical trials conducted in abdominopelvic surgery, comparing the effect of IPCDs alone or in combination with no prophylaxis, GCS and chemical prophylaxis. The review identified studies reported from 1966 to 2022 in Medline, Embase, PubMed and Cochrane databases for randomized controlled trials.

RESULTS

Thirteen RCTs involving 1914 participants were identified. IPCDs were superior to placebo (OR VTE 0.39; 95% CI 0.20-0.76) but not superior to other forms of prophylaxis (OR 0.83; 95% CI 0.30-2.27) or to GCS alone (OR 0.9; 95% CI 0.24-3.36). The addition of IPCDs to GCS compared with GCS alone was beneficial (OR 0.45; 95% CI 0.23-0.91) as was the addition of IPCDs to standard perioperative chemoprophylaxis (OR 0.25; 95% CI 0.09-0.74). The overall quality and reliability of trials were low, with high risk of bias.

CONCLUSIONS

IPCDs are more effective than placebo in reducing VTE rates but are not more effective than other forms of thrombo-prophylaxis (chemical or mechanical) following abdominal and pelvic surgery. There is poor quality evidence to suggest that they might have a role as additional prophylaxis when combined with GCS and chemical prophylaxis.

Role of Neuromuscular Electrical Stimulation in Increasing Femoral Venous Blood Flow After Total Hip Prosthesis

Objective: This study aimed to investigate the role of neuromuscular electrical stimulation (NMES) in increasing femoral venous blood flow after total hip prosthesis and to evaluate its potential effects on preventing postoperative deep vein thrombosis (DVT).

Materials and methods: A total of 64 patients who underwent total hip prosthesis were randomly separated into two groups. The NMES group (n=32) received low-molecular-weight heparin+NMES. And the non-NMES group (n=32) received a low-molecular-weight heparin+compression bandage.

Results: There was no difference between the groups in terms of the presence of preoperative and postoperative leg edema. The calf diameter was significantly lower in the NMES group than in the non-NMES group in both the preoperative (p=0.003) and postoperative (p=0.008) period. Although the femoral vein peak velocity (VPV) was similar between the groups in the preoperative period, it was significantly higher in the NMES group than in the non-NMES group postoperatively (p=0.001). The femoral VPV after total hip prosthesis increased more in the NMES group (43.2%) compared with the non-NMES group (16.3%). In the non-NMES group, the D-dimer value in the preoperative period was lower than on postoperative days one and five (p<0.05). There was no significant difference between the D-dimer values on postoperative days one and five. In the NMES group, a statistically significant difference was determined between the preoperative and postoperative test results (F(2.93)=20.86, p=0.001). The preoperative D-dimer values were compared to the postoperative values on the first and fifth day, and according to the post hoc test results, the D-dimer values were significantly lower on the fifth postoperative day than on the first postoperative day, and the preoperative value was significantly lower than the fifth postoperative day value (p<0.05). 

Conclusion: Although the two groups were similar in terms of leg edema, there was a significant increase in femoral VPV in the NMES group. This could indicate a potential effect of NMES in preventing postoperative DVT and needs to be confirmed with further studies.

Intermittent Pneumatic Compression in Addition to Standard Prophylaxis of Postoperative Venous Thromboembolism in Extremely High-risk Patients (IPC SUPER): A Randomized Controlled Trial

OBJECTIVE

To assess the efficacy of adjunctive IPC to standard prophylaxis of postoperative VTE in patients at extremely high-risk.

SUMMARY OF BACKGROUND DATA

The standard prophylaxis for postoperative VTE is insufficient in extremely high-risk patients. It is unclear whether an adjunctive use of IPC would result in a lower incidence of postoperative venous thrombosis.

METHODS

We randomly assigned patients who underwent major surgery and had a Caprini score of ≥11 to receive either IPC in addition to standard prophylaxis with anti-embolic stockings (pressure of 18-21 mm Hg at the ankle) and low-molecular-weight heparin (IPC group) or standard prophylaxis alone (control group). The primary outcome was an asymptomatic venous thrombosis of the lower limbs, as detected by duplex ultrasound scan performed before inclusion and every 3-5 days after surgery.

RESULTS

A total of 407 patients underwent randomization, of which 204 were assigned to the IPC group and 203 to the control group. The primary outcome occurred in 1 (0.5%) patient in the IPC group and 34 (16.7%) patients in the control group [relative risk, 0.03, 95% confidential interval (CI): 0.01-0.21]. Pulmonary embolism occurred in none of the 204 patients in the IPC group and in 5 (2.5%) patients in the control group (relative risk, 0.09; 95% CI, 0.01-1.63), and postoperative death occurred in 6 (2.9%) patients in the IPC group and 10 (4.9%) in the control group (relative risk, 0.50; 95% CI, 0.50-1.60).

CONCLUSIONS

Among patients with a Caprini score of ≥11 who received standard prophylaxis for VTE, adjunctive IPC resulted in a significantly lower incidence of asymptomatic venous thrombosis.

Improving SCD compliance in trauma patients at Kings County Hospital Center: a quality improvement report

Venous thromboembolism (VTE) is the fourth most commonly reported complication in trauma patients. For these patients, thromboprophylaxis is a standard of care. Patient compliance with sequential compression devices (SCDs), a form of mechanical VTE prophylaxis, has been a focus of efforts to improve patient safety. At our institution, a baseline audit in July 2020 revealed that patients admitted to the trauma floors have poor compliance with the use of SCDs. In this quality improvement project, we developed a patient education intervention to improve SCD compliance. We distributed an informational flyer to patients and led short educational sessions on VTE risk factors and proper SCD use. Our aim was to increase our SCD compliance rate by 30% in 4 weeks. We used three plan-do-study-act (PDSA) cycles to implement and refine our intervention. We measured SCD compliance during morning and afternoon patient observations and generated run charts to understand how our cycles were leading to change. After a 4-week period, we did not achieve our aim, but increased our overall compliance from 45% to 60% and sustained this improvement throughout our PDSA cycles. Morning compliance was lower than afternoon compliance both at baseline (45% vs 48.5%) and at the end the project (45% vs 53%). Our results suggest that patient education should be coupled with interventions that address other barriers to SCD compliance.

Primary prophylaxis for venous thromboembolism in people undergoing major amputation of the lower extremity

BACKGROUND

People undergoing major amputation of the lower limb are at increased risk of venous thromboembolism (VTE). Risk factors for VTE in amputees include advanced age, sedentary lifestyle, longstanding arterial disease and an identifiable hypercoagulable condition. Evidence suggests that pharmacological prophylaxis (e.g. heparin, factor Xa inhibitors, vitamin K antagonists, direct thrombin inhibitors, antiplatelets) is effective in preventing deep vein thrombosis (DVT), but is associated with an increased risk of bleeding. Mechanical prophylaxis (e.g. antiembolism stockings, intermittent pneumatic compression and foot impulse devices), on the other hand, is non-invasive and has minimal side effects. However, mechanical prophylaxis is not always appropriate for people with contraindications such as peripheral arterial disease (PAD), arteriosclerosis or bilateral lower limb amputations. It is important to determine the most effective thromboprophylaxis for people undergoing major amputation and whether this is one treatment alone or in combination with another. This is an update of the review first published in 2013.

OBJECTIVES

To determine the effectiveness of thromboprophylaxis in preventing VTE in people undergoing major amputation of the lower extremity.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, Cochrane Central Register of Controlled Trials, MEDLINE, Embase and Cumulative Index to Nursing and Allied Health Literature databases, the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 5 November 2019. We planned to undertake reference checking of identified trials to identify additional studies. We did not apply any language restrictions.

SELECTION CRITERIA

We included randomised controlled trials and quasi-randomised controlled trials which allocated people undergoing a major unilateral or bilateral amputation (e.g. hip disarticulation, transfemoral, knee disarticulation and transtibial) of the lower extremity to different types or regimens of thromboprophylaxis (including pharmacological or mechanical prophylaxis) or placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, extracted data and assessed risk of bias. We resolved any disagreements by discussion. Outcomes of interest were VTE (DVT and pulmonary embolism (PE)), mortality, adverse events and bleeding. We used GRADE criteria to assess the certainty of the evidence. The two included studies compared different treatments, so we could not pool the data in a meta-analysis.

MAIN RESULTS

We did not identify any eligible new studies for this update. Two studies with a combined total of 288 participants met the inclusion criteria for this review. Unfractionated heparin compared to low molecular weight heparin One study compared unfractionated heparin with low molecular weight heparin and found no evidence of a difference between the treatments in the prevention of DVT (odds ratio (OR) 1.23, 95% confidence interval (CI) 0.28 to 5.35; 75 participants; very low-certainty evidence). No bleeding events occurred in either group. Deaths and adverse events were not reported. This study was open-label and therefore at a high risk of performance bias. Additionally, the study did not report the method of randomisation, so the risk of selection bias was unclear. Heparin compared to placebo In the second study, there was no evidence of a benefit from heparin use in preventing PE when compared to placebo (OR 0.84, 95% CI 0.35 to 2.01; 134 participants; low-certainty evidence). Similarly, no evidence of improvement was detected when the level of amputation was considered, with a similar incidence of PE between the two treatment groups: above knee amputation (OR 0.79, 95% CI 0.31 to 1.97; 94 participants; low-certainty evidence); and below knee amputation (OR 1.53, 95% CI 0.09 to 26.43; 40 participants; low-certainty evidence). Ten participants died during the study; five underwent a post-mortem and three were found to have had a recent PE, all of whom had been on placebo (low-certainty evidence). Bleeding events were reported in less than 10% of participants in both treatment groups, but the study did not present specific data (low-certainty evidence). There were no reports of other adverse events. This study did not report the methods used to conceal allocation of treatment, so it was unclear whether selection bias occurred. However, this study appeared to be free from all other sources of bias. No study looked at mechanical prophylaxis.

AUTHORS' CONCLUSIONS

We did not identify any eligible new studies for this update. As we only included two studies in this review, each comparing different interventions, there is insufficient evidence to make any conclusions regarding the most effective thromboprophylaxis regimen in people undergoing lower limb amputation. Further large-scale studies of good quality are required.

Hemodynamic regulation of perivalvular endothelial gene expression prevents deep venous thrombosis

Deep venous thrombosis (DVT) and secondary pulmonary embolism cause approximately 100,000 deaths per year in the United States. Physical immobility is the most significant risk factor for DVT, but a molecular and cellular basis for this link has not been defined. We found that the endothelial cells surrounding the venous valve, where DVTs originate, express high levels of FOXC2 and PROX1, transcription factors known to be activated by oscillatory shear stress. The perivalvular venous endothelial cells exhibited a powerful antithrombotic phenotype characterized by low levels of the prothrombotic proteins vWF, P-selectin, and ICAM1 and high levels of the antithrombotic proteins thrombomodulin (THBD), endothelial protein C receptor (EPCR), and tissue factor pathway inhibitor (TFPI). The perivalvular antithrombotic phenotype was lost following genetic deletion of FOXC2 or femoral artery ligation to reduce venous flow in mice, and at the site of origin of human DVT associated with fatal pulmonary embolism. Oscillatory blood flow was detected at perivalvular sites in human veins following muscular activity, but not in the immobile state or after activation of an intermittent compression device designed to prevent DVT. These findings support a mechanism of DVT pathogenesis in which loss of muscular activity results in loss of oscillatory shear-dependent transcriptional and antithrombotic phenotypes in perivalvular venous endothelial cells, and suggest that prevention of DVT and pulmonary embolism may be improved by mechanical devices specifically designed to restore perivalvular oscillatory flow.

Comparison of the Hemodynamic Performance of Two Neuromuscular Electrical Stimulation Devices Applied to the Lower Limb

Currently, 1% of the population of the Western world suffers from venous leg ulcers as a result of chronic venous insufficiency. Current treatment involves the use of moist wound healing, compression bandages, and intermittent pneumatic compression. Neuromuscular electrical stimulation is a novel potential new therapeutic method for the promotion of increased lower limb hemodynamics. The aim of this study was to measure the hemodynamic changes in the lower limb with the use of two neuromuscular electrical stimulation devices. Twelve healthy volunteers received two neuromuscular stimulation device interventions. The Geko^TM and National University of Ireland (NUI) Galway neuromuscular electrical stimulation devices were randomized between dominant and non-dominant legs. Hemodynamic measurements of peak venous velocity (cm/s), the time average mean velocity (TAMEAN) (cm/s), and ejected volume (mL) of blood were recorded. Peak venous velocity was significantly increased by the Geko^TM and the NUI Galway device compared to baseline blood flow (p < 0.0001), while only the voluntary contraction produced significant increases in TAMEAN and ejected volume (both p < 0.05). Neuromuscular muscular electrical stimulation can produce adequate increases in lower limb hemodynamics sufficient to prevent venous stasis. Greater use of neuromuscular stimulation devices could be considered in the treatment of conditions related to chronic venous insufficiency but requires further research.

The Effect of Sequential Compression Devices on Fibrinolysis in Plastic Surgery Outpatients: A Randomized Trial

BACKGROUND

Sequential compression devices are often considered a mainstay of prophylaxis against deep venous thromboses in surgical patients. The devices are believed to produce a milking action on the deep veins to prevent venous stasis. A systemic fibrinolytic effect has also been proposed, adding a second mechanism of action. The plasma levels of tissue plasminogen activator and plasminogen activator inhibitor-1 reflect fibrinolytic activity.

METHODS

A randomized trial was conducted among 50 consecutive plastic surgery outpatients undergoing cosmetic surgery performed by the author under total intravenous anesthesia and without paralysis. Patients were randomized to receive calf-length sequential compression devices or no sequential compression devices during surgery. Blood samples were obtained from the upper extremity preoperatively and at hourly intervals until the patient was discharged from the postanesthesia care unit. Tissue plasminogen activator and plasminogen activator inhibitor-1 levels were measured. Ultrasound surveillance was used in all patients. There was no outside funding for the study.

RESULTS

All patients agreed to participate (inclusion rate, 100 percent). No patient developed clinical signs or ultrasound evidence of a deep venous thrombosis. There were no significant changes in tissue plasminogen activator levels or plasminogen activator inhibitor-1 levels from the preoperative measurements at any hourly interval and no differences in levels comparing patients treated with or without sequential compression devices.

CONCLUSIONS

No significant change in systemic fibrinolytic activity occurs during outpatient plastic surgery under total intravenous anesthesia. Sequential compression devices do not affect tissue plasminogen activator or plasminogen activator inhibitor-1 levels, suggesting no fibrinolytic benefit.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, I.

Venous Thromboembolism Incidence and Prophylaxis Use After Gastrectomy Among Korean Patients With Gastric Adenocarcinoma: The PROTECTOR Randomized Clinical Trial

Importance

The guidelines by the National Comprehensive Cancer Network and the American Society for Clinical Oncology recommend the routine use of thromboprophylaxis for patients with gastric adenocarcinoma. However, many physicians in Asian countries use venous thromboembolism (VTE) prophylaxis much less often because of the perceived lower VTE incidence in this population.

Objectives

To evaluate the incidence of postgastrectomy VTE in Korean patients with gastric adenocarcinoma, and to identify the complications and evaluate the efficacy and safety of VTE prevention methods.

Design, Setting, and Participants

The Optimal Prophylactic Method for Venous Thromboembolism After Gastrectomy in Korean Patients (PROTECTOR) randomized clinical trial was conducted between August 1, 2011, and March 31, 2015. Patients with histologically confirmed gastric adenocarcinoma presenting to a single center (Seoul St Mary's Hospital in Seoul, South Korea) were enrolled. Patients were randomized to either an intermittent pneumatic compression (IPC)-only group or an IPC+low-molecular-weight (LMW) heparin sodium group. The data were analyzed on intention-to-treat and per protocol bases. Data analysis was performed from April 1, 2016, to October 30, 2017.

Main Outcomes and Measures

Venous thromboembolism incidence was the primary outcome. Postoperative complications, particularly those associated with VTE prophylaxis methods, were the secondary end point.

Results

Of the 682 patients enrolled and randomized, 447 (65.5%) were male and 245 (34.5%) were female, with a mean (SD) age of 57.67 (12.94) years. Among the 666 patients included in the analysis, the overall incidence of VTE was 2.1%. The incidence of VTE was statistically significantly higher in the IPC-only group compared with the IPC+LMW heparin group (3.6%; 95% CI, 2.05%-6.14% vs 0.6%; 95% CI, 0.17%-2.18%; P = .008). Among the 14 patients (2.1%) with VTE, 13 were asymptomatic and received a deep vein thrombosis diagnosis, whereas 1 patient received a symptomatic pulmonary thromboembolism diagnosis. The overall incidence of bleeding complications was 5.1%. The incidence of bleeding complications was significantly higher in the IPC+LMW heparin group compared with the IPC-only group (9.1% vs 1.2%; P < .001). No cases of VTE-associated mortality were noted.

Conclusions and Relevance

Use of IPC alone is inferior to the use of IPC+LMW heparin in preventing postoperative VTE. Because LMW heparin is associated with a high bleeding risk, further study is needed to stratify the patients at high risk for perioperative development of VTE.

Trial Registration

ClinicalTrials.gov Identifier: NCT01448746.

Research quality in the study of mechanical methods of deep vein thrombosis prophylaxis

There is a lack of good-quality recent clinical data to support the use of mechanical methods to prevent deep vein thrombosis. Recommendations and meta-analyses have to rely on old data from evaluations of devices that are no longer available, with diagnostic methods that are obsolete. The aim of this narrative review is to examine the reasons why better recent evidence is not available, and how this will affect innovation in mechanical deep vein thrombosis prophylaxis. Analysis of recent published trials shows great variability in techniques and technologies, which complicates evaluation of the effectiveness of properties of intermittent pneumatic compression, graduated compression stockings, and electrical stimulation devices. Negative controlled trials have become difficult to conduct, and low rates of deep vein thrombosis have left many comparative trials of devices underpowered. There is a risk that if new approaches to enable clinical research are not developed that technological advancement of mechanical prophylaxis will be inhibited.

A soft ring oscillator

Periodic actuation of multiple soft, pneumatic actuators requires coordinated function of multiple, separate components. This work demonstrates a soft, pneumatic ring oscillator that induces temporally coordinated periodic motion in soft actuators using a single, constant-pressure source, without hard valves or electronic controls. The fundamental unit of this ring oscillator is a soft, pneumatic inverter (an inverting Schmitt trigger) that switches between its two states (“on” and “off”) using two instabilities in elastomeric structures: buckling of internal tubing and snap-through of a hemispherical membrane. An odd number of these inverters connected in a loop produces the same number of periodically oscillating outputs, resulting from a third, system-level instability; the frequency of oscillation depends on three system parameters that can be adjusted. These oscillatory output pressures enable several applications, including undulating and rolling motions in soft robots, size-based particle separation, pneumatic mechanotherapy, and metering of fluids. The soft ring oscillator eliminates the need for hard valves and electronic controls in these applications.

Electrical stimulation devices for the prevention of venous thromboembolism: Preliminary studies of physiological efficacy and user satisfaction

Introduction

Electrical stimulation could provide an alternative method for preventing venous thromboembolism in stroke patients. The purpose of this preliminary study was to explore the effects of electrical stimulation and intermittent pneumatic compression on enhancing lower limb venous return in healthy and chronic stroke patients and also to evaluate patient and nurse satisfaction.

Methods

We investigated the effectiveness of two electrical stimulation devices: Geko (Firstkind Ltd, High Wycombe, UK) and Orthopaedic Microstim 2V2 (Odstock Medical Ltd, Salisbury, UK); and one intermittent pneumatic compression device: Huntleigh Flowstron Universal (Huntleigh Healthcare Ltd, Cardiff, UK). We recruited 12 healthy and 5 chronic stroke participants. The devices were fitted sequentially, and Doppler ultrasound measurements were taken. Eight patients and nurses were also recruited for a separate usability evaluation.

Results

The electrical stimulation devices emulated the blood flow characteristics of intermittent pneumatic compression in both healthy and stroke participants provided that the intensity of electrical stimulation was sufficient. Patients and nurses also felt that the electrical stimulation devices were acceptable.

Conclusions

Electrical stimulation may offer benefit as an alternative method for venous thromboembolism prevention in stroke patients. The apparent benefit is sufficient to warrant further investigation in a full powered randomised controlled trial.

Venous Thromboembolism Incidence After Craniofacial Surgery

INTRODUCTION

Current protocols for venous thromboembolism (VTE) prophylaxis after craniofacial surgery (CFS) vary widely with substantial disagreements in both indications and managements. An evidence-based approach to this issue requires the following: the incidence of postoperative VTE, comorbidities associated with coagulopathy, risk reduction after VTE prophylaxis, and complications attributable to prophylaxis. This study addresses the first two.

DESIGN

Retrospective cross-sectional study.

METHODS

Discharge data from 64,170 patients undergoing CFS between 2008 and 2013 extracted from the Healthcare Cost and Utilization Project Nationwide Inpatient Sample were analyzed. The outcome measures extracted were: deep venous thrombosis, pulmonary embolism, demographic data, common comorbidities, length of stay, total cost, and discharge outcome.

RESULTS

Diagnoses of deep venous thrombosis or pulmonary embolism, collectively classified as VTE, were observed in 355 (0.55%) of 64,170 patients discharged after CFS. Other surgeries exhibited a VTE rate of 1.17%. Men exhibited nearly double the incidence of VTE relative to women (0.69% compared with 0.37% respectively, P < 0.001), and the risk factors of adulthood, advanced age, cardiovascular disease, obesity, and malignancy were associated with increased VTE incidence with odds ratios of 9.93, 3.66, 1.80, 2.02, and 2.02, respectively (P < 0.005). Tobacco use did not exhibit any significant association (odds ratio, 0.94; P = 0.679). Afflicted patients experienced 4.60 times longer hospital stays averaging 23.8 days (95% confidence interval, 21.4-26.2; P < 0.001) compared the average of 5.2 days experienced by CFS patients without VTE. They incurred an average cost of US $298,228 (95% confidence interval, 262,726 to 333,731; P < 0.001) which was 4.17 times the US $72,376 expense of treating other CFS patients. The likelihood for a CFS patient to experience a poor outcome at the time of discharge was 54.6% higher after VTE.

CONCLUSIONS

The risk of postoperative VTE after CFS is significantly increased in adults, patients with advanced age, cardiovascular disease, obesity, and malignancy. However even in those high-risk cases, postoperative VTE incidence remains relatively low after CFS. These findings in conjunction with further study regarding the risk associated with the addition of VTE chemoprophylaxis compared against mechanical VTE prophylaxis, such as sequential pneumatic compression stockings, may determine whether routine use of VTE chemoprophylaxis is appropriate.

Effect of postoperative pneumatic compression after volar plate fixation of distal radial fractures: a randomized controlled trial

We investigated the difference between postoperative rehabilitation with or without adjunctive intermittent pneumatic compression therapy following distal radial fracture treated with volar plating. A total of 115 patients were randomized to a control or to an experimental group. After 4 weeks of immobilization the experimental group received intermittent pneumatic compression therapy in addition to conventional postoperative rehabilitation. Primary outcome up to 1 year postoperatively was assessed using the Canadian Occupational Performance Measure. No significant differences between groups were found. There were no clinically relevant differences regarding the secondary outcome measures swelling, strength, pain and flexibility. We conclude that postoperative intermittent pneumatic compression treatment had no major benefits. The results of the present study do not support general use of intermittent pneumatic compression initiated 4 weeks following volar plating surgery for distal radial fracture.

LEVEL OF EVIDENCE

I.

Thromboprophylaxis in Pregnancy

Venous thromboembolism is a leading cause of maternal morbidity and mortality worldwide. Identifying women who are at greatest risk for venous thromboembolism, and managing their pregnancies with appropriate thromboprophylaxis is essential to decreasing this life-threatening condition. Those at greatest risk are patients with thrombophilias, a personal or family history of venous thromboembolism, and those undergoing cesarean delivery. Current international guidelines on thromboprophylaxis vary in details, but all strategies rely on risk factor identification and thromboprophylaxis for the highest risk patients. All guidelines require clinicians to think critically about individual patient's risk factors throughout pregnancy and the postpartum period.

A novel exercise device for venous thromboembolism prophylaxis improves venous flow in bed versus ankle movement exercises in healthy volunteers

PURPOSE

Venous thromboembolism prophylaxis is crucial. To facilitate active ankle movement in postoperative and bedridden patients, we developed a novel leg exercise apparatus (LEX). We investigated the effect of the LEX by comparing increases in lower extremity venous flow during different modes of exercise using the LEX.

METHODS

In eight healthy participants, we measured venous flow volume and velocity in the femoral vein using duplex ultrasonography at 1, 10, 20, and 30 min after completing three modes of 1-min LEX exercises. The exercises involved (1) rapid single motion (ankle dorsi-plantar flexion; 60 cycles/min); (2) slow single motion (30 cycles/min); and (3) slow combined leg motion.

RESULTS

Flow volumes after modes 1, 2, and 3 were 1.63-, 1.39-, and 1.53-fold above baseline at 30 min, respectively. Short periods of rapid single motion, with the LEX, improved postexercise lower extremity venous flow volumes at 30 min and mean venous flow velocity at 20 min, compared to slow single motion exercise. Even at slow speeds, combined-motion improved flow volume compared to single motion.

CONCLUSION

Short periods of rapid single motion exercise, with the LEX, improved postexercise venous flow volumes in the lower extremities at 30 min and mean venous flow velocity at 20 min. These effects were greater than those produced by slow single motion exercises. However, even at slow speeds, combined-motion exercises improved flow volume compared to single motion. Therefore, LEX may prove effective at preventing thromboembolism in postoperative and bedridden patients.

Prevention of perioperative venous thromboembolism in pediatric patients: Guidelines from the Association of Paediatric Anaesthetists of Great Britain and Ireland (APAGBI)

The Association of Paediatric Anaesthetists of Great Britain and Ireland (APAGBI) Guidelines Working Group on Thromboprophylaxis in Children has reviewed the literature and where possible provided advice on the care of children in the perioperative period. Areas reviewed include the incidence of perioperative venous thromboembolism (VTE), risk factors, evidence for mechanical and chemical prophylaxis, and complications. Safe practice of regional anesthesia with anticoagulant prophylaxis is detailed. In summary, there are few areas of strong evidence. Routine prophylaxis cannot be recommended for young children. Postpubertal adolescents (approximately 13 years and over) are at a slightly increased risk of VTE and should be assessed for prophylaxis and may warrant intervention if other risk factors are present. However, the incidence of VTE is significantly lower than in the adult population. This special interest review presents a summary and discussion of the key recommendations, a decision-making algorithm and a risk assessment chart. For the full guideline, go to www.apagbi.org.uk/publications/apa-guidelines.

Incidence of deep venous thrombosis following periacetabular and derotational femoral osteotomy: a case for mechanical prophylaxis

There are currently no established guidelines for appropriate antithrombotic prophylaxis following periacetabular osteotomy (PAO) or derotational femoral osteotomy (DFO). The purpose of this study was to determine the incidence of clinical deep venous thrombosis (DVT) following PAO and/or DFO wherein a portable, mechanical device and low-dose aspirin were used postoperatively for DVT prophylaxis. Patients who had undergone staged hip arthroscopy and primary PAO and/or DFO were prospectively reviewed. Following PAO/DFO, patients were prophylactically treated for thromboembolic disease with a portable, mechanical compression device for 3 weeks and low-dose aspirin for 4 weeks. Patients were followed in clinic until 24 months postoperatively. During the study period, 145 hips (124 patients) underwent surgery (PAO: 109, DFO: 24, PAO + DFO: 12). Overall, the incidence of clinically apparent DVT was 0% in the study cohort. Average estimated blood loss during surgery was 601 mL and five cases required blood transfusions of 1 or 2 units. Ten patients were seen in the emergency room 10–20 days after surgery presenting with calf tenderness and DVT was ruled out in all cases with ultrasound. There were no postoperative bleeding or wound complications. A portable, mechanical compression device and low-dose aspirin effectively lessens the risk of DVT following staged hip arthroscopy and PAO/DFO without an increased risk of bleeding complications.

Neuromuscular electrical stimulation for the prevention of venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE) is a serious but preventable cause of morbidity and mortality. Neuromuscular electrical stimulation systems (NMES) for the prevention of VTE may be beneficial for patients in whom pharmacological or standard mechanical prophylaxis methods are contraindicated or are regarded as unsafe or impractical. Although findings of experimental studies suggest that NMES reduce venous stasis, the clinical utility and effectiveness of NMES in VTE prevention remain controversial.

OBJECTIVES

To assess the effectiveness of neuromuscular electrical stimulation in the prevention of venous thromboembolism.

SEARCH METHODS

The Cochrane Vascular Group Information Specialist (CIS) searched the Specialised Register (22 March 2017) and the Cochrane Central Register of Controlled Studies (CENTRAL (2017, Issue 2)). The CIS also searched trial registries for details of ongoing and unpublished studies. The review authors searched the bibliographic lists of relevant articles and reviews to look further for potentially eligible trials.

SELECTION CRITERIA

We planned to include randomised controlled trials (RCTs) and quasi-randomised trials that compared any form of neuromuscular electrical stimulation as an intervention for VTE prophylaxis (alone or combined with pharmacological or other mechanical methods) versus no prophylaxis and other mechanical or pharmacological methods of VTE prophylaxis.

DATA COLLECTION AND ANALYSIS

At least two independent review authors were involved in study selection, data extraction, methodological quality assessment of included studies, and data analysis. We resolved disagreements by discussion between the two review authors. If no agreement could be reached, a third review author acted as an adjudicator. The main outcomes of the review were total deep vein thrombosis (DVT), symptomatic and asymptomatic DVT, pulmonary embolism (PE), total VTE and bleeding (major and minor). The quality of evidence was assessed using the GRADE approach and is indicated in italics.

MAIN RESULTS

We included in the review five randomised controlled trials and three quasi-randomised trials, enrolling a total of 904 participants. Among these, four studies included patients undergoing major surgical procedures; one study included patients undergoing surgery for hip fracture under spinal anaesthesia; one study included trauma patients with a contraindication for prophylactic heparin; one study included neurosurgical patients who were operated on under general anaesthesia; and one study included patients with non-functional spinal cord injuries. Overall, eight studies investigated 22 treatment arms. Four studies compared the NMES arm with a no prophylaxis arm, and five studies compared the NMES arm with alternative methods of prophylaxis arms. Alternative methods of prophylaxis included low-dose heparin (5000 IU subcutaneously) - two studies, Dextran 40 - one study, graduated compression stockings (GCS) and intermittent pneumatic compression devices (IPCD) - one study. One study compared combined NMES and low-dose heparin versus no prophylaxis or low-dose heparin alone.We found no clear difference in risks of total DVT (odds ratio (OR) 1.01, 95% confidence interval (CI) 0.60 to 1.70, P = 0.98; 6 studies, 415 participants; low-quality evidence), asymptomatic DVT (OR 1.61, 95% CI 0.40 to 6.43, P = 0.50; 1 study, 89 participants; low-quality evidence), symptomatic DVT (OR 0.40, 95% CI 0.02 to 10.07, P = 0.58; 1 study, 89 participants; low-quality evidence), PE (OR 1.31, 95% CI 0.38 to 4.48, P = 0.67; 2 studies, 126 participants;low-quality evidence), and total VTE (OR 0.92, 95% CI 0.34 to 2.52, P = 0.88; 1 study, 72 participants; low-quality evidence) between prophylaxis with NMES and alternative methods of prophylaxis. None of the studies in this comparison reported bleeding.Compared with no prophylaxis, NMES showed lower risks of total DVT (OR 0.40, 95% CI 0.23 to 0.70, P = 0.02; 4 studies, 576 participants; moderate-quality evidence) and total VTE (OR 0.23, 95% CI 0.09 to 0.59, P = 0.002; 1 study, 77 participants; low-quality evidence). Data show no clear differences in risk of asymptomatic DVT (OR 0.32, 95% CI 0.06 to 1.62, P = 0.17; 1 study, 200 participants; low-quality evidence), symptomatic DVT (OR 0.06, 95% CI 0.00 to 1.36, P = 0.08; 1 study, 160 participants;low-quality evidence), or PE (OR 0.36, 95% CI 0.12 to 1.07, P = 0.07; 1 study, 77 participants; low-quality evidence) between prophylaxis with NMES and no prophylaxis. None of the studies in this comparison reported bleeding.In comparison with low-dose heparin, NMES was associated with higher risk of total DVT (OR 2.78, 95% CI 1.19 to 6.48, P = 0.02; 2 studies, 194 participants; low-quality evidence), but data were inadequate for other comparisons (NMES vs Dextran 40, NMES vs GCS, or NMES vs IPCD) and for other clinical outcomes such as symptomatic or asymptomatic DVT, PE, total VTE, and bleeding in individual comparisons.Overall, we judged the quality of available evidence to be low owing to high or unclear risk of bias and imprecise effect estimates due to small numbers of studies and events.

AUTHORS' CONCLUSIONS

Low-quality evidence shows no clear difference in the risk of DVT between NMES and alternative methods of prophylaxis but suggest that NMES may be associated with lower risk of DVT compared with no prophylaxis (moderate-quality evidence) and higher risk of DVT compared with low-dose heparin (low-quality evidence). The best available evidence about the effectiveness of NMES in the prevention of VTE is not adequately robust to allow definitive conclusions. Adequately powered high-quality randomised controlled trials are required to provide adequately robust evidence.

Does preoperative mechanical prophylaxis have additional effectiveness in preventing postoperative venous thromboembolism in elderly patients with hip fracture?-Retrospective case-control study

Background

Elderly patients undergoing hip fracture surgery (HFS) are at increased risk of postoperative venous thromboembolism (VTE). To reduce this risk, combined postoperative mechanical and chemical thromboprophylaxis has been routinely performed after HFS in these patients. This retrospective case-control study was conducted to evaluate the additional effectiveness of preoperative mechanical thromboprophylaxis for the prevention of VTE following HFS in elderly patients.

Methods

Of 539 consecutive patients aged 70 years or older undergoing HFS, 404 (control group) did not receive preoperative mechanical thromboprophylaxis, while 135 (study group) received mechanical thromboprophylaxis using an intermittent pneumatic compression device and graduated compression stockings from the time of admission until surgery. All patients received combined postoperative mechanical and chemical thromboprophylaxis following HFS in accordance with the same protocol. The incidence of symptomatic VTE confirmed based on clinical symptoms and 3-dimensional CT angiography within one month of surgery was investigated in both groups.

Results

The American Society of Anesthesiologists grade was higher (p = 0.016) in the study group and more patients in this group had concomitant cardiovascular and neurologic diseases (p = 0.005 and p = 0.009, respectively). In addition, more patients in the study group had received anticoagulant medication preinjury owing to comorbidities (39% vs 28%, p = 0.025). The overall incidences of symptomatic deep vein thrombosis (DVT) and pulmonary embolism (PE) were 7.4% and 3.7%, and 2.2% and 1.5% in the control and study groups, respectively. According to multiple logistic regression, symptomatic DVT significantly reduced in the study group (OR 0.28, p = 0.042), while there was no significant difference in the incidence of symptomatic PE between the two groups (p = 0.223).

Conclusions

Preoperative mechanical thromboprophylaxis may confer an additional benefit by preventing postoperative VTE without adding more risk of perioperative bleeding in elderly patients with hip fracture.

The Training Effect of Early Intervention with a Hybrid Assistive Limb after Total Knee Arthroplasty

After total knee arthroplasty (TKA), it is important for patients to show early improvements in knee joint function and walking to regain independence in performing the activities of daily life. We conducted for 4 weeks an intervention one week after TKA using a hybrid assistive limb (HAL: unilateral leg type) as an exoskeleton robotic device to facilitate knee joint function and walking. The intervention improved the range of knee extension movement safely and without pain compared to preoperation. In addition, we found that training with the HAL improved walking ability, speed, and rate, as well as the time taken to perform the timed up and go (TUG) test compared to preoperation. The strength of the quadriceps muscle did not improve with training; however, the patient was able to induce a knee extensor moment during the initial stance phase, as measured by kinetics and kinematics, and these actions could be performed without pain. HAL training soon after TKA improved knee joint function in a 76-year-old patient who presented with OA of the knee. The improvements in knee extension lag and knee extensor moment allowed the patient to walk without pain and regain ADL in comparison with preoperation.

Establishing a Multidisciplinary Approach to the Management of Neurologic Disease Affecting the Urinary Tract

Neurologic diseases often affect the urinary tract and may be congential or acquired. The progressive nature of many neurologic diseases necessitates routine surveillance and treatment with a multidisciplinary approach. Urologic treatments may interact with pharmacologic or procedural interventions planned by other specialists, mandating close coordination of care and communication among providers. Primary care and nursing often can serve as the quarterbacks of the multidisciplinary team by identifying when a slowly progressive condition warrants further investigation and management by specialists.

Target range of motion for rehabilitation after total knee arthroplasty

Objective: Postoperative knee range of motion (ROM) is among the most important factors influencing patient satisfaction after total knee arthroplasty (TKA). The purpose of this study was to clarify the time course of improvement in knee ROM up to 12 months after TKA, including intraoperative knee ROM after implantation, and to clarify a target ROM for rehabilitation after TKA.

Patients and Methods: In total, 39 knee joints in 26 patients with osteoarthritis who underwent TKA (retaining the posterior cruciate ligament) were evaluated. Goniometry was used to measure the knee range of extension and flexion preoperatively; intraoperatively; at 1 and 2 weeks after TKA; and then at 1, 3, 6, and 12 months after TKA.

Results: The postoperative extension range gradually improved up to a maximum at 6 months after TKA; there were no significant differences in the extension range between intraoperative and 6 months after TKA, intraoperative and 12 months after TKA, or 6 and 12 months after TKA. The postoperative flexion range gradually improved, with the maximum improvement observed at 3 months after TKA; there were no significant differences in the flexion range before TKA and 3, 6, and 12 months after TKA. There were no significant differences between flexion ROM measured at 3, 6, and 12 months after TKA.

Conclusions: The changes in the knee range of extension plateaued 6 months after TKA, and those in the knee range of flexion plateaued 3 months after TKA. The target range of extension for rehabilitation from 6 months to 12 months after TKA was the intraoperative range, and the target range of flexion for rehabilitation from 3 months to 12 months after TKA was the preoperative range.

Efficacy in Deep Vein Thrombosis Prevention With Extended Mechanical Compression Device Therapy and Prophylactic Aspirin Following Total Knee Arthroplasty: A Randomized Control Trial

BACKGROUND

Aspirin at 325 mg twice daily is now included as a nationally approved venous thromboembolism (VTE) prophylaxis protocol for low-risk total knee arthroplasty (TKA) patients. The purpose of this study is to examine whether there is a difference in deep vein thrombosis (DVT) occurrence after a limited tourniquet TKA using aspirin-based prophylaxis with or without extended use of mechanical compression device (MCD) therapy.

METHODS

One hundred limited tourniquet TKA patients, whose DVT risk was managed with aspirin 325 mg twice daily for 3 weeks, were randomized to either using an MCD during hospitalization only or extended use at home up to 6 weeks postoperatively. Lower extremity duplex venous ultrasonography (LEDVU) was completed on the second postoperative day, 14 days postoperatively, and at 3 months postoperatively to confirm the absence of DVT after treatment.

RESULTS

The DVT rate for the postdischarge MCD therapy group was 0% and 23.1% for the inpatient MCD group (P < .001). All DVTs resolved by 3 months postoperatively. Patient satisfaction was 9.56 (±0.82) for postdischarge MCD patients vs 8.50 (±1.46) for inpatient MCD patients (P < .001).

CONCLUSION

Limited tourniquet TKA patients who were mobilized early, managed with aspirin for 3 weeks postoperatively, and on MCD therapy for up to 6 weeks postoperatively experienced superior DVT prophylaxis than patients receiving MCD therapy only as an inpatient (P < .05). The 0% incidence of nonsymptomatic DVTs prevented by aspirin and extended-use MCD further validates this type of prophylaxis in low DVT risk TKA patients.

Deep Vein Thrombosis and Pulmonary Embolism Considerations in Orthopedic Surgery

Patients undergoing orthopedic surgery have an increased risk for deep venous thrombosis (DVT) and pulmonary embolism (PE). These complications are considered detrimental, as they cause major postoperative morbidity and mortality and lead to a substantial health care burden. Because of the high incidence and serious nature of these complications, it is essential for orthopedic surgeons to have a comprehensive knowledge of the risk factors, diagnosis, and treatment of acute DVT and PE. Perioperative management of orthopedic patients to prevent postoperative DVT and PE and optimize postoperative outcomes is also discussed in this review.

Intermittent Pneumatic Compression for the Prevention of Venous Thromboembolism after Total Hip Arthroplasty

BACKGROUND

Venous thromboembolism (VTE) is a relatively common and potentially life threatening complication after major hip surgery. There are two main types of prophylaxis: chemical and mechanical. Chemical prophylaxis is very effective but causes bleeding complications in surgical wounds and remote organs. On the other hand, mechanical methods are free of hemorrhagic complications but are less effective. We hypothesized that mechanical prophylaxis is effective enough for Asians in whom VTE occurs less frequently. This study evaluated the effect of intermittent pneumatic compression (IPC) in the prevention of VTE after major hip surgery.

METHODS

Incidences of symptomatic VTE after primary total hip arthroplasty with and without application of IPC were compared. A total of 379 patients were included in the final analysis. The IPC group included 233 patients (106 men and 127 women) with a mean age of 54 years. The control group included 146 patients (80 men and 66 women) with a mean age of 53 years. All patients took low-dose aspirin for 6 weeks after surgery. IPC was applied to both legs just after surgery and maintained all day until discharge. When a symptom or a sign suspicious of VTE, such as swelling or redness of the foot and ankle, Homans' sign, and dyspnea was detected, computed tomography (CT) angiogram or duplex ultrasonogram was performed.

RESULTS

Until 3 months after surgery, symptomatic VTE occurred in three patients in the IPC group and in 6 patients in the control group. The incidence of VTE was much lower in the IPC group (1.3%) than in the control group (4.1%), but the difference was not statistically significant. Complications associated with the application of IPC were not detected in any patient. Patients affected by VTE were older and hospitalized longer than the unaffected patients.

CONCLUSIONS

The results of this study suggest that IPC might be an effective and safe method for the prevention of postoperative VTE.

Hemodynamic effects of electrical muscle stimulation in the prophylaxis of deep vein thrombosis for intensive care unit patients: a randomized trial

Background

Deep vein thrombosis (DVT) is a major complication in critical care. There are various methods of prophylaxis, but none of them fully prevent DVT, and each method has adverse effects. Electrical muscle stimulation (EMS) could be a new effective approach to prevent DVT in intensive care unit (ICU) patients. We hypothesized that EMS increases the venous flow of the lower limbs and has a prophylactic effect against the formation of DVT.

Methods

This study included 26 patients admitted to a single ICU. We enrolled patients who could not move themselves due to spinal cord injury, head injury, central nervous system abnormalities, and sedation for mechanical ventilation. The patients were randomly allocated to either the EMS group or the control group. Patients in the EMS group received 30-min sessions of EMS applied to the bilateral lower extremities on arbitrary days within 14 days after admission. The control patients received no EMS. The peak flow velocity and diameter of the popliteal vein (Pop.V) and common femoral vein (CFV) were measured by ultrasound and then the volumes of venous flow were calculated using a formula.

Results

There were no statistically significant differences in patient characteristics between the two groups except for the mortality rate. In the EMS group, the median and interquartile range (IQR, 25th–75th percentile) of velocities of the Pop.V and CFV were higher during EMS compared with at rest: 10.6 (8.0–14.8) vs 24.5 (15.1–37.8) cm/s and 17.0 (12.3–23.8) vs 24.3 (17.0–33.0) cm/s, respectively (p < 0.05). The median (IQR) of volumes of venous flow of the Pop.V and CFV at rest and during EMS were 4.2 (2.7–7.2) vs 8.6 (5.4–16.1) cm³/s and 12.9 (9.7–21.4) vs 20.8 (12.3–34.1) cm³/s, respectively (p < 0.05). There were no major complications related to EMS.

Conclusions

EMS increased the venous flow of the lower limbs. EMS could be one potential method for venous thromboprophylaxis.

Trial registration

UMIN000013642

Intermittent pneumatic compression and deep vein thrombosis prevention in postoperative patients

High incidence of venous thromboembolism (VTE) makes prophylaxis, screening and treatment extremely important. Both pharmacological and mechanical techniques can be used to reduce the risk of deep vein thrombosis (DVT). Mechanical methods have been studied much less intensively than pharmacological options. The principal mechanical methods of prophylaxis are graduated compression stockings and intemittent pneumatic compression devices. We conducted a meta-analysis of all randomized controlled trials to determine the effectiveness of intermittent pneumatic compression (IPC) devices in the preventon of DVT in post-surgical patients. The results of this analysis indicate that IPC devices reduced the risk of DVT by 60% when compared with patients with no mechanical or pharmacological prophylaxis. Contemporary randomized trials should be undertaken to test the utility of IPC in medcal patients as well as combined pharmacological plus IPC prophylaxis in both medical patients.

Cohort feasibility study of an intermittent pneumatic compression device within a below-knee cast for the prevention of venous thromboembolism

OBJECTIVES

To determine the likely enrolment rate of eligible participants into a randomised controlled trial (RCT) in which a within-cast intermittent pneumatic compression device using Jet Impulse Technology (IPC/JIT) is 1 of 3 possible interventions in a RCT for the prevention of venous thromboembolism (VTE) in the clinical setting of isolated lower limb cast immobilisation.

DESIGN

A prospective, open-label feasibility study of the IPC/JIT device placed within a lower limb cast.

SETTING

Wellington Regional Hospital Fracture Clinic.

PARTICIPANTS

Individuals aged 18-70 who presented with a lower limb injury requiring a minimum of 4 weeks below-knee cast immobilisation.

INTERVENTION

Placement of an IPC/JIT device within lower limb cast.

OUTCOME MEASURES

The main outcome measure was the proportion of eligible participants who participated in the feasibility study. Secondary outcome measures included adherence to device usage throughout the study, ease of application of the device and adverse events potentially associated with its use.

RESULTS

The proportion of potentially eligible participants for the IPC/JIT device was only 7/142 (5%), 95% CI 2 to 9.9. Devices were used for a mean (range) of 4.1 (1.9 to 10.2) hours per day and none of 7 participants had adequate adherence to the device. 3 of the 7 participants suffered an adverse event, including 1 deep vein thrombosis, 2 dorsal foot ulcer and 1 skin maceration.

CONCLUSIONS

A within-cast IPC/JIT device is unlikely to be a feasible randomisation arm for a RCT assessing possible interventions for the reduction of VTE risk in the clinical setting of lower limb injury requiring below knee cast immobilisation for a minimum of 4 weeks.

TRIAL REGISTRATION NUMBER

ANZCTR 12615000192583.

The Use of Intermittent Pneumatic Compression in Orthopedic and Neurosurgical Postoperative Patients: A Systematic Review and Meta-analysis

OBJECTIVE

The objective of this systematic review and meta-analysis was to carry out an up-to-date evaluation on the use of compression devices as deep vein thrombosis (DVT) prophylaxis methods in orthopedic and neurological patients.

SUMMARY OF BACKGROUND DATA

There is an increased risk of DVT with surgery, particularly in patients who are not expected to mobilize soon after their procedures, such as orthopedic and neurosurgical patients. Compression devices are often employed for DVT prophylaxis in these patients. However, the true efficacy of these devices and the standardization of use with these devices are yet to be established.

METHODS

Medline, CINAHL, Embase, Google Scholar, and the Cochrane library electronic databases were searched to identify randomized controlled trials and observational studies reporting on the use of compression devices for DVT prevention.

RESULTS

Nine studies were included for review and meta-analysis. Use of an intermittent pneumatic compression device alone is neither superior nor inferior to chemoprophylaxis.

CONCLUSIONS

In the absence of large randomized multicenter trials comparing the use of intermittent pneumatic compression or chemoprophylaxis alone to a combination of both treatments, the current evidence supports the use of a combined approach in high-risk surgical patients.

Preventing Venous Thromboembolism with Use of Intermittent Pneumatic Compression after Total Hip Arthroplasty in Korean Patients

Intermittent Pneumatic Compression (IPC) device has been used to prevent venous thromboembolism (VTE). This study investigated the effectiveness of IPC device. We evaluated incidences of deep vein thrombosis (DVT) and pulmonary embolism (PE) in total hip arthroplasty (THA) patients after use of IPC device, and compared with historical incidences from our institution. We applied IPC device in 741 patients who underwent 870 elective primary THAs from January 2010 to December 2013, DVT was detected in 3 patients (0.3%) by sonography, and one (0.1%) of them was symptomatic. Symptomatic PE occurred in 1 patient (0.1%) and there were no cases of fatal PE. The incidence of symptomatic DVT was significantly lower than the historical control (P = 0.042). The IPC is a safe and effective prophylaxis of VTE after primary THA in Korea.

Electrical muscle stimulation in thomboprophylaxis: review and a derived hypothesis about thrombogenesis-the 4th factor

INTRODUCTION

Electrical muscle stimulation (EMS) is an FDA-approved thromboprophylactic method. Thrombus pathogenesis is considered to depend on factors related to components of the vessel wall, the velocity of blood, and blood consistency-collectively known as, the Virchow's triad.

OBJECTIVE

The testimony supporting the thromboprophylactic effects of the EMS is reviewed. An emphasis is placed on the fact that, EMS has demonstrated, in certain circumstances, an efficacy rate that cannot be fully explained by the Virchow's triad; also that, in reviewing relevant evidence and the theorized pathophysiological mechanisms, several findings collectively point to a potentially missed point. Remarkably, venous thromboembolic disease (VTE) is extremely more common in the lower versus the upper extremities even when the blood velocities equalize; EMS had synergistic effects with intermittent compressive devices, despite their presumed identical mechanism of action; sleep is not thrombogenic; non-peroperative EMS is meaningful only if applied ≥5 times daily; neural insult increases VTEs more than the degree expected by the hypomobility-related blood stasis; etc. These phenomena infer the presence of a 4th thrombogenetic factor: neural supply to the veins provides direct antithrombic effects, by inducing periodic vessel diameter changes and/or by neuro-humoral, chemically acting factors. EMS may stimulate or substitute the 4th factor. This evidence-based hypothesis is analyzed.

CONCLUSION

A novel pathophysiologic mechanism of thrombogenesis is supported; and, based on this, the role of EMS in thromboprophylaxis is expanded. Exploration of this mechanism may provide new targets for intervention.