Effects of a Foot Pump on the Incidence of Deep Vein Thrombosis After Total Knee Arthroplasty in Patients Given Edoxaban: A Randomized Controlled Study

Venous Thromboembolism Prophylaxis Compliance in Orthopedic Patients With Cardiac Risk Factors

Introduction Venous thromboembolism (VTE) is a critical condition that includes deep vein thrombosis (DVT) and pulmonary embolism (PE), both of which can lead to severe complications, including death, if not adequately managed. Objective This study aimed to evaluate adherence to prophylactic measures and identify factors influencing compliance. Methodology This study was done in Shalamar Hospital, Lahore, from October 2023 to October 2024. Baseline assessments were conducted to gather demographic and clinical data, including age, gender, body mass index (BMI), comorbidities, and cardiac risk factors such as atrial fibrillation or coronary artery disease. Details of the surgical procedures, including type, duration, and anesthesia used, were also recorded. Compliance with VTE prophylaxis was monitored through patient interviews, direct observation, and medical record reviews. Pharmacological prophylaxis compliance involved evaluating the administration of anticoagulants regarding dosage, timing, and frequency. Mechanical prophylaxis adherence was assessed by monitoring the use of compression stockings and pneumatic devices. Compliance was measured as the percentage of patients who adhered to the prescribed prophylaxis protocols. Primary outcomes included the incidence of VTE events, such as DVT or PE, within 30 days post-surgery. Follow-ups were conducted through in-person visits or telephonic interactions to monitor compliance and postoperative outcomes. Data were analyzed using IBM SPSS Statistics for Windows, Version 26.0 (Released 2019; IBM Corp., Armonk, New York, United States). Continuous variables, such as age and BMI, were summarized using means and standard deviations, while categorical variables, like compliance rates, were expressed as frequencies and percentages. Subgroup analyses were conducted to identify variations in compliance rates based on demographic and clinical factors using t-tests. Results The study included 90 patients, with a mean age of 58.9±8.4 years and a nearly equal gender distribution (54% male and 46% female). The mean BMI of the participants was 28.5±3.2 kg/m². Hypertension was the most common cardiac risk factor, affecting 67% (n=60) of patients, followed by atrial fibrillation (22%; n=20) and heart failure (11%; n=10). Among the surgeries, 65% (n=58) were elective, while 35% (n=32) were emergency procedures. VTE incidence was 6.7% (n=6), with 4.4% (n=4) developing DVT and 2.2% (n=2) experiencing PE. Bleeding complications occurred in 8.9% (n=8) of patients, with 6.7% (n=6) experiencing minor bleeding and 2.2% (n=2) reporting major bleeding. Patients undergoing elective surgeries exhibited higher pharmacological compliance at 78% (n=45) and mechanical compliance at 88% (n=51), resulting in an overall compliance rate of 84% (n=49). In contrast, patients undergoing emergency surgeries had lower compliance rates, with 63% (n=20) for pharmacological prophylaxis and 69% (n=22) for mechanical prophylaxis, leading to an overall compliance rate of 63% (n=20). Conclusion It is concluded that compliance with VTE prophylaxis plays a pivotal role in reducing the risk of thromboembolic events in orthopedic patients with cardiac risk factors.

Effect of venous foot pump intervention on prevention of venous thromboembolism in patients with major orthopedic surgery: a systematic review and meta-analysis

Background

Venous thromboembolism (VTE) is a common complication after major orthopedic surgery. The venous foot pump (VFP) is an effective mechanical preventive measure against VTE in patients. However, the differences in effectiveness based on varying usage times of VFP remain unclear.

Objective

To explore the effectiveness of VFP with different usage times in preventing VTE in patients undergoing major orthopedic surgery.

Methods

Nine databases (PubMed, Web of Science, CINAHL, Embase, Cochrane Library, CBM, VIP, CNKI, and Wanfang) were searched to identify randomized controlled trials (RCTs) evaluating VFP interventions for VTE prevention in major orthopedic surgery patients. The risk of bias in each study was assessed using the Cochrane Collaboration tool. Meta-analysis was conducted using RevMan 5.3.

Results

A total of 36 RCTs involving 3,791 patients undergoing major orthopedic surgery were included. Meta-analysis revealed significant differences in VTE incidence between the VFP and blank control groups (RR = 0.27, 95% confidence interval CI: 0.19-0.38, P < 0.001) and between the VFP plus chemoprophylaxis and chemoprophylaxis alone groups (RR 0.39, 95% CI: 0.29-0.53, P < 0.001). However, no statistically significant difference was observed between the VFP and the LMWH groups (RR = 0.93, 95% CI: 0.54-1.61, P = 0.8). Subgroup analysis showed no significant difference in effectiveness based on different VFP usage durations (VFP vs. Blank: Chi-square = 0.54, P = 0.46, I2 = 0%; VFP Plus chemoprophylaxis vs. chemoprophylaxis alone: Chi-square = 1.93, P = 0.86, I2 = 0%).

Conclusion

The current evidence indicates that VFP significantly reduces the incidence of postoperative VTE in patients undergoing major orthopedic surgery. VFP can be considered an add-on strategy to LMWH for patients at low risk of bleeding and an alternative strategy to LMWH in patients at high risk of bleeding. This study found no significant difference in effectiveness between various VFP usage interventions. Future research should focus on economic cost-effectiveness and patient acceptance to help policymakers determine the most efficient usage duration, providing practical guidance for thromboprophylaxis.

Effect of different application duration of a venous foot pump on prevention of venous thromboembolism after hip and knee arthroplasty: a multicenter prospective clinical trial

OBJECTIVE

To investigate the optimal duration of applying a venous foot pump (VFP) in the prevention of venous thromboembolism (VTE) following hip and knee arthroplasty.

METHODS

A total of 230 patients undergoing hip and knee arthroplasty between March 2021 and March 2022 in orthopaedic departments of four major teaching hospitals were prospectively enrolled. Patients were randomly divided into five groups based on the duration of the VFP application. Postoperative deep vein thromboses (DVT), including proximal, distal, and intermuscular DVT, were recorded for analysis. Postoperative blood coagulation examinations, such as D-dimer and active partial thromboplastin time (APTT), pain outcome, and degree of comfort were also collected.

RESULTS

Two of the 230 patients withdrew due to early discharge from the hospital, and 228 patients were included in the final analysis. The mean age was 60.38 ± 13.33 years. The baseline characteristics were comparable among the five groups. Compared with the other groups, patients treated with 6-hour VFP had the lowest incidence of DVT (8.7%, 4/46), followed by those treated with 1-hour VFP (15.2%, 7/46), 12-hour VFP (15.6%, 7/45), 18-hour VFP(17.8%, 8/45) and 20-hour VFP(21.7%, 10/46), but with no significant difference (P = 0.539). Regarding postoperative blood coagulation examinations, patients treated with 6-hour VFP had the lowest D-dimer (P = 0.658) and the highest APTT (P = 0.262) compared with the other four groups. 6-hour VFP also had the lowest pain score (P = 0.206) and the highest comfort score (P = 0.288) compared with the other four groups.

CONCLUSIONS

Six hours may be the optimal duration of applying VFP for the prevention of VTE in patients undergoing hip and knee arthroplasty in terms of VTE incidence, postoperative blood coagulation examinations, pain outcomes, and comfort scores.

Venous Thromboembolism Prophylaxis in Major Orthopedic Surgeries and Factor XIa Inhibitors

Venous thromboembolism (VTE), comprising pulmonary embolism (PE) and deep vein thrombosis (DVT), poses a significant risk during and after hospitalization, particularly for surgical patients. Among various patient groups, those undergoing major orthopedic surgeries are considered to have a higher susceptibility to PE and DVT. Major lower-extremity orthopedic procedures carry a higher risk of symptomatic VTE compared to most other surgeries, with an estimated incidence of ~4%. The greatest risk period occurs within the first 7-14 days following surgery. Major bleeding is also more prevalent in these surgeries compared to others, with rates estimated between 2% and 4%. For patients undergoing major lower-extremity orthopedic surgery who have a low bleeding risk, it is recommended to use pharmacological thromboprophylaxis with or without mechanical devices. The choice of the initial agent depends on the specific surgery and patient comorbidities. First-line options include low-molecular-weight heparins (LMWHs), direct oral anticoagulants, and aspirin. Second-line options consist of unfractionated heparin (UFH), fondaparinux, and warfarin. For most patients undergoing knee or hip arthroplasty, the initial agents recommended for the early perioperative period are LMWHs (enoxaparin or dalteparin) or direct oral anticoagulants (rivaroxaban or apixaban). In the case of hip fracture surgery, LMWH is recommended as the preferred agent for the entire duration of prophylaxis. However, emerging factor XI(a) inhibitors, as revealed by a recent meta-analysis, have shown a substantial decrease in the occurrence of VTE and bleeding events among patients undergoing major orthopedic surgery. This discovery poses a challenge to the existing paradigm of anticoagulant therapy in this specific patient population and indicates that factor XI(a) inhibitors hold great promise as a potential strategy to be taken into serious consideration.

Effect of Intermittent Pneumatic Compression in Addition to Pharmacologic Prophylaxis for Thromboprophylaxis in Hospitalized Adult Patients: A Systematic Review and Meta-Analysis

Venous thromboembolic events (VTE) are frequent complications in hospitalized patients and a leading cause of preventable death in hospital. Pharmacologic prophylaxis is a standard of care to prevent VTE in patients at risk, the additional value of intermittent pneumatic compression (IPC) is uncertain. We aimed to evaluate the efficacy of adding IPC to pharmacologic prophylaxis to prevent VTE in hospitalized adults.

DATA SOURCES

We searched the Cochrane Central Register of Controlled Trials, Embase, MEDLINE, Cumulative Index to Nursing and Allied Health Literature, ClinicalTrials.gov, and the International Clinical Trials Registry Platform from inception to July 2022.

STUDY SELECTION

We included randomized controlled trials comparing the use of IPC in addition to pharmacological thromboprophylaxis to pharmacological thromboprophylaxis alone in hospitalized adults.

DATA EXTRACTION

Meta-analyses were performed to calculate risk ratio (RR) of VTE, deep venous thrombosis (DVT), and pulmonary embolism (PE). We assessed the risk of bias using the Cochrane Risk of Bias Tool for Randomized Trials, Version 2 and the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation approach.

DATA SYNTHESIS

We included 17 trials enrolling 8,796 participants. The IPC was mostly applied up to the thigh and pharmacological thromboprophylaxis was primarily low-molecular-weight heparin. Adjunctive IPC was associated with a decreased risk of VTE (15 trials, RR = 0.53; 95% CI [0.35-0.81]) and DVT (14 trials, RR = 0.52; 95% CI [0.33-0.81]) but not PE (seven trials, RR = 0.73; 95% CI [0.32-1.68]). The quality of evidence was graded low, downgraded by risk of bias and inconsistency. Moderate and very low-quality evidence, respectively, suggests that adjunctive IPC is unlikely to change the risk of all-cause mortality or adverse events. Subgroup analyses indicate a more evident apparent benefit in industry-funded trials.

CONCLUSIONS

Results indicate low-quality evidence underpinning the additional use of IPC to pharmacological thromboprophylaxis for prevention of VTE and DVT. Further large high-quality randomized trials are warranted to support its use and to identify patient subgroups for whom it could be beneficial.

Combined intermittent pneumatic leg compression and pharmacological prophylaxis for prevention of venous thromboembolism

BACKGROUND

It is generally assumed by practitioners and guideline authors that combined modalities (methods of treatment) are more effective than single modalities in preventing venous thromboembolism (VTE), defined as deep vein thrombosis (DVT) or pulmonary embolism (PE), or both. This is the second update of the review first published in 2008.

OBJECTIVES

The aim of this review was to assess the efficacy of combined intermittent pneumatic leg compression (IPC) and pharmacological prophylaxis compared to single modalities in preventing VTE.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, and AMED databases, and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 18 January 2021. We searched the reference lists of relevant articles for additional studies.  SELECTION CRITERIA: We included randomised controlled trials (RCTs) or controlled clinical trials (CCTs) of combined IPC and pharmacological interventions used to prevent VTE compared to either intervention individually.

DATA COLLECTION AND ANALYSIS

We independently selected studies, applied Cochrane's risk of bias tool, and extracted data. We resolved disagreements by discussion. We performed fixed-effect model meta-analyses with odds ratios (ORs) and 95% confidence intervals (CIs). We used a random-effects model when there was heterogeneity. We assessed the certainty of the evidence using GRADE. The outcomes of interest were PE, DVT, bleeding and major bleeding.

MAIN RESULTS

We included a total of 34 studies involving 14,931 participants, mainly undergoing surgery or admitted with trauma. Twenty-five studies were RCTs (12,672 participants) and nine were CCTs (2259 participants). Overall, the risk of bias was mostly unclear or high. We used GRADE to assess the certainty of the evidence and this was downgraded due to the risk of bias, imprecision or indirectness. The addition of pharmacological prophylaxis to IPC compared with IPC alone reduced the incidence of symptomatic PE from 1.34% (34/2530) in the IPC group to 0.65% (19/2932) in the combined group (OR 0.51, 95% CI 0.29 to 0.91; 19 studies, 5462 participants, low-certainty evidence). The incidence of DVT was 3.81% in the IPC group and 2.03% in the combined group showing a reduced incidence of DVT in favour of the combined group (OR 0.51, 95% CI 0.36 to 0.72; 18 studies, 5394 participants, low-certainty evidence). The addition of pharmacological prophylaxis to IPC, however, increased the risk of any bleeding compared to IPC alone: 0.95% (22/2304) in the IPC group and 5.88% (137/2330) in the combined group (OR 6.02, 95% CI 3.88 to 9.35; 13 studies, 4634 participants, very low-certainty evidence). Major bleeding followed a similar pattern: 0.34% (7/2054) in the IPC group compared to 2.21% (46/2079) in the combined group (OR 5.77, 95% CI 2.81 to 11.83; 12 studies, 4133 participants, very low-certainty evidence). Tests for subgroup differences between orthopaedic and non-orthopaedic surgery participants were not possible for PE incidence as no PE events were reported in the orthopaedic subgroup. No difference was detected between orthopaedic and non-orthopaedic surgery participants for DVT incidence (test for subgroup difference P = 0.19).  The use of combined IPC and pharmacological prophylaxis modalities compared with pharmacological prophylaxis alone reduced the incidence of PE from 1.84% (61/3318) in the pharmacological prophylaxis group to 0.91% (31/3419) in the combined group (OR 0.46, 95% CI 0.30 to 0.71; 15 studies, 6737 participants, low-certainty evidence). The incidence of DVT was 9.28% (288/3105) in the pharmacological prophylaxis group and 5.48% (167/3046) in the combined group (OR 0.38, 95% CI 0.21 to 0.70; 17 studies; 6151 participants, high-certainty evidence). Increased bleeding side effects were not observed for IPC when it was added to anticoagulation (any bleeding: OR 0.87, 95% CI 0.56 to 1.35, 6 studies, 1314 participants, very low-certainty evidence; major bleeding: OR 1.21, 95% CI 0.35 to 4.18, 5 studies, 908 participants, very low-certainty evidence). No difference was detected between the orthopaedic and non-orthopaedic surgery participants for PE incidence (test for subgroup difference P = 0.82) or for DVT incidence (test for subgroup difference P = 0.69).

AUTHORS' CONCLUSIONS

Evidence suggests that combining IPC with pharmacological prophylaxis, compared to IPC alone reduces the incidence of both PE and DVT (low-certainty evidence). Combining IPC with pharmacological prophylaxis, compared to pharmacological prophylaxis alone, reduces the incidence of both PE (low-certainty evidence) and DVT (high-certainty evidence). We downgraded due to risk of bias in study methodology and imprecision. Very low-certainty evidence suggests that the addition of pharmacological prophylaxis to IPC increased the risk of bleeding compared to IPC alone, a side effect not observed when IPC is added to pharmacological prophylaxis (very low-certainty evidence), as expected for a physical method of thromboprophylaxis. The certainty of the evidence for bleeding was downgraded to very low due to risk of bias in study methodology, imprecision and indirectness. The results of this update agree with current guideline recommendations, which support the use of combined modalities in hospitalised people (limited to those with trauma or undergoing surgery) at risk of developing VTE. More studies on the role of combined modalities in VTE prevention are needed to provide evidence for specific patient groups and to increase our certainty in the evidence.

Spontaneous HIT syndrome: Knee replacement, infection, and parallels with vaccine-induced immune thrombotic thrombocytopenia

Heparin-induced thrombocytopenia (HIT) is characterized clinically by thrombocytopenia, hypercoagulability, and increased thrombosis risk, and serologically by platelet-activating anti-platelet factor 4 (PF4)/heparin antibodies. Heparin-"induced" acknowledges that HIT is usually triggered by a proximate immunizing exposure to heparin. However, certain non-heparin medications (pentosan polysulfate, hypersulfated chondroitin sulfate, fondaparinux) can trigger "HIT". Further, naturally-occurring polyanions (bacterial lipopolysaccharide, DNA/RNA) can interact with PF4 to recapitulate HIT antigens. Indeed, immunologic presensitization to naturally-occurring polyanions could explain why HIT more closely resembles a secondary, rather than a primary, immune response. In 2008 it was first reported that a HIT-mimicking disorder can occur without any preceding exposure to heparin or polyanionic medications. Termed "spontaneous HIT syndrome", two subtypes are recognized: (a) surgical (post-orthopedic, especially post-total knee arthroplasty, and (b) medical (usually post-infectious). Recently, COVID-19 adenoviral vector vaccination has been associated with a thrombotic thrombocytopenic disorder associated with positive PF4-dependent enzyme-immunoassays and serum-induced platelet activation that is maximal when PF4 is added. Vaccine-induced immune thrombotic thrombocytopenia (VITT) features unusual thromboses (cerebral venous thrombosis, splanchnic vein thrombosis) similar to those seen in spontaneous HIT syndrome. The emerging concept is that classic HIT reflects platelet-activating anti-PF4/heparin antibodies whereas spontaneous HIT syndrome and other atypical "autoimmune HIT" presentations (delayed-onset HIT, persisting HIT, heparin "flush" HIT) reflect heparin-independent platelet-activating anti-PF4 antibodies-although the precise relationships between PF4 epitope targets and the clinical syndromes remain to be determined. Treatment of spontaneous HIT syndrome includes non-heparin anticoagulation (direct oral Xa inhibitors favored over direct thrombin inhibitors) and high-dose immunoglobulin.

American Society of Hematology 2021 guidelines for management of venous thromboembolism: prevention and treatment in patients with cancer

BACKGROUND

Venous thromboembolism (VTE) is a common complication among patients with cancer. Patients with cancer and VTE are at a markedly increased risk for morbidity and mortality.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about the prevention and treatment of VTE in patients with cancer.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The guideline development process was supported by updated or new systematic evidence reviews. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess evidence and make recommendations.

RESULTS

Recommendations address mechanical and pharmacological prophylaxis in hospitalized medical patients with cancer, those undergoing a surgical procedure, and ambulatory patients receiving cancer chemotherapy. The recommendations also address the use of anticoagulation for the initial, short-term, and long-term treatment of VTE in patients with cancer.

CONCLUSIONS

Strong recommendations include not using thromboprophylaxis in ambulatory patients receiving cancer chemotherapy at low risk of VTE and to use low-molecular-weight heparin (LMWH) for initial treatment of VTE in patients with cancer. Conditional recommendations include using thromboprophylaxis in hospitalized medical patients with cancer, LMWH or fondaparinux for surgical patients with cancer, LMWH or direct oral anticoagulants (DOAC) in ambulatory patients with cancer receiving systemic therapy at high risk of VTE and LMWH or DOAC for initial treatment of VTE, DOAC for the short-term treatment of VTE, and LMWH or DOAC for the long-term treatment of VTE in patients with cancer.

American Society of Hematology 2019 guidelines for management of venous thromboembolism: prevention of venous thromboembolism in surgical hospitalized patients

BACKGROUND

Venous thromboembolism (VTE) is a common source of perioperative morbidity and mortality.

OBJECTIVE

These evidence-based guidelines from the American Society of Hematology (ASH) intend to support decision making about preventing VTE in patients undergoing surgery.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline-development process, including performing systematic reviews. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 30 recommendations, including for major surgery in general (n = 8), orthopedic surgery (n = 7), major general surgery (n = 3), major neurosurgical procedures (n = 2), urological surgery (n = 4), cardiac surgery and major vascular surgery (n = 2), major trauma (n = 2), and major gynecological surgery (n = 2).

CONCLUSIONS

For patients undergoing major surgery in general, the panel made conditional recommendations for mechanical prophylaxis over no prophylaxis, for pneumatic compression prophylaxis over graduated compression stockings, and against inferior vena cava filters. In patients undergoing total hip or total knee arthroplasty, conditional recommendations included using either aspirin or anticoagulants, as well as for a direct oral anticoagulant over low-molecular-weight heparin (LMWH). For major general surgery, the panel suggested pharmacological prophylaxis over no prophylaxis, using LMWH or unfractionated heparin. For major neurosurgery, transurethral resection of the prostate, or radical prostatectomy, the panel suggested against pharmacological prophylaxis. For major trauma surgery or major gynecological surgery, the panel suggested pharmacological prophylaxis over no prophylaxis.

Definitions, adjudication, and reporting of pulmonary embolism-related death in clinical studies: A systematic review

BACKGROUND

Pulmonary embolism (PE)-related death is a component of the primary outcome in many venous thromboembolism (VTE) studies. The absence of a standardized definition for PE-related death hampers study outcome evaluation and between-study comparisons.

OBJECTIVES

To summarize definitions for PE-related death used in recent VTE studies and to assess the PE-related death rate.

PATIENTS/METHODS

A systematic literature search was conducted on 26 April 2018 from 1 January 2014 up to the search date in MEDLINE, Embase, and CENTRAL. Cohort studies and randomized trials in which PE-related death was included in the primary outcome were eligible. Screening of titles, abstracts, and full-text articles, and data extraction were independently performed in duplicate by two authors. Study outcomes included the definition for PE-related death, VTE case-fatality rate, and death due to PE rate. Descriptive statistics were used to analyze the data.

RESULTS

Of the 6807 identified citations, 83 studies were included of which 27% were randomized trials, 31% were prospective, and 42% retrospective cohort studies. Thirty-five studies (42%) had a central adjudication committee. Thirty-eight (46%) reported a definition for PE-related death of which the most frequently used components were "autopsy-confirmed PE" (50%), "objectively confirmed PE before death" (55%), and "unexplained death" (58%). Median VTE case-fatality rate was 1.8% (interquartile range, 0.0-13).

CONCLUSIONS

Only half of the included studies reported definitions for PE-related death, which were very heterogeneous. Case-fatality rate of VTE events varied widely across studies. Standardization of the definition and guidance on adjudication and reporting of PE-related death is needed.

Mechanical thromboprophylaxis would suffice after total knee arthroplasties in Asian patients?

PURPOSE

Our prospective study evaluated the incidence and location of deep vein thrombosis (DVT), the risk factors for PE and the natural history of DVT after TKA in patients who have received only mechanical compression device without having any chemical thromboprophylaxis or therapeutic treatment.

METHODS

We studied 408 consecutive patients (691 knees) who underwent primary TKA; 283 patients had one-stage bilateral TKAs and 125 had unilateral TKAs. Coagulation assays, the full blood count and blood typing tests, and serum chemical profiles were undertaken in all patients on three separate occasions. Molecular genetic testing was performed preoperatively to detect the genetic traits involving DVT. Bilateral simultaneous or unilateral venograms were carried out at 6 or 7 days after operation. Perfusion lung scanning was undertaken before and at 7 or 8 days after operation.

RESULTS

In the 691 venograms in 408 patients, only 4 knees (0.6%) were positive for fresh thrombi. In the 4 knees with DVT, thrombi were located in the calf veins. We observed factor V Leiden mutation, antithrombin-III level, and prothrombin promoter G20210A mutation were absent in all patients. We saw no relationship between DVT and coagulation or thrombophilic data. No pulmonary embolism (PE) occurred as shown by negative perfusion lung scan and absence of symptoms.

CONCLUSION

We concluded that the combinations of absent thrombophilic polymorphisms with low clinical prothrombotic risk factors led to low prevalence of DVT and virtually absent PE after TKA in the current series of patients, who had received mechanical compression device only without chemical thromboprophylaxis.

Pneumatic compression device does not show effective thromboprophylaxis following total knee arthroplasty in a low incidence population

INTRODUCTION

Purpose of this study was to assess whether the intermittent pneumatic compression (IPC) device would be an effective prophylaxis for deep vein thrombosis (DVT) following total knee arthroplasty (TKA) in a low incidence population.

HYPOTHESIS

The mechanical thromboprophylaxis could reduce the incidence of DVT compared to non-prophylaxis group and would have similar efficacy as the chemoprophylaxis following TKA in a low DVT incidence population.

MATERIALS AND METHODS

From January 2009 to June 2016, 1259 elective primary TKA with preoperative diagnosis of primary osteoarthritis in a single institute were enrolled. Patients were divided into three groups: those who were managed with chemoprophylaxis (CPX group, 414 cases), with mechanical prophylaxis (IPC group, 425 cases), or without pharmacological and mechanical prophylaxis (control group, 420 cases). All patients underwent preoperative ultrasonography and computed tomographic venography on postoperative day 6 to assess development of DVT. The incidence of overall, proximal, symptomatic DVT and symptomatic pulmonary embolism (PE) were compared among the groups. Major and minor bleeding complications were also evaluated.

RESULTS

The incidence of overall DVT was 14.8% in control group, 6.3% in CPX group and 11.3% in IPC group respectively and CPX group showed significantly lower incidence than other two groups (p<0.001). The incidence of proximal DVT was 1.9% in control group, 0.7% in CPX group and 0.9% in IPC group respectively (p>0.05). The incidence of symptomatic DVT was 0.7% in control group, 0% in CPX group and 0.7% in IPC group respectively (p>0.05). There was no case of symptomatic PE diagnosed during hospital stay in all patients.

DISCUSSION

Single use of IPC device could not reach significant level of DVT prophylaxis compared to control group and only chemoprophylaxis showed significantly reduce the incidence of overall DVT following TKA. Single use of IPC device does not show effective thromboprophylaxis in a low DVT incidence population.

LEVEL OF EVIDENCE

III, case control study.

Efficacy and risks of fondaparinux 7.5 mg for deep vein thrombosis after total knee arthroplasty

OBJECTIVES

High-dose fondaparinux therapy at 7.5 mg/day (FPX 7.5 mg) for deep vein thrombosis (DVT) may increase the risk of hemorrhage. We investigated the efficacy and safety of FPX 7.5 mg to treat DVT after total knee arthroplasty.

METHODS

This study included 101 patients (91 with osteoarthritis, 10 with rheumatoid arthritis; mean age at total knee arthroplasty: 72.9 years) with asymptomatic postoperative DVT. Medical prophylaxis for DVT was started on postoperative day 1. Vascular ultrasound was conducted within 2 days postoperatively; patients were switched to FPX 7.5 mg after DVT diagnosis. Ultrasound was repeated to monitor DVT resolution. Adverse reactions were assessed.

RESULTS

DVT resolved in 72 patients (71.3%) receiving FPX 7.5 mg. There were no significant differences between patients with versus without DVT resolution in the timing of FPX 7.5 mg therapy, treatment period, age, body mass index, or D-dimer or hemoglobin levels. There was no significant difference in DVT outcome between patients starting FPX 7.5 mg within 4 days postoperatively versus on day 5 or later, or between patients treated for ≤7 versus ≥8 days. Hemoglobin decreased to ≤7 g/dL in three patients (2.9%).

CONCLUSIONS

FPX 7.5 mg can be expected to resolve DVT in 71.3% of patients; however, the risk of associated hemorrhagic complications may be higher than the risk of pulmonary embolism. To treat DVT with FPX 7.5 mg without compromising safety, patients should be selected carefully and the timing of treatment should be adjusted appropriately.

A prospective randomized comparative study to determine appropriate edoxaban administration period, to prevent deep vein thromboembolism in patients with total knee arthroplasty

BACKGROUND

This study aimed to determine the appropriate administration duration of edoxaban 15 mg (a factor Xa inhibitor) for the prevention of deep vein thrombosis (DVT) after total knee arthroplasty (TKA).

METHODS

Our study comprised 202 patients who underwent TKA (excluding bilateral TKA) at our institution between 2014 and 2015. The subjects received edoxaban 15 mg daily for 1 (n = 93) or 2 (n = 109) weeks; group assignment was random. B-mode ultrasonography was performed 7 and 14 days post-TKA for the detection of DVT. We compared the incidence of DVT between the groups and examined for side effects.

RESULTS

The demographic data of the patients in the 1- and 2-week administration groups were similar at baseline. DVT incidence did not differ significantly between the groups at 1 week post-TKA. However, it was significantly lower in the 2-week administration group (n = 0) than in the 1-week administration group (n = 7; p = 0.004) at 2 weeks post-DVT. Neither group exhibited symptomatic DVT. A total of six patients withdrew during the study period because of hepatic dysfunction.

CONCLUSIONS

Our results show that the administration of edoxaban 15 mg is more effective in preventing DVT after TKA when administered for 2 weeks than for 1 week.

Induction of anti-PF4/heparin antibodies after arthroplasty for rheumatic diseases

Heparin-induced thrombocytopenia (HIT) is an immune complication of heparin therapy caused by antibodies to complexes of platelet factor 4 (PF4) and heparin. These pathogenic antibodies against PF4/heparin bind and activate cellular FcγRIIa on platelets to induce a hypercoagulable state culminating in thrombosis. Recent studies indicate several conditions, including joint surgery, induce spontaneous HIT, which can occur without exposure to heparin. To determine the real-world evidences concerning the incidences of venous thromboembolism (VTE) after total joint arthroplasty for rheumatic disease, we conducted a multicenter cohort study (J-PSVT) designed to document the VTE and seroconversion rates of anti-PF4/heparin antibody in 34 Japanese National hospital organization (NHO) hospitals. J-PSVT indicated that prophylaxis with fondaparinux, not enoxaparin, reduces the risk of deep vein thrombosis in patients undergoing arthroplasty. Multivariate analysis revealed that dynamic mechanical thromboprophylaxis (intermittent plantar device) was an independent risk factor for seroconversion of anti-PF4/heparin antibodies, which was also confirmed by propensity-score matching. Seroconversion rates of anti-PF4/heparin antibodies were significantly reduced in rheumatoid arthritis (RA) patients compared with osteoarthritis (OA) patients, which may link with the findings that IgG fractions isolated from RA patients not OA patients contained PF4. Our study indicated that a unique profile of anti-PF4/heparin antibodies is induced by arthroplasty for rheumatic diseases.

Combined intermittent pneumatic leg compression and pharmacological prophylaxis for prevention of venous thromboembolism

BACKGROUND

It is generally assumed by practitioners and guideline authors that combined modalities (methods of treatment) are more effective than single modalities in preventing venous thromboembolism (VTE), defined as deep vein thrombosis (DVT) or pulmonary embolism (PE), or both. This is an update of the review first published in 2008.

OBJECTIVES

The aim of this review was to assess the efficacy of combined intermittent pneumatic leg compression (IPC) and pharmacological prophylaxis versus single modalities in preventing venous thromboembolism.

SEARCH METHODS

For this update the Cochrane Vascular Information Specialist (CIS) searched the Specialised Register (May 2016). In addition the CIS searched the Cochrane Register of Studies (CENTRAL (2016, Issue 4)). Clinical trials databases were searched for details of ongoing or unpublished studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) or controlled clinical trials (CCTs) of combined IPC and pharmacological interventions used to prevent VTE.

DATA COLLECTION AND ANALYSIS

We independently selected trials and extracted data. Disagreements were resolved by discussion. We performed fixed-effect model meta-analyses with odds ratios (ORs) and 95% confidence intervals (CIs). We used a random-effects model when there was heterogeneity.

MAIN RESULTS

We included a total of 22 trials (9137 participants) of which 15 were randomized trials (7762 participants). The overall risk of bias was mostly unclear or high due to selection and performance bias. We used GRADE to assess the quality of the evidence and this was downgraded from high to moderate or very low due to the risk of bias, imprecision or indirectness.The rate of PE in the studies comparing IPC alone with combined IPC and pharmacological prophylaxis was low, underpowering the analyses. The incidence of symptomatic PE was 0.79% with IPC, but ranged between 0.1 to 1% with combined IPC and pharmacological prophylaxis (OR 0.49, 95% CI 0.18 to 1.34; 12 studies, 3017 participants, moderate quality evidence). The incidence of DVT was 4.10% in the IPC group and 2.19% in the combined group showing a reduced incidence of DVT in favour of the combined group (OR 0.52, 95% CI 0.33 to 0.82; 11 studies, 2934 participants, moderate quality evidence). The addition of an anticoagulant to IPC, however, increased the risk of any bleeding compared to IPC alone; 0.66% (7/1053) in the IPC group and 4.0% (44/1102) in the combined group (OR 5.04, 95% CI 2.36 to 10.77; 7 studies, 2155 participants, moderate quality evidence). Major bleeding followed a similar pattern; 0.1% (1/1053) in the IPC group to 1.5% (17/1102) in the combined group (OR 6.81, 95% CI 1.99 to 23.28; 7 studies, 2155 participants, moderate quality evidence).We detected no difference between the type of surgery subgroups such as orthopedic and non-orthopedic participants for DVT incidence (P = 0.16). Tests for differences between type of surgery subgroups were not possible for PE incidence.Compared with pharmacological prophylaxis alone, the use of combined IPC and pharmacological prophylaxis modalities reduced the incidence of symptomatic PE from 2.92% to 1.20% (OR 0.39, 95% CI 0.23 to 0.64; 10 studies, 3544 participants, moderate quality evidence). The incidence of DVT was 6.2% in the pharmacological prophylaxis group and 2.9% in the combined group showing no difference between the combined and pharmacological prophylaxis groups (OR 0.42, 95% CI 0.18 to 1.03; 11 studies, 2866 participants, moderate quality evidence). Increased bleeding side effects were not observed for IPC when it was added to anticoagulation (bleeding: OR 0.80, 95% CI 0.30 to 2.14, very low quality evidence; major bleeding: OR 1.21, 95% CI 0.35 to 4.18, very low quality evidence, 3 studies, 244 participants).No difference was detected between the type of surgery subgroups for PE incidence (P = 0.68) or for DVT incidence (P = 0.10).

AUTHORS' CONCLUSIONS

Moderate quality evidence suggests that combining IPC and pharmacological prophylaxis, compared with IPC or pharmacological prophylaxis alone, decreases the incidence of DVT when compared to compression, and incidence of PE when compared to anticoagulation. Moderate quality evidence suggests that there is no difference between combined and single modalities in the incidence of PE when compared with compression alone and DVT when compared with anticoagulation alone. The quality of evidence for PE or DVT was downgraded to moderate due to imprecision or risk of bias in study methodology, highlighting the need for further research. Moderate quality evidence suggests the addition of pharmacological prophylaxis to IPC, increased the risk of bleeding compared to IPC alone, a side effect not observed for IPC when added to pharmacological prophylaxis (very low quality evidence), as expected for a physical method of thromboprophylaxis. The quality of evidence for bleeding was downgraded to moderate due to indirectness or very low due to risk of bias in study methodology, indirectness and imprecision highlighting the need for further research. Nevertheless, the results of the current review agree with current guideline recommendations, which support the use of combined modalities in hospitalised patients (limited to those with trauma or undergoing surgery) at risk of developing VTE. More studies on the role of combined modalities in VTE prevention are needed.

Reduced induction of anti-PF4/heparin antibody in RA patients after total knee arthroplasty

BACKGROUND

Heparin-induced thrombocytopenia is caused by antibodies (Abs) specific to platelet factor 4 (PF4)/heparin complexes. In this study, we evaluated the rates of seroconversion of anti-PF4/heparin Ab between patients with rheumatoid arthritis (RA) and with osteoarthritis (OA) who underwent total knee arthroplasty.

METHODS

The subjects of this randomized controlled trial were 124 patients who underwent total knee arthroplasty (TKA) and received edoxaban with or without a foot pump as thromboprophylaxis. We measured anti-PF4/heparin Abs before and 10 days after surgery, as well as preoperative PF4, using commercially available ELISAs. We also used the database of J-PSVT, a hospital-based, prospective cohort study designed to document the effectiveness of thromboprophylactic agents during arthroplasty.

RESULTS

The rates of seroconversion to anti-PF4/heparin Ab were lower in RA patients (4.0 %) than in OA patients (25.5 %). The anti-PF4/heparin IgG optical density (OD) values did not differ before and after surgery in RA patients. In contrast, there was a significant increase in anti-PF4/heparin IgG OD values in OA patients after TKA. In the J-PSVT data, the postoperative seroconversion rates of anti-PF4/heparin Ab were lower in RA patients (10.4 %) than in OA patients (21.8 %) who received fondaparinux. The titers of anti-CCP Ab were significantly lower in RA patients with postoperative ant-PF4/heparin Ab compared with those without postoperative ant-PF4/heparin Ab There was no significant difference in preoperative PF4 levels between RA patients and OA patients. The heparin-binding affinity of the circulating PF4 was similar between RA patients and OA patients; however, the IgG fractions isolated from the sera of RA patients contained PF4 more frequently (69.2 %) than those from OA patients (10.2 %).

CONCLUSIONS

Our results showed a reduced likelihood of postoperative anti-PF/heparin Ab production in RA patients compared with OA patients. This suggests that the mechanisms underlying the anti-PF4 immune response in RA patients differ from the mechanisms of the anti-PF4/heparin immune response seen in OA patients after joint replacement.

TRIAL REGISTRATION

ISRCTN 18090286. Registered 8 July 2016.