[Is a general pharmacologic thromboembolism prophylaxis necessary in ambulatory treatment by plaster cast immobilization in lower limb injuries?]

Thromboprophylaxis in lower limb immobilisation after injury (TiLLI)

Venous thromboembolic disease is a major global cause of morbidity and mortality. An estimated 10 million episodes are diagnosed yearly; over half of these episodes are provoked by hospital admission/procedures and result in significant loss of disability adjusted life years. Temporary lower limb immobilisation after injury is a significant contributor to the overall burden of venous thromboembolism (VTE). Existing evidence suggests that pharmacological prophylaxis could reduce overall VTE event rates in these patients, but the proportional reduction of symptomatic events remains unclear. Recent studies have used different pharmacological agents, dosing regimens and outcome measures. Consequently, there is wide variation in thromboprophylaxis strategies, and international guidelines continue to offer conflicting advice for clinicians. In this review, we provide a summary of recent evidence assessing both the clinical and cost effectiveness of thromboprophylaxis in patients with temporary immobilisation after injury. We also examine the evidence supporting stratified thromboprophylaxis and the validity of widely used risk assessment methods.

Different strategies for pharmacological thromboprophylaxis for lower-limb immobilisation after injury: systematic review and economic evaluation

BACKGROUND

Thromboprophylaxis can reduce the risk of venous thromboembolism (VTE) during lower-limb immobilisation, but it is unclear whether or not this translates into meaningful health benefit, justifies the risk of bleeding or is cost-effective. Risk assessment models (RAMs) could select higher-risk individuals for thromboprophylaxis.

OBJECTIVES

To determine the clinical effectiveness and cost-effectiveness of different strategies for providing thromboprophylaxis to people with lower-limb immobilisation caused by injury and to identify priorities for future research.

DATA SOURCES

Ten electronic databases and research registers (MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Database of Abstracts of Review of Effects, the Cochrane Central Register of Controlled Trials, Health Technology Assessment database, NHS Economic Evaluation Database, Science Citation Index Expanded, ClinicalTrials.gov and the International Clinical Trials Registry Platform) were searched from inception to May 2017, and this was supplemented by hand-searching reference lists and contacting experts in the field.

REVIEW METHODS

Systematic reviews were undertaken to determine the effectiveness of pharmacological thromboprophylaxis in lower-limb immobilisation and to identify any study of risk factors or RAMs for VTE in lower-limb immobilisation. Study quality was assessed using appropriate tools. A network meta-analysis was undertaken for each outcome in the effectiveness review and the results of risk-prediction studies were presented descriptively. A modified Delphi survey was undertaken to identify risk predictors supported by expert consensus. Decision-analytic modelling was used to estimate the incremental cost per quality-adjusted life-year (QALY) gained of different thromboprophylaxis strategies from the perspectives of the NHS and Personal Social Services.

RESULTS

Data from 6857 participants across 13 trials were included in the meta-analysis. Thromboprophylaxis with low-molecular-weight heparin reduced the risk of any VTE [odds ratio (OR) 0.52, 95% credible interval (CrI) 0.37 to 0.71], clinically detected deep-vein thrombosis (DVT) (OR 0.40, 95% CrI 0.12 to 0.99) and pulmonary embolism (PE) (OR 0.17, 95% CrI 0.01 to 0.88). Thromboprophylaxis with fondaparinux (Arixtra®, Aspen Pharma Trading Ltd, Dublin, Ireland) reduced the risk of any VTE (OR 0.13, 95% CrI 0.05 to 0.30) and clinically detected DVT (OR 0.10, 95% CrI 0.01 to 0.94), but the effect on PE was inconclusive (OR 0.47, 95% CrI 0.01 to 9.54). Estimates of the risk of major bleeding with thromboprophylaxis were inconclusive owing to the small numbers of events. Fifteen studies of risk factors were identified, but only age (ORs 1.05 to 3.48), and injury type were consistently associated with VTE. Six studies of RAMs were identified, but only two reported prognostic accuracy data for VTE, based on small numbers of patients. Expert consensus was achieved for 13 risk predictors in lower-limb immobilisation due to injury. Modelling showed that thromboprophylaxis for all is effective (0.015 QALY gain, 95% CrI 0.004 to 0.029 QALYs) with a cost-effectiveness of £13,524 per QALY, compared with thromboprophylaxis for none. If risk-based strategies are included, it is potentially more cost-effective to limit thromboprophylaxis to patients with a Leiden thrombosis risk in plaster (cast) [L-TRiP(cast)] score of ≥ 9 (£20,000 per QALY threshold) or ≥ 8 (£30,000 per QALY threshold). An optimal threshold on the L-TRiP(cast) receiver operating characteristic curve would have sensitivity of 84-89% and specificity of 46-55%.

LIMITATIONS

Estimates of RAM prognostic accuracy are based on weak evidence. People at risk of bleeding were excluded from trials and, by implication, from modelling.

CONCLUSIONS

Thromboprophylaxis for lower-limb immobilisation due to injury is clinically effective and cost-effective compared with no thromboprophylaxis. Risk-based thromboprophylaxis is potentially optimal but the prognostic accuracy of existing RAMs is uncertain.

FUTURE WORK

Research is required to determine whether or not an appropriate RAM can accurately select higher-risk patients for thromboprophylaxis.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017058688.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Correlation of Interleukin-18 and High-Sensitivity C-Reactive Protein with Perioperative Deep Vein Thrombosis in Patients with Ankle Fracture

BACKGROUND

In the present study, we aimed to inspect the correlation of interleukin-18 (IL-18) and high-sensitivity C-reactive protein (hs-CRP), if any present, with the occurrence of perioperative deep vein thrombosis (DVT) in patients suffering from an ankle fracture (AF).

METHODS

Sixty-seven AF patients with complicated DVT (DVT group) and 448 AF patients without DVT (non-DVT group) were enrolled in the present study. To begin with, hemorheological indexes were detected. Turbidimetric immunoassay and enzyme-linked immunosorbent assay were used for the determination of the expressions of hs-CRP and IL-18, respectively. Coagulation method was used to detect prothrombin time (PT), thrombin time (TT), fibrinogen, and activated partial thromboplastin time (APTT). Logistic regression analysis was used to analyze the independent risk factors for DVT occurrence in AF patients after operation.

RESULTS

The results revealed that the DVT group presented an increased expression of hs-CRP and IL-18 1 day before operation and 1, 3, and 7 days after operation in comparison with the non-DVT group. The DVT group also had increased levels of PT, APTT, and prolonged TT and fibrinogen at 3 and 7 days after operation compared to the non-DVT group. After operation, it was observed that the patients in the DVT group had increased plasma viscosity, whole blood reduced viscosity, red blood cell (RBC) aggregation index, RBC deformation index, erythrocyte sedimentation rate, and declined erythrocrit. The independent risk factors for the occurrence of DVT were identified to be high-energy injury, TT, fibrinogen, hs-CRP, and IL-18 in AF patients after operation.

CONCLUSIONS

Based on the results obtained from the study, it was concluded that AF patients with DVT have higher levels of IL-18 and hs-CRP expressions, which is associated with the occurrence and development of DVT. These results may be particularly useful for diagnosis and treatment on DVT occurrence in AF patients.

Low molecular weight heparin for prevention of venous thromboembolism in patients with lower-limb immobilization

BACKGROUND

Immobilization of the lower limb is a risk factor for venous thromboembolism (VTE). Low molecular weight heparins (LMWHs) are anticoagulants, which might be used in adult patients with lower-limb immobilization to prevent deep venous thrombosis (DVT) and its complications. This is an update of the review first published in 2008.

OBJECTIVES

To assess the effectiveness of low molecular weight heparin for the prevention of venous thromboembolism in patients with lower-limb immobilization in an ambulatory setting.

SEARCH METHODS

For this update, the Cochrane Vascular Information Specialist searched the Specialised Register, CENTRAL, and three trials registers (April 2017).

SELECTION CRITERIA

Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that described thromboprophylaxis by means of LMWH compared with no prophylaxis or placebo in adult patients with lower-limb immobilization. Immobilization was by means of a plaster cast or brace.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed risk of bias and extracted data. The review authors contacted the trial authors for additional information if required. Statistical analysis was carried out using Review Manager 5.

MAIN RESULTS

We included eight RCTs that fulfilled our criteria, with a total of 3680 participants. The quality of evidence, according GRADE, varied by outcome and ranged from low to moderate. We found an incidence of DVT ranging from 4.3% to 40% in patients who had a leg injury that had been immobilized in a plaster cast or a brace for at least one week, and who received no prophylaxis, or placebo. This number was significantly lower in patients who received daily subcutaneous injections of LMWH during immobilization, with event rates ranging from 0% to 37% (odds ratio (OR) 0.45, 95% confidence interval (CI) 0.33 to 0.61; with minimal evidence of heterogeneity: I² = 26%, P = 0.23; seven studies; 1676 participants, moderate-quality evidence). Comparable results were seen in the following groups of participants: patients with below-knee casts, conservatively treated patients (non-operated patients), operated patients, patients with fractures, patients with soft-tissue injuries, and patients with distal or proximal thrombosis. No clear differences were found between the LMWH and control groups for pulmonary embolism (OR 0.50, 95% CI 0.17 to 1.47; with no evidence of heterogeneity: I² = 0%, P = 0.56; five studies, 2517 participants; low-quality evidence). The studies also showed less symptomatic VTE in the LMWH groups compared with the control groups (OR 0.40, 95% CI 0.21 to 0.76; with minimal evidence of heterogeneity: I² = 16%, P = 0.31; six studies; 2924 participants; low-quality evidence). One death was reported in the included studies, but no deaths due to pulmonary embolism were reported. Complications of major adverse events were rare, with minor bleeding the main adverse events reported.

AUTHORS' CONCLUSIONS

Moderate-quality evidence showed that the use of LMWH in outpatients reduced DVT when immobilization of the lower limb was required, when compared with no prophylaxis or placebo. The quality of the evidence was reduced to moderate because of risk of selection and attrition bias in the included studies. Low-quality evidence showed no clear differences in PE between the LMWH and control groups, but less symptomatic VTE in the LMWH groups. The quality of the evidence was downgraded due to risk of bias and imprecision.

Leg massage by mother resulting in fatal pulmonary thromboembolism

We report the sudden death of a 23-year-old male with hairline ankle fracture after massage of the leg by his mother. Autopsy confirmed the cause of death as pulmonary thromboembolism due to deep vein thrombosis of the leg veins which was dislodged and travelled to his lungs consequent to the leg massage. The treating doctors did not warn the patient of the risk of developing pulmonary thromboembolism.

The efficiency of O-(beta-hydroxyethyl)-rutosides in reducing the incidence of superficial venous insufficiency in patients with calf muscle pump dysfunction

Objective We aimed to evaluate the efficiency of O-(beta-Hydroxyethyl)-rutosides (Oxerutin) in reducing the incidence of venous system disease among patients with calf muscle pump dysfunction secondary to immobilization due to lower-limb fractures. Methods A total of 60 patients with lower-limb fractures and immobilized in plaster casts were included in this study randomized into control (n = 30; mean: 30.37 ± 6.03 years; 73.3% males; no treatment) and experiment (n = 30; mean: 31.67 ± 4.76 years; 66.6% males; Oxerutin, 500 mg po q12hr) treatment groups. Doppler ultrasound was performed to evaluate the effect of oxerutin on the alterations in the venous circulation. Results Patients in the control group were determined to be more commonly affected from the below-knee immobilization in terms of venous dysfunction in the great saphenous vein in the below-knee region when compared with the patients in the oxerutin treatment group (46.7 vs. 13.3%, respectively; p = 0.011). Incidence of reflux in the small saphenous vein was more common in the control group during the healing period when compared with the experiment group (40.0 vs. 10.0%, respectively; p = 0.017). None of the patients developed venous thrombosis. Conclusions In conclusion, the impairment of the lower extremity muscle pump should be considered as an important risk factor for venous disease, and should be evaluated. O-(beta-Hydroxyethyl)-rutosides during 6-8 week cast immobilization for a lower limb fracture may be an effective prophylactic regimen in reducing the incidence of reflux in the below-knee superficial veins.

Guidelines in Emergency Medicine Network (GEMNet): guideline for the use of thromboprophylaxis in ambulatory trauma patients requiring temporary limb immobilisation

The Guidelines in Emergency Medicine Network (GEMNet) has been created to promote best medical practice in a range of conditions presenting to emergency departments (EDs) in the UK. This guideline presents a summary of the best available evidence to guide the use of thromboprophylaxis in adult ambulatory outpatients who present to the ED following acute limb trauma and require temporary immobilisation. The document has been developed following discussion among emergency physicians and collegiate fellows to decide which topics would benefit from the development of clinical guidelines. The document is intended as a guideline for use in the ED by emergency physicians and is based on the review of the best existing evidence for treatments used in this setting. The document is summarised as a Clinical Decision Support Guideline that has been presented as an easy to follow algorithm. The intention is for each guideline to be updated and reviewed as further evidence becomes available. The formal revision date has been set at 5 years from publication, though the guideline is subject to continuous informal review.

Low molecular weight heparin for prevention of venous thromboembolism in patients with lower-leg immobilization

BACKGROUND

Immobilization of the lower leg is associated with venous thromboembolism (VTE). Low molecular weight heparin (LMWH) is an anticoagulant treatment which might be used in adult patients with lower-leg immobilization to prevent deep venous thrombosis (DVT) and its complications. This is an update of the review first published in 2008.

OBJECTIVES

To assess the effectiveness of low molecular weight heparin for the prevention of venous thromboembolism in patients with lower-leg immobilization in an ambulant setting.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched June 2013) and CENTRAL (2013, Issue 5).

SELECTION CRITERIA

Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that described thromboprophylaxis by means of LMWH compared with no prophylaxis or placebo in adult patients with lower-leg immobilization. Immobilization was by means of a plaster cast or brace.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. The review authors contacted the trial authors for additional information if required. Statistical analysis was carried out using Review Manager (RevMan 5).

MAIN RESULTS

We included six RCTs fulfilling the above criteria with a total of 1490 patients. We found an incidence of VTE ranging from 4.3% to 40% in patients who had a leg injury that had been immobilized in a plaster cast or a brace for at least one week and who received no prophylaxis, or placebo. This number was significantly lower in patients who received daily subcutaneous injections of LMWH during immobilization (event rates ranging from 0% to 37%; odds ratio (OR) 0.49; fixed 95% confidence interval (CI) 0.34 to 0.72; with minimal evidence of heterogeneity with an I(2) of 20%, P = 0. 29). Comparable results were seen in the following subcategories: operated patients, conservatively treated patients, patients with fractures, patients with soft-tissue injuries, patients with proximal thrombosis, patients with distal thrombosis and patients with below-knee casts. Complications of major bleeding events were extremely rare (0.3%) and there were no reports of heparin-induced thrombocytopenia.

AUTHORS' CONCLUSIONS

Use of LMWH in outpatients significantly reduces VTE when immobilization of the lower leg is required.

Deep vein thrombosis following below knee immobilization: the need for chemoprophylaxis

Background

There is controversy regarding routine prophylaxis for deep vein thrombosis (DVT) in patients treated via a short leg cast or splint following lower extremity trauma.

Objectives

The main aim of this study is to evaluate the incidence of DVT and need for chemoprophylaxis in these patients.

Materials and Methods

Patients with ankle sprains or stable foot/ankle fractures were entered in this cross-sectional study. Serum D-dimer levels were measured 2 weeks following fixation. If the D-dimer levels were above 0.2 micrograms/ml the test was considered positive and the patient was referred for Doppler ultrasound examination (DUE) to confirm or rule out the diagnosis of DVT. Finally, the incidence of DVT was calculated and the role of predisposing factors was investigated.

Results

There were 95 patients with an average age of 38 ± 13.7 (77.9% males); 46 patients had at least one risk factor for DVT. The D-dimer test was positive in 21(22.1%) patients. DVT was confirmed by DUE in 3 patients (3.1%). The incidence of DVT significantly increased in the presence of 3 or more risk factors (P = 0.01).

Conclusions

It seems that DVT is not a common complication of below knee fixation and chemoprophylaxis is not necessary when the patient has less than 3 predisposing factors. With 3 or more risk factors chemoprophylaxis and periodic follow-ups must be considered.

Thromboprophylaxis in patients with lower limb immobilisation - review of current status

The risk for venous thromboembolism (VTE) associated with lower limb immobilisation is unclear, owing to of a lack of evidence from studies in this patient group. However, six small, randomised control trials (RCTs), totalling 1536 patients, compared low molecular weight heparin (LMWH) with controls and showed a significant reduction in asymptomatic deep vein thrombosis (DVT) from 17.1% to 9.8%, with very low bleeding rates. This is likely to be an underestimate of the real risk reduction as most trials excluded high-risk patients from randomisation. There have been no other controlled trials in cast-immobilised patients using alternative prophylactic measures. Together with the RCTs, other cohort studies have identified risk factors that increase the risk for VTE in lower limb immobilisation. In summary, patients in lower limb cast (or brace) immobilisation should be risk assessed and those deemed high risk for VTE should receive prophylactic LMWH for at least the duration of cast immobilisation.

Insufficient Evidence for Routine Use of Thromboprophylaxis in Ambulatory Patients with an Isolated Lower Leg Injury Requiring Immobilization: Results of a Meta-Analysis

BACKGROUND

There are no generally accepted guidelines for the prevention of venous thromboembolism (VTE) in ambulatory patients requiring immobilization after an isolated lower leg injury. Our objective was to evaluate the effectiveness and safety of pharmacological interventions for preventing VTE in these patients.

STUDY DESIGN

Meta-analysis of randomized controlled trials.

MATERIALS AND METHODS

We searched PubMed/Medline, EMBASE and the Cochrane Central Register of Controlled Trials for trials with random allocation of thromboprophylaxis, notably low molecular weight heparin (LMWH) versus no prophylaxis or placebo, in ambulatory patients with below-knee or lower leg (including the knee joint) immobilization. Outcome was analyzed using MIX to calculate the pooled risk ratio/relative risk (RR) for each outcome, along with its 95% confidence interval (CI).

RESULTS

The RR of asymptomatic deep vein thrombosis (DVT) was 0.66 (95% CI 0.44; 1.02) for below-knee immobilization and 0.51 (95% CI 0.37; 0.70) for lower leg immobilization. Low molecular weight heparin versus no prophylaxis or placebo was evaluated. The incidence of symptomatic DVT and PE was too low to show any statistically significant difference between thromboprophylaxis and controls in both groups. Although only one adverse bleeding event was considered to bemajor, the RR for any adverse bleeding event was 1.94 (95% CI 1.03; 3.67).

CONCLUSION

There is insufficient evidence to warrant routine use of thromboprophylaxis in ambulatory patients with below-knee or lower leg immobilization after an isolated lower leg injury. The incidence of symptomatic VTE is too low to show a relevant clinical benefit from thromboprophylaxis.

Low molecular weight heparin for prevention of venous thromboembolism in patients with lower-leg immobilization

BACKGROUND

Immobilization of the lower leg is associated with venous thromboembolism. Low molecular weight heparin (LMWH) is an anticoagulant treatment which might be used in adult patients with lower-leg immobilization to prevent deep venous thrombosis and its complications.

OBJECTIVES

To investigate the current literature on thromboprophylactic practice for patients with lower-limb injuries who are immobilized in plaster casts or braces, to assess the need for concrete guidelines, and to assess whether it is possible to come to an evidence-based conclusion.

SEARCH STRATEGY

The Cochrane Peripheral Vascular Disease Group searched their Specialized Register (last searched 20 May 2008) and the Central Register of Controlled Trials (CENTRAL) (last searched The Cochrane Library 2008, Issue 2). We searched MEDLINE (until May 2008) and EMBASE (until May 2008) and reference lists of articles. We contacted pharmaceutical companies of LMWHs for relevant studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that described thromboprophylaxis by means of LMWH compared with no prophylaxis or placebo in adult patients with lower-leg immobilization. Immobilization was by means of a plaster cast or brace.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. The review authors contacted the trial authors for additional information if required. Statistical analysis was carried out using Review Manager (RevMan 5).

MAIN RESULTS

We included six RCTs fulfilling the above criteria with a total of 1490 patients. We found an incidence of venous thromboembolism ranging from 4.3% to 40%, in patients who had a leg injury that had been immobilized in a plaster cast or a brace for at least one week and who received no prophylaxis, or placebo. This number was significantly lower in patients who received daily subcutaneous injections of LMWH during immobilization (event rates ranging from 0% to 37%; odds ratio (OR) 0.49; fixed 95% confidence interval (CI) 0.34 to 0.72; with minimal evidence of heterogeneity with an I(2) of 20%, P = 0. 29). Comparable results were seen in the following subcategories: operated patients, conservatively treated patients, patients with fractures, patients with soft-tissue injuries, patients with proximal thrombosis, patients with distal thrombosis and patients with below-knee casts. Complications of major bleeding events were extremely rare (0.3%) and there were no reports of heparin-induced thrombocytopenia.

AUTHORS' CONCLUSIONS

Use of LMWH in outpatients significantly reduces VTE when immobilization of the lower leg is required.

Incidence of deep-vein thrombosis in patients with fractures of the ankle treated in a plaster cast

Stable fractures of the ankle can be successfully treated non-operatively by a below-knee plaster cast. In some centres, patients with this injury are routinely administered low-molecular-weight heparin, to reduce the risk of deep-vein thrombosis (DVT). We have assessed the incidence of DVT in 100 patients in the absence of any thromboprophylaxis. A colour Doppler duplex ultrasound scan was done at the time of the removal of the cast. Five patients did develop DVT, though none had clinical signs suggestive of it. One case involved the femoral and another the popliteal vein. No patient developed pulmonary embolism. As the incidence of DVT after ankle fractures is low, we do not recommend routine thromboprophylaxis.