Developing guidelines for venous thromboembolism for The National Institute for Clinical Excellence

Prophylactic Enoxaparin Dosing in Obese Orthopedic Patients: A Literature Search

Objective: The objective of the study was to review the current literature for prophylactic enoxaparin dosing in obese orthopedic patients. Method: A literature search was undertaken using OVID Medline, OVID Embase, and Cochrane Central databases, accessed through hospital library websites. Key search terms (in UK and US spelling) included orthopaedics, low-molecular-weight heparin, enoxaparin, venous thromboembolism prophylaxis, weight, obese, morbid obesity. Possible related subheadings, such as bone, fractures, anticoagulants, overweight, body mass index, deep vein thrombosis, pulmonary embolism, were also included in the database search to optimize the search strategies. The search was restricted to human subjects and limited to articles published from 1998 to the present. Results: The search identified 429 potentially relevant articles. Once duplicates were removed, 345 were screened for inclusion in this review. Only 3 articles (a case-control study, an observational prospective study, and a case report) met both the inclusion and exclusion criteria. The findings from this review need to be interpreted cautiously due to limitations in study designs and the potential for confounding bias. Conclusion: The results of a multiple database search draw one to the conclusion that there is very limited evidence in the literature with regard to prophylactic enoxaparin dosing in obese orthopedic-specific patients. Orthopedic patients are among the highest risk of all surgical specialties for venous thromboembolism. There is strong evidence to support an increased prophylactic low-molecular-weight heparin doses in obese patients; thus, the authors recommend higher prophylactic enoxaparin dosing in obese orthopedic patients.

Association of Aspirin With Prevention of Venous Thromboembolism in Patients After Total Knee Arthroplasty Compared With Other Anticoagulants: A Noninferiority Analysis

Importance

There has been significant debate in the surgical and medical communities regarding the appropriateness of using aspirin alone for venous thromboembolism (VTE) prophylaxis following total knee arthroplasty (TKA).

Objective

To determine the acceptability of aspirin alone vs anticoagulant prophylaxis for reducing the risk of postoperative VTE in patients undergoing TKA.

Design, Setting, and Participants

Noninferiority study of a retrospective cohort of TKA cases submitted to the Michigan Arthroplasty Registry Collaborative Quality Initiative at 29 member hospitals, ranging from small community hospitals to large academic and nonacademic medical centers in Michigan. The study included 41 537 patients who underwent primary TKA between April 1, 2013, and October 31, 2015. Clinical events were monitored for 90 days after surgery. Data were analyzed between September and October 2016.

Exposures

The method of pharmacologic prophylaxis: neither aspirin nor anticoagulants for 668 patients (1.6%), aspirin only for 12 831 patients (30.9%), anticoagulant only (eg, low-molecular-weight heparin, warfarin, and Xa inhibitors) for 22 620 patients (54.5%), and both aspirin/anticoagulant for 5418 patients (13.0%). Most patients were also using intermittent pneumatic compression stockings.

Main Outcome and Measures

The primary composite outcome was the first occurrence of VTE or death. The noninferiority margin was specified as 0.3. The secondary outcome was bleeding events.

Results

Of the 41 537 patients, 14 966 were men (36%), and the mean age was 65.8 years. A VTE event occurred in 573 of 41 537 patients (1.38%); 32 of 668 (4.79%) who received no pharmacologic prophylaxis, 149 of 12 831 (1.16%) treated with aspirin alone, 321 of 22 620 (1.42%) with anticoagulation alone, and 71 of 5418 (1.31%) prescribed both aspirin and anticoagulation. Aspirin only was noninferior for the composite VTE outcome compared with those receiving other chemoprophylaxis (adjusted odds ratio, 0.85; 95% CI, 0.68-1.07, P for inferiority = .007). Bleeding occurred in 457 of 41 537 patients (1.10%), 10 of 668 (1.50%) without prophylaxis, 116 of 12 831 (0.90%) in the aspirin group, 258 of 22 620 (1.14%) with anticoagulation, and 73 of 5418 (1.35%) of those receiving both. Aspirin alone was also noninferior for bleeding complications (adjusted odds ratio, 0.80; 95% CI, 0.63-1.00, P for inferiority <.001).

Conclusions and Relevance

In this study of patients undergoing TKA, aspirin was not inferior to other anticoagulants in the postoperative rate of VTE or death. Aspirin alone may provide similar protection from postoperative VTE compared with other anticoagulation treatments.

Aspirin: are patients actually taking it?-A quality assessment study

BACKGROUND

The purpose of the study was to assess patient adherence to an aspirin-based prophylactic deep venous thromboembolism (DVT) care management plan after total lower extremity arthroplasty.

METHODS

Using a cross-sectional study design, patients who underwent total hip or knee replacement surgery by a single senior surgeon were surveyed at their routine 6-week follow-up appointment regarding adherence to aspirin DVT prophylaxis. Postoperatively, patients were advised to take 325 mg of aspirin twice daily for 6 weeks to prevent DVT.

RESULTS

Of the 101 patients surveyed, 45 underwent total hip arthroplasty while 56 underwent total knee arthroplasty. There were 48 (48%) patients who were still taking aspirin at their routine 6-week postoperative follow-up appointment and 53 (52%) patients who were not taking aspirin (nonadherent group). Of the latter, 3 (6%) never took aspirin postoperatively, 14 (26%) discontinued within 2 weeks postoperatively, and 23 (43%) did not take it any longer for half the time prescribed. In the nonadherent group, 8 patients reported that they felt they did not need the aspirin prophylaxis, 5 experienced side effects, and 10 were unsure of how long they needed to take it. There was 1 patient with a calf DVT and no episodes of pulmonary embolism.

CONCLUSIONS

Over half of our study, patients did not finish their aspirin regimen. We suggest a consistent outline of medication duration throughout the pre/postop course and communication regarding aspirin cessation.

Venous thromboembolism and its prophylaxis in elective knee arthroplasty: an international perspective

INTRODUCTION

Patients undergoing knee arthroplasty are at high risk of developing post-operative deep vein thrombosis (DVT) or a pulmonary embolus (PE). Despite best efforts, the best prophylaxis for thromboembolic disease remains controversial. This article aims to update the reader on the newest guidelines concerning venous thromboembolism (VTE) prophylaxis for elective knee arthroplasty, highlighting their inconsistencies and why variations in recommendations exist.

METHODS

The Medline database and the Internet were searched for VTE prophylaxis guidelines in English. 12 guidelines were found and compared. The comparison looked at the recommendations made, the grade of recommendation, the level of evidence available for these recommendations and any inconsistencies between the guidelines.

RESULTS

Nearly all the guidelines advocate the use of low molecular weight heparin (LMWH) and Fondaparinux. There is little consensus in terms of other recommended drugs, the doses, duration and their recommendation grades. There are marked differences in the methodologies adopted by the different guideline working-groups.

CONCLUSION

There is still uncertainty about the optimal methods of thromboprophylaxis in elective knee arthroplasty. Although there are always going to be disagreements about the endpoints amongst guideline makers, guidelines should achieve uniformity in their reporting of end-points, criteria for levels of evidence and recommendation grades, facilitating the clinician's decision-making process.

Safety and efficacy of multimodal thromboprophylaxis following total knee arthroplasty: a comparative study of preferential aspirin vs. routine coumadin chemoprophylaxis

Multimodal thromboprophylaxis encompasses preoperative VTE risk stratification, regional anesthesia, mechanical prophylaxis, and early mobilization. We determined if aspirin can be safely used for adjuvant chemoprophylaxis in patients who have a low thromboembolic risk. 1016 consecutive patients undergoing TKA received multimodal thromboprophylaxis. Aspirin was used in 67% of patients and Coumadin 33% (high risk patients, or who were on Coumadin before surgery). This study group was compared to 1001 consecutive patients who received multimodal thromboprophylaxis and routine Coumadin chemoprophylaxis. There was no significant difference in rates of VTE, PE, bleeding, complications, readmission and 90-day mortality between the two groups. There was a significantly higher rate of wound related complications in the control group (p=0.03). Multimodal thromboprophylaxis with aspirin given to the majority of patients at a low VTE risk is safe and effective in patients undergoing primary TKA.

Implementing NICE guidelines on risk assessment for venous thromboembolism: failure, success and controversy

PURPOSE

Venous thromboembolism (VTE) prophylaxis guidelines were originally published by the National Institute of Clinical Excellence (NICE) in April 2007. Controversy eclipsed their release. Consequently, the VTE prophylaxis publication was reviewed and republished in January 2010. The NICE guidelines recommend that all patients are assessed for risk before pharmacological prophylaxis is offered and reassessed at 24 hours to check adverse reactions; and that prophylaxis is appropriate. This paper aims to look at their implementation.

DESIGN/METHODOLOGY/APPROACH

A prospective audit and re-audit in one orthopaedic department was completed to see how well the new guidelines were adhered to, find out first-hand what problems there were, and how they might be remedied.

FINDINGS

Audit and re-audit highlighted that attaching an assessment tool to drug charts is plausible.

RESEARCH LIMITATIONS/IMPLICATIONS

The study was limited to one centre and used a relatively weak research design.

PRACTICAL IMPLICATIONS

As a process, the clinical impact of risk assessment for VTE is questionable as many patients will be high risk. Removing reassessment at 24 hours from the NICE guidance is recommended.

ORIGINALITY/VALUE

The authors put the NICE guideline into clinical practice, demonstrating how effectively it can work with their method, but also highlighting its flaws.

Prevention of venous thromboembolism in patients admitted to Australian hospitals: summary of National Health and Medical Research Council clinical practice guideline

Each year in Australia, about 1 in 1000 people develop a first episode of venous thromboembolism (VTE), which approximates to about 20,000 cases. More than half of these episodes occur during or soon after a hospital admission, which makes them potentially preventable. This paper summarises recommendations from the National Health and Medical Research Council's 'Clinical Practice Guideline for the Prevention of Venous Thromboembolism in Patients Admitted to Australian Hospitals' and describes the way these recommendations were developed. The guideline has two aims: to provide advice on VTE prevention to Australian clinicians and to support implementation of effective programmes for VTE prevention in Australian hospitals by offering evidence-based recommendations which local hospital guidelines can be based on. Methods for preventing VTE are pharmacological and/or mechanical, and they require appropriate timing, dosing and duration and also need to be accompanied by good clinical care, such as promoting mobility and hydration whilst in hospital. With some procedures or injuries, the risk of VTE is sufficiently high to require that all patients receive an effective form of prophylaxis unless this is contraindicated; in other clinical settings, the need for prophylaxis requires individual assessment. For optimal VTE prevention, all patients admitted to hospital should have early and formal assessments of: (i) their intrinsic VTE risk and the risks related to their medical conditions; (ii) the added VTE risks resulting from surgery or trauma; (iii) bleeding risks that would contraindicate pharmacological prophylaxis; (iv) any contraindications to mechanical prophylaxis, culminating in (v) a decision about prophylaxis (pharmacological and/or mechanical, or none). The most appropriate form of prophylaxis will depend on the type of surgery, medical condition and patient characteristics. Recommendations for various clinical circumstances are provided as summary tables with relevance to orthopaedic surgical procedures, other types of surgery and medical inpatients. In addition, the tables indicate the grades of supporting evidence for the recommendations (these range from Grade A which can be trusted to guide practice, to Grade D where there is more uncertainty; Good Practice Points are consensus-based expert opinions).

UK national survey of venous thromboembolism prophylaxis in ankle fracture patients treated with plaster casts

BACKGROUND

Ankle fractures are one of the commonest orthopaedic injuries. A substantial proportion of these are treated non-operatively at outpatient clinics with cast immobilization. We conducted this survey to assess the current practice in UK regarding thromboembolism prophylaxis in these patients.

METHODS

A telephonic survey was carried out on junior doctors within orthopaedic departments of 56 hospitals across the UK. A questionnaire was completed regarding venous thromboembolism risk assessment, prophylaxis, hospital guidelines, etc.

RESULTS

84% (n=47) hospitals did not routinely use any prophylaxis for these patients, while 7% (n=4) hospitals used chemo-prophylaxis. Only 5.3% (n=3) hospitals had DVT prophylaxis guidelines regarding these patients while other 9% (n=5) hospitals were in process of developing such guidelines. In 64% (n=36) hospitals, no formal DVT risk assessment was carried out.

CONCLUSION

A large variation exists across NHS hospitals and a poor risk assessment is being carried out in these patients. Development of local guidelines and extension of national guidelines to include high risk outpatients may improve the situation.

Venous thromboembolism and its prophylaxis in elective total hip arthroplasty: an international perspective

INTRODUCTION

Patients undergoing total hip arthroplasty (THA) are at high risk of developing post-operative deep vein thrombosis (DVT) or a subsequent pulmonary embolus (PE). Despite best efforts, the best prophylaxis for thromboembolic disease remains controversial. This article aims to update the reader on the newest guidelines concerning venous thromboembolism (VTE) prophylaxis for elective THAs, considering their advantages and disadvantages and highlighting their inconsistencies.

METHODS

The Medline database and the Internet were searched for VTE prophylaxis guidelines in English. Nine guidelines were found and compared. The comparison looked at the recommendations made, the grade of recommendation, the level of evidence available for these recommendations and any inconsistencies between the guidelines.

RESULTS

All guidelines advocate the use of LMWH and almost all advocate the use of mechanical methods of prophylaxis. The recommended duration ranges from 7-35 days and in many cases, the duration is not specified. There is little consensus in terms of other recommended drugs, the doses, duration and their recommendation grades.

CONCLUSION

There is still uncertainty about the optimal methods of thromboprophylaxis in elective total hip arthroplasty. Although there are always going to be disagreements about the endpoints amongst guideline makers, guidelines should achieve uniformity in their criteria for levels of evidence and recommendation grades, facilitating the clinician's decision-making process.

Aspirin for elective hip and knee arthroplasty: a multimodal thromboprophylaxis protocol

PURPOSE

Multimodal thromboprophylaxis includes preoperative thromboembolic risk stratification and autologous blood donation, surgery performed under regional anaesthesia, postoperative rapid mobilisation, use of pneumatic compression devices and chemoprophylaxis tailored to the patient's individual risk. We determined the 90-day rate of venous thromboembolism (VTE), other complications and mortality in patients who underwent primary elective hip and knee replacement surgery with multimodal thromboprophylaxis.

METHODS

A total of 1,568 consecutive patients undergoing hip and knee replacement surgery received multimodal thromboprophylaxis: 1,115 received aspirin, 426 received warfarin and 27 patients received low molecular weight heparin and warfarin with or without a vena cava filter.

RESULTS

The rate of VTE, pulmonary embolism, proximal deep vein thrombosis (DVT) and distal DVT was 1.2, 0.36, 0.45 and 0.36 %, respectively, in patients who received aspirin. The rates in those who received warfarin were 1.4, 0.9, 0.47 and 0.47 %, respectively. The overall 90-day mortality rate was 0.2 %.

CONCLUSIONS

Multimodal thromboprophylaxis in which aspirin is administered to low-risk patients is safe and effective following primary total joint replacement.

Incidence of venous thromboembolism in elective foot and ankle surgery with and without aspirin prophylaxis

The incidence of deep-vein thrombosis (DVT) and pulmonary embolism (PE) is thought to be low following foot and ankle surgery, but the routine use of chemoprophylaxis remains controversial. This retrospective study assessed the incidence of symptomatic venous thromboembolic (VTE) complications following a consecutive series of 2654 patients undergoing elective foot and ankle surgery. A total of 1078 patients received 75 mg aspirin as routine thromboprophylaxis between 2003 and 2006 and 1576 patients received no form of chemical thromboprophylaxis between 2007 and 2010. The overall incidence of VTE was 0.42% (DVT, 0.27%; PE, 0.15%) with 27 patients lost to follow-up. If these were included to create a worst case scenario, the overall VTE rate was 1.43%. There was no apparent protective effect against VTE by using aspirin. We conclude that the incidence of VTE following foot and ankle surgery is very low and routine use of chemoprophylaxis does not appear necessary for patients who are not in the high risk group for VTE.

Thromboprophylaxis in spinal surgery: a survey

BACKGROUND

Venous Thromboembolism (VTE) is the most common complication following major joint surgery. While attention has been focused upon the incidence of thromboembolic disease following total hip or knee arthroplasty or emergency surgery for hip fracture, there exists a gap in the medical literature examining the incidence of VTE in spinal surgery. Evidence suggests that the prevalence of DVT after spinal surgery is higher than generally recognized but with a shortage of epidemiological data, guidelines for optimal prophylaxis are limited. This survey, of individuals attending the 2009 British Association of Spinal Surgeons Annual Meeting, sought to examine prevailing trends in VTE thromboprophylaxis in spinal surgery, adherence to guideline outlined by the National Institute for Health and Clinical Excellence (NICE) and to compare selections made by orthopaedic and neurosurgeons.

METHODS

We developed a questionnaire with eight clinical scenarios. Participants were asked to supply details on their specialty and to select which method(s) of thromboprophylaxis they would employ for each scenario. Chi squared analysis was used for statistical comparison of the questionnaire responses.

RESULTS

73% of neurosurgical respondents' and 31% of orthopaedic surgeons employed low molecular weight heparin (p < 0.001). Neurosurgeons also selected anti-embolism stockings more frequently (79% v 50%) while orthopaedic surgeons preferred mechanical prophylaxis (26% v 9%). There was no significant difference between trauma and non-trauma scenarios (p = 0.05).

CONCLUSION

There is no clear consensus in thromboprophylaxis in spinal surgery. There was a significant difference in selections across surgical disciplines with neurosurgeons more closely adhering to national guidelines. Further research examining the epidemiology of venous thromboembolism in spinal surgery and the risks-benefit relationship of thromboprophylaxis is warranted.

Current controversies in hip surgery

An international faculty of orthopaedic surgeons presented their work on the current challenges in hip surgery at the London Hip Meeting which was attended by over 400 delegates. The topics covered included femoroacetabular impingement, thromboembolic phenomena associated with hip surgery, bearing surfaces (including metal-on-metal articulations), outcomes of hip replacement surgery and revision hip replacement. We present a concise report of the current opinions on hip surgery from this meeting with appropriate references to the current literature.

Are current thrombo-embolic prophylaxis guidelines applicable to unicompartmental knee replacement?

Symptomatic and asymptomatic deep-vein thrombosis (DVT) is a common complication of knee replacement, with an incidence of up to 85% in the absence of prophylaxis. National guidelines for thromboprophylaxis in knee replacement are derived from total knee replacement (TKR) data. No guidelines exist specific to unicompartmental knee replacement (UKR). We investigated whether the type of knee arthroplasty (TKR or UKR) was related to the incidence of DVT and discuss the applicability of existing national guidelines for prophylaxis following UKR.

Data were collected prospectively on 3449 knee replacements, including procedure type, tourniquet time, surgeon, patient age, use of drains and gender. These variables were related to the incidence of symptomatic DVT.

The overall DVT rate was 1.6%. The only variable that had an association with DVT was operation type, with TKR having a higher incidence than UKR (2.2% versus 0.3%, p < 0.001). These data show that the incidence of DVT after UKR is both clinically and statistically significantly lower than that after TKR.

TKR and UKR patients have different risk profiles for symptomatic DVT. The risk-benefit ratio for TKR that has been used to produce national guidelines may not be applicable to UKR. Further research is required to establish the most appropriate form of prophylaxis for UKR.

Thromboprophylaxis in elective foot and ankle patients--current practice in the United Kingdom

BACKGROUND

The incidence of venous thromboembolism (VTE) is unknown in elective foot and ankle surgery. The National Institute for Health and Clinical Excellence (NICE) recently published guidelines on reducing the risk of venous thromboembolism in surgical patients. This includes patients undergoing elective foot and ankle surgery.

METHOD

In March 2010 we surveyed the current practice in VTE prophylaxis in elective foot and ankle surgery amongst members of the British Orthopaedic Foot and Ankle Society (BOFAS).

RESULTS

The response rate was 84 (53%). The total number of elective foot and ankle operations performed by the surveyed group was 33,500 per annum. The estimated incidence of DVT, PE and fatal PE was 0.6%, 0.1% and 0.02%. In our study the number of patients needed to treat to prevent a single fatal PE is 10,000 although this figure is open to important bias.

CONCLUSION

We question the applicability of the NICE guidelines to patients undergoing elective foot and ankle surgery. We consider that this data justifies the prospective study of the incidence of VTE in patients undergoing elective foot and ankle surgery, without the use of chemical thromboprophylaxis.

Venous thromboembolic events following foot and ankle surgery in the English National Health Service

Diagnostic and operative codes are routinely collected for every patient admitted to hospital in the English NHS. Data on post-operative complications following foot and ankle surgery have not previously been available in large numbers. Data on symptomatic venous thromboembolism events and mortality within 90 days were extracted for patients undergoing fixation of an ankle fracture, first metatarsal osteotomy, hindfoot fusions and total ankle replacement over a period of 42 months. For ankle fracture surgery (45 949 patients), the rates of deep-vein thrombosis (DVT), pulmonary embolism and mortality were 0.12%, 0.17% and 0.37%, respectively. For first metatarsal osteotomy (33 626 patients), DVT, pulmonary embolism and mortality rates were 0.01%, 0.02% and 0.04%, and for hindfoot fusions (7033 patients) the rates were 0.03%, 0.11% and 0.11%, respectively. The rate of pulmonary embolism in 1633 total ankle replacement patients was 0.06%, and there were no recorded DVTs and no deaths. Statistical analysis could only identify risk factors for venous thromboembolic events of increasing age and multiple comorbidities following fracture surgery.

Venous thromboembolism following foot and ankle surgery is extremely rare, but this subset of fracture patients is at a higher risk. However, there is no evidence that thromboprophylaxis reduces this risk, and these national data suggest that prophylaxis is not required in most of these patients.

Return to theatre following total hip and knee replacement, before and after the introduction of rivaroxaban: a retrospective cohort study

Rivaroxaban has been recommended for routine use as a thromboprophylactic agent in patients undergoing lower-limb arthroplasty. However, trials supporting its use have not fully evaluated the risks of wound complications. This study of 1048 total hip/knee replacements records the rates of return to theatre and infection before and after the change from a low molecular weight heparin (tinzaparin) to rivaroxaban as the agent of chemical thromboprophylaxis in patients undergoing lower-limb arthroplasty. During a period of 13 months, 489 consecutive patients undergoing lower-limb arthroplasty received tinzaparin and the next 559 consecutive patients received rivaroxaban as thromboprophylaxis. Nine patients in the control (tinzaparin) group (1.8%, 95% confidence interval 0.9 to 3.5) returned to theatre with wound complications within 30 days, compared with 22 patients in the rivaroxaban group (3.94%, 95% confidence interval 2.6 to 5.9). This increase was statistically significant (p = 0.046). The proportion of patients who returned to theatre and became infected remained similar (p = 0.10). Our study demonstrates the need for further randomised controlled clinical trials to be conducted to assess the safety and efficacy of rivaroxaban in clinical practice, focusing on the surgical complications as well as the potential prevention of venous thromboembolism.