Is the May-Thurner Syndrome a Major Risk Factor for Deep Vein Thrombosis in Total Hip Arthroplasty?

Background

May-Thurner syndrome (MTS) is iliac vein compression syndrome associated with postoperative deep vein thrombosis (DVT) resulting from chronic compression of the left iliac vein against lumbar vertebrae by the overlying right or left common iliac artery. MTS is not well known as a risk factor for DVT after total hip arthroplasty (THA). We evaluated the incidence of DVT after THA and analyzed if the MTS is a risk factor for DVT after THA. We hypothesized that MTS would be associated with an increased risk of developing DVT after THA.

Methods

All patients > 65 years of age who underwent THA between January 1, 2009, and January 12, 2017, were identified. Among them, the patients who presented for postoperative DVT of the lower extremity were reviewed with medical record data. MTS was diagnosed with computed tomography (CT) angiography of the lower extremity. We analyzed the demographic data, symptoms, diagnoses, and treatment of MTS patients.

Results

A total of 492 consecutive patients aged > 65 years who underwent operation for THA were enrolled. Among them, 5 patients (1.0%) presented for postoperative DVT of the lower extremity. After reviewing the CT angiography of the lower extremity, 4 out of 5 DVT patients (80%) were identified as having MTS. All MTS patients were female and presented with pain and swelling of the left leg. All MTS patients were treated with systemic anticoagulation, aspiration thrombectomy, and percutaneous transluminal angioplasty. Complete resolution of thrombus was observed in all patients.

Conclusions

If the diagnosis of MTS is delayed, the morbidity and mortality rates are significantly increased. Orthopedic surgeons should be aware of MTS as a risk factor for DVT after THA. Moreover, preoperative evaluation with duplex sonography or CT angiography to confirm MTS should be considered. In this regard, this study is considered to have sufficient clinical value for early diagnosis and appropriate treatment of MTS after THA.

Venous thromboembolism risk assessment, prophylaxis practices and interventions for its improvement (AVAIL-ME Extension Project, Iran)

BACKGROUND

Venous thromboembolism (VTE) is a major health issue worldwide. Data about VTE prophylaxis practices in developing countries are scarce.

OBJECTIVES

The primary objectives of this survey were to define the VTE risk factors in hospitalized patients, to determine the rates of VTE prophylaxis administration and guideline compliance and to assess the effects of an educational program on VTE prophylaxis practices in Iran.

PATIENTS AND METHODS

Data on 1219 patients from twenty hospitals in Iran were extracted from the AVAIL-ME Extension project main databank. VTE risks were categorized according to the Caprini Risk Assessment Model. Logistic regression analysis was carried out to assess factors influencing VTE prophylaxis. We also examined the impact of an educational program which consisted of awareness, risk assessment, internal protocol implementation and re-assessment, on VTE prophylaxis practices.

RESULTS

Of 1219 patients, 789 (65%) and 430 (35%) were surgical and medical, respectively. VTE risks, categorized in low, moderate, high and very high were detected in 14%, 17%, 26% and 43% of patients respectively with a total of 1042(85%) patients being at risk for VTE. Of 882 (85%) eligible patients for VTE prophylaxis, 737 (83.5%) received any drug prophylaxis of whom 265 (62%) were medical and 472 (60%) were surgical. ACCP guidelines compliance was 60% and 33% in surgical and medical patients respectively. Any VTE prevention, drug prophylaxis, mechanical prophylaxis and guideline adherence were, 48% vs. 64%, 45% vs. 60%, 6% vs. 9% and 34% vs. 45% respectively (p<00.1) before and after implementation of the VTE educational program.

CONCLUSIONS

Despite an overall improvement in VTE prevention, areas such as inappropriate use of VTE prophylaxis in a large number of patients, significant under-use of mechanical devices and guideline adherence require closer attention. VTE awareness education is beneficial in improving VTE prophylaxis in Iran.

Deep venous thrombosis: report of 2 cases

Postsurgical deep venous thrombosis (DVT) is an established complication with rare incidence in maxillofacial surgery. We report 2 cases of postsurgical proximal DVT after hemimandibulectomy from 2000 to 2009 along with pathogenesis, clinical findings, and management of DVT.

The AVAIL ME Extension: a multinational Middle Eastern survey of venous thromboembolism risk and prophylaxis

BACKGROUND

Venous thromboembolism (VTE) is a major worldwide problem.

OBJECTIVES

The primary objectives of this survey were to identify patients at risk for VTE, to define the rate of patients receiving appropriate VTE prophylaxis and to examine the frequency of the presence of guidelines and their application.

PATIENTS AND METHODS

Ten countries, 101 hospitals and a total of 4983 patients were included in this multinational cross-sectional survey. Standardized case report forms were filled out by trained individuals on one predefined day. Risks were categorized according to the Caprini Risk Assessment Model. Logistic regressions were carried out to assess factors that determined VTE prophylaxis.

RESULTS

Of 4983 patients, 3368 (68%) and 1615 (32%) were surgical and medical, respectively. Seven hundred and seventy-two (15.5%) were considered to be at low risk, 1001 (20%) at moderate risk, 1289 (26%) at high risk and 1921 (38.5%) at very high risk for VTE. Of 3575 (72%) patients who were eligible to receive VTE prophylaxis, 2747 (77%) received any drug prophylaxis. Among these patients 720/1056 (68%) and 2027/2519 (80%) were medical and surgical patients, respectively. The overall compliance with ACCP guidelines was 38%, being 24% for medical patients and 44% for surgical patients.

CONCLUSIONS

The results of this large multinational survey, although indicating overall improvement in VTE prophylaxis, identify a considerable number of patients who either did not receive any VTE prophylaxis or received it inappropriately. Although more medical patients were at risk for VTE, they were given prophylaxis less frequently than surgical patients. Concordance with VTE prophylaxis guidelines was higher in surgical patients, but overall application of these tools was unacceptably low.

The AVAIL ME study: a multinational survey of VTE risk and prophylaxis

Venous thromboembolism (VTE) is a major public health issue that is frequently underestimated. The primary objective of this multinational survey was to identify patients at risk for VTE, and to define the rate of patients receiving appropriate prophylaxis in the Middle Eastern region. Standardized case report forms were filled by trained individuals on one predefined day in selected hospitals. Data were then entered and analyzed by independent biostatisticians. Risk was categorized according to American College of Chest Physicians (ACCP) guidelines, 2004. Logistic regressions were carried out to assess factors that determined VTE prophylaxis. 845 (37%) medical and 1421 (63%) surgical patients were eligible for the study. Patients were at low (4.2%), moderate (51.7%), high (9%) and very high risk (35.2%) for VTE. Any VTE prevention was given in 17.9, 41.7, 60.6 and 66.9% of respective risk categories, while ACCP guidelines were applied in 86.3, 41.1, 48.3 and 24.5% of these categories. Surgical patient type, immobility on admission, and contraceptive use were the most important drivers of VTE prophylaxis in those who were eligible to it (OR ≥ 2). Surgical patient type, immobility during hospitalization, existence of a VTE protocol and chronic heart failure were the most important drivers for VTE prophylaxis application in patients who were not eligible for it (OR ≥ 3). A concordance κ value of 0.16 was found between eligibility for VTE prophylaxis on one hand and its application in practice (P < 0.001). Risk factors for VTE and eligibility for VTE prophylaxis are common, but VTE prophylaxis and guidelines application are low.

The use of prophylaxis in patients undergoing diagnostic tests for suspected venous thromboembolism

Objectives

The purpose of this study was to describe the use of pharmacological and mechanical prophylaxis and clinical outcomes of patients undergoing diagnostic tests for suspected venous thromboembolism (VTE).

Methods

The medical records of 660 consecutive inpatients referred for suspected VTE at an academic medical centre were retrospectively reviewed.

Results

Acute VTE was diagnosed in 138 (21%) of the 660 patients; the incidence of deep vein thrombosis and pulmonary embolism was 18–25%, respectively. Only 61% of eligible patients received pharmacological prophylaxis and 43% of patients received mechanical prophylaxis. The incidence of VTE was higher in patients who did not receive pharmacological prophylaxis (30%) compared with patients who did (16%, P value <0.001).

Conclusions

Preventive measures for VTE, including both pharmacological and mechanical prophylaxis, were underutilized in hospitalized patients undergoing diagnostic tests for suspected VTE.

WITHDRAWN: Heparin for the prevention of venous thromboembolism in general medical patients (excluding stroke and myocardial infarction)

BACKGROUND

Venous thromboembolic disease has been extensively studied in surgical patients. The benefit of thromboprophylaxis is now generally accepted, but it is medical patients who make up the greater proportion of the hospital population. Medical patients differ from surgical patients with regard to their health and the pathogenesis of thromboembolism and the impact that preventative measures can have. The extensive experience from thromboprophylaxis studies in surgical patients is therefore not necessarily applicable to non-surgical patients.

OBJECTIVES

To determine the effectiveness and safety of heparin thromboprophylaxis in general medical patients.

SEARCH STRATEGY

The Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last searched 24 April 2009) and the Cochrane Central Register of Controlled Trials in The Cochrane Library (last searched Issue 2, 2009)We handsearched meeting abstracts, and consulted with colleagues and investigators as well as the manufacturers of the various LMWH preparations to identify unpublished or missed studies.

SELECTION CRITERIA

Randomised controlled trials comparing unfractionated heparin (UFH) or low molecular weight heparin (LMWH) with placebo or no treatment, or comparing UFH with LMWH.

DATA COLLECTION AND ANALYSIS

One author identified possible trials, and the other author confirmed eligibility for inclusion in the review. Both authors extracted the data. Disagreements were resolved by discussion. We performed the meta-analysis as a fixed-effect model with relative risks.

MAIN RESULTS

A significant risk reduction in deep vein thrombosis (DVT) by 60% (relative risk (RR) 0.40; 95% confidence interval CI 0.31 to 0.53; P < 0.00001) and pulmonary embolism (PE) by 42% (RR 0.58; 95% CI 0.43 to 0.80; P = 0.0007) was observed with heparin compared with placebo or no treatment. However, heparin resulted in a significant increase in major haemorrhage (RR 2.18; 95% CI 1.28 to 3.72; P = 0.004) and minor haemorrhage (RR 1.74; 95% CI 1.26 to 2.41; P = 0.0008). There was no statistically significant difference in efficacy between LMWH and UFH. There was a statistically significant 72% risk reduction in major bleeding when LMWH was compared with UFH (RR 0.28; 95% CI 0.10 to 0.78; P = 0.02).

AUTHORS' CONCLUSIONS

The data from this review support the use of heparin thromboprophylaixs in medical patients presenting with an acute medical illness. Although the analysis found no significant difference in efficacy between LMWH and UFH, it did note differences in the incidence of DVT and clinical PE with a significantly reduced risk of bleeding in favour of LMWH.

Heparin for the prevention of venous thromboembolism in general medical patients (excluding stroke and myocardial infarction)

BACKGROUND

Venous thromboembolic disease has been extensively studied in surgical patients. The benefit of thromboprophylaxis is now generally accepted, but it is medical patients who make up the greater proportion of the hospital population. Medical patients differ from surgical patients with regard to their health and the pathogenesis of thromboembolism and the impact that preventative measures can have. The extensive experience from thromboprophylaxis studies in surgical patients is therefore not necessarily applicable to non-surgical patients.

OBJECTIVES

To determine the effectiveness and safety of heparin thromboprophylaxis in general medical patients.

SEARCH STRATEGY

The Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last searched 24 April 2009) and the Cochrane Central Register of Controlled Trials in The Cochrane Library (last searched Issue 2, 2009)We handsearched meeting abstracts, and consulted with colleagues and investigators as well as the manufacturers of the various LMWH preparations to identify unpublished or missed studies.

SELECTION CRITERIA

Randomised controlled trials comparing unfractionated heparin (UFH) or low molecular weight heparin (LMWH) with placebo or no treatment, or comparing UFH with LMWH.

DATA COLLECTION AND ANALYSIS

One author identified possible trials, and the other author confirmed eligibility for inclusion in the review. Both authors extracted the data. Disagreements were resolved by discussion. We performed the meta-analysis as a fixed-effect model with relative risks.

MAIN RESULTS

A significant risk reduction in deep vein thrombosis (DVT) by 60% (relative risk (RR) 0.40; 95% confidence interval CI 0.31 to 0.53; P < 0.00001) and pulmonary embolism (PE) by 42% (RR 0.58; 95% CI 0.43 to 0.80; P = 0.0007) was observed with heparin compared with placebo or no treatment. However, heparin resulted in a significant increase in major haemorrhage (RR 2.18; 95% CI 1.28 to 3.72; P = 0.004) and minor haemorrhage (RR 1.74; 95% CI 1.26 to 2.41; P = 0.0008). There was no statistically significant difference in efficacy between LMWH and UFH. There was a statistically significant 72% risk reduction in major bleeding when LMWH was compared with UFH (RR 0.28; 95% CI 0.10 to 0.78; P = 0.02).

AUTHORS' CONCLUSIONS

The data from this review support the use of heparin thromboprophylaixs in medical patients presenting with an acute medical illness. Although the analysis found no significant difference in efficacy between LMWH and UFH, it did note differences in the incidence of DVT and clinical PE with a significantly reduced risk of bleeding in favour of LMWH.

An evaluation of practice pattern for venous thromboembolism prevention in Lebanese hospitals

BACKGROUND

Venous thromboembolism (VTE) is a major cause of death among hospitalized patients. Many VTE prophylaxis guidelines have been developed, including the American College of Chest Physicians (ACCP). VTE prophylaxis is required in specific patients; however, its practice is not always optimal, and often depends on the hospitals' protocols. In Lebanon, information about the appropriateness of VTE prophylaxis in health care centers is lacking.

OBJECTIVE

The primary objective of this study was to evaluate the pattern of VTE prophylaxis application, including agents, doses, duration of treatment, and route of administration, in Lebanese health care centers.

METHODS

A Lebanese multi-center, prospective, chart review study was conducted over 4 months. Data on demographics, VTE prophylaxis medication, dose, route, duration, and associated risk factors were collected by pharmacy students. The appropriateness of VTE prophylaxis was determined as per ACCP guidelines. Patients receiving VTE treatment were excluded from the study. Institutional review board (IRB) approval was obtained from each hospital center.

RESULTS

A total of 840 patients were included. Both gender groups were equally represented in the sample and the mean age was 59 +/- 19.53 years. The majority (639/840, 76.1%) of the sample were at high risk for deep venous thrombosis (DVT), and inappropriate VTE prophylaxis was reported in 35% of the low-risk group, in 70% of the moderate-risk group, and in 39% of the high-risk group (P < 0.0001). Comparing proper VTE prophylaxis practice between intensive care unit (ICU) and non-ICU patients, there was no statistical difference observed in teaching hospitals (67.2% vs. 65.5%, P = 0.312). However, in non-teaching hospitals, appropriate VTE prophylaxis practice was more prevalent in ICU than non-ICU patients (65.9% vs. 51.2%, P = 0.004). The average duration of VTE prophylaxis was less than 10 days. Missing data was a major limitation for this study, where, for instance, the duration of prophylaxis could not be accurately abstracted in half of the sample. Another limitation was the absence of laboratory results needed for clinical assessment of the regimen used.

CONCLUSION

This study reflected the importance of assessing VTE prophylaxis in Lebanese hospitals, thus, the need for implementing established guidelines to improve the overall patient safety.

A dose escalation study of YM150, an oral direct factor Xa inhibitor, in the prevention of venous thromboembolism in elective primary hip replacement surgery

BACKGROUND

YM150, a new oral direct factor Xa inhibitor is used as prophylaxis for venous thromboembolism (VTE), a well-known risk after orthopaedic surgery.

OBJECTIVES

To assess the safety and efficacy of thromboprophylaxis with YM150 in a dose escalation study.

PATIENTS/METHODS

Patients (174) undergoing hip replacement surgery were randomized per cohort to oral once daily YM150 or subcutaneous enoxaparin (40 mg daily) in a 4:1 ratio for 7-10 days treatment. The YM150 doses were 3, 10, 30 and 60 mg by sequential four-dose escalation cohorts. The primary endpoint was major and/or clinically relevant non-major bleeding. The incidence of VTE was defined as a composite of verified symptomatic events and/or positive findings at bilateral venography on the last treatment day. An independent adjudication committee evaluated blindly the outcomes of the open-label study.

RESULTS

No major and three clinically relevant non-major bleeds were reported, 1 (2.9%; 95% CI, 0.1-15.1) in the 3 mg and 2 (5.7%; 95% CI, 1.0-18.8) in the 10 mg YM150 dose groups. Of 147 patients (84%) with an evaluable venogram, VTE was observed in 51.9% (95% CI, 31.9-71.4), 38.7% (95% CI, 22.6-57.0), 22.6% (95% CI, 9.7-39.4), and 18.5% (95% CI, 7.5-36.5) in the YM150 dose groups 3, 10, 30 and 60 mg, respectively. A significant YM150 dose-related trend in VTE incidence was found (P=0.006). VTE with enoxaparin was 38.7% (95% CI, 22.6-57.0).

CONCLUSIONS

YM150, 10-60 mg daily, starting 6-10 h after primary hip replacement, was shown to be safe, well tolerated and effective.

Prevention of venous thromboembolism in surgical patients with breast cancer

Background

No randomized trial has yet studied venous thromboembolism (VTE) prophylaxis in patients undergoing surgery for breast cancer.

Methods

Relevant articles were identified using Medline searches. Secondary articles were identified from the reference lists of key papers.

Results and conclusion

The absence of randomized trials comparing different methods of VTE prophylaxis with controls makes an evidence-based consensus among breast cancer surgeons difficult. Intermittent pneumatic compression (IPC) and graduated compression (GC) are effective in reducing VTE without the haemorrhagic complications associated with heparin; their effects are additive. The authors suggest the following strategy. All patients undergoing surgery for breast cancer should receive both IPC and GC, with heparin reserved for those at very high risk. A controlled trial should randomize women to receive heparin or not, and all women should have both IPC and GC. The primary endpoints should be the development of VTE and/or haemorrhagic complications.

Optimal duration of prophylaxis for venous thromboembolism following total hip arthroplasty and total knee arthroplasty

Elective total hip arthroplasty and total knee arthroplasty are associated with a high risk of postoperative venous thromboembolism. Traditionally, antithrombotic prophylaxis has been administered during the hospital stay. However, with patients spending less time in the hospital after surgery, there is a need to continue thromboprophylaxis beyond hospital discharge. The current recommendation for prophylaxis in total joint arthroplasty patients is a minimum of 10 days, with extended prophylaxis up to 28 to 35 days following total hip arthroplasty. Prophylaxis with low-molecular-weight heparins for approximately 4 weeks following hip arthroplasty has resulted in clinically significant reductions in the incidence of venographically confirmed deep vein thrombosis. Currently, no data support extended thromboprophylaxis beyond 10 days following total knee arthroplasty. Using weighted risk factors to assess individual risk for venous thromboembolism can help the physician determine the optimal duration of prophylaxis.

A need for a simplified approach to venous thromboembolism prophylaxis in acute medical inpatients

Venous thromboembolism (VTE) is a major cause of morbidity and mortality in the UK. Studies have shown that pulmonary embolism causes or contributes to approximately 1 in 10 hospital deaths of medical patients admitted to general hospitals in the UK (Lindblad B, Sternby NH, Bergqvist D. BMJ 1991; 302: 709-11), with pulmonary embolus being the most common preventable cause of hospital death. Thromboprophylaxis is safe, highly effective and cost effective, but despite various current clinical guidelines, physicians fail to prescribe prophylaxis for the majority of medical inpatients at risk of VTE. This article outlines the current evidence for VTE prophylaxis in medical patients and discusses the reasons behind the insufficient use of prophylaxis in the acute medical setting.

Symptomatic venous thromboembolism after orthognathic operations: An audit

We report the incidence of symptomatic venous thromboembolism confirmed by venography after 129 consecutive orthognathic operations between 1998 and 2002. Two patients developed deep vein thromboses (DVT) and there were no symptomatic pulmonary emboli.

Evidence for the prevention of venous thromboembolism

Patients undergoing major orthopaedic surgery are at high risk of developing venous thromboembolism (VTE). VTE is preventable and venous prophylaxis consensus groups recommend that each patient is assessed for risk of VTE and then stratified into one of the three categories of risk. Rick stratification enables the choice of the most appropriate preventative interventions. This article examines a decision making framework for VTE prevention with particular focus on a validated risk assessment model (RAM) to facilitate risk stratification. The relevant literature is also scrutinised in terms of the best venous antithrombotic strategies, for patients undergoing major orthopaedic surgery, according to scientific evidence.

Thromboprophylaxis following cast immobilisation for lower limb injuries--survey of current practice in United Kingdom

The risk of deep vein thrombosis (DVT) and pulmonary embolism (PE) is well documented in patients following cast immobilisation for injuries of lower extremities. There are no generally accepted approaches to preventing this complication and hence there remains substantial practice variation amongst surgeons regarding the use of anticoagulation measures. The present survey was conducted to investigate the current chemothromboprophylaxis practice among UK orthopaedic departments for patients immobilised with plasters for lower extremity injuries and establish any variations in practice. A telephone questionnaire survey was conducted on junior doctors (Senior House Officers and Registrars) in orthopaedic departments of 70 randomly selected hospitals in United Kingdom. This survey assessed the thromboprophylaxis practice for lower limb injuries in plaster casts. Our results show substantial variation amongst British orthopaedic surgeons in the use of chemothromboprophylaxis measures. Sixty-two percent of the departments do not use any DVT prophylaxis in this group of trauma. Furthermore, only 11.4% of the departments performed risk stratification on their patients. Ninety-nine percent of the respondents were unaware of any existing guidelines in this regard. Although the incidence of DVT in patients in plaster for lower extremity injuries is low compared to the Hip/Knee arthroplasty group, this is not insignificant. Both over and under treatment with thromboprophylaxis can have implications in terms of side effects and costs. One possible solution is to use risk stratification to identify individuals who are likely to benefit from prophylaxis. There is a substantial variation and inconsistency in practice among orthopaedic departments in United Kingdom due to a lack of clinical guidelines in this group of trauma and it remains underused even in high-risk group.

Thromboprophylaxis for acetabular injuries in the UK What prophylaxis is used?

Due to chronic underfunding and the absence of a comprehensive and coordinated national approach to the management of acetabular trauma throughout the UK, patients can incur prolonged recumbancy. We have performed a postal questionnaire to establish the current clinical practice in the specialist pelvic and acetabular units throughout the UK, with respect to time to surgery from injury, thromboprophylaxis, and surveillance. We have identified 21 units, and 37 surgeons in the NHS who deal with acetabular trauma. The mean time to surgery from injury in the UK is 8.5 days (range 2-19 days). Mechanical thromboprophylaxis was used in 67% (14) of the units. No unit routinely uses prophylactic IVC filters. Chemical thromboprophylaxis is routinely used in 100% (21) of the units. Ninety-five percent (20) used prophylactic doses of LDH or LMWH. Clinical surveillance alone for thromboembolism is employed in 90% (19) of the units. Only 2 (10%) units routinely perform radiological surveillance with ultrasound Doppler, pre-operatively. Currently there is no published directory of dedicated pelvic and acetabular surgeons in the UK. There is no general consensus on the approach to thromboprophylaxis and surveillance in acetabular trauma in the UK. There is no consensus approach to thromboprophylaxis and surveillance in the literature.

Introduction to venous thromboembolism and prophylaxis

The majority of fatal pulmonary emboli arise from deep vein thromboses in the lower limb. Pulmonary embolism continues to be a major cause of death in hospitalized patients. The classification, history, epidemiology, pathophysiology and prognosis are disclosed. An overview of the current recommendations for venous thromboembolism in surgical and medical patients and the failure of its application are discussed. The use of adequate thromboprophylaxis in approximately only one-third of patients is a familiar account. Prophylaxis guidelines use risk stratification systems, which lend to confusion by clinicians with the inevitable consequence of failed prophylaxis implementation. The National Institute of Health and Clinical Excellence are due to provide national prophylactic guidelines in May 2007. Simplified guidelines, a national consensus, and continued education of patients and health care professions to maintain compliance, is the solution to thromboprophylaxis.

Venous thromboprophylaxis in UK medical inpatients

We prospectively assessed the implementation of venous thromboembolism (VTE) prophylaxis guidelines and the impact of grand round presentation of the data in changing clinical practice. Two NHS teaching hospitals were studied for 24 months from January 2003. Patients were risk stratified according to the THRIFT (thromboembolic risk factor) consensus group guidelines and compared with the recommendations of the THRIFT and ACCP (American College of Chest Physicians) consensus groups. Six months following presentation of the initial results, a further analysis was made to assess changes in clinical practice. 1128 patients were assessed of whom 1062 satisfied the inclusion criteria for thromboprophylaxis. 89% of all patients were stratified as having high or moderate risk of developing VTE. Of these only 28% were prescribed some form of thromboprophylaxis-4% received the THRIFT-recommended and 22% received the ACCP-recommended thromboprophylaxis. The vast majority (72%) received no thromboprophylaxis at all. Reassessment, following data presentation at grand rounds, showed a significant increase to 31% inpatients receiving THRIFT (P<0.0001) and ACCP (P=0.002) recommended thromboprophylaxis. However,the proportion of patients receiving no form of prophylaxis barely changed (72% to 69%: P=0.59). We found a gross underutilization of thromboprophylaxis in hospitalized medical patients. A simple grand-round presentation of the data and recommended guidelines to clinicians significantly increased the proportion of patients receiving recommended thromboprophylaxis but did not increase the overall proportion of patients receiving it. We therefore conclude that a single presentation of guidelines is not enough to achieve the desired levels. Such presentations may only serve to make DVT (deep venous thromboembolism) aware clinicians prescribe prophylaxis more accurately.

Are we good at thromboembolic disease prophylaxis - an audit of the use of risk assessment forms in emergency medical admissions

Venous thromboembolism (VTE) is a major cause of morbidity and mortality in hospitalised patients. Thromboprophylaxis is an effective strategy for VTE prevention in high-risk patients. An initial audit in our district general hospital trust showed poor adherence to the thromboembolic risk factors consensus group recommendations and so a risk assessment form (RAF) was devised. We present repeated audits to assess the RAF uptake and its effects on VTE thromboprophylaxis. We also present data analysing perceptions among doctors of the RAF and reasons for its poor completion. We provide compelling evidence that the RAF is an invaluable tool in the assessment of VTE thromboprophylaxis.

Prevention of venous thromboembolism: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy

This article discusses the prevention of venous thromboembolism (VTE) and is part of the Seventh American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy: Evidence-Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following. We recommend against the use of aspirin alone as thromboprophylaxis for any patient group (Grade 1A). For moderate-risk general surgery patients, we recommend prophylaxis with low-dose unfractionated heparin (LDUH) (5,000 U bid) or low-molecular-weight heparin (LMWH) [< or = 3,400 U once daily] (both Grade 1A). For higher risk general surgery patients, we recommend thromboprophylaxis with LDUH (5,000 U tid) or LMWH (> 3,400 U daily) [both Grade 1A]. For high-risk general surgery patients with multiple risk factors, we recommend combining pharmacologic methods (LDUH three times daily or LMWH, > 3,400 U daily) with the use of graduated compression stockings and/or intermittent pneumatic compression devices (Grade 1C+). We recommend that thromboprophylaxis be used in all patients undergoing major gynecologic surgery (Grade 1A) or major, open urologic procedures, and we recommend prophylaxis with LDUH two times or three times daily (Grade 1A). For patients undergoing elective total hip or knee arthroplasty, we recommend one of the following three anticoagulant agents: LMWH, fondaparinux, or adjusted-dose vitamin K antagonist (VKA) [international normalized ratio (INR) target, 2.5; range, 2.0 to 3.0] (all Grade 1A). For patients undergoing hip fracture surgery (HFS), we recommend the routine use of fondaparinux (Grade 1A), LMWH (Grade 1C+), VKA (target INR, 2.5; range, 2.0 to 3.0) [Grade 2B], or LDUH (Grade 1B). We recommend that patients undergoing hip or knee arthroplasty, or HFS receive thromboprophylaxis for at least 10 days (Grade 1A). We recommend that all trauma patients with at least one risk factor for VTE receive thromboprophylaxis (Grade 1A). In acutely ill medical patients who have been admitted to the hospital with congestive heart failure or severe respiratory disease, or who are confined to bed and have one or more additional risk factors, we recommend prophylaxis with LDUH (Grade 1A) or LMWH (Grade 1A). We recommend, on admission to the intensive care unit, all patients be assessed for their risk of VTE. Accordingly, most patients should receive thromboprophylaxis (Grade 1A).

Zinopin--the rationale for its use as a food supplement in Traveller's thrombosis and motion sickness

Venous thrombo-embolism (VTE) has been associated with periods of prolonged immobility during air, sea and road travel. Motion sickness (MS) has also been reported during both long and short journeys. Current prophylactic therapies for both these indications are generally associated with side effects. Physiological profiles of Pycnogenol and Standardized Ginger Root Extract (SGRE) representing active constituents of Zinopin have been described and reviewed in relation to their activities involved in the patho-physiology of VTE (Traveller's Sickness) and MS and their safe use as food supplement, in traveller's thrombosis and motion sickness. The pathophysiology of VTE and MS is discussed in light of epidemiological data and risk factors associated with these conditions. Rationale of development of Zinopin and its mechanism of action are discussed based on physiological synergy of Pycnogenol and SGRE. Conclusions are made in light of preliminary clinical findings obtained in an open controlled clinical trial. Further clinical study on Zinopin on these lines is suggested.

Prevention of Venous Thromboembolism in the ICU

BACKGROUND

Although venous thromboembolism (VTE) is an important cause of morbidity and mortality in critical care unit patients, the risk of VTE and its prevention have been poorly characterized in this population. Evidence-based thromboprophylaxis guidelines are also not available for these critically ill patients.

OBJECTIVES

To review the prevalence of VTE, to summarize the available clinical trials of thromboprophylaxis, and to outline a practical approach to the prevention of VTE in critical care unit patients.

METHODS

Systematic review of the relevant literature.

RESULTS

Most patients in critical care units have at least one major risk factor for VTE, and many patients have multiple risk factors. Objectively confirmed deep-vein thrombosis (DVT) rates varied from 13 to 31% among the four prospective studies in which critical care unit patients did not receive prophylaxis. We were able to identify only three randomized trials of thromboprophylaxis conducted in critical care units. The results of these studies suggest that both low-dose heparin and low-molecular-weight heparin are efficacious in preventing DVT compared with no prophylaxis. Fourteen studies reported that compliance with some form of thromboprophylaxis occurred in 33 to 100% of critically ill patients.

CONCLUSIONS

There is a paucity of data assessing the risks and prevention of VTE in critical care settings. Selection of prophylaxis for these challenging patients involves a consideration of the thromboembolic and bleeding risks, both of which may vary in the same patient from day to day.

A review of thigh-length vs knee-length antiembolism stockings

Knee-length and thigh-length antiembolism (AE) stockings are used to prevent deep vein thrombosis in medical and surgical patients who are at risk because of periods of immobilization while in hospital. The aim of this review was to compare the effectiveness of both lengths of stocking and consider the implications for nursing practice. An electronic search was performed using Medline and Cinahl and a hand search was also conducted. Four studies and a literature review were selected. These studies indicated that knee-length AE stockings were equally effective as were associated with better patient compliance and were more cost-effective than thigh-length stockings. However, as with thigh-length stockings, they require accurate measurement and correct fitting if associated complications are to be avoided, highlighting the need for better education for both practitioners and patients.

Attitudes to the use of prophylaxis for thrombo-embolism in neurosurgical patients

Neurosurgical patients are at significant risk of thromboembolic complications. A survey of 58 consultant neurosurgeons in United Kingdom confirmed that 84.5% regularly used some form of prophylaxis. For all forms of neurosurgery, the most preferred method of prophylaxis was mechanical (graduated compression stockings-TEDS and intra-operative pneumatic calf compressors-IPC) or in the post-operative period a combination of mechanical methods and low molecular weight heparin (LMWH). LMWH was rarely administered in the perioperative period. The majority of neurosurgeons believed that TEDS and LMWH reduced post-operative DVT (79% and 90%, respectively) and PE (43% and 67%), but 29% associated LMWH with bleeding complications. A review of current literature revealed that TEDS, IPC, and LMWH are effective in reducing the incidence of DVT, but the evidence over the safety of heparin is inconclusive in neurosurgical patients. There is still room for improvement as a minority of neurosurgeons continue to ignore the importance of prophylaxis against thrombo-embolism in neurosurgery.

Prevention of venous thromboembolism in medical patients with enoxaparin: a subgroup analysis of the MEDENOX study

The Medical Patients with Enoxaparin (MEDENOX) trial was a randomized, placebo-controlled study that defined the risk of venous thromboembolism (VTE) in acutely ill, immobilized, general medical patients and the efficacy of the low-molecular-weight heparin, enoxaparin, in preventing thrombosis. We performed a post-hoc analysis to evaluate the effect of 40 mg enoxaparin once daily on MEDENOX patient outcome in different types of acute medical illness (heart failure, respiratory failure, infection, rheumatic disorder and inflammatory bowel disease) and pre-defined risk factors (chronic heart and chronic respiratory failure, age, immobility, previous VTE and cancer). The primary outcome was the occurrence of documented VTE between days 1 and 14. The relative risk reduction [95% confidence intervals (CI)] for VTE comparing 40 mg enoxaparin with placebo in the subgroups were: acute heart failure, 0.29 (95% CI, 0.10-0.84); acute respiratory failure, 0.25 (95% CI, 0.10-0.65); acute infectious disease, 0.28 (95% CI, 0.09-0.81); and acute rheumatic disorder, 0.48 (95% CI, 0.11-2.16). The relative risk reduction for VTE in the pre-defined risk factor subgroups were: chronic heart failure, 0.26 (95% CI, 0.08-0.92); chronic respiratory failure, 0.26 (95% CI, 0.10-0.68); age, 0.22 (95% CI, 0.09-0.51); immobility, 0.53 (95% CI, 0.14-1.72); previous VTE, 0.49 (95% CI, 0.15-1.68); and cancer, 0.50 (95%o CI, 0.14-1.72). The beneficial effects of enoxaparin extend to a wide range of acutely ill medical patients.

Venous thromboprophylaxis in acutely ill patients: nursing role

Venous thromboembolism (VTE) is a serious medical problem and is one of the most important preventable causes of mortality and morbidity in hospitalized patients. This article reviews the prevention of VTE with thromboprophylaxis in acutely ill general medical patients. We review recent studies which show that general medical patients are at moderate risk of VTE and that low-molecular-weight heparin reduces this risk. Nurses have a key role to play in changing clinical practice by increasing awareness of the risk of VTE in medical patients, helping in the process of risk assessment and ensuring appropriate prophylaxis.

DVT prophylaxis in the perioperative setting

In last month's BJPB, Agnes Arnold discussed the pathophysiology of deep vein thrombosis and suggested ways that the risk could be reduced, particularly with respect to DVTs resulting from endothelial damage in surgery. In this, the second of a two-part series, Agnes continues by looking at hypercoagulability of blood and venous stasis and the impact of these conditions on the risk of DVT.

DVT prophylaxis in the perioperative setting

This is the first of a two-part article in which Agnes Arnold examines the role of the perioperative nurse in the prophylaxis of lower limb deep vein thrombosis (DVT). This part discusses the pathophysiology of DVT and the methods of assessing an individual's risk of developing the disorder. Part 2, which will appear in the September edition of BJPN, will deal with prophylaxis of DVT. It will critically analyse the research, cost-effectiveness, side-effects and target patient population of each prophylactic regimen.

Venous thromboembolic prophylaxis for transurethral prostatectomy: practice among British urologists

Venous thromboembolism (VTE) is an occasional cause of death after transurethral prostatectomy but there are no established guidelines for its prevention in relation to this operation. We assessed practice in the UK by mailing a questionnaire to 460 consultant members of the British Association of Urological Surgeons. 362 (79%) completed questionnaires were received. 280 of 362 (77%) respondents routinely used VTE prophylaxis with transurethral prostatectomy; 82 (23%) did not. 230 of the 280 urologists who took precautions used mechanical methods; 50 used low dose heparin, either with stockings or alone. This survey indicates that, despite a lack of clear evidence, most British urologists favour some form of precaution against VTE in patients undergoing transurethral prostatectomy.

Pathophysiology of venous thromboembolism

Venous thromboembolism remains an important cause of morbidity and mortality for surgical and non-surgical patients, and its pathophysiology in acutely ill, non-surgical patients is not well understood. The clinically silent nature of thromboembolism makes it a significant threat to hospital patients.

Effective risk stratification of surgical and nonsurgical patients for venous thromboembolic disease

Effective and safe methods of preventing venous thromboembolism (VTE) are now widely available, but a significant proportion of patients develop VTE either because thromboprophylaxis has not been used or because the intensity of thromboprophylaxis is not matched to the level of risk. Thromboembolic risk varies widely according to the clinical setting and presence of underlying risk factors, but VTE may not be suspected even in high-risk patients. Clinical risk factors for VTE include recent surgery, cancer, stroke, previous VTE, immobilization, and advanced age. Recent attention has focused on the role of inherited and acquired molecular factors in determining overall thromboembolic risk. These factors include the classic thrombophilias-deficiencies of antithrombin III, protein C, and protein S-and several newly described molecular risk factors: factor V Leiden, the prothrombin 20210A gene mutation, and hyperhomocysteinemia. Based on emerging knowledge of risk factors, several risk assessment models (RAMs) have been devised that stratify patients according to overall VTE risk, allowing thromboprophylaxis to be tailored appropriately. Compared with older risk assessment formulas, current RAMs are simpler and include specific recommendations for thromboprophylaxis based on the available scientific evidence. Consensus documents on VTE prevention classify patients into low-, moderate-, and high-risk categories. More recently, a new risk group, very high risk, has been described. Very-high-risk patients are especially prone to thromboembolic complications and need intensive and in some cases prolonged thromboprophylaxis.

Benefits of deep-vein thrombosis prophylaxis in the nonsurgical patient: The MEDENOX trial

Venous thromboembolism (VTE) is a common complication of hospitalized patients, imposing a major clinical and economic burden. Three of four cases of fatal pulmonary embolism occur in nonsurgical settings, but thromboprophylaxis is far less common in medical than in surgical patients. This is mainly attributable to the heterogeneity of nonsurgical populations and lack of high-quality evidence to support specific thromboprophylactic measures. The recent Prophylaxis of Venous Thromboembolism in MEDical Patients With ENOXaparin (MEDENOX) trial addressed this deficiency by assessing the need for and the benefit:risk ratio of thromboprophylaxis in a well-defined group of medical patients immobilized with severe illness. The MEDENOX study showed that these patients are at significant risk of VTE. Enoxaparin, 40 mg once daily for 6 to 14 days, reduced the risk of VTE by 63% without increasing adverse events. It is anticipated that data from the MEDENOX study will be incorporated into future consensus guidelines on the prevention of VTE. Further studies are required to assess the benefit:risk ratio of therapy in other clearly-defined medical groups.

Clinical and economic aspects of managing venous thromboembolism in the outpatient setting

Low-molecular-weight heparins (LMWHs) are at least as effective and safe as unfractionated heparin (UFH) in the prevention and initial treatment of venous thromboembolism (VTE), and their fixed-dose, once- or twice-daily dosing regimen without laboratory monitoring makes them suitable for outpatient use. Postoperative thromboprophylaxis usually continues until hospital discharge, but evidence demonstrates that the VTE risk persists for several weeks. Economic pressures, changes in clinical practice, and patient preferences make hospital stays shorter. As a result, outpatient thromboprophylaxis with LMWH has been investigated. LMWH self-administered at home once daily for up to 4 weeks after hospital discharge is safe and well tolerated and significantly reduces the incidence of postdischarge VTE after hip replacement. Targeted appropriately, extended thromboprophylaxis may be cost effective, and the development of an autoinjection device may increase the proportion of patients eligible for home management. LMWHs may also be of value as long-term secondary thromboprophylaxis in patients with contraindications to oral anticoagulants. Standard initial treatment for VTE comprises intravenous UFH administered to the patient in the hospital. However, three large-scale studies have demonstrated the efficacy and safety of outpatient treatment of acute VTE using LMWHs. The economic benefits of shortening or eliminating inpatient therapy are substantial, but successful home treatment requires careful patient selection, intensive education and a comprehensive system of professional support to optimize compliance and safety.

Cost effectiveness of desirudin compared with a low molecular weight heparin in the prevention of deep vein thrombosis after total hip replacement surgery

OBJECTIVES

This prospective pharmacoeconomic study analyses and discusses the cost effectiveness (expressed as cost per life-year gained) of desirudin in comparison with a low molecular weight heparin (LMWH), enoxaparin, as prophylaxis against deep vein thrombosis (DVT) in total hip replacement.

METHODS

The cost effectiveness was analysed on the basis of results from a clinical trial that compared the recombinant hirudin, desirudin, with the LMWH, enoxaparin. The trial results regarding the incidence of DVT are included together with epidemiological data in a decision tree, simulating long term cost effectiveness of patients undergoing elective hip replacement. The model includes Markov processes simulating patients up to the age of 85 years, including the costs of DVT-related long term complications.

RESULTS

The average total thrombosis-related cost per patient under prophylactic therapy with enoxaparin is 7,022 Swedish kronor (SEK) compared with SEK7,497 when using desirudin (1998 values). The total costs with desirudin are 7% higher. Prophylaxis with desirudin in those patients undergoing elective hip replacement surgery adds, on average, 7 days of life per patient when compared with treatment using enoxaparin. This is equivalent to 1.91 additional years of life per 100 patients treated. The incremental cost-effectiveness ratio of prophylaxis with desirudin in patients undergoing elective hip replacement surgery is SEK24,864 per life-year gained in comparison with enoxaparin.

CONCLUSION

The present study demonstrates that prophylactic therapy with desirudin is a cost-effective approach for the prevention of DVT in patients undergoing total hip replacement.

Management of venous and cardiovascular thrombosis: enoxaparin

Enoxaparin has strong clinical evidence that supports its license in a broad spectrum of therapeutic indications, including thromboprophylaxis in surgical patients, medical patients bedridden because of acute illness, the once-daily treatment of venous thromboembolism and the treatment of unstable angina and non-Q wave myocardial infarction.

Thromboprophylaxis in medical patients

Recent clinical studies have confirmed that acutely ill medical patients are at substantial risk of venous thromboembolism, which can be reduced by thromboprophylaxis with low molecular weight heparin. These studies have resulted in approval of a low molecular weight heparin (enoxaparin) for the prophylaxis of venous thromboembolism in medical patients bedridden as a result of acute illness.

Acp. Best practice no 155. Pathological investigation of deaths following surgery, anaesthesia, and medical procedures

The pathological investigation of deaths following surgery, anaesthesia, and medical procedures is discussed. The definition of "postoperative death" is examined and the classification of deaths following procedures detailed. The review of individual cases is described and the overall approach to necropsy and interpretation considered. There are specific sections dealing with the cardiovascular system (including air embolism, perioperative myocardial infarction, cardiac pacemakers, central venous catheters, cardiac surgery, heart valve replacement, angioplasty, and vascular surgery); respiratory system (postoperative pneumonia, pulmonary embolism, pneumothorax); central nervous system (dissection of cervical spinal cord), hepatobiliary and gastrointestinal system; musculoskeletal system; and head and neck region. Deaths associated with anaesthesia are classified and the specific problems of epidural anaesthesia and malignant hyperthermia discussed. The article concludes with a section on the recording of necropsy findings and their communication to clinicians and medicolegal authorities.

Current Clinical Practice: Low-Molecular-Weight Heparins in The Prophylaxis and Treatment of Thrombo-Embolic Disease

Low-Molecular-Weight Heparin (LMWH) fractions are prepared from standard unfractionated heparin (UFH) and are thus similar to it in many aspects. The major advantages of LMWH are improved efficacy and safety, longer half-life and reduced need for laboratory monitoring. In addition, the dangers of UFH administered by continuous infusion in the hospital setting are often not fully appreciated and the necessary monitoring and dosage adjustment poorly carried out resulting in inadequate doses being given. LMWHs are the drug of choice in many clinical situations. Four LMWHs are now licensed in the UK for prophylaxis of venous thrombo-embolism during or after surgery (Certoparin, Dalteparin [Fragmin], Enoxaparin [Lovenox/Clexane] and Tinzaparin [Inno-hep]; a fifth is licensed but not currently available in the UK. Dalteparin, Enoxaparin and Tinzaparin are licensed for the treatment of Deep Vein Thrombosis (DVT), and Tinzaparin additionally for the treatment of Pulmonary Embolism (PE), but so far none is licensed for use in pregnancy or paediatrics.