Duration and magnitude of the postoperative risk of venous thromboembolism in middle aged women: prospective cohort study

Prevention of VTE in nonorthopedic surgical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

VTE is a common cause of preventable death in surgical patients.

METHODS

We developed recommendations for thromboprophylaxis in nonorthopedic surgical patients by using systematic methods as described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines. Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

We describe several alternatives for stratifying the risk of VTE in general and abdominal-pelvic surgical patients. When the risk for VTE is very low (< 0.5%), we recommend that no specific pharmacologic (Grade 1B) or mechanical (Grade 2C) prophylaxis be used other than early ambulation. For patients at low risk for VTE (∼1.5%), we suggest mechanical prophylaxis, preferably with intermittent pneumatic compression (IPC), over no prophylaxis (Grade 2C). For patients at moderate risk for VTE (∼3%) who are not at high risk for major bleeding complications, we suggest low-molecular-weight heparin (LMWH) (Grade 2B), low-dose unfractionated heparin (Grade 2B), or mechanical prophylaxis with IPC (Grade 2C) over no prophylaxis. For patients at high risk for VTE (∼6%) who are not at high risk for major bleeding complications, we recommend pharmacologic prophylaxis with LMWH (Grade 1B) or low-dose unfractionated heparin (Grade 1B) over no prophylaxis. In these patients, we suggest adding mechanical prophylaxis with elastic stockings or IPC to pharmacologic prophylaxis (Grade 2C). For patients at high risk for VTE undergoing abdominal or pelvic surgery for cancer, we recommend extended-duration, postoperative, pharmacologic prophylaxis (4 weeks) with LMWH over limited-duration prophylaxis (Grade 1B). For patients at moderate to high risk for VTE who are at high risk for major bleeding complications or those in whom the consequences of bleeding are believed to be particularly severe, we suggest use of mechanical prophylaxis, preferably with IPC, over no prophylaxis until the risk of bleeding diminishes and pharmacologic prophylaxis may be initiated (Grade 2C). For patients in all risk groups, we suggest that an inferior vena cava filter not be used for primary VTE prevention (Grade 2C) and that surveillance with venous compression ultrasonography should not be performed (Grade 2C). We developed similar recommendations for other nonorthopedic surgical populations.

CONCLUSIONS

Optimal thromboprophylaxis in nonorthopedic surgical patients will consider the risks of VTE and bleeding complications as well as the values and preferences of individual patients.

Stratifying the risk of venous thromboembolism in otolaryngology

OBJECTIVE

The consequences of perioperative venous thromboembolism (VTE) are devastating; identifying patients at risk is an essential step in reducing morbidity and mortality. The utility of perioperative VTE risk assessment in otolaryngology is unknown. This study was designed to risk-stratify a diverse population of otolaryngology patients for VTE events.

STUDY DESIGN

Retrospective cohort study.

SETTING

Single-institution academic tertiary care medical center.

SUBJECTS AND METHODS

Adult patients presenting for otolaryngologic surgery requiring hospital admission from 2003 to 2010 who did not receive VTE chemoprophylaxis were included. The Caprini risk assessment was retrospectively scored via a validated method of electronic chart abstraction. Primary study variables were Caprini risk scores and the incidence of perioperative venous thromboembolic outcomes.

RESULTS

A total of 2016 patients were identified. The overall 30-day rate of VTE was 1.3%. The incidence of VTE in patients with a Caprini risk score of 6 or less was 0.5%. For patients with scores of 7 or 8, the incidence was 2.4%. Patients with a Caprini risk score greater than 8 had an 18.3% incidence of VTE and were significantly more likely to develop a VTE when compared to patients with a Caprini risk score less than 8 (P < .001). The mean risk score for patients with VTE (7.4) was significantly higher than the risk score for patients without VTE (4.8) (P < .001).

CONCLUSION

The Caprini risk assessment model effectively risk-stratifies otolaryngology patients for 30-day VTE events and allows otolaryngologists to identify patient subgroups who have a higher risk of VTE in the absence of chemoprophylaxis.

Complications following anterior cruciate ligament reconstruction in the English NHS

Unlike the English National Joint Registry (NJR) for arthroplasty, no surgeon driven national database currently exists for ligament surgery in England. Therefore information on outcome and adverse events following anterior cruciate ligament (ACL) surgery is limited to case series. This restricts the ability to make formal recommendations upon surgical care. Prospectively collected data, which is routinely collected on every NHS patient admitted to hospital in England, was analysed to determine national rates of 90-day symptomatic deep venous thrombosis (DVT), pulmonary thromboembolism (PTE) rate, 30-day wound infection and readmission rates following primary ACL reconstruction between March 2008 and February 2010 (13,941 operations, annual incidence 13.5 per 100,000 English population). 90-day DVT and PTE rates were 0.30% (42) and 0.18% (25) respectively. There were no in-hospital deaths. 0.75% (104) of the consecutive patient cohort had a wound complication recorded. 0.25% (35) underwent a further procedure to wash out the infected knee joint and 1.36% (190) were readmitted to an orthopaedic ward within 30days. This is the first national comprehensive study of the incidence of significant complications following ACL surgery in England. This should allow meaningful interpretation of future baseline data supporting the development of a national ligament registry.

Postoperative enoxaparin prevents symptomatic venous thromboembolism in high-risk plastic surgery patients

BACKGROUND

Venous thromboembolism is a major patient safety issue. The Plastic Surgery Foundation-sponsored Venous Thromboembolism Prevention Study examined whether postoperative enoxaparin prevents symptomatic venous thromboembolism in adult plastic surgery patients.

METHODS

In 2009, four sites uniformly adopted a clinical protocol. Patients with a Caprini score of 3 or higher received postoperative enoxaparin prophylaxis for the duration of inpatient stay. Venous Thromboembolism Prevention Study historical control patients had an operation between 2006 and 2008 but received no chemoprophylaxis for 60 days after surgery. The primary study outcome was symptomatic 60-day venous thromboembolism.

RESULTS

Three thousand three hundred thirty-four patients (1876 controls and 1458 enoxaparin patients) were included. Notable risk reduction was present in patients with a Caprini score greater than 8 (8.54 percent versus 4.07 percent; p=0.182) and a Caprini score of 7 to 8 (2.55 percent versus 1.15 percent; p=0.230) who received postoperative enoxaparin. Logistic regression was limited to highest risk patients (Caprini score≥7) and demonstrated that length of stay greater than or equal to 4 days (adjusted odds ratio, 4.63; p=0.007) and Caprini score greater than 8 (odds ratio, 2.71; p=0.027) were independent predictors of venous thromboembolism. When controlling for length of stay and Caprini score, receipt of postoperative enoxaparin was protective against venous thromboembolism (odds ratio, 0.39; p=0.042).

CONCLUSIONS

In high-risk plastic surgery patients, postoperative enoxaparin prophylaxis is protective against 60-day venous thromboembolism when controlling for baseline risk and length of stay. Hospitalization for 4 or more days is an independent risk factor for venous thromboembolism.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, III.

Prophylaxis of venous thromboembolism in general surgery: guidelines differ and we still need local policies

INTRODUCTION

Venous thromboembolism (VTE) prophylaxis has become a major issue for surgeons both in the UK and worldwide. Several different sources of guidance on VTE prophylaxis are available but these differ in design and detail.

METHODS

Two similar audits were performed, one year apart, on the VTE prophylaxis prescribed for all general surgical inpatients during a single week (90 patients and 101 patients). Classification of patients into different risk groups and compliance in prescribing prophylaxis were examined using different international, national and local guidelines.

RESULTS

There were significant differences between the numbers of patients in high, moderate and low-risk groups according to the different guidelines. When groups were combined to indicate simply 'at risk' or 'not at risk' (in the manner of one of the guidelines), then differences were not significant. Our compliance improved from the first audit to the second. Patients at high risk received VTE prophylaxis according to guidance more consistently than those at low risk.

CONCLUSIONS

Differences in guidance on VTE prophylaxis can affect compliance significantly when auditing practice, depending on the choice of 'gold standard'. National guidance does not remove the need for clear and detailed local policies. Making decisions about policies for lower-risk patients can be more difficult than for those at high risk.

Risks and benefits of thoracic epidural anaesthesia

Thoracic epidural anaesthesia (TEA) reduces cardiac and splanchnic sympathetic activity and thereby influences perioperative function of vital organ systems. A recent meta-analysis suggested that TEA decreased postoperative cardiac morbidity and mortality. TEA appears to ameliorate gut injury in major surgery as long as the systemic haemodynamic effects of TEA are adequately controlled. The functional benefit in fast-track and laparoscopic surgery needs to be clarified. Better pain control with TEA is established in a wide range of surgical procedures. In a setting of advanced surgical techniques, fast-track regimens and a low overall event rate, the number needed to treat to prevent one death by TEA is high. The risk of harm by TEA is even lower, and other methods used to control perioperative pain and stress response also carry specific risks. To optimize the risk-benefit balance of TEA, safe time intervals regarding the use of concomitant anticoagulants and consideration of reduced renal function impairing their elimination must be observed. Infection is a rare complication and is associated with better prognosis. Close monitoring and a predefined algorithm for the diagnosis and treatment of spinal compression or infection are crucial to ensure patient safety with TEA. The risk-benefit balance of analgesia by TEA is favourable and should foster clinical use.

Are we missing post-thrombotic syndrome syndrome? An orthopaedic perspective in lower limb arthroplasty

2-5% of patients undergoing hip or knee arthroplasty develop a symptomatic DVT; there is evidence to suggest that without prophylaxis 40-60% of patients have a subclinical DVT. This can be reduced by around half with appropriate thromboprophylaxis; there still remains a significant incidence of subclinical DVT. Therefore, it is important to know, as orthopaedic surgeons, if our patients undergoing large joint arthroplasty are being adversely affected. Post-thrombotic syndrome (PTS) is usually associated with symptomatic DVT, and the purpose of this paper is to address if asymptomatic DVT is also associated with an increased risk of PTS. The majority of evidence gathered does not support a link; therefore, there is no evidence to warrant a change in practice to warn patients of a potential risk or to routinely screen asymptomatic patients.

Perioperative pharmacologic prophylaxis for venous thromboembolism in colorectal surgery

BACKGROUND

To determine the effectiveness of pharmacologic prophylaxis in preventing clinically relevant venous thromboembolic (VTE) events and deaths after surgery. The Surgical Care Improvement Project recommends that VTE pharmacologic prophylaxis be given within 24 hours of the operation. The bulk of evidence supporting this recommendation uses radiographic end points.

STUDY DESIGN

The Surgical Care and Outcomes Assessment Program is a Washington State quality improvement initiative with data linked to hospital admission/discharge and vital status records. We compared the rates of death, clinically relevant VTE, and a composite adverse event (CAE) in the 90 days after elective, colon/rectal resections, based on receipt of pharmacologic prophylaxis (within 24 hours of surgery) at 36 Surgical Care and Outcomes Assessment Program hospitals (2005-2009).

RESULTS

Of 4,195 (mean age 61.1 ± 15.6 years; 54.1% women) patients, 56.5% received pharmacologic prophylaxis. Ninety-day death (2.5% vs 1.6%; p = 0.03), VTE (1.8% vs 1.1%; p = 0.04), and CAE (4.2% vs 2.5%; p = .002) were lower in those who received pharmacologic prophylaxis. After adjustment for patient and procedure characteristics, the odds were 36% lower for CAE (odds ratio = 0.64; 95% CI, 0.44-0.93) with pharmacologic prophylaxis. In any given quarter, hospitals where patients more often received pharmacologic prophylaxis (highest tertile of use) had the lowest rates of CAE (2.3% vs 3.6%; p = 0.05) compared with hospitals in the lowest tertile.

CONCLUSIONS

Using clinical end points, this study demonstrates the effectiveness of VTE pharmacologic prophylaxis in patients having elective colorectal surgery. Hospitals that used pharmacologic prophylaxis more often had the lowest rates of adverse events.

Venous thromboembolism prophylaxis after hospital discharge: transition to preventive care

Deep vein thrombosis and pulmonary embolism, the common clinical manifestations of venous thromboembolism (VTE), are among the most preventable complications of hospitalized patients. However, survey data repeatedly show poor rates of compliance with guideline-based preventive strategies. This has led the Centers for Medicare and Medicaid Services to deny reimbursement for hospital readmission for thromboembolic complications in patients undergoing total hip or knee arthroplasty. Multiple strategies and national initiatives have been developed to improve rates of VTE prophylaxis during hospitalization; however, most VTE occurs in the outpatient setting. Epidemiologic data suggest that recent surgery or hospitalization is a strong risk factor for the development of VTE and that this risk may persist for up to 6 months. These observations call into question whether VTE prophylaxis should be administered only during hospitalization or if this preventive strategy should be continued after hospital discharge. Many of the randomized trials showing efficacy of VTE prophylaxis have used longer durations of prophylaxis than are typical for current length of hospital stay, highlighting the issue of how long the duration of prophylaxis should be. Several patient groups have undergone formal testing to evaluate the risks and benefits of extended-duration VTE prophylaxis, but this issue is less clear for other categories of patients. Although there is clear consensus that most hospitalized patients should receive VTE prophylaxis, there is uncertainty about whether to continue VTE prophylaxis in the immediate post-hospital period or for an extended duration. The transition from inpatient to outpatient care is a key event in the coordination of continuity of care, but VTE-specific care transition guidance is limited. In this article, we review the evidence for both standard- and extended-duration VTE prophylaxis and discuss the difficulties in effectively maintaining VTE prophylaxis during the transition from inpatient to outpatient care.

Venous thromboembolic events are rare after shoulder surgery: analysis of a national database

BACKGROUND

Data on venous thromboembolic (VTE) events after different types of shoulder surgery have not previously been available in large numbers in the United Kingdom. We aimed to determine baseline postoperative complication rates with reference to national thromboembolic prophylaxis guidelines.

METHODS

Diagnostic and operative codes are routinely collected on every patient admitted to the hospital in the English NHS. Data for a 42-month period were analyzed for planned shoulder surgery (total replacement, hemiarthroplasty, or arthroscopy) and proximal humeral fracture surgery (internal fixation or replacement). In addition, complications during the two 6-month periods before and after the implementation of national thromboprophylaxis guidelines were compared. Rates of symptomatic deep venous thrombosis, pulmonary embolism, and mortality within 90 days were extracted.

RESULTS

For total shoulder replacement (4,061 patients), deep venous thrombosis, pulmonary embolism, and mortality rates were 0%, 0.20%, and 0.22%, respectively. For arthroscopic procedures (65,302 patients), the rates were less than 0.01%, 0.01%, and 0.03%, respectively. For proximal humeral fracture surgery (internal fixation or replacement, 4,696 patients), the rates were 0.19%, 0.40%, and 3.02%, respectively. There was no significant difference in the VTE event or mortality rates before and after the introduction of the 2007 National Institute for Health and Clinical Excellence guidelines after arthroscopy or proximal humeral fracture surgery. A statistically significant decrease in total shoulder replacement-related mortality was found, from 0.72% (5 patients) to 0%.

DISCUSSION

VTE disease is not a significant problem after shoulder surgery, and thromboprophylaxis may not be required, even in high-risk patients. National thromboprophylaxis guidelines did not affect VTE event rates.

Identification of patient venous thromboembolism risk across the continuum of care

Venous thromboembolism (VTE) complications are the leading cause of preventable in-hospital mortality and morbidity in the United States. Initiatives by the National Quality Forum, the Joint Commission, and the Surgical Care Improvement Project aim to improve the prevention of VTE and emphasize the need to recognize the risk of the condition in hospitalized patients. In clinical practice, individual risk assessment using a validated scoring system provides patients with the best care in the prevention of VTE. This is accomplished by a weighted scoring of risk factors, selection of the most appropriate prevention strategy for patients at risk, and regular risk review across the continuum of care. All hospitals should have a local, written, care pathway which assesses inpatient risk of VTE as early as possible upon admission and identifies members of the health care team responsible for applying risk assessment. Venous thromboembolism risk should be regularly reassessed for any changes in the level of risk, with extended out-of-hospital prophylaxis considered for patients with continued risk factors, such as prolonged immobility or illness, treated at home, or in a long-term care facility. Finally, a mandatory alert system requiring the clinician to address the issue of prophylaxis before any orders are carried out by the nursing staff is one way to protect all hospitalized patients.

Temporal changes in deep venous thrombosis risk after electrical injury

Previous work has used the National Burn Repository to examine deep venous thrombosis (DVT) after electrical injury. However, these studies were limited and could not examine when DVT occurs after electrical injury. In addition, the utility of risk assessment models for DVT risk stratification has not been examined in this patient population. The authors performed a retrospective chart review of electrically injured patients at a single, American Burn Association- and American College of Surgeons-verified burn center over a 9-year period. Risk factors were identified and used to calculate Caprini scores at baseline and time of discharge. Outcomes of interest included symptomatic DVT or pulmonary embolism and time to DVT or pulmonary embolism. A total of 77 electrically injured patients were identified. DVT incidence was 6.5%. Patients with DVT had significantly higher TBSA (27.8% vs 3.8%), mean number of operations (4.8 vs 0.3), central venous catheter insertion (100% vs 5.3%), ventilator days (16.2 vs 0.3), intensive care unit days (24.4 vs 0.9), and mean change in Caprini score (18.6 vs 1.3) during hospitalization. Baseline Caprini scores were low, and DVT events occurred only after multiple risk factors were present; the average time-to-event was hospital day 17. Among patients with Caprini score >8, DVT incidence increased to 62%. In our single-center experience, the Caprini score was able to quantify DVT risk after electrical injury. In our series of 77 patients, the overall incidence of DVT was 6.5%. However, among patients whose Caprini score reached >8 during hospitalization, DVT incidence increased to 62%.

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.

Defining higher-risk surgery

PURPOSE OF REVIEW

Defining the contemporary high-risk noncardiac surgical population using objective clinical outcomes data is paramount for the rational allocation of healthcare resources, truly informed patient consent and improving patient-centered outcomes.

RECENT FINDINGS

Data from independent healthcare systems have identified that the development, and consequences, of postoperative morbidity extend beyond the immediate postoperative hospital period and confer substantially increased risk of death. Cardiac insufficiency, rather than the relatively heavily explored paradigm of perioperative cardiac ischemia, is emerging as the dominant factor associated with excess risk of prolonged postoperative morbidity. The development of prospective, validated, time-sensitive morbidity data collection tools has also helped define patients at higher risk of noncardiac morbidities and short-term perioperative outcomes.

SUMMARY

Higher risk surgical patients present an increasingly major challenge for healthcare resource utilization. Detailed outcome studies using validated morbidity tools are urgently required to establish the extent to which postoperative morbidity may be predicted. Robust identification of patients at the highest risk of perioperative morbidity may permit further clinic-to-bench translational understanding of the pathophysiologic mechanisms underlying postoperative organ dysfunction. Defining the high-risk surgical patient population is as critically important for global public health planning as it is for the perioperative team.

Recent respiratory infection and risk of venous thromboembolism: case-control study through a general practice database

Background The association between respiratory infection and risk of heart attacks and strokes is well established. However, less evidence exists for an association between respiratory infection and venous thromboembolism (VTE). In this article, we describe the associations between respiratory infection and VTE.

Methods All cases aged ≥18 years of first-time diagnosis of deep-vein thrombosis (DVT) or pulmonary embolism (PE) were identified together with single-matched controls from a primary care general practice database. In addition to the matching characteristics, information was collected on other potentially important confounding factors.

Results There were 457/11 557 (4.0%) DVT cases with respiratory infection in the year before the index date (73 in the preceding month) compared with 262/11 557 (2.3%) controls (24 in the preceding month). There was an increased risk of DVT in the month following infection [adjusted odds ratio (OR) = 2.64, 95% confidence interval (95% CI) 1.62–4.29] which persisted up to a year. There were 180/5162 (3.5%) PE cases with respiratory infection in the year before the index date compared with 94/5162 (1.8%) controls excluding those in the preceding month to avoid the possible misdiagnosis of early PE. There was an increased risk of PE in the 3 months following infection (adjusted OR = 2.50, 95% CI 1.33–4.72) which may have persisted up to a year.

Conclusions There are strong associations between recent respiratory infection and VTE. There should be less distinction between venous and arterial events in decisions about preventing or aborting infections, especially in high-risk patients.

Evidence-based review of enhancing postoperative recovery after breast surgery

BACKGROUND

The introduction of enhanced recovery after surgery (ERAS) protocols has revolutionized preoperative and postoperative care. To date, however, the principles of enhanced recovery have not been applied specifically to patients undergoing breast surgery.

METHODS

Based on the core features of ERAS, individual aspects of postoperative care in breast surgery were defined. A comprehensive search of MEDLINE, PubMed, Embase and the Cochrane Library database was performed from 1980 to 2010 to determine the best evidence for perioperative care in oncological breast surgery. A graded recommendation based on the best level of evidence was then proposed for each feature of ERAS.

RESULTS

Twelve core features of enhanced recovery after breast surgery were identified. Use of the thoracic block, from both analgesic and anaesthetic viewpoints, is well supported by evidence and should be encouraged. Trials specific to breast surgery regarding aspects such as perioperative fasting, preanaesthetic medication, prevention of hypothermia and postdischarge support are scarce, and evidence was extrapolated from non-breast trials. Trials on postoperative analgesia and prevention of postoperative nausea and vomiting in breast surgery are generally of small numbers. In addition, there is heterogeneity between studies.

CONCLUSION

This review suggests that the principles of enhanced recovery can be adopted in breast surgery. A 12-point protocol is proposed for prospective evaluation.

Prevention of VTE in women with cancer

The prevention of venous thromboembolism (VTE) in women with cancer requires special consideration. The presence of cancer results in both non-surgical and surgical patients having increased risk of VTE. This usually leads to a modification of the recommended preventive therapy, affecting the type, dose and length of therapy. Cancer patients have other factors which may predispose them to bleeding. Prevention of VTE in cancer patients is important in a number of settings and has been investigated in many of these. These can be broadly classified into three areas: (1) Non-surgical patients in hospital and outpatient care: (1.1) Acutely ill medical patients with incidental cancer or with complications related to cancer; (1.2) Cancer patients receiving therapy--chemotherapy, hormonal therapy, radiotherapy. (2) Surgical care: (2.1) Surgical procedures for cancer therapy; (2.2) Surgical procedures for non-cancer indications in cancer patients. (3) Long-term prevention of VTE in otherwise well outpatients with cancer and its effect on mortality.

Oral dabigatran versus enoxaparin for thromboprophylaxis after primary total hip arthroplasty (RE-NOVATE II*). A randomised, double-blind, non-inferiority trial

This trial compared the efficacy and safety of oral dabigatran, a direct thrombin inhibitor, versus subcutaneous enoxaparin for extended thromboprophylaxis in patients undergoing total hip arthroplasty. A total of 2,055 patients were randomised to 28-35 days treatment with oral dabigatran, 220 mg once-daily, starting with a half-dose 1-4 hours after surgery, or subcutaneous enoxaparin 40 mg once-daily, starting the evening before surgery. The primary efficacy outcome was a composite of total venous thromboembolism [VTE] (venographic or symptomatic) and death from all-causes. The main secondary composite outcome was major VTE (proximal deep-vein thrombosis or non-fatal pulmonary embolism) plus VTE-related death. The main safety outcome was major bleeding. In total, 2,013 were treated, of whom 1,577 operated patients were included in the primary efficacy analysis. The primary efficacy outcome occurred in 7.7% of the dabigatran group versus 8.8% of the enoxaparin group, risk difference (RD) -1.1% (95%CI -3.8 to 1.6%); p<0.0001 for the pre-specified non-inferiority margin. Major VTE plus VTE-related death occurred in 2.2% of the dabigatran group versus 4.2% of the enoxaparin group, RD -1.9% (-3.6% to -0.2%); p=0.03. Major bleeding occurred in 1.4% of the dabigatran group and 0.9% of the enoxaparin group (p=0.40). The incidence of adverse events, including liver enzyme elevations and cardiac events, during treatment was similar between the groups. Extended prophylaxis with oral dabigatran 220 mg once-daily was as effective as subcutaneous enoxaparin 40 mg once-daily in reducing the risk of VTE after total hip arthroplasty, and superior to enoxaparin for reducing the risk of major VTE. The risk of bleeding and safety profiles were similar.

Risk of venous thromboembolism in people admitted to hospital with selected immune-mediated diseases: record-linkage study

BACKGROUND

Venous thromboembolism (VTE) is a common complication during and after a hospital admission. Although it is mainly considered a complication of surgery, it often occurs in people who have not undergone surgery, with recent evidence suggesting that immune-mediated diseases may play a role in VTE risk. We, therefore, decided to study the risk of deep vein thrombosis (DVT) and pulmonary embolism (PE) in people admitted to hospital with a range of immune-mediated diseases.

METHODS

We analysed databases of linked statistical records of hospital admissions and death certificates for the Oxford Record Linkage Study area (ORLS1:1968 to 1998 and ORLS2:1999 to 2008) and the whole of England (1999 to 2008). Rate ratios for VTE were determined, comparing immune-mediated disease cohorts with comparison cohorts.

RESULTS

Significantly elevated risks of VTE were found, in all three populations studied, in people with a hospital record of admission for autoimmune haemolytic anaemia, chronic active hepatitis, dermatomyositis/polymyositis, type 1 diabetes mellitus, multiple sclerosis, myasthenia gravis, myxoedema, pemphigus/pemphigoid, polyarteritis nodosa, psoriasis, rheumatoid arthritis, Sjogren's syndrome, and systemic lupus erythematosus. Rate ratios were considerably higher for some of these diseases than others: for example, for systemic lupus erythematosus the rate ratios were 3.61 (2.36 to 5.31) in the ORLS1 population, 4.60 (3.19 to 6.43) in ORLS2 and 3.71 (3.43 to 4.02) in the England dataset.

CONCLUSIONS

People admitted to hospital with immune-mediated diseases may be at an increased risk of subsequent VTE. Our findings need independent confirmation or refutation; but, if confirmed, there may be a role for thromboprophylaxis in some patients with these diseases.

Validation of the Caprini risk assessment model in plastic and reconstructive surgery patients

BACKGROUND

The Venous Thromboembolism Prevention Study (VTEPS) Network is a consortium of 5 tertiary referral centers established to examine venous thromboembolism (VTE) in plastic surgery patients. We report our midterm analyses of the study's control group to evaluate the incidence of VTE in patients who receive no chemoprophylaxis, and validate the Caprini Risk Assessment Model (RAM) in plastic surgery patients.

STUDY DESIGN

Medical record review was performed at VTEPS centers for all eligible plastic surgery patients between March 2006 and June 2009. Inclusion criteria were Caprini score ≥3, surgery under general anesthesia, and postoperative hospital admission. Patients who received chemoprophylaxis were excluded. Dependent variables included symptomatic deep vein thrombosis (DVT) or pulmonary embolism (PE) within the first 60 postoperative days and time to DVT or PE.

RESULTS

We identified 1,126 historic control patients. The overall VTE incidence was 1.69%. Approximately 1 in 9 (11.3%) patients with Caprini score >8 had a VTE event. Patients with Caprini score >8 were significantly more likely to develop VTE when compared with patients with Caprini score of 3 to 4 (odds ratio [OR] 20.9, p < 0.001), 5 to 6 (OR 9.9, p < 0.001), or 7 to 8 (OR 4.6, p = 0.015). Among patients with Caprini score 7 to 8 or Caprini score >8, VTE risk was not limited to the immediate postoperative period (postoperative days 1-14). In these high-risk patients, more than 50% of VTE events were diagnosed in the late (days 15-60) postoperative period.

CONCLUSIONS

The Caprini RAM effectively risk-stratifies plastic and reconstructive surgery patients for VTE risk. Among patients with Caprini score >8, 11.3% have a postoperative VTE when chemoprophylaxis is not provided. In higher risk patients, there was no evidence that VTE risk is limited to the immediate postoperative period.

Does using the WHO surgical checklist improve compliance to venous thromboembolism prophylaxis guidelines?

BACKGROUND

Using the World Health Organisation (WHO) surgical checklist has been shown to improve the safety of patients undergoing surgery. Its effect on the compliance to venous thromboembolism (VTE) guidelines has not been established before. Our objective was to assess if using the WHO checklist improved compliance to VTE prophylaxis guidelines.

METHODS

Compliance to NICE VTE guidelines were prospectively assessed in all general surgery patients over two separate audit periods, before and after 6 months of the routine use of the WHO checklist. Correct completion of the checklist was verified.

RESULTS

370 patients (173 [47%] male, 197 [53%] female, mean age 61.6 yrs). Non compliance to NICE VTE guidelines was reduced form 16/233 (6.9%) to 3/137 (2.1%) after introduction of the checklist (p = 0.046 Fisher exact test). Non compliance was reduced in both emergency and elective procedures.

CONCLUSIONS

Establishment of the WHO checklist for routine use in all general surgery patients may significantly improve VTE guideline compliance of all general surgery patients.

Prolonged and increased postoperative risk of venous thromboembolism: rationale for even more 'extended' prophylaxis?

It is well known that the risk of venous thromboembolism is increased after surgery; however, specific data on how long this risk lasts or how the risk varies by type of surgery is limited. The Million Women Study is a population-based prospective study that recruited 1.3 million women through the National Health Service breast screening program. This study used data from the Million Women Study to examine the magnitude and the duration of the risk of venous thromboembolism after different types of surgery with a mean follow-up duration of 6.2 years. The risk was found to be higher and longer lasting than previously thought, with considerable variation among different types of surgery; therefore, raising important questions regarding the optimal duration of prophylaxis.

Risk of deep venous thrombosis and pulmonary embolism in urogynecologic surgical patients

OBJECTIVE

We sought to determine the incidence of symptomatic deep venous thrombosis and pulmonary embolism, collectively referred to as venous thromboembolic events (VTE), in patients undergoing urogynecologic surgery to guide development of a VTE prophylaxis policy for this patient population.

STUDY DESIGN

We conducted a retrospective analysis of VTE incidence among women undergoing urogynecologic surgery over a 3-year period. All patients wore sequential compression devices intraoperatively through hospital discharge.

RESULTS

Forty of 1104 patients (3.6%) undergoing urogynecologic surgery were evaluated with chest computed tomography, lower extremity ultrasound, or both for suspicion of VTE postoperatively. The overall rate of venous thromboembolism in this population was 0.3% (95% confidence interval, 0.1-0.8).

CONCLUSION

Most women undergoing incontinence and reconstructive pelvic surgery are at a low risk for VTE. Sequential compression devices appear to provide adequate VTE prophylaxis in this patient population.

Enoxaparin Versus Dabigatran or Rivaroxaban for Thromboprophylaxis After Hip or Knee Arthroplasty

Background—

Dabigatran and rivaroxaban are novel oral anticoagulants approved for prevention of venous thromboembolism after hip or knee arthroplasty. However, information assessing clinically important efficacy and bleeding outcomes of these 2 new agents versus low-molecular-weight heparin (enoxaparin) is lacking.

Methods and Results—

We separately pooled efficacy and safety data from 6 phase III randomized trials (18 405 participants) comparing equivalent durations of treatment with enoxaparin (40 mg once daily [od] or 30 mg twice daily) versus dabigatran (220 mg od) or versus rivaroxaban (10 mg od) after hip or knee arthroplasty. Odds ratios (OR) for individual outcomes were calculated for each trial and were pooled using the Mantel-Haenszel method. Compared with dabigatran, enoxaparin had a similar risk of symptomatic venous thromboembolism plus all-cause mortality (0.9% versus 1.1%; OR, 0.76; 95% confidence interval [CI], 0.44 to 1.31; I 2 =76%) and bleeding (5.0% versus 5.6%; OR, 0.90; 95% CI, 0.71 to 1.15; I 2 =0%). Compared with rivaroxaban, enoxaparin had a 2-fold higher risk of symptomatic venous thromboembolism plus all-cause mortality (1.2% versus 0.6%; OR, 2.04; 95% CI, 1.32 to 3.17; P <0.001; number needed to treat, 167; I 2 =0%) but demonstrated a significant lower risk of bleeding (2.5% versus 3.1%; OR, 0.79; 95% CI, 0.62 to 0.99; P =0.049; number needed to harm, 167; I 2 =0%).

Conclusions—

In patients undergoing hip or knee arthroplasty, enoxaparin and dabigatran showed similar rates of efficacy and bleeding. Enoxaparin was less effective than rivaroxaban but had a lower risk of bleeding. These results may have important implications for the choice of prophylactic agent in major joint arthroplasty.

Venous thromboembolism risk factor assessment and prophylaxis

Venous thromboembolism is a common and potentially preventable disease in hospitalized patients. Risk assessment and prophylaxis is also an important quality of care measure. Herein, we discuss the negative impact of VTE on surgical patients, review the risk factors for VTE, the risk assessment tools, available prophylaxis, and then summarize the use of biomarkers for VTE diagnosis.

Clinical burden of venous thromboembolism

BACKGROUND

Venous thromboembolism (VTE), which includes deep vein thrombosis and pulmonary embolism (PE), is a major cause of morbidity and mortality. VTE is a common disorder, with an estimated annual incidence of approximately 5-12 persons per 10,000. The prognosis for patients who develop VTE is exacerbated by the risk of recurrent VTE, post-thrombotic syndrome and chronic pulmonary hypertension as a long-term complication of PE.

SCOPE

To assess the clinical burden of VTE a literature search was carried out to identify references published between 1997 and 2008 using Medline, the Cochrane Library and the Health Economic Evaluations Database.

FINDINGS

VTE is a frequent clinical problem, both in the general population, in hospitalised patients and in particular in patients undergoing major orthopaedic surgery, after trauma, or those with malignancy, and related complications are frequent. VTE imposes significant consequences on patients and on the healthcare systems that support them - extending hospital stays and precipitating additional hospitalisations. Limitations of the review are that the sources quoted may not adequately reflect all publications and all perspectives on the topic.

CONCLUSIONS

Even among high-risk groups it is not possible to identify individuals who will go on to develop VTE, and, therefore, thromboprophylaxis is a recommended component of the management of high-risk patients. Ensuring patients receive safe, effective, easily administered antithrombotic therapy both in hospital and post-discharge, for a sufficient length of time, should be central to any strategy to reduce incident or recurrent VTE and minimise the risk of long-term complications.

Elastic compression stockings for prevention of deep vein thrombosis

BACKGROUND

One of the settings where deep vein thrombosis (DVT) in the lower limb and pelvic veins occurs is in hospital with prolonged immobilisation of patients for various surgical and medical illnesses. Using graduated compression stockings (GCS) in these patients has been proposed to decrease the risk of DVT. This is an update of a Cochrane review first published in 2000 and updated in 2003.

OBJECTIVES

To determine the magnitude of effectiveness of GCS in preventing DVT in various groups of hospitalised patients.

SEARCH STRATEGY

For this update the Cochrane Peripheral Vascular Diseases Group searched their Specialised Register and the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, Issue 4) for randomised controlled trials of elastic or graduated compression stockings for prevention of DVT.

SELECTION CRITERIA

Randomised controlled trials (RCTs) involving GCS alone; or GCS used on a background of any other DVT prophylactic method.

DATA COLLECTION AND ANALYSIS

One author extracted the data, assessed the quality of trials and analysed the results; which were cross-checked and authenticated by a second author.

MAIN RESULTS

Eighteen RCTs were identified. GCS were applied on the day before surgery or on the day of surgery and were worn up until discharge or until the patients were fully mobile. In the majority of the included studies DVT was identified by the radioactive I(125) uptake test.For GCS alone, eight RCTs were identified involving 1279 analytic units (887 patients). In the treatment group (GCS), of 662 units, 86 developed DVT (13%) in comparison to the control group (without GCS) of 617 units where 161 (26%) developed DVT. The Peto's odds ratio (OR) was 0.35 (95% confidence interval (CI) 0.26 to 0.47) with an overall effect favouring treatment with GCS (P < 0.00001). For GCS on a background of another prophylactic method, 10 RCTs were identified involving 1248 analytic units (576 patients). In the treatment group (GCS plus another method), of 621 units, 26 (4%) developed DVT, in the control group (the other method alone), of 627 units, 99 (16%) developed DVT (OR 0.25, 95% CI 0.17 to 0.36). The overall effect also favoured treatment with GCS on a background of another DVT prophylactic method (P < 0.00001).

AUTHORS' CONCLUSIONS

GCS are effective in diminishing the risk of DVT in hospitalised patients. Data examination also suggests that GCS on a background of another method of prophylaxis is more effective than GCS on its own.

Post-operative thromboprophylaxis: new oral thrombin and factor X inhibitors and their place in clinical practice

Thromboprophylaxis can reduce the incidence of postoperative thromboembolic events by two-thirds. Traditionally, unfractionated heparin, low-molecular-weight heparins, vitamin K antagonists, and mechanical methods have been used. Recently, thrombin and factor Xa (FXa) antagonists have been introduced in clinical practice. Advantages are oral administration, potentially higher efficacy in reducing thromboembolic events without increasing major bleeding, and no need for monitoring of the anticoagulatory effect. So far these drugs have mainly been tested after total hip and knee arthroplasties. However, data after most other orthopedic and surgical procedures are sparse. In special populations - for example, patients with renal failure - these drugs have not been sufficiently tested yet. Accordingly, the clinical use of these promising new drugs should be restricted to situations where efficacy has been proven with clear evidence from controlled clinical trials.

Defining the population in need of thromboprophylaxis - making hospitals safer

Venous thromboembolism in adults is related to recent hospitalisation in approximately half of all cases and approximately half of all hospitalised adult patients are considered to be at risk by conventional criteria. Due to advances in surgical practice, the identification of surgical patients in need of prophylaxis has become less rather than more certain. Faster surgical technique, regional anaesthesia and early mobilisation are considered to reduce the risk of venous thromboembolism and hence possibly obviate the need for prophylaxis after early discharge from hospital. An increasing proportion of patients with hospital-acquired venous thromboembolism are medical patients, but the need to identify medical patients that require thromboprophylaxis is a new aspect of clinical practice for many physicians and prophylaxis remains under-utilised in non-surgical hospitalised patients. In this review prevention of hospital-acquired venous thromboembolism is considered as a patient safety issue in the context of changing clinical practice. Strategies for refining and validating risk assessment models and evaluating the effect of risk assessment and thromboprophylaxis are suggested.

Thrombosis in cancer: an update on prevention, treatment, and survival benefits of anticoagulants

Thromboembolism is a common, complex, and costly complication in patients with cancer. Management has changed significantly in the past decade, but remains firmly dependent on the use of anticoagulants. Low-molecular-weight heparin is the preferred anticoagulant for prevention and treatment, although its limitations open opportunities for newer oral antithrombotic agents to further simplify therapy. Multiple clinical questions remain, and research is focusing on identifying high-risk patients who might benefit from primary thromboprophylaxis, treatment options for those with established or recurrent thrombosis, and the potential antineoplastic effects of anticoagulants. Risk-assessment models, targeted prophylaxis, anticoagulant dose escalation for treatment, and ongoing research studying the interaction of coagulation activation in malignancy may offer improved outcomes for oncology patients.