Prophylaxis of venous thromboembolism in medical patients

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.

Variations in risk assessment models may contribute to the existing gap between venous thromboembolism prophylaxis guidelines and adherence

BACKGROUND

Risk assessment models (RAMs) may allow the clinician to determine need for deep vein thrombosis (DVT) prophylaxis. Individual healthcare facilities often develop their own RAMs. The purpose of this study was to determine: 1.) inter-RAM variability in DVT risk factors and contraindications; 2.) inter-rater variability and inter-RAM variability when applying a RAM to a standard case; and 3.) inter-rater and inter-RAM variability in outcome as far as type of prophylaxis. A convenience sample of RAMs was obtained from various institutions and ten reviewers were recruited to apply the RAMs to three patient cases.

FINDING

The review resulted in 390 separate assessments. Patient 1 did not receive any chemoprophylaxis in 67% of the evaluations, patient 2 in 27% of the evaluations and patient 3 in 2.3% of the evaluations. There was statistically significant variation in the provision of chemoprophylaxis per RAM for patient 1 (p=0.001) and no significant variation for patients 2 and 3. When analyzing the rate of chemoprophylaxis per reviewer, there was statistically significant variation for patients 1 and 2 (p=0.026 and <0.0001 respectively) but not for patient 3 (p=0.123).

CONCLUSION

There may be significant inter-RAM and inter-reviewer variability when utilizing RAMs for assessing DVT risk.

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.

Simple multidisciplinary education of junior doctors and nurses improves prescription of venous thromboembolism prophylaxis

Venous thromboembolism is the most common preventable cause of hospital death. Rates of thromboprophylaxis were studied prospectively in 158 surgical patients before and after multidisciplinary intervention. Prescription of mechanical prophylaxis improved from 58.8% to 76.6% (p = 0.015) following multidisciplinary education. Non-significant increases were seen in pharmacological prescription. Simple multidisciplinary education improves prescription of thromboprophylaxis. As postgraduate curricula for junior doctors and nurses evolve, we advocate routine inclusion of such sessions.

The use of an exclusion-based risk-assessment model for venous thrombosis improves uptake of appropriate thromboprophylaxis in hospitalized medical patients

BACKGROUND

Venous thromboembolism is a common condition in hospitalized medical patients. Numerous studies have demonstrated that low molecular weight heparin significantly reduces this risk but, despite this, the use of thromboprophylaxis remains poor.

AIM

To evaluate the use of an exclusion based risk-assessment model (RAM) for venous thrombosis in improving the uptake of appropriate thromboprophylaxis in hospitalized medical patients.

DESIGN

A survey with a subsequent audit cycle of three separate audits over 36 months.

METHODS

497 hospitalized patients with acute medical conditions on general medical wards were audited at a secondary care centre in London, UK. The survey and subsequent audits were performed by reviewing the notes and medication charts of medical patients, prior to the launch of the RAM and at 12, 28 and 36 months following its introduction.

RESULTS

Prior to launching the RAM, 49% of hospitalized medical patients received appropriate thromboprophylaxis. This did not change 12 months after the RAM was introduced but increased significantly to 71% following formal education of the health care professionals involved in thromboprophylaxis prescription. This improvement was maintained as demonstrated by a subsequent audit 8 months later (75.9%).

CONCLUSION

The introduction of a simple exclusion-based RAM for venous thrombosis in medical patients significantly improved delivery of thromboprophylaxis. The successful uptake of the RAM appears to have been dependent on direct education of those health carers involved in its use. A similar exclusion-based model used nationally could have a significant impact on the burden of VTE currently experienced in the UK.

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.

Awareness of venous thromboembolism prophylaxis must be increased

In a media-fuelled society becoming progressively more critical of the medical profession, we persist in not automatically providing our patients with appropriate venous thromboembolism prophylaxis. Are we placing not just our patients but also our professional credibility at risk?

Effects of elastic compression stockings on wall shear stress in deep and superficial veins of the calf

The purpose of this study was to estimate wall shear stress (WSS) in individual vessels of the venous circulation of the calf and quantify the effects of elastic compression based on change of vessel geometry and velocity waveform. The great saphenous vein and either a peroneal or posterior tibial vein have been imaged in four healthy subjects using magnetic resonance imaging, with and without the presence of a grade 1 medical stocking. Flow through image-based reconstructed geometries was numerically simulated for both a range of steady flow rates and ultrasound-derived transient velocity waveforms, scaled to give a standardized time averaged flow rate. For steady flow, the stocking produced an average percentage increase in mean WSS of approximately 100% in the great saphenous vein across a range of 0.125-1.25 ml/s. The percentage increase in the peroneal/posterior tibial veins varied from 490 to 650% across a range of 0.5-5 ml/s. In addition, application of the stocking eliminated periods of very low or zero flow from the transient waveforms. The average minimum value of WSS in all vessels without the stocking was <0.1 Pa. With the stocking, this was increased to 0.7 Pa in the great saphenous and 0.9 Pa in the peroneal/posterior tibial veins. The pathophysiological effects of these changes are discussed. In conclusion, the flight stocking was effective in raising venous WSS levels in prone subjects, and this effect was much more pronounced in the deep vessels. The stocking also tended to prevent cessation of flow during periods of increased downstream pressure produced by respiration.

Role of MRI in investigating the effects of elastic compression stockings on the deformation of the superficial and deep veins in the lower leg

PURPOSE

To evaluate the potential of MRI to investigate the mechanical effects of compression stockings on the veins of the lower limb.

MATERIALS AND METHODS

The right calves of eight healthy volunteers were imaged in the prone position, with and without the presence of a compression stocking. Cross-sectional areas of all peroneal and posterior tibial veins, both saphenous veins, and any sufficiently large superficial veins were segmented in all subjects at mid-calf level in both cases. Variation in cross-sectional area along the axis of the great saphenous vein and a peroneal vein was also examined in three subjects.

RESULTS

The mean cross-sectional area reduction was found to be greater in the deep veins (64%) than in the superficial veins (39%). Deep-vein cross-sections were generally elliptical, while superficial veins were approximately circular. Significant axial fluctuations were found in the cross-sectional areas.

CONCLUSION

MRI offers a precise source of data on the mechanical effects of lower-limb compression. Ultrasound (US) may be more cost-effective, but the data acquired are less comprehensive. Future biomechanical studies of lower-limb compression should make use of MRI.

Underutilization of venous thromboemoblism prophylaxis in medical patients in a tertiary care center

BACKGROUND

New recommendations concerning the use of prophylactic anticoagulation for medically ill patients have been in use for some time now. This study aims at assessing how much house-staff in a tertiary care setting are implementing these new recommendations in the hope that through quantitative analysis of the deficiency we would be able to identify areas of weakness.

METHODS

About 250 patients were randomly selected from all patients admitted to the American University of Beirut Medical Center (AUBMC) during the year 2005 and stayed more than 48 h. The risk factor profiles, contraindications to thromboprophylaxis, if present, and whether these patients received the appropriate VTE pharmacologic prophylaxis during their stay in hospital were recorded.

RESULTS

About 139 patients were found to have two or more risk factors, with no absolute contraindications. About 37 patients (26.6%) received VTE prophylaxis. Upon reviewing the risk factors profile, the majority of patients (71.3%) were found to have 2-4 risk factors. Among risk factors studied, age > 40 years, admission to ICU, prior VTE, chronic lung disease, infection, respiratory failure, and central venous catheter were significantly associated with receiving prophylaxis.

CONCLUSIONS

VTE prophylaxis is underutilized at AUBMC, a tertiary care teaching hospital in the Middle East. Critical care patients were being acceptably anti-coagulated, whereas cancer patients are doing the worst.

Prevention of venous thromboembolism in medically ill patients: a clinical update

The risk of venous thromboembolism (VTE) in hospitalised medically ill patients is often underestimated, despite the fact that it remains a major cause of preventable morbidity and mortality in this group. It is not well recognised that the risk of VTE in many hospitalised medically ill patients is at least as high as in populations after surgery. This may partly be attributed to the clinically silent nature of VTE in many patients, and the difficulty in predicting which patients might develop symptoms or fatal pulmonary embolism. Two large studies, Prospective Evaluation of Dalteparin Efficacy for Prevention of VTE in Immobilized Patients Trial and prophylaxis in MEDical patients with ENOXaparin, have shown that low-molecular-weight heparins provide effective thromboprophylaxis in medically ill patients, without increasing bleeding risk. Recent guidelines from the American College of Chest Physicians recommend that acutely medically ill patients admitted with congestive heart failure or severe respiratory disease, or those who are confined to bed and have at least one additional risk factor for VTE, should receive 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.

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.

Venous thromboembolism in the medically ill patient: a call to action

The risk of venous thromboembolism (VTE) in medical patients is generally underestimated. However, recent studies including two large double-blind placebo-controlled trials, the Prospective Evaluation of Dalteparin Efficacy for Prevention of VTE in Immobilised Patients trial (PREVENT) and prophylaxis in MEDical patients with ENOXaparin, study show that low-molecular-weight heparins (LMWHs) provide effective thromboprophylaxis for medical patients at risk from VTE without increasing the risk of bleeding. In PREVENT the significant 45%, reduction in VTE among patients receiving dalteparin 5000 IU once daily for 14 days was attributed entirely to a reduction in clinically relevant VTE. The recently published guidelines for the prevention and treatment of VTE, issued by the American College of Chest Physicians, recommend prophylaxis with LMWHs (or low-dose unfractionated heparin) in acutely ill medical patients with risk factors for VTE (grade 1A). Current evidence should encourage the more widespread adoption of thromboprophylaxis in at-risk medical patients, and thus reduce the number of preventable deaths and complications due to VTE.

Venous thromboembolism prophylaxis in medically ill patients and the development of strategies to improve prophylaxis rates

Venous thromboembolism (VTE) is common but often unrecognized in medically ill patients. Over the past 5 years, three large-scale placebo-controlled trials enrolling a total of 5500 medically ill patients have highlighted the risk of VTE in this group. These trials have helped to define a specific at-risk patient profile, including those admitted to the hospital with severe congestive heart failure, respiratory illness, acute infection, and inflammatory bowel disease. We performed a retrospective review of patients admitted to the medical service at our tertiary care center to define how common the at-risk medical patient is and to evaluate and improve prophylaxis rates in this patient group. The study was conducted in two phases. Based on admission characteristics, patients were stratified into high-risk or low-risk groups for the development of VTE. During the pre-intervention phase, 75% of patients admitted to the medical service were characterized as increased risk for VTE, yet only 43% of these high-risk patients received prophylaxis of any sort. After interventions designed to increase awareness of VTE, we conducted a second review period. In this post-intervention phase, where 79% of patients were at risk for VTE, prophylaxis rates improved to 72%. Based on these results, we conclude that the majority of patients admitted to the medical service at our tertiary care center constitute a high-risk population that warrants consideration for VTE prophylaxis. Implementation of strategies to improve prophylaxis rates, including educational sessions and risk stratification guidelines, can be successful and improve identification and prophylaxis of this population.

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.