Assessing, preventing, and treating venous thromboembolism: Evidence-based approaches

Venous thromboembolism risk screening, training and provider awareness in Australian residential aged care facilities

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality in the geriatric post-surgical population, and its prevention is a public health priority. The aim of this study was to assess the use of VTE risk screening and training protocols, and VTE awareness in the Australian residential aged care sector. A cross-sectional survey was conducted that was directed at facility and policy managers of community aged care facilities with ≥10 residents in two Australian states and territories. Forty-nine of 301 (16.3%) providers responded, representing 249/871 (28.6%) aged care facilities and 20,958/66,121 (31.7%) residents. VTE risk screening protocols were used by 1.2% of facilities (3/249), and 79.5% (198/249) were unaware that VTE is an issue in this population. Only 0.8% (2/249) were aware that risk screening and prophylaxis is required to prevent VTE; none were acting upon this. No facility had specific VTE risk assessment or prevention processes in place. Most residential aged care facilities surveyed do not have VTE risk screening protocols and were unaware of the risk that may be associated with this omission. These results have implications for development and implementation of national and international VTE risk screening guidelines in community care.

Thigh-length graduated compression stocking cannot increase blood velocity of the common femoral vein in patients awaiting total hip arthroplasty

Objectives

Graduated compression stocking (GCS) is one of the mechanical prophylaxes commonly used for deep vein thrombosis (DVT). The present study was designed to observe the effects of graduated compression stockings on the vein deformation and hemodynamics of lower limbs in patients awaiting total hip arthroplasty (THA).

Methods

The lower extremity veins of 22 patients awaiting THA were examined by ultrasound, when they rested in supine position with or without thigh-length GCS. The deformation parameters we measured included antero-posterior (AP) diameters, latero-medial (LM) diameters, and cross-sectional area (CSA) of great saphenous vein (GSV), posterior tibial vein (PTV), popliteal vein (PV), gastrocnemius vein (GV), and superficial femoral vein (SFV). We measured peak velocity and mean velocity of GSV, common femoral vein (CFV), junction of GSV and CFV to represent for hemodynamics of veins.

Results

Significant compression was observed in almost all measured veins with the use of thigh-length GCS, while it was unable to significantly compress GSV in latero-medial diameter. The mean latero-medial diameter reductions for GSV, PTV, GV, PV and SFV were 19.4, 30.2, 43.2, 29.7 and 20.4%, respectively. GCS significantly compressed antero-posterior diameter of GSV, PTV, GV, PV and SFV by 43.4, 33.3, 42.1, 37.5, and 27.8%, respectively. The mean reduction of cross-section area was 44.8% for GSV, 49.6% for PTV, 60.0% for GV, 57.4% for PV, and 36.2% for FV. No significant changes were observed in the mean blood velocity of GSV, CFV, and junction. GCS was able to significantly reduce peak velocity of CFV (17.6 ± 5.6 cm/s to 16.1 ± 6.0 cm/s) and junction (23.3 ± 9.5 cm/s to 21.3 ± 9.7 cm/s), while it did not change the peak velocity of GSV.

Conclusion

Thigh-length GCS is sufficient to compress lower extremity veins in patients awaiting THA in supine position with the greatest compression in GV, while it was unable to significantly increase blood velocity of common femoral vein or GSV. GCS may prevent DVT through more than simply increasing blood flow. Further studies are needed to determine the specific effects of GCS.

Prophylaxis against Deep Venous Thrombosis in Patients Hospitalized in Surgical Wards in One of the Hospitals in Iran: Based on the American College of Chest Physician's Protocol

Background

There is not enough studies to determine the frequency of using the prophylaxis against deep venous thrombosis (DVT) based on the American College of Chest Physician's (ACCP) guidelines in Iran. Thus, providing such statistics is essential to improve thromboprophylaxis in hospital. The present study aimed to determine the frequency of using the prophylaxis against DVT based on ACCP guidelines in patients hospitalized in surgical wards in one of teaching hospital in Ilam, Iran.

Methods

In a cross-sectional, the samples were selected among medical records of patients who were hospitalized and underwent surgery in surgical wards of the hospital from April 2012 to September 2013. Type of prophylaxis was determined based on ACCP guidelines. After reviewing inclusion and exclusion criteria, patients' data were extracted from medical records based on required variables.

Results

In reviewing 169 qualified samples, 46.2% (78 patients) were women. Of these, 132 patients were at risk of DVT and needed prophylaxis, only 39 patients (29.5%) received prophylaxis. Thromboprophylaxis based on ACCP guidelines had been fully implemented only in 30 cases (22.7%) of patients with the risk of DVT.. The highest thromboprophylaxis was in the intensive care unit (46.6%) and neurosurgery (37.5%), and the least rate was in urology (0%).

Conclusions

As the results of this study, there are differences between clinical practice and the ACCP guidelines recommendation in prophylaxis against DVT. Thromboprophylaxis has not been implemented based on ACCP guidelines in more than 75% of patients with the risk of DVT. Thus, new strategies are needed to implement thromboprophylaxis against DVT in Iranian hospitals.

The cost of intraoperative adverse events in abdominal and pelvic surgery: A systematic review

BACKGROUND

The assessment of intra-operative adverse events (iAEs) is a vastly under researched area with the potential to provide new methods on how to improve patient outcomes and hospital costs. Our objective was to determine the relationship between iAEs and total hospital costs in abdominal and pelvic surgery.

DATA SOURCES

We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework. Embase, MEDLINE and EBM Reviews online databases were searched to identify all studies that reported iAE rates and total hospital costs. We then analyzed the costing approach used in each article using the Drummond tool and evaluated articles quality using the GRADE method.

CONCLUSIONS

In total, 1709 unique references were identified through our literature search. After review, 23 were included. All studies that reported iAE rates and cost as the primary outcome found that iAEs significantly increased total hospital costs. We identified a relationship between iAEs and increased hospital costs. Future studies need to be performed to further evaluate the relationship between iAEs and cost as current studies are of low quality.

The Perception of Evidence for Venous Thromboembolism Prophylaxis Current Practices after Cardiac Surgery: A Canadian Cross-Sectional Survey

Background. Venous thromboembolism (VTE) is the third leading cause of cardiovascular death in patients undergoing surgery. However, VTE prophylaxis practices in cardiac surgery are based on noncardiac surgical literature. The objective of our study was to extract current patterns of VTE prophylaxis practices in cardiac surgery patients. We also aimed to identify health care professionals knowledge of available evidence supporting VTE prophylaxis in adult cardiac surgery patients. Methods. A web-based survey was developed and sent to all Canadian cardiac surgery centers with the intent to have the survey distributed to all personnel involved in the perioperative care of adult cardiac surgery patients. Participation in the questionnaire was voluntary and anonymized. Results. Thirty-five responses were obtained. Sixty-nine percent reported having an established protocol for VTE prophylaxis. However, 83% reported using VTE prophylaxis in their daily practice despite lack of protocol. The majority (60%) believed that the class of recommendation was high despite the lack of evidence. Conclusions. Our survey demonstrated the following. (a) Majority of Canadian centers employ VTE prophylaxis, with considerable variability. (b) There is a misconception among health care professionals about the strength of evidence supporting VTE prophylaxis in cardiac surgery. Our findings highlight the need for appropriately designed studies to fill this knowledge gap.

A randomised clinical trial comparing the patient comfort and efficacy of three different graduated compression stockings in the prevention of postoperative deep vein thrombosis

AIMS AND OBJECTIVES

To compare the comfort levels of patients regarding the use of three different graduated compression stockings and to analyse the efficacies of the graduated compression stockings in relation to patient comfort and compliance in prevention of postoperative deep vein thrombosis.

BACKGROUND

Graduated compression stockings are very important with other prophylaxis methods in postoperative deep vein thrombosis prophylaxis. In meta-analyses and systematic review studies, it was reported that knee-length and thigh-length graduated compression stockings had similar efficacies. However, there is no randomised study in literature regarding the patient problems and levels of comfort with the use of graduated compression stockings of different sizes and pressures.

DESIGN

A randomised clinical trial design.

METHODS

A total of 219 patients were randomised into three groups (n = 73 in each group). Group I was given low-pressure, knee-length graduated compression stockings, group II was given low-pressure, thigh-length graduated compression stockings and group III was given moderate-pressure, knee-length graduated compression stockings. The level of patients comfort regarding the graduated compression stockings and occurrence of deep vein thrombosis were examined.

RESULTS

The vast majority of the patients (79·5%) in group III and 52·1% of the patients in group II stated experiencing problems during the use of the graduated compression stockings (p < 0·001). The graduated compression stockings were reported by the patients as being very comfortable in the group I (p < 0·001). No findings of thrombosis were observed in any of the groups.

CONCLUSION

The low-pressure, knee-length graduated compression stockings are as effective as the other graduated compression stockings of different pressures and sizes in the postoperative deep vein thrombosis prophylaxis, and the patients have fewer problems while using these graduated compression stockings with a high satisfaction.

RELEVANCE TO CLINICAL PRACTICE

The combined use of pharmacological, mechanical and physical methods and patient education is effective in the prevention of postoperative deep vein thrombosis. The use of low-pressure, knee-length graduated compression stockings in clinical practice may be recommended, as the patients have fewer problems while using these graduated compression stockings with a high satisfaction.

Impact of the national venous thromboembolism risk assessment tool in secondary care in England: retrospective population-based database study

Venous thromboembolism (VTE) is a common and important cause of death in hospital patients. We therefore investigated possible associations between the introduction of the compulsory national VTE risk assessment tool in England in 2010 and patient outcomes. A retrospective database study, using data from the Health and Social Care Information Centre and Office of National Statistics, was undertaken. The main outcome measures were VTE-related secondary diagnosis rates, 30-day and 90-day readmission rates and mortality rates. The observed mean VTE-related secondary diagnosis rate for 2011–2012 was 91% of the rate estimated from a linear regression model of the data for 2006–2007 to 2010–2011 (P = 0.001). Similarly, the observed mean 30-day VTE-related readmission rate for 2011 was 96% of the estimated rate (P = 0.067) and the observed mean 90-day VTE-related readmission rate for 2011 was 96% of the estimated rate (P = 0.022). The observed annual VTE-related national mortality rate was 91% of the estimated rate for 2011 and 92% of the estimated rate for 2012. This study shows a reduction in VTE-related secondary diagnoses and readmissions among adults admitted to hospital, and a reduction in VTE-related population mortality, since the introduction of a national VTE risk assessment screening tool in England. Despite some study limitations, this suggests that the concerted effort made by NHS England to improve prevention of hospital-acquired VTE has been successful.

Weight based heparin dosing for thromboembolic disease is associated with earlier anticoagulation in surgical patients

INTRODUCTION

Achievement of early therapeutic anticoagulation with unfractionated heparin (UFH) is associated with improved outcomes in thromboembolic disease. Weight based UFH expedites time to therapeutic anticoagulation. Treatment with UFH is challenging in surgical patients due to their high propensity for bleeding. We sought to test the hypothesis that an initial weight based UFH infusion in surgical patients increases the percentage of patients who achieve early therapeutic anticoagulation without increasing the risk of hemorrhagic events.

METHODS

Using a non-concurrent retrospective cohort study design, adult surgical patients receiving UFH for venous thromboembolism (VTE) at a tertiary care center were included. Two groups were identified: the weight based (WB) and the under-dosed (UD) heparin groups. For our primary outcome, we compared percentage of patients in each group that achieved a therapeutic PTT within 24 h. Secondary outcomes included the incidence of supratherapeutic PTT levels, hemorrhagic events, and complications associated with VTE.

RESULTS

73 subjects met study criteria, which included 8 subjects in the WB group and 65 in the UD group. The demographic, baseline laboratory, admitting service and type of VTE were similar between the 2 groups. The percentages of WB and UD subjects who achieved a therapeutic PTT within 24 h were 75% and 28%, respectively (p < 0.01). There was no difference in the incidence of supratherapeutic PTT or hemorrhagic events.

CONCLUSION

Surgical patients who received an initial weight based UFH infusion achieved earlier therapeutic anticoagulation compared to under-dosed UFH without increasing the occurrence of supratherapeutic PTT levels or hemorrhagic events.

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.

Anticoagulant use in real time

Venous thromboembolism (VTE) encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE). Each year, VTE affects about 300,000 to 600,000 people in the United States, and death is the first manifestation in one-fourth of this population.(1){Beckman, 2010 #79} Moreover, approximately 10% of the US population has genetic factors that increase their risk for developing thrombosis.(1) In addition to inherited disorders, factors that contribute to VTE include prolonged immobilization, trauma, surgery, cancer, and critically ill patients.(2) Routine assessment and prophylaxis are recommended in these groups to avoid DVT-related complications.(2) Anticoagulants are the mainstay of drugs used in DVT/PE prevention and treatment. Despite the availability of evidence-based guidelines for anticoagulant therapy, there is suboptimal implementation of DVT prophylaxis in hospitalized patients.(3) All anticoagulants are "high-alert" drugs, and judicious use is mandatory to prevent bleeding complications.(4) This review discusses treatment guidelines, monitoring, side effects, and reversal agents available for some anticoagulant drugs approved for VTE. Dissemination of the knowledge via pharmacy education programs significantly improves the adherence to VTE prophylaxis.(5) Understanding the clinical aspects of anticoagulant dispensing as presented in this review is hoped to facilitate implementation of the theoretical knowledge as well as evidence-based guidelines in order to maximize patient benefit.

Venous Thromboembolism in Cancer Patients Undergoing Major Abdominal Surgery: Prevention and Management

Cancer is an important risk factor for venous thrombosis. Venous thromboembolism is one of the most common complications of cancer and the second leading cause of death in these patients. Recent research has given insight into mechanism and various risk factors in cancer patients which predispose to thromboembolism. The purpose of this review is to summarize the current knowledge on the prophylaxis, diagnosis, and management of venous thromboembolism in these patients.

The potential clinical relevance of visible particles in parenteral drugs

Visible particulates (VP) are one subclass of defects seen during the final visual inspection of parenteral products and are currently one of the top ten reasons for recalls 1,2. The risk posed by particles is still unclear with limited experience reported in humans but remains an important consideration during the manufacture and use of parenteral products. From the experimental and clinical knowledge of the distribution of particulate matter in the body, clinical complications would include events occurring around parenteral administration e.g., as a result of mechanical pulmonary artery obstruction and injection site reaction, or sub-acute or chronic events e.g., granuloma. The challenge is to better understand the implication for patients of single vials with VP and align the risk with the probabilistic detection process used by manufacturers for accept/reject decisions of individual units of product.

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.

Hypercoagulability in porcine hemorrhagic shock is present early after trauma and resuscitation

INTRODUCTION

The understanding of coagulopathy associated with trauma continues to evolve. Trauma patients are frequently coagulopathic early after injury and become hypercoagulable within days of injury. Thrombelastography (TEG) allows real-time evaluation of the coagulation status of patients. We hypothesized that TEG will identify post-traumatic hypercoagulable state in our porcine model of hemorrhagic shock and resuscitation.

METHODS

Fourteen male Yorkshire pigs were sedated, instrumented, and splenectomized via laparotomy. Eight of these animals underwent a shock protocol consisting of a pulmonary contusion via captive bolt gun, 35% hemorrhage and two liver fractures. Vitals, hemodynamics, physiologic parameters and TEG were measured at baseline, after shock and at intervals after injury thru 72 h post-injury.

RESULTS

Animals undergoing surgery and instrumentation demonstrated the same hypercoagulable patterns as animals that received shock, injury, and resuscitation. In this model, hypercoagulability was present in both groups at 4 h after injury and continued for 72 h post-injury (increased angle and maximum amplitude, P < 0.05, compared to baseline). Statistically significant differences between the groups were noted at both 16 and 48 h post-injury.

CONCLUSIONS

Hypercoagulability is present early after surgical intervention and trauma. This finding has implications for use of deep venous thrombosis (DVT) prophylaxis in trauma patients.

Microsurgical complications in the upper extremity

Although many advances have been made in microsurgery, it is not without complications. As microsurgeons continue to make advances in technology, technique, and applications that expand the utility of this field to more and more patients, they must be prepared to deal with the complications related to donor and recipient sites and the medical comorbidity that accompanies these large endeavors in the pre-, post-, and intraoperative periods.

Review article: thromboprophylaxis after total hip replacement

The risk of secondary haematologic complications such as deep vein thrombosis or pulmonary embolism increases significantly when a transient period of hypercoagulability is induced after total hip replacement (THR). A number of drug-based anticoagulant approaches are available to modulate this risk, but the optimal length of therapy for such approaches remains unclear. The literature was reviewed for evidence-based support of the routine use of an extended course (>14 days) of thromboprophylaxis after THR. Electronic databases and real-time online literature searches were performed, using the PubMed (Medline), EMBASE, CINAHL and GoogleScholar, and the Cochrane and British Medical Journal Clinical Evidence libraries. Author-defined key word searches were performed. Only articles in the English language, for which full text could be retrieved, were reviewed. There is robust evidence to support an extended course (>14 days) of thromboprophylaxis after THR. Such recommendations have been translated into the guidelines of key professional bodies, including those of the American College of Chest Physicians. Meta-review suggests a clear benefit of such regimens and supports wider adoption, even when weighed against a small increase in adverse events.

Hospital-Acquired Venous Thromboembolism: A Retrospective Analysis of Risk Factor Screening and Prophylactic Therapy

Purpose

To identify the incidence of hospital-acquired venous thromboembolism (HAVTE), evaluate the VTE risk factor screening, and evaluate the use and effectiveness of prophylactic agents used in HAVTE patients at St Vincent's Medical Center (SVMC).

Methods

The SVMC's database was queried from January 2005 to December 2006 for all the discharges with a secondary diagnosis of deep vein thrombosis (DVT) and/or pulmonary embolism (PE) and patients with a primary diagnosis of DVT and/or PE who were readmitted within 30 days of their previous admission from SVMC.

Results

A total of 421 charts were screened and 91 charts, representing patients with HAVTE, were included. Among these patients, 56% of subjects suffered from a DVT, 31% had a PE, and 13% had both a DVT and PE. Thirty-five percent of the patients' prophylactic therapy was noncompliant with the American College of Chest Physician's (ACCP) 2004 VTE prophylaxis guideline recommendations. Documentation of patient risk factors was present in 8.8% of all the patients with HAVTE. Twenty-one percent of the patients were not prescribed any VTE prophylactic agent, of which 89% qualified for VTE prophylaxis.

Conclusions

The incidence of HAVTE was found to be 2.24 cases per 1000 discharges from SVMC. The prophylactic therapy among the patients with HAVTE was compliant with the ACCP's VTE guideline recommendations in 65% of cases. The documentation of risk factor screening was found to be 8.8%. The current DVT/PE protocol at SVMC needs revision to provide a more consistent assessment of patient risk factor, and implementation of DVT/PE prophylaxis throughout the continuum of care based on the current guidelines.

Preventing and treating VTE in the elderly patient

While deaths from cardiovascular disease have decreased dramatically over the past several decades, mortality and morbidity from venous thromboembolism (VTE) continues to threaten hundreds of thousands of patients in the United States each year. Because the risk of VTE increases with age, the problem will only worsen as the population ages. Raising the awareness of health care practitioners and patients about the ways to prevent and treat VTE-including the most recent changes to the guidelines issued by the American College of Chest Physicians-is critical to successfully addressing this significant public health problem.

Eficácia da compressão pneumática intermitente (CPI) nos membros inferiores sobre o fluxo sanguíneo das veias femorais comuns

CONTEXTO: A profilaxia do tromboembolismo venoso pode ser feita por métodos farmacológicos ou de forma mecânica, com o uso de meias antitrombo e compressão pneumática (CPI). A CPI é um método mecânico de profilaxia que merece melhor atenção da comunidade médica. OBJETIVO: Avaliar o efeito do uso de compressão pneumática intermitente (CPI) nos pés, pernas e coxas de adultos saudáveis sobre o fluxo sanguíneo nas veias femorais comuns. MÉTODOS: A amostra foi constituída de 10 voluntários (sete mulheres e três homens) adultos (20-40 anos), sem antecedente de tromboembolismo venoso. Após repouso (10 min) em decúbito dorsal, o fluxo sanguíneo era medido (três vezes) por ultra-sonografia vascular na veia femoral, a 1 cm acima da junção safeno-femoral, em ambos os membros, sem controle e com CPI no pé, perna e na coxa. A compressão (130 mmHg no pé e 45 mmHg na perna e na coxa) foi aplicada em ciclos de 11 segundos de compressão e 20-60 segundos de esvaziamento. As aferições de fluxo foram realizadas no pico de fluxo do ciclo de compressão. Os valores foram comparados por análise de variância (teste de Tukey), com p < 0,05 indicando diferença estatisticamente significante. RESULTADO: A utilização de CPI nos membros inferiores, esquerdo e direito, promoveu elevações percentuais relativas no fluxo venoso femoral de 37,6 e 70,8% (pés), 143,9 e 164,7% (pernas) e 132,6 e 128,9% (coxas), respectivamente. As variações foram estatisticamente significantes para as aplicações nas pernas e coxas. CONCLUSÃO: A CPI melhora o fluxo sanguíneo quando aplicada na perna ou na coxa.

Reversible biotinylated oligosaccharides: a new approach for a better management of anticoagulant therapy

OBJECTIVE

In order to obtain a neutralizable antithrombotic, a chimeric molecule (SSR126517E) containing the sequence of a long-lasting antithrombin (AT)-dependent anti-factor Xa pentasaccharide, idraparinux, linked to a biotin molecule was synthesized and tested for anticoagulant and antithrombotic activity.

METHODS

SSR126517E was tested in several models in vitro and in vivo for its pharmacological properties as well as its ability to be neutralized by avidin.

RESULTS

SSR126517E displayed exactly the same properties as idraparinux. In vitro, SSR126517E had a very high affinity for AT (K(d) < 1 nm) and showed a potent anti-FXa effect and inhibition of thrombin generation with IC(50) values similar to those of idraparinux. Ex vivo, after intravenous administration to rats, SSR126517E produced a potent and long-lasting anti-FXa effect comparable to that obtained with idraparinux; as with idraparinux, the subcutaneous bioavailability was 100%. In vivo, SSR126517E was a potent antithrombotic in rat and mouse venous and arterial thrombosis models. Direct comparison in rats showed that SSR126517E was as active as idraparinux, when administered at the same molar dose. Furthermore, injection of avidin triggered the immediate elimination of SSR126517E from the bloodstream, resulting in complete neutralization of the antithrombotic activity of SSR126517E.

CONCLUSIONS

These results show for the first time that coupling an oligosaccharide with biotin has no effect on the former's pharmacokinetic and pharmacologic properties and renders neutralization easy by injection of avidin.

Prevalence of pulmonary thromboemboli among referred cadavers having hospitalization records to Tehran Legal Medicine Center

BACKGROUND

Pulmonary thromboemboli are one of the main causes of sudden death especially in hospitalized patients and appeared with different nonspecific manifestations. The aim of this study was to determine the prevalence of thromboemboli.

MATERIALS AND METHODS

In this cross sectional study, pulmonary autopsies of 200 cadavers who were selected randomly from all cadavers with clinical suspicion of thromboemboli referred to Tehran University Tissue Archive in different months from January 2005 to 2006 and the prevalence of pulmonary embolism in these cases and its relation with demographic characteristics and sources of disease was assessed. Also, agreement degree of clinical and histopathological diagnosis of pulmonary embolism was calculated.

RESULTS

The prevalence of pulmonary embolism was estimated at 13.5%. There were positive relationship between prevalence of pulmonary embolism and increased of age (P=0.001). Interpretation of results of macroscopic and histopathological studies for diagnosis of embolism showed moderate agreement (kappa=0.59) and interpretation of results of clinical diagnosis of disease before death and pathologic findings after death showed poor agreement (kappa=0.34). The most frequent detected location of emboli were end branches of pulmonary artery.

CONCLUSION

Considering the apparent high prevalence of pulmonary embolism in our study, we recommend increased use of anti-deep vein thrombosis measures in all appropriate patients within the Tehran hospital population, according to evidence-based guidelines.

Fondaparinux: use in thromboprophylaxis of acute medical patients

Fondaparinux is a synthetic pentasaccharide that inhibits thrombin formation and thrombus development via selective antithrombin mediated inhibition of factor Xa. The complete bioavailability (100%) and elimination half-life of approximately 17 hours allows once-daily administration of fondaparinux. In a well designed trial (ARTEMIS) in acute medical patients aged > or = 60 years, fondaparinux was significantly more effective than placebo in terms of reducing the incidence of venous thromboembolism (VTE) up to day 15. The beneficial effect of fondaparinux therapy was observed in all subgroups of patients irrespective of underlying illness (e.g. acute heart failure or acute respiratory disease) in a predefined subgroup analysis of the ARTEMIS trial. Similarly, in a retrospective analysis of the trial, age and renal function did not appear to affect the incidence of VTE in fondaparinux and placebo recipients. Fondaparinux was generally well tolerated in this clinical trial. In patients receiving fondaparinux, the incidence of major bleeding was similar to that in patients receiving placebo and the incidence of minor bleeding was <3%.