Long-term outcomes after deep venous thrombosis of the lower extremities

Noninvasive and invasive imaging of lower-extremity acute and chronic venous thrombotic disease

The spectrum of venous thromboembolic (VTE) disease encompasses both acute deep venous thrombosis (DVT) and chronic postthrombotic changes (CPC). A large percentage of acute DVT patients experience recurrent VTE despite adequate anticoagulation, and may progress to CPC. Further, the role of iliocaval venous obstruction (ICVO) in lower-extremity VTE has been increasingly recognized in recent years. Imaging continues to play an important role in both acute and chronic venous disease. Venous duplex ultrasound remains the gold standard for diagnosing acute VTE. However, imaging of CPC is more complex and may involve computed tomography, magnetic resonance, contrast-enhanced ultrasound, or intravascular ultrasound. In this narrative review, we aim to discuss the full spectrum of venous disease imaging for both acute and chronic venous thrombotic disease.

Patterns and Distribution of Deep Vein Thrombosis and Its Effects on Clinical Outcomes After Opening-Wedge High Tibial Osteotomy

Background:

Although a few studies have reported the incidence of deep vein thrombosis (DVT) after opening-wedge high tibial osteotomy (OWHTO), previous studies focused only on symptomatic DVT. Information is lacking regarding the overall incidence of DVT after OWHTO, thrombus location, and the relationship between DVT and clinical outcome.

Purpose:

To determine the overall incidence of DVT and classify the location of DVT after OWHTO. We also determined whether significant differences in clinical improvement exist in patients with and without DVT at 6 months and at 2 years after OWHTO.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

This study included 46 patients (47 knees) who underwent OWHTO. All patients were instructed to perform knee range of motion exercises and partial weightbearing after drain removal. None of the patients received a chemoprophylaxis for DVT except intermittent pneumatic compression. DVT was diagnosed using 128-row multidetector computed tomography performed before discharge on the fourth postoperative day. The location was classified into 6 segments in the distal portion (muscular and axial veins) and proximal portion (popliteal, femoral, and common femoral veins and veins located above the iliac vein). International Knee Documentation Committee (IKDC) score was assessed preoperatively and postoperatively at 6 months, 1 year, and 2 years using a linear mixed model.

Results:

Although the incidence of symptomatic DVT was 8.5% (n = 4), the overall incidence of early DVT was 44.7% (n = 21). All DVTs were located in the distal portion of the lower extremity vein, and 76.2% of the DVTs were located in an axial vein. The IKDC scores were 33.6 ± 7.2 and 35.3 ± 9.1 (P = .910) preoperatively, 38.1 ± 5.6 and 40.6 ± 8.4 (P = .531) at 6 months after surgery, and 44.8 ± 6.9 and 45.9 ± 11.4 (P = .786) at 2 years after surgery in patients without and those with DVT, respectively.

Conclusion:

The overall incidence of early DVT after OWHTO was 44.7%. DVT after OWHTO was found particularly around the osteotomy site (76.2%). Patients with DVT did not have inferior short-term clinical outcomes after surgery.

Which orally administered antithrombotic agent is most effective for preventing venous thromboembolism after total knee arthroplasty? A propensity score-matching analysis

Purpose

Even today, total knee arthroplasty (TKA) is associated with venous thromboembolism (VTE). The purpose of our study is to report the incidence of postoperative VTE and to compare the efficacy of commonly used orally administered antithrombotic agents.

Materials and methods

Seven hundred ad ninety-nine patients who underwent primary TKA were retrospectively reviewed. The patients were prescribed one of three antithrombotic agents: aspirin (n = 168), rivaroxaban (n = 117), or apixaban (n = 514). Before surgery, patient demographics and risk factors were matched via propensity scoring. After surgery, all three groups took the agent for 7 days and underwent ultrasonography to check for VTE.

Results

The overall incidence of postoperative VTE was 15.4% (123/799). Only one patient developed symptomatic VTE. Female sex and staged bilateral TKA were risk factors for postoperative VTE. The postoperative VTE rates in the aspirin, rivaroxaban, and apixaban groups were 16.2%, 6.0%, and 17.1%, respectively, significantly lower in the rivaroxaban group (p <  0.02). The majority of VTEs in all three groups were calf-vein thromboses.

Conclusions

All agents showed enough efficacy as antithrombotic agents. Considering that aspirin is inexpensive, aspirin is a cost-effective option for preventing postoperative VTE.

Predictors of Poor Quality of Life after Primary Lower Limb Deep Venous Thrombosis: A Perspective from a Developing Nation

Objective: We aimed to determine predictors of poor long term quality of life, using the VEINES Quality of Life (QOL) questionnaire, in patients with lower limb deep venous thrombosis (DVT).

Material and Methods: This study included adult patients with primary lower limb DVT between January 2007 and December 2017. Post thrombotic syndrome (PTS) was assessed using the Villalta score and Quality of Life (QoL) by the VEINES quality of life questionnaire.

Results: Our study included 125 patients, 57 (45.6%) of whom were males. The patient population’s median age was 41 years (IQR: 34–47 years). The median follow up was 450 days (IQR: 390–1020 days). PTS occurred in 49 (39.2%) patients. Independent predictors of poor quality of life post DVT were progression to PTS, complete occlusion of vein, proximal (Ileofemoral) DVT, poor control of INR, poor compliance with compression stockings, severity of PTS, ileofemoral DVT and poor control of therapeutic anticoagulation.

Conclusion: Predictors who are independently associated with poor quality of life post DVT are PTS, inability to maintain therapeutic anticoagulation and ileofemoral DVT.

Association between hypertension and deep vein thrombosis after orthopedic surgery: a meta-analysis

Background

We aimed to analyze the association between hypertension and deep vein thrombosis (DVT) after orthopedic surgery.

Methods

Relevant studies were identified by a search of PubMed, Embase, China National Knowledge Infrastructure, Wanfang, the Chinese Biomedical Literature, and Weipu database until December 2015. The association between hypertension and DVT after orthopedic surgery was assessed by pooled odds ratios (ORs) and 95 % confidence intervals (CIs). Heterogeneity was evaluated by the Chi-square test based on Q statistic and I² statistics. Finally, publication bias was evaluated by Egger’s test.

Results

A total of 16 articles with 68,955 males and 53,057 females were eventually identified. Studies yielded effects for homogeneous (Q = 38.41, P = 0.0008, and I² = 60.9 %). Meta-analysis showed that hypertension was associated with DVT orthopedic surgery (OR 2.89, 95 % CI 2.18–3.83, Z = 7.38, P < 0.05). No statistical evidence of publication bias was found among studies (t = 1.90, P = 0.08). The funnel plot was symmetry, and the results were reliable.

Conclusions

Hypertension may promote DVT after orthopedic surgery, and may be an important risk factor of DVT occurrence.

Femoral Vessel Blood Flow Is Preserved Throughout Direct Anterior Total Hip Arthroplasty

Posterolateral and anterolateral approach THA disrupts femoral vessel blood flow, however, this has not been established for the direct anterior (DA) approach. Ten patients undergoing primary DA THA had peak vascular flow rates for the femoral artery and vein calculated via Doppler ultrasound at specified points: incision, acetabular preparation, femoral preparation and final reduction. Peak femoral arterial and venous flow decreased over baseline, but not significantly, during acetabular preparation (P=0.88, P=0.98) and femoral preparation (P=0.97, P=0.97). At final reduction, arterial peak flow was restored (P=1) with an increase in venous flow (P=0.55). Although there were alterations to peak flow, no vessel occlusion occurred at any point during DA THA.

Call to action to prevent venous thromboembolism

Deep venous thrombosis and pulmonary embolism, together called venous thromboembolism, remain a serious national health problem. Estimates suggest that over 900,000 cases occur in the United States per year, with 300,000 deaths per year. Because of the significant and serious nature of this problem, a workshop was held in May of 2006, which resulted in the Acting U.S. Public Health Service Surgeon General's Call to Action to Prevent Deep Vein Thrombosis and Pulmonary Embolism. On September 15, 2008, Acting Surgeon General, Rear Admiral Steven K. Galson, MD, MPH, and Elizabeth Nabel, MD, Director National Heart, Lung, and Blood Institute, announced the Call to Action. The Call to Action highlights public awareness about the risk factors, triggering events, and symptoms of venous thrombosis and pulmonary embolism, and encourages the development of evidence based practices for screening, prevention, diagnosis, and treatment of venous thrombosis and pulmonary embolism. It is designed to encourage new scientific investigation in an effort to obtain needed evidence to fill in the gaps of knowledge about venous thrombosis and pulmonary embolism. This knowledge should be quickly and easily disseminated to the public and put into practice by health professionals. The Surgeon General's Call to Action represents one of the most important advances in the field of venous thromboembolism and sets the stage for multidisciplinary efforts to combat this serious national health problem.

Haemodynamic performance of neuromuscular electrical stimulation (NMES) during recovery from total hip arthroplasty

Background

Patients post total hip arthroplasty (THA) remain at high risk of developing Deep Vein Thrombosis (DVT) during the recovery period following surgery despite the availability of effective pharmacological and mechanical prophylactic methods. The use of calf muscle neuromuscular electrical stimulation (NMES) during the hospitalised recovery period on this patient group may be effective at preventing DVT. However, the haemodynamic effectiveness and comfort characteristics of NMES in post-THA patients immediately following surgery have yet to be established.

Methods

The popliteal veins of 11 patients, who had undergone unilateral total hip replacement surgery on the day previous to the study, were measured using Doppler ultrasound during a 4 hour neuromuscular electrical stimulation (NMES) session of the calf muscles. The effect of calf muscle NMES on peak venous velocity, mean venous velocity and volume flow were compared to resting values. Comfort was assessed using a 100mm non-hatched visual analogue scale taken before application of NMES, once NMES was initiated and before NMES was withdrawn.

Results

In the operated limb NMES produced increases in peak venous velocity of 99% compared to resting. Mean velocity increased by 178% compared to resting and volume flow increased by 159% compared to resting. In the un-operated limb, peak venous velocity increased by 288%, mean velocity increased by 354% and volume flow increased by 614% compared to basal flow (p<0.05 in all cases). There were no significant differences observed between the VAS scores taken before the application of NMES, once NMES was initiated and before NMES was withdrawn (p=.211).

Conclusions

NMES produces a beneficial hemodynamic response in patients in the early post-operative period following orthopaedic surgery. This patient group found extended periods of calf-muscle NMES tolerable.

Trial registration

ClinicalTrials.gov NCT01785251

The Anticoagulation of Calf Thrombosis (ACT) project: study protocol for a randomized controlled trial

BACKGROUND

Half of all lower limb deep vein thrombi (DVT) in symptomatic ambulatory patients are located in the distal (calf) veins. While proximal disease warrants therapeutic anticoagulation to reduce the associated risks, distal DVT often goes untreated. However, a proportion of untreated distal disease will undoubtedly propagate or embolize. Concern also exists that untreated disease could lead to long-term post thrombotic changes. Currently, it is not possible to predict which distal thrombi will develop such complications. Whether these potential risks outweigh those associated with unrestricted anticoagulation remains unclear. The Anticoagulation of Calf Thrombosis (ACT) trial aims to compare therapeutic anticoagulation against conservative management for patients with acute symptomatic distal deep vein thrombosis.

METHODS

ACT is a pragmatic, open-label, randomized controlled trial. Adult patients diagnosed with acute distal DVT will be allocated to either therapeutic anticoagulation or conservative management. All patients will undergo 3 months of clinical and assessor blinded sonographic follow-up, followed by 2-year final review. The project will commence initially as an external pilot study, recruiting over a 16-month period at a single center to assess feasibility measures and clinical event rates. Primary outcome measures will assess feasibility endpoints. Secondary clinical outcomes will be collected to gather accurate data for the design of a definitive clinical trial and will include: (1) a composite endpoint combining thrombus propagation to the popliteal vein or above, development of symptomatic pulmonary embolism or sudden death attributable to venous thromboembolic disease; (2) the incidence of major and minor bleeding episodes; (3) the incidence of post-thrombotic leg syndrome at 2 years using a validated screening tool; and (4) the incidence of venous thromboembolism (VTE) recurrence at 2 years.

DISCUSSION

The ACT trial will explore the feasibility of comparing therapeutic anticoagulation to conservative management in acute distal DVT, within a modern cohort. We also aim to provide contemporary data on clot propagation, bleeding rates and long-term outcomes within both groups. These results will inform the conduct of a definitive study if feasibility is established.

Healthcare burden associated with the post-thrombotic syndrome and potential impact of the new oral anticoagulants

Deep-vein thrombosis (DVT) can have a significant impact on a patient's life. In particular, the development of post-thrombotic syndrome as a long-term complication of DVT can have devastating consequences for the individual and impose a substantial economic burden on healthcare systems. Anticoagulants are the mainstay of DVT treatment; however, the current standard of care, a parenteral anticoagulant followed by a vitamin K antagonist, is associated with complex patient management, often resulting in suboptimal therapy. New, oral anticoagulants have been developed, and a direct thrombin inhibitor--dabigatran etexilate--and two direct Factor Xa inhibitors--rivaroxaban and apixaban--have completed and/or have ongoing phase III trials in the treatment of venous thromboembolism. These agents do not have the drawbacks of the vitamin K antagonists and hold promise for more effective treatment of DVT, possibly resulting in a reduction in the incidence of post-thrombotic syndrome.

Pathophysiology of Post-Thrombotic Syndrome: The Effect of Recurrent Venous Thrombosis and Inherited Thrombophilia

Post-thrombotic syndrome is an important chronic complication of deep vein thrombosis. This syndrome can be debilitating to patients and has a major economic impact on health care services. The pathophysiology of post-thrombotic syndrome is currently incompletely understood. Because therapeutic options for post-thrombotic syndrome are extremely limited and results are often disappointing, recognizing of the pathophysiology and risk factors of this syndrome is essential to prevent the disabling consequences of this disease. The present paper focuses on risk determinants of post-thrombotic syndrome after deep vein thrombosis. The contribution of recurrent venous thrombosis and inherited thrombophilia to the pathogenesis of this syndrome is reviewed and discussed in details.

Diagnosis and treatment of deep-vein thrombosis and approach to venous thromboembolism in obstetrics and gynecology

Deep vein thrombosis (DVT) is a common condition in which the approach to its diagnosis has evolved over the years. Currently, an algorithm strategy combining pre-test probability, D-Dimer testing and compression ultrasound imaging allows for safe and convenient investigation of suspected lower-extremity thrombosis. Patients with low pre-test probability and a negative D-Dimer test result can have proximal DVT excluded without the need for diagnostic imaging. The mainstay of treatment of DVT is anticoagulation therapy, whereas interventions such as thrombolysis and placement of inferior vena cava filters are reserved for special situations. The use of low-molecular-weight heparin (LMW) allows for outpatient management of most patients with DVT. The duration of anticoagulation therapy depends on whether the primary event was idiopathic or secondary to a transient risk factor. More research is required to optimally define the factors that predict an increased risk of recurrent DVT to determine which patients can benefit from extended anticoagulant therapy. DVT is also a serious problem in the antenatal and postpartum period of pregnancy. Thromboembolic complications are the leading cause of both maternal and fetal morbidity and mortality. The incidence of venous thromboembolism during normal pregnancy is six-fold higher than in the general female population of childbearing age. The treatment of DVT during pregnancy deserves special mention, since oral anticoagulation therapy is generally avoided during pregnancy because of the teratogenic effects in the first trimester and the risk of fetal intracranial bleeding in the third trimester. LMW heparin is the treatment of choice for DVT during pregnancy. If acute DVT occurs near term, interrupting anticoagulation therapy may be hazardous because of the risk of pulmonary embolism. In this situation, placement of a retrievable inferior vena cava filter must be considered. However, there is no consensus as to what the appropriate dose should be and whether anti-Xa levels need to be monitored.

Pharmacoeconomics of dabigatran etexilate for prevention of thromboembolism after joint replacement surgery

Dabigatran etexilate (DE) is a novel oral anticoagulant indicated for the prevention of venous thromboembolism in patients undergoing total hip or total knee replacement surgery. The majority of these patients receive some kind of thromboprophylaxis, most commonly low-molecular-weight heparin (LMWH). However, the subcutaneous route of LMWH administration may act as a barrier to the continuation of effective anticoagulant prophylaxis after discharge from hospital. The oral route of DE administration may allow more patients to receive extended thromboprophylaxis and may reduce costs, such as those associated with nurse time for LMWH administrations, platelet monitoring, needlestick injuries and sharps disposal. This article presents an overview of the clinical evidence for DE and a systematic review of the economic evaluations of the drug.

Iliac vein stenting in postmenopausal leg swelling

BACKGROUND

Leg swelling in menopausal women is well known. Prevailing concept in primary care is that it is polycentric and a treatable cause may not be found. Patients are placed on empiric diuretics often without benefit. Our clinical experience indicates that iliac venous vein obstruction is the core cause; a variety of secondary factors common in postmenopausal women precipitate symptoms.

PATIENTS AND METHODS

A total of 163 limbs in 150 postmenopausal women (≥ 55 years of age) with leg swelling unresponsive to conservative therapy underwent intravascular ultrasound-guided iliac vein stenting over an 11-year period. Preoperative investigations included duplex, airplethysmography, venous pressure tests, contrast studies, and lymphangiography. The postmenopausal group constituted 9% of all limbs (n = 1760) stented for chronic venous disease (CVD) during the same period and 18% of those stented for swelling (n = 922). Median age was 67 (range, 55-92) and left-to-right ratio 2:1.

RESULTS

Iliac vein obstruction was "primary" (nonthrombotic) in 65% and postthrombotic in 35% of limbs; 35% of limbs had obstruction only and 65% combined obstruction/reflux. Lymphatic dysfunction was present in 21% of the limbs. Mean intravascular ultrasound area stenosis was 68% ± 22 SD. Mean follow-up was 22 months (± 26 SD) (range, 1-113 months). Secondary stent patency (6 years) was 100% in primary and 91% in postthrombotic limbs; overall 98%. Swelling improved significantly (P < .0001) from preoperative grade 2.5 (± 0.8 SD) to postoperative grade 1.2 (1.2 SD). Associated pain also improved significantly (P < .0001) from preoperative visual analog scale 3.5 (± 3 SD) to postoperative 0.9 (2.1 ± SD). Quality-of-life (CIVQ) scores improved significantly in every category and overall (P < .0001).

CONCLUSIONS

Patients with postmenopausal leg swelling often have obstructive venous pathology even though suggestive venous history and other signs are often absent. Morbidity arises from painful swelling that affects mobility, quality of life, and ability of self-care at later stages of life. Outpatient percutaneous iliac vein stenting affords substantial symptom relief and improvement in quality-of-life measures. Recognition of the clinical complex as a distinct entity of venous origin may lead to greater awareness and effective treatment.

P-selectin/ PSGL-1 inhibitors versus enoxaparin in the resolution of venous thrombosis: a meta-analysis

BACKGROUND

P-selectin antagonism has been shown to decrease thrombogenesis and inflammation in animal models of deep venous thrombosis (DVT).

OBJECTIVE

To determine the effectiveness of P-selectin inhibitors versus saline and enoxaparin in venous thrombus resolution in nonhuman primate models of venous thrombosis.

METHODS

Studies reporting vein re-opening, inflammation expressed as Gadolinium enhancement and coagulation parameters were searched in the literature and pooled into a meta-analysis using an inverse variance with random effects.

RESULTS

Five studies were identified comparing P-selectin/ PSGL-1 inhibitors versus saline or enoxaparin regarding venous thrombosis resolution. Vein re-opening was significantly higher on P-selectin/ PSGL-1 compounds, when compared to saline (Inverse Variance [IV] 95% CI; 44.37 [17.77-70.96], p=0.001, I(2)=97%) and similar to enoxaparin (IV 95% CI; 5.03 [-8.88-18.95], p=0.48, I(2)=41%). Inflammation, reflected as Gadolinium enhancement at magnetic resonance venography (MRV), was significantly decreased in the P-selectin treated group when compared to saline (IV 95% CI; -17.84 [-14.98-(-8.30)], p<0.00001, I(2)=80%). No significant differences on vein wall inflammation were observed between P-selectin/ PSGL-1 inhibitors and enoxaparin treated animals (IV95% CI; -3.59 [-10.67-3.48], p=0.32, I(2)=66%). In addition, there was no differences in the coagulation parameters (aPTT, TCT, BT, D-Dimer, fibrinogen, platelets) between P-selectin/ PSGL-1 inhibitors and enoxaparin (IV 95% CI; -1.12[-2.36-0.11], p=0.07, I(2)=92%), although there was a trend showing less of a prolongation in TCT with P-selectin/PSGL-1 inhibitors compared to enoxaparin (p<0.0001).

CONCLUSION

P-selectin antagonism successfully paralleled the low-molecular-weight-heparin enoxaparin, for the treatment of DVT in nonhuman primate models, by decreasing both thrombus burden and inflammation without causing any bleeding complications and without increasing coagulation times.

Economic evaluation of dabigatran etexilate for the prevention of venous thromboembolism after total knee and hip replacement surgery

OBJECTIVE

This was an evaluation of the cost-effectiveness of oral dabigatran etexilate compared with subcutaneous low-molecular-weight heparin (enoxaparin) for the prevention of venous thromboembolism (VTE) after total knee replacement (TKR) and total hip replacement (THR) surgery from the perspective of the UK National Health Service.

METHODS

Dabigatran etexilate (220 mg once daily) was compared with enoxaparin (40 mg once daily) in patients undergoing TKR (duration of prophylaxis, 6-10 days) and THR (duration of prophylaxis, 28-35 days). The 10-week acute postsurgical phase was modeled using a decision tree. A Markov process (1-year cycle length) was used to model long-term events (recurrent VTE, postthrombotic syndrome, and consequences of intracranial hemorrhage) for patients' remaining lifetimes. Relative risks for VTE and bleeding events were derived from 2 Phase III studies that compared dabigatran etexilate with enoxaparin 40 mg once daily. The probabilities of long-term events were estimated using data from published longitudinal studies.

RESULTS

Rates of VTE and bleeding events did not differ significantly between dabigatran etexilate and enoxaparin. Dabigatran etexilate was less costly than enoxaparin in TKR and substantially less costly in THR, primarily due to differences in administration costs. The cost of prophylaxis for THR patients, including drugs and administration costs, was estimated at pound 137 for dabigatran etexilate and pound 237 for enoxaparin ( pound 7 for nursing time during the hospital stay, pound 91 for nurse home visits for administration after hospital discharge, and an additional pound 2 in drug costs). At a willingness-to-pay threshold of pound 20,000 per quality-adjusted life-year, the probability of cost-effectiveness for dabigatran etexilate was 75% in TKR and 97% in THR. These results were robust across a range of sensitivity analyses.

CONCLUSION

From the perspective of the UK National Health Service, thromboprophylaxis with dabigatran etexilate was cost-saving compared with enoxaparin 40 mg once daily, with comparable efficacy and safety profiles.

Cost-effectiveness of venous thromboembolism prophylaxis in total hip and knee replacement surgery: the evolving application of health economic modelling over 20 years

OBJECTIVES

In the last two decades, there has been considerable evolution of methods for cost-effectiveness modelling. Some of the first models were developed in the area of venous thromboembolism (VTE) prophylaxis. Hence, this area can serve as an important example to illustrate evolving standards. Our objectives are to document evolving methodology by describing VTE models, assess their critical strengths and weaknesses, and inform future advances for models in this therapeutic area.

RESEARCH DESIGN AND METHODS

A systematic review of economic models of primary VTE prevention following hip and knee replacement surgery was undertaken. Electronic searches of PubMed, EMBASE, the Cochrane library, and grey literature were conducted (1985-2006). Reference lists of included articles and reviews were examined for relevant studies.

RESULTS

Twenty-nine cost-effectiveness models were identified. Nineteen other cost-effectiveness analyses were excluded because they were not model-based; 16 were simple cost calculations and three were analyses of resource use data collected alongside clinical trials. The majority of models (24) were constructed as decision trees, frequently utilising previously published model structures, with some adaptation for new comparators, and/or addition of relevant events omitted by earlier models (e.g., bleeding due to prophylactic treatment). Later models have included Markov processes to model potential long-term consequences of VTE (recurrent VTE and post-thrombotic syndrome) over longer time horizons. Systematic identification of clinical evidence and more sophisticated analysis methods (e.g., Bayesian mixed-treatment comparisons and probabilistic sensitivity analyses) have recently been introduced.

CONCLUSIONS

Model structures have evolved substantially in this highly studied therapeutic area, with improvements made to the model structure, the comprehensiveness of clinical evidence included, and the underlying calculation methodology.

Estimated annual costs of prophylaxis and treatment of venous thromboembolic events associated with major orthopedic surgery in France

Venous Thromboembolism (VTE) remains a major complication following orthopedic surgery despite heparin prophylaxis. Clinical consequences associated with this complication are deep vein thrombosis (DVT), pulmonary embolism, and long-term consequences of DVT, especially Postthrombotic syndrome (PTS). The purpose of the present study was to estimate the annual direct costs of VTE following major orthopedic surgery of the lower limb in France. This cost of illness study was performed by using available information from health system databases (1999) and literature and specific surveys (2002). Direct costs were calculated by using estimates of the number of patients with major orthopedic surgery in France during one year. Patients presenting with VTE were identified from the national disease-related group inpatient database. Additional resource consumption was identified by comparison with disease-related groups without the VTE complications. Ambulatory care costs after hospitalization, for recurrences and PTS, were estimated from specific surveys of general practitioners and venous disease specialists. Total annual costs of VTE associated with major orthopedic surgery for the French Sickness Fund were estimated to be approximately 60 million euros over 1 year with 28 million euros for inpatient care and 30 million euros for recurrences and PTS.

Diagnosis and treatment of deep-vein thrombosis

Deep-vein thrombosis (DVT) is a common condition that can lead to complications such as postphlebitic syndrome, pulmonary embolism and death. The approach to the diagnosis of DVT has evolved over the years. Currently an algorithm strategy combining pretest probability, D-dimer testing and compression ultrasound imaging allows for safe and convenient investigation of suspected lower-extremity thrombosis. Patients with low pretest probability and a negative D-dimer test result can have proximal DVT excluded without the need for diagnostic imaging. The mainstay of treatment of DVT is anticoagulation therapy, whereas interventions such as thrombolysis and placement of inferior vena cava filters are reserved for special situations. The use of low-molecular-weight heparin allows for outpatient management of most patients with DVT. The duration of anticoagulation therapy depends on whether the primary event was idiopathic or secondary to a transient risk factor. More research is required to optimally define the factors that predict an increased risk of recurrent DVT to determine which patients can benefit from extended anticoagulant therapy.

Introduction to venous thromboembolism and prophylaxis

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

Optimisation de l’interrogatoire dans l’évaluation du risque de maladie thromboembolique veineuse : l’étude OPTIMEV

Venous thromboembolism (VTE) is a frequent disease and remains a major cause of mortality and morbidity among our patients. During the 20 past years, clinical description, diagnostic tools, and treatment have changed dramatically. Most published data describing risk factors for VTE no longer apply to the patients seen in daily practice. We present here the rationale, aims, and methodology of the OPTIMEV Study (OPTimisation de l'Interrogatoire pour la Maladie thromboEmbolique Veineuse).

RATIONALE

Risk factors for VTE are numerous, complex and interactions between them and their clinical importance is difficult to measure (table I). For example, odds ratios for VTE recurrence vary greatly across longitudinal studies. We searched the National Library of Medecine (PubMed) and the Amedeo website using the following keywords: "venous thromboembolism", "pulmonary embolism", "deep vein thrombosis", "risk factors". We selected 84 relevant articles published between 1972 and 2005. Based on this literature analysis, we identified the following major risk factors: VTE recurrence, surgery, cancer, immobilization, age, biological factors. For these factors, data are lacking and some questions are proposed.

OBJECTIVES

The broad objective of the study is to better evaluate clinical risk factors that fit today's practice against VTE. Specific aims are: 1) to determine whether risk factors are different between proximal and distal deep vein thrombosis (DVT); 2) to develop and prospectively validate a new prediction rule for outpatients. The primary hypothesis is that careful assessment of VTE recurrence, adequate surgical thromboprophylaxis, cancer staging, and varicose vein stratification according to the CEAP classification, is mandatory for accurate evaluation of thromboembolic disease risk.

METHODS

We conducted a multicenter, prospective, cohort study of 10000 patients. Enrollees are inpatients and outpatients presenting with a clinical suspicion of VTE in Emergency Departments and outpatient clinics in France. 4173 patients have been enrolled at this time (Figure 2). All eligible patients are enrolled during a selected period of time through different seasons. Data are collected by physicians in charge of the patients using an electronic case recording form. Collected data include baseline characteristics, risk factors, results of diagnostic investigations. Outcome measures obtained through telephone interview at 3 and 12 months include cancer diagnosis, VTE recurrence, haemorrhagic events, treatments, death. Univariate and multivariate analysis will be performed using multilevel logistic regression. The study organization is performed by the Centre d'Investigation Clinique de Grenoble and is sponsored by the French Society of Vascular Medicine. First results, to be published in 2006, will allow development of new prediction rules for VTE diagnosis.

Ambulation and Compression After Deep Vein Thrombosis: Dispelling Myths

The traditional dogma of putting mobile patients with acute deep vein thrombosis into bed for several days has been challenged by some studies that showed a better clinical outcome with walking exercises under good compression. Repeated lung scans did not show an increased risk of new pulmonary embolism. There was a faster and more intense reduction of pain and swelling and a clear quality-of-life benefit. Immediate ambulation with compression reduces the propagation of thrombi and has a positive impact regarding development of postthrombotic syndrome. Patients selected for home therapy should not only be instructed how to inject their low-molecular-weight heparin but should also be educated to walk around with good compression. Until now the important principle of avoiding the venous stasis associated with bed rest has found broad acceptance in the field of primary prevention of venous thromboembolism. Modern antithrombotic management of patients with acute venous thrombosis should include early ambulation in conjunction with appropriate compression therapy.

Hepatic Findings in Long-Term Clinical Trials of Ximelagatran

OBJECTIVE

In clinical trials, the efficacy and safety of the oral direct thrombin inhibitor ximelagatran have been evaluated in the prevention or treatment of thromboembolic conditions known to have high morbidity and mortality. In these studies, raised aminotransferase levels were observed during long-term use (>35 days). The aim of this analysis is to review the data regarding these hepatic findings in the long-term trials of ximelagatran.

PATIENTS AND METHODS

The prospective analysis included 6948 patients randomised to ximelagatran and 6230 patients randomised to comparator (warfarin, low-molecular weight heparin followed by warfarin or placebo). Of these, 6931 patients received ximelagatran for a mean of 357 days and 6216 patients received comparator for a mean of 389 days. An algorithm was developed for frequent testing of hepatic enzyme levels. A panel of four hepatologists analysed all cases of potential concern with regard to causal relation to ximelagatran treatment using an established evaluation tool (Roussel Uclaf Causality Assessment Method [RUCAM]).

RESULTS

An elevated alanine aminotransferase (ALT) level of >3 x the upper limit of normal (ULN) was found in 7.9% of patients in the ximelagatran group versus 1.2% in the comparator group. The increase in ALT level occurred 1-6 months after initiation of therapy and data were available to confirm recovery of the ALT level to <2 x ULN in 96% of patients, whether they continued to receive ximelagatran or not. There was some variability in the incidence of ALT level elevation between indications, those with simultaneous acute illnesses (acute myocardial infarction or venous thromboembolism) having higher incidences. Combined elevations of ALT level of >3 x ULN and total bilirubin level of >2 x ULN (within 1 month of the ALT elevation), regardless of aetiology, were infrequent, occurring in 37 patients (0.5%) treated with ximelagatran, of whom one sustained a severe hepatic illness that appeared to be resolving when the patient died from a gastrointestinal haemorrhage. No death was observed directly related to hepatic failure caused by ximelagatran.

CONCLUSION

Treatment with ximelagatran has been associated with mainly asymptomatic elevation of ALT levels in a mean of 7.9% of patients in the long-term clinical trial programme and nearly all of the cases occurred within the first 6 months of therapy. Rare symptomatic cases have been observed. An algorithm has been developed for testing ALT to ensure appropriate management of patients with elevated ALT levels. Regular ALT testing should allow the clinical benefits of ximelagatran to reach the widest population of patients while minimising the risk of hepatic adverse effects.

Treatment of venous thromboembolism and long-term prevention of recurrence: present treatment options and ximelagatran

Despite the effectiveness of anticoagulant therapy for the treatment of acute venous thromboembolism and the prevention of recurrent venous thromboembolism, existing antithrombotic therapies are suboptimal. Unfractionated heparin, low-molecular-weight heparin (LMWH) and warfarin have practical limitations and carry the risk of treatment-related adverse events that restrict their clinical benefits and reduce cost-effectiveness. Efforts to achieve optimal venous thromboembolism prophylaxis by modifying the intensity of oral warfarin treatment have produced equivocal results, and there is a need for new, efficacious antithrombotic drugs providing predictable, well-tolerated oral dosing without the need for coagulation monitoring. Such agents would ideally have no significant food or drug interactions, and be suitable for both short- and long-term treatment. Ximelagatran, the first oral direct thrombin inhibitor, has the potential to fulfill many of the unmet needs in the management of venous thromboembolism.

Pharmacoeconomics of Thrombosis Management

Venous thromboembolism (VTE) is the cause of significant morbidity and mortality and may lead to other complications, including recurrent VTE and long-term postthrombotic syndrome. Venous thromboembolism represents a huge health economic burden of nearly 500 million dollars/year in the United States. Without adequate prophylaxis, patients undergoing major orthopedic surgery are at high risk of developing VTE. Prophylaxis with either unfractionated heparin or warfarin not only substantially reduces the risk of VTE after orthopedic surgery, but also is more cost-effective than no prophylaxis. Low-molecular-weight heparins (LMWHs) have been shown to be superior to unfractionated heparin or warfarin, and despite the fact that they are more expensive, they are cost-effective. Large-scale clinical trials have shown that fondaparinux further reduces the likelihood of VTE complications after major orthopedic surgery. A review of the pharmacoeconomic evaluations of fondaparinux leads to the conclusion that fondaparinux is a cost-effective alternative to LMWHs in VTE prophylaxis.

Cost-effectiveness of testing for hypercoagulability and effects on treatment strategies in patients with deep vein thrombosis

PURPOSE

Among patients with deep vein thrombosis, hypercoagulable conditions impart a substantial risk of recurrent thrombosis. We sought to determine the cost-effectiveness of testing for these disorders, as well as which tests should be selected and how results should be used.

METHODS

Using a Markov state-transition model, strategies of testing or not testing for a hypercoagulable state followed by anticoagulation for 6 to 36 months were compared in a hypothetical cohort of patients with apparently idiopathic deep vein thrombosis who were followed for life. Strategies were compared based on lifetime costs, quality-adjusted life-years (QALYs), and marginal cost-effectiveness.

RESULTS

In the base case, testing followed by 24 months of anticoagulation in patients with a hypercoagulable condition was more cost-effective ($54,820; 23.76 QALYs) than usual care, which comprised 6 months of anticoagulation without testing ($55,260; 23.72 QALYs). All hypercoagulable conditions tested were common enough and associated with a sufficient risk of recurrence to justify inclusion in a test panel. Twenty-four months of initial anticoagulation was preferred (<$50,000/QALY) for most conditions, whereas lifetime anticoagulation was preferred for patients with antiphospholipid antibody syndrome ($2928/QALY) or homozygous factor V Leiden mutation ($3804/QALY). Models using newer evidence on recurrence suggested 18 to 36 months of anticoagulation without testing as the preferred approach.

CONCLUSION

Testing for hypercoagulable disorders in patients with idiopathic deep vein thrombosis followed by 2 years of anticoagulation in affected patients is cost-effective. A simpler approach of treating all patients with prolonged anticoagulation without testing is justified if data confirm the persistent risk of recurrent thrombosis.

Measuring the outcomes and pharmacoeconomic consequences of venous thromboembolism prophylaxis in major orthopaedic surgery

Patients who have undergone orthopaedic surgery represent a high-risk group for venous thromboembolism (VTE). Despite the routine prophylactic use of antithrombotic agents, patients still experience thrombotic events that can result in mortality and acute morbidity and, in significant numbers of patients, may lead to long-term consequences such as the post-thrombotic syndrome. Increasingly, initial VTE events occur after hospital discharge since the length of stay in hospital after major orthopaedic surgery has decreased in many countries. There is a need for further improvement in the prevention of VTE. As well as undergoing extensive safety and efficacy studies for registration purposes, new prophylactic strategies need to be evaluated from a pharmacoeconomic perspective to help guide their introduction into routine clinical practice. Over the past 15 years a number of pharmacoeconomic evaluation studies of VTE prophylaxis have been carried out in orthopaedic patients, most of which evaluated short-term clinical endpoints. During the same period, improvements in our understanding of the natural history of VTE as well as the emergence of new treatments have led to changes in the management of patients with, or at risk of, VTE. The aim of this paper was to address how best to conduct pharmacoeconomic analyses of new antithrombotic agents in light of changes in practice patterns for orthopaedic patients and greater understanding of the disease process. We put forward recommendations for relevant outcome measures, timeframes, endpoints and epidemiologic data sources. We also suggest a structure for a pharmacoeconomic model. In this model, the outcomes and costs of VTE-related care during both the acute and chronic phases of the disease are incorporated. Symptomatic deep vein thrombosis and pulmonary embolism, recurrent VTE, post-thrombotic syndrome, major hemorrhage and all-cause death are included. We also recommend that the relevance of quality-adjusted survival is investigated, and that economic appraisals are presented in both cost-consequence and budget-impact approaches. These recommendations are based on extensive examination of recent advances in the management of VTE combined with a greater understanding of its natural history.

The rationale and evidence for the treatment of lower-extremity deep venous thrombosis with thrombolytic agents

This article presents the rationale and evidence for the treatment of lower-extremity deep venous thrombosis (DVT) with thrombolytic agents. DVT is a common condition that has both acute and chronic complications. Standard treatment including anticoagulation therapy and compression stockings may not be entirely adequate, because a significant proportion of patients eventually develop severe post-thrombotic syndrome (PTS). Thrombolytic agents offer a potential advantage because they may reduce residual vein stenosis and valve damage. The authors performed a systematic review of published randomized trials evaluating thrombolytic agents for DVT. The authors determined that thrombolysis therapy results in greater lysis and complication rates than does anticoagulation alone. The authors also found that PTS incidence is lower in patients treated with thrombolytics. However, several methodological flaws limit the conclusions with respect to reduction in PTS. Therefore, the authors conclude that although the lysis rate is greater for thrombolytic agents, they cannot be recommended routinely for DVT treatment.

Bed rest versus ambulation in the initial treatment of patients with proximal deep vein thrombosis

A large number of trials have shown that many patients with venous thromboembolism can be treated as outpatients by using low molecular weight heparin. However, the amount of physical activity is neither mentioned in the study protocols nor in the instruction brochures, which are given to the patients. In most institutions, the fear of dislodging clots by ambulation is more common than the consideration of thrombus propagation and of recurrence; therefore, bed rest is recommended at least for the initial stage. There have been two randomized trials showing that bed rest as a part of the initial treatment of patients with deep vein thrombosis (DVT) is not able to substantially reduce the incidence of pulmonary emboli detected by repeat lung scanning. In one study performed in patients with proximal DVT, it could be demonstrated that leg compression and walking exercises are able to reduce edema and pain more rapidly and more effectively than bed rest. Progression of the thrombus size assessed by an independent Duplex examiner was statistically significantly greater in those patients confined to bed when compared with ambulatory patients with compression therapy. By counteracting against venous stasis, walking exercises and compression therapy have an important impact on the clinical outcome and should therefore be addressed in future studies.

DVT: the forgotten factor in leg ulcer prevention

Although deep vein thrombosis is often a primary cause of venous leg ulceration, many nurses are unaware of how it can be prevented. More attention must be paid to this area of practice, says Christina Lindholm.

Underlying factors influencing the development of the post-thrombotic limb

PURPOSE

This study was designed to determine whether patients having underlying venous disease in their contralateral limbs indicates a more severe long-term clinical outcome in the ipsilateral limb after a deep vein thrombosis (DVT) and to determine what other factors may influence the long-term outcome.

METHODS

An acute DVT was initially diagnosed by means of duplex ultrasound scanning. Follow-up clinical examinations and bilateral duplex reflux studies were performed for a mean period as long as 3 years. The patients were divided into two groups: group I, those with no history of a contralateral DVT, and group II, those with a history of a contralateral DVT. The patients were classified at their final examination according to the Clinical, Etiology, Anatomic, Pathophysiologic (CEAP) classification, and the ipsilateral and contralateral limbs were compared. Predisposing factors were compared with the final clinical outcome.

RESULTS

Sixty-three patients were monitored in a mean follow-up period of 3 years. There was a significant difference in the incidence of symptoms between the ipsilateral limbs (P <.01) and the contralateral limbs (P <.001) for both groups. There was no significant difference between the incidence of superficial reflux between the ipsilateral and contralateral limbs, but the deep venous system and perforator veins were involved more often in the ipsilateral limbs. In group I, only six patients (10%) had no evidence of venous dysfunction (CEAP = 0) in their ipsilateral or contralateral limbs at the time of the final examination, and all patients had reversible risk factors. Of patients who had a mild clinical outcome (CEAP score, 1 to 3), 64% had a healthy contralateral limb, and the remaining 36% had mild to moderate disease. Eighty percent of patients with the most severe clinical outcome (CEAP > 3) had mild to moderate venous disease in their contralateral limb and had nonreversible risk factors.

CONCLUSION

There are a significant number of patients with an acute DVT who had an underlying venous disease in the uninvolved contralateral limb. An ipsilateral post-thrombotic limb is more likely to develop in patients with primary venous reflux after an acute DVT. The level of venous dysfunction in the contralateral limb is an indication of the severity of disease developing in the ipsilateral limb. The initial risk factors of the patients have an influence on the final clinical outcome.

Post-thrombotic syndrome after primary event of deep venous thrombosis 10 to 20 years ago

AIMS

We investigated the impact of the extent of primary deep venous thrombosis (DVT) and recurrent thrombotic events in accordance to other presumed prognostic factors for long-term clinical outcome after first DVT.

PATIENTS AND METHODS

All consecutive in-patients, who were treated following first acute DVT between January 1, 1978 and December 31, 1988 at the Department of Angiology were identified by admission lists. Localisation, extent of primary DVT, etiology and concomitant pulmonary embolism (PE) at the time of initial presentation and occurrence of post-thrombotic syndrome (PTS) at follow-up visits were assessed by chart review. The duration and quality of the compression therapy, as well as the accuracy of the oral anticoagulant (OAC) treatment were documented. Recurrence of thrombosis embolism and/or PE with respect to the intensity of OAC was analyzed. Patients were invited to participate in clinical reinvestigation. Patients' history and clinical stage of PTS were re-evaluated and patients were asked for compliance in wearing compression stockings. A survey concerning restriction in quality of life was conducted. Hemodynamic measurements by strain-gauge plethysmography (SGP) were performed.

RESULTS

One hundred and sixty-one patients were eligible for the study. Out of these 132 patients, 82% suffered from the PTS, defined as signs of chronic venous insufficiency (CVI) secondary to DVT of the lower limbs: 74 patients (46%) presented with clinical stage I after Widmer, 47 patients (29%) with clinical stage II and 11 patients (7%) with clinical stage III. No sign of PTS was seen in 29 patients (18%). The mean follow-up period of 6.6 years was statistically not different between the three severity groups of PTS. The severity of clinical symptoms was significantly associated with the recurrence of ipsilateral thrombosis (n = 26/16%). Highest risk for developing severe PTS was seen after four-level DVT and deep vein thrombosis of the lower leg. Patients having had a non-sufficient OAC (Hepatoquick > 25% in more than 50% of measurements) exhibited worse progradient clinical stages. Besides the high rate of bleeding complications after thrombolytic therapy, this strategy did not show more efficiency in prevention of development of severe PTS than heparin therapy alone.

CONCLUSION

Our results show that primary four-level DVT, calf vein thrombosis, recurrence of ipsilateral DVT and a non-sufficient oral anticoagulation are of prognostic significance for developing clinically relevant PTS within 10 to 20 years after first DVT.

Factor V Leiden: the venous thrombotic risk in thrombophilic families

Factor V Leiden (FVL) leads to a sevenfold increased risk of venous thrombosis and is present in 50% of individuals from families referred because of unexplained familial thrombophilia. We assessed the association of FVL with venous thromboembolism (VTE) in 12 thrombophilic families of symptomatic probands with FVL in a retrospective follow-up study. We screened 182 first- and second-degree relatives of the 12 unrelated propositi for the FVL mutation and the occurrence of VTE. The incidence rate of VTE in carriers of FVL (0.56%/year) was about six times the incidence for the Dutch population (0.1%/year). The incidence rate in non-carriers also appeared to be higher (0.15% per year). At the age of 50 years, the probability of not being affected by VTE was reduced to 75% for carriers and to 93% for non-carriers (P = 0.009). Identification of carriers of FV Leiden may be worthwhile in young symptomatic individuals and their relatives with a strong positive family history of venous thromboembolism or a history of recurrent venous thrombosis who may be at risk (e.g. pregnancy, use of oral contraceptives). After adjustment for prothrombin G20210A (present in two families), even higher thrombotic incidence rates were found in carriers and non-carriers of FVL. This makes the presence of other unknown prothrombotic risk factors more probable in these families.

Prevalence of the post-thrombotic syndrome in young women with previous venous thromboembolism

The prevalence of mild, moderate and severe post-thrombotic syndrome (PTS) among 43 young women with a previous single episode of deep vein thrombosis (DVT) was 67%, 7% and 0% respectively. Subjects were assessed at a mean 51 months after the event. Moderate PTS was more common in women with recurrent (n = 9) DVT (44%, P < 0.001). Chronic venous insufficiency, assessed by light reflection rheography (LRR), was significantly (P < 0.05) more prevalent in women with single previous DVT (n = 40), recurrent DVT (n = 9) and isolated pulmonary embolism (PE) (n = 19) compared with healthy age-matched controls (odds ratios 10.9, 52.4 and 3.8 respectively). LRR findings correlated with moderate, but not mild, PTS. There was no correlation between development of PTS and body mass index.