Incidence, natural history and risk factors of deep vein thrombosis in elective knee arthroscopy

AIMS: to determine the incidence, anatomical distribution and extent of deep vein thrombosis (DVT) in limbs undergoing elective unilateral knee arthroscopy without active prophylaxis, to evaluate its effect on venous function following early diagnosis, and to quantify the impact of risk factors on its incidence. METHODS: 102 consecutive patients undergoing unilateral knee arthroscopy without prophylaxis were studied. A history was obtained with emphasis on the risk factors for thromboembolism, and physical examination and colour duplex were performed prior to and within a week after surgery. Patients who developed calf DVT were given aspirin (150 mg) and compression stockings; those with proximal DVT were admitted for anticoagulation (heparin followed by warfarin). Follow-up (mean 118 [range 84-168] days) entailed weekly physical and duplex examinations during the first month and monthly thereafter. RESULTS: 8 patients developed calf DVT in the operated leg (incidence 7.84% [95% CI: 2.7%-13.2%]); thrombosis was asymptomatic in 4 of those (50%), caused calf tenderness in 4 (50%) and a positive Homan's sign in one (12.5%). DVT occurred in the following veins: peroneal 4 subjects (50%), soleal 4 (50%), gastrocnemial 2 (25%) and tibial 2 (25%). Propagation of a calf DVT to the popliteal vein was identified in 1 patient (12.5%). After a median period of 118 days, total clot lysis was found in 50% of DVTs. with partial thrombus resorption in the rest; reflux in the thrombosed veins was present in 75% of limbs with DVT. 43% of patients had 1 risk factor for DVT and 20% had > or = 2. The incidence of DVT was higher amongst those with two or more risk factors for thromboembolism (p <.05) or those with previous thrombosis alone (p <.005). Symptoms or signs of pulmonary embolism were not documented. CONCLUSIONS: Elective unilateral knee arthroscopy performed without prophylaxis is complicated by ipsilateral calf DVT in 7.8% (95% CI: 2.7%-13.2%) of cases. The risk is higher in the presence of previous thrombosis (relative risk: 8.2) and two or more risk factors for DVT (relative risk: 2.94). Thrombosis may propagate to the proximal veins, despite early diagnosis. 50% of calf clots totally lyse in 4 months, yet reflux develops in at least 75% of limbs with DVT. Further studies to determine optimal prophylaxis are warranted.     

Comparison of real-time B-mode ultrasonography and bilateral ascending phlebography for detection of postoperative deep vein thrombosis following elective hip surgery. The Venous Thrombosis Group

A prospective study compared real-time B-mode ultrasound examination with bilateral ascending phlebography in the diagnosis of postoperative deep vein thrombosis in 60 patients undergoing elective total hip replacement. The overall sensitivity and specificity of the ultrasound method were 54 and 91%, respectively, and the positive and negative predictive values were 83 and 69%, respectively. The rather low overall sensitivity of the ultrasound method in this study was due to difficulty in detecting thrombi smaller than 1 cm wherever they were located in the deep veins, and in diagnosing thrombi in the calf, regardless of their size. We conclude that real-time B-mode ultrasonography is a technique that can easily be used routinely for detection of postoperative DVT in hip surgery, but its sensitivity for proximal thrombosis (63%) is too low for it to be used alone.     

全膝关节置换后下肢静脉血栓：完全加压超声联合彩色血流多普勒显像评估

目的：分析完全加压超声联合彩色血流多普勒显像对全膝关节置换后下肢深静脉血栓的诊断价值。 方法：随机抽取2006-03/09择期行全膝关节初次置换患者42例59膝，其中左膝14例，右膝11例，双膝17例。均选用美国Depuy公司含庆大霉素骨水泥固定假体。置换后（13±2）d均由专人做双下肢完全加压超声联合彩色血流多普勒显像检查和静脉造影检查。 结果：完全加压超声联合彩色血流多普勒显像检查共发现急性下肢深静脉血栓者12例，有症状者3例，其中单膝1例，双膝2例。血栓部位均在远端，其中左下肢者5例，右下肢者3例，双下肢者4例。静脉造影检查共发现急性下肢深静脉血栓者7例，有症状者3例，其中单膝1例，双膝2例；血栓部位均在远端，其中血栓部位在左下肢者3例，右下肢者2例，双下肢者2例。与静脉造影检查相比，完全加压超声联合彩色血流多普勒显像检查在下肢深静脉血栓的诊断方面，其精密度达到0.714,特异度为0.80。 结论：采用完全加压超声联合彩色血流多普勒显像检查可以形成特定的声像资料，与静脉造影相比具有较高的特异性和灵敏度。     

An evaluation of suloctidil in the prevention of deep vein thrombosis in neurosurgical patients

Suloctidil (200 mg t.i.d.) was compared with placebo in a randomized, double-blind trial to assess its value in preventing deep venous thrombosis (DVT) in high-risk neurosurgical patients, comprising 136 patients with brain or spinal tumour, head or spinal injury, or subarachnoid or intracranial hemorrhage. 125I fibrinogen leg scanning and impedance plethysmography were performed for up to 14 days to detect DVT. The two groups were also evenly balanced for DVT risk factors. Seventeen of 68 patients (25%) (95% confidence interval, 15-35%) treated with suloctidil and 12 of 68 patients (21%) (95% confidence interval, 11-32%) treated with placebo developed deep venous thrombosis. This observed difference in outcomes is not statistically significant (X2 = 1.096; p = 0.30). The estimated 95% confidence interval for the true difference in the incidence of DVT between suloctidil-treated and placebo-treated patients ranges from an 11% benefit in favour of suloctidil to an 18% benefit in favour of placebo. Major deep vein thrombosis occurred in two patients on suloctidil and three patients in the placebo group; there were no fatal pulmonary emboli during the 14-day study period, during which time four patients in each group died of non-thromboembolic complications. There was no observed difference in hemorrhagic complications. Long-term outcomes at three-months follow-up were similar between the two treatment groups. It is concluded that there is no real evidence that suloctidil (200 mg t.i.d.) is an effective regimen for the prevention of DVT in high-risk neurosurgical patients.     

The effect of different anaesthetic techniques on the incidence of thrombosis following total hip replacement

We performed a retrospective analysis on the influence of three types of anaesthesia on the incidence of deep vein thrombosis (DVT) following total hip replacement (THR) in consecutive patients randomized to either the low molecular weight heparinoid Org 10172 (97 patients), or placebo (99 patients). Ninety patients were operated under epidural anaesthesia, 77 patients under psoas compartment block with additional inhalation anaesthesia, and 29 patients under general anaesthesia. DVT assessment was performed by bilateral venography between days 8 and 12 postoperatively. The overall incidence of DVT in the 196 patients was 37% in the epidural anaesthesia group, 35% in the psoas compartment block group, and 36% in the general anaesthesia group. Although the incidence of DVT in patients randomized to placebo was similar in the two anaesthesia groups (53%), there was an important reduction of the occurrence of proximal DVT by the heparinoid in the psoas compartment block group (from 20 to 0%), compared to the epidural anaesthesia group (from 27 to 18%) (p less than 0.0061). Significantly more minor wound hematomas occurred in the psoas compartment block group as compared to the epidural anaesthesia group (p less than 0.05). Synergism of thrombin generation inhibition by the heparinoid and inhibition of platelet aggregation at the damaged vessel wall, by high local concentrations of bupivacaine in the psoas compartment block technique, is proposed as a possible mechanism behind this observation.     

A comparison of general anesthesia and regional anesthesia as a risk factor for deep vein thrombosis following hip surgery: a critical review

We evaluated the evidence in support of the suggestion that the risk of deep vein thrombosis after hip surgery is lower with regional than with general anesthesia. A literature search was performed to retrieve all articles which reported on the incidence of postoperative thrombosis in both fractured and elective hip surgery. Articles were included if the method of anesthesia used was reported and if they used mandatory venography. Based upon the quality of study design the level of evidence provided by a study was graded. In patients who did not receive prophylaxis there were high level studies in elective and fractured hip surgery. All studies showed a statistically significantly lower incidence of postoperative deep vein thrombosis with regional anesthesia (relative risk reductions of 46-55%). There were no direct comparative studies in patients who received prophylaxis. However, between study comparisons did not show even a trend towards to lower incidence of postoperative thrombosis with regional anesthesia.     

高血压性脑出血患者并发下肢静脉血栓的危险因素及对策

目的探讨高血压性脑出血后下肢静脉血栓形成的危险因素和防治措施。方法回顾分析9例高血压性脑出血患者发生下肢静脉血栓的临床资料。确诊后均给予抬高患肢、抗血小板、溶栓及抗凝治疗。结果 9例患者中痊愈6例,好转2例,死亡1例。患者肢体瘫痪、高凝状态、下肢血液回流缓慢、静脉壁损伤及血管内异物为下肢静脉血栓形成的高危因素。结论一旦发生下肢深静脉血栓,积极给予抗血小板、溶栓及抗凝等治疗措施,并采取抬高患肢、减少活动是防止血栓脱落发生致死性肺动脉栓塞的关键。     

Management of warfarin-related intracerebral hemorrhage

Warfarin-related intracerebral hemorrhage (WICH) is a medical and neurosurgical emergency with a 1-month mortality of approximately 50%. Warfarin is commonly is used in patients with atrial fibrillation to prevent ischemic stroke and to prevent progression of deep vein thrombosis to pulmonary embolism. Owing to the ageing population, and increased incidence of atrial fibrillation with age and warfarin use, the incidence of WICH is expected to rise in the future. When WICH occurs, immediate discontinuation of warfarin with rapid warfarin reversal remains the first-line intervention, often with neurosurgical intervention. The optimal agent for rapid warfarin anticoagulation reversal remains to be defined owing to the lack of prospective randomized trials. We review current literature and prospects for future research for this devastating neurologic emergency.     

Doppler ultrasonographic examination of the leg veins of patients with Parkinson disease.

OBJECTIVE: To determine the incidence of deep venous thrombosis (DVT) in patients with Parkinson disease. DESIGN: Prospective study. SETTING: Outpatient neurology clinic. PATIENTS: Eighty-one patients with Parkinson disease. OUTCOME MEASURES: Duplex ultrasonographic scans consisting of M mode images and compression images, Doppler flow assessment and augmentation of flow assessment. RESULTS: Four patients had leg DVT; in 3 of the patients the thrombi were in calf veins, whereas in 1 patient the thrombosis was in the superficial femoral vein. Of the patients with DVT, 1 (1.23%) had stage 2 Parkinson disease, 1 (1.23%) had stage 2.5, and the other 2 (2.46%) had stage 4. CONCLUSIONS: There was no statistically significant difference in the incidence of DVT among patients who were more severely disabled by Parkinson disease. However, an overall incidence of DVT of 4.9% in a group of asymptomatic patients is clinically meaningful, suggesting that patients with Parkinson disease are at risk for asymptomatic leg DVT.     

神经外科术后下肢深静脉血栓形成临床分析

目的探讨分析神经外科术后合并下肢深静脉血栓(DVT)形成的危险因素,有效防治措施及预后。方法回顾分析32例神经外科术后并发下肢DVT病例的临床资料。结果合并基础病、手术、术后脱水治疗、术后偏瘫及长期卧床、下肢长期深静脉置管等是神经外科术后并发下肢DVT的危险因素。经抗凝、抗血小板凝集和扩血管等内科综合治疗,临床治愈30例,好转1例,死亡1例。结论神经外科术后存在并发DVT的诸多危险因素,早期预防、及时有效的诊断治疗可改善预后,提高生存质量。     

Application of a diagnostic clinical model for the management of hospitalized patients with suspected deep-vein thrombosis

The purpose of this study was to evaluate whether the determination of pretest probability using a simple clinical model and the SimpliRED D-dimer could be used to improve the management of hospitalized patients with suspected deep-vein thrombosis. Consecutive hospitalized patients with suspected deep-vein thrombosis, had their pretest probability determined using a clinical model and had a SimpliRED D-dimer assay. Patients at low pretest probability underwent a single ultrasound test. A negative ultrasound excluded the diagnosis of deep-vein thrombosis whereas a positive ultrasound was confirmed by venography. Patients at moderate pretest probability with a positive ultrasound were treated for deep-vein thrombosis whereas patients with an initial negative ultrasound underwent a single follow-up ultrasound one week later. Patients at high pretest probability with a positive ultrasound were treated whereas those with negative ultrasound underwent venography. All patients were followed for three months for the development of venous thromboembolic complications. Overall, 28% (42/150), and 10% (5/50), 21% (14/71) and 76% (22/29) of the low, moderate and high pretest probability patients. respectively, had deep vein thrombosis. Two of 111 (1.8%; 95% CI = 0.02% to 6.4%) patients considered to have deep vein thrombosis excluded had events during three-month follow-up. Overall 13 of 150 (8.7%) required venography and serial testing was limited to 58 of 150 (38.7%) patients. The negative predictive value of the SimpliRED D-dimer in patients with low pretest probability was 96.2%, which is not statistically different from the negative predictive value of a negative ultrasound result in low pretest probability patients (97.8%). Management of hospitalized patients with suspected deep-vein thrombosis based on clinical probability and ultrasound of the proximal deep veins is safe and feasible.     

Deep vein thrombosis and fibrinolysis. Defective urokinase type plasminogen activator release.

In the present study 57 consecutive patients with a first episode of venographically proven deep vein thrombosis were investigated to evaluate the release of tissue-type plasminogen activator (t-PA) and of urokinase-type plasminogen activator (u-PA) in response to DDAVP stimulation as well as the resting plasminogen activator inhibitor (PAI) concentration, comparing this to the results obtained in 66 similar patients with a clinical suspicion of thrombosis but with a normal venogram. All assays were performed without knowledge of the patient's status. Four patients in the deep vein thrombosis-group (7%) had an absent u-PA antigen response upon DDAVP infusion, while a normal response was observed in all control subjects. Patients and controls showed similar increases in t-PA antigen level upon DDAVP. High resting PAI antigen levels were encountered in 5 patients in the deep vein thrombosis-group (9%) and in 6 subjects in the control group (9%). The results from this controlled study indicate that a defective release of u-PA may occur in patients with deep vein thrombosis and may have pathogenetic significance. Furthermore it is concluded that elevation of PAI levels cannot be considered as a specific risk factor for venous thrombosis.     

Possible contribution of cytomegalovirus infection to the high risk of (recurrent) venous thrombosis after renal transplantation

Renal transplant recipients are at an increased risk of venous thrombosis, which has been regarded as a postoperative complication, although it may persist afterwards. As numerous case reports have shown that active cytomegalovirus (CMV) infection can be found at time of onset of venous thrombosis, and is frequently found in renal transplant recipients, we hypothesized that one might be the result of the other. To calculate the risk of (recurrent) venous thrombosis in renal transplant recipients, and to see whether CMV infection influenced this risk, we retrospectively analysed 606 living consecutive renal transplant recipients. CMV status at time of transplantation and at time of enrolment was determined. Absolute risks of first venous thrombosis and recurrence were compared with CMV status, and were corrected for surgery related venous thrombosis, age, and anticoagulant treatment. Annual incidence of venous thrombosis was 0.88% (95% CI, 0.65-1.15) in all recipients and 0.59% (95% CI, 0.41-0.83) corrected for surgery related venous thrombosis. CMV positive and seroconverted recipients tended to have an increased risk of venous thrombosis compared to CMV negative recipients; corrected relative risks were 2.0 (95% CI, 0.9-5.2) and 1.7 (95% CI, 0.6-4.7), respectively. The cumulative 10-year recurrence rate of venous thrombosis in CMV seronegative, seroconverted, and seropositive recipients was 10%, 51% and 59%, respectively. We conclude that CMV infection tended to be associated with an increased risk of (recurrent) venous thrombosis. Prospective studies are warranted to establish this observation, which suggests that CMV infection influences the high risk of (recurrent) venous thrombosis in renal transplant recipients.     

High prevalence of asymptomatic deep vein thrombosis on admission in a medical unit among elderly patients

The prevention of venous thromboembolism in medical patients remains questioned. All consecutive outpatients admitted in our medical unit were considered for inclusion in this study which aimed to estimate the prevalence of asymptomatic venous thrombosis on admission and the incidence during hospital stay. Exclusion criteria were: age <18 years, suspicion of venous thromboembolism, stay <4 days, ongoing anticoagulant therapy. Venous compression ultrasonography of the lower limbs was performed within 48 h. 234 patients were included. The prevalence of asymptomatic deep vein thrombosis on admission and the incidence during hospital follow-up were respectively 5.5% (95% confidence interval, 3.1 to 9.5%) and 2.6 per 1,000 person-days (95% confidence interval, 0.0 to 5.2). The prevalence and the incidence reached respectively 17.8% (95% confidence interval, 8.5 to 32.6%) and 6.0 per 1,000 person-days (95% confidence interval, 0.0 to 12.7) among patients over 80 years. A high prevalence of asymptomatic deep vein thrombosis on admission was suggested particularly among elderly medical patients.     

Intermittent pneumatic compression and deep vein thrombosis prevention. A meta-analysis in postoperative patients

Our objective was to overview the effectiveness of intermittent pneumatic compression (IPC) devices to prevent deep vein thrombosis (DVT) in postoperative patients, using meta-analysis methodology. We searched the Medline, metaRegister of Controlled Trials, and Cochrane database for studies published between 1970 and October 2004. Our inclusion criteria were: 1) randomized controlled trial of IPC versus no prophylaxis, 2) at least 20 patients per group, 3) at least one diagnostic DVT imaging test in all patients, and 4) clinical follow-up for at least the duration of hospitalization. A total of 2,270 patients were included in 15 eligible studies: 1,125 and 1,145 in the IPC and no prophylaxis group, respectively. The included studies formed a total of 16 treatment groups and were conducted in orthopedic (5), general surgical (4),oncologic (3), neurosurgical (3) and urologic (1) patient populations. In comparison to no prophylaxis, IPC devices reduced the risk of DVT by 60% (relative risk 0.40, 95% CI 0.29 - 0.56; p < 0.001). Contemporary randomized trials should be undertaken to test the utility of IPC in hospitalized medical patients as well as combined pharmacological plus IPC prophylaxis in both medical and surgical patients.     

Prevention of postoperative venous thrombosis: a randomized trial comparing unfractionated heparin with low molecular weight heparin in patients undergoing total hip replacement

A double blind randomized trial comparing subcutaneous enoxaparin (40 mg once daily) with standard unfractionated calcium heparin administered at a dose of 5,000 units every 8 hours in patients undergoing elective hip replacement has been performed. Treatment regimens began 12 hours preoperatively with enoxaparin, 2 hours preoperatively with standard unfractionated calcium heparin, and were continued for 15 days or until discharge. Venography was performed in all patients. Two hundred thirty-seven patients were included in the study: 113 received unfractionated heparin and 124 received enoxaparin. The incidence of proximal deep vein thrombosis was reduced from 18.5% in the unfractionated heparin group to 7.5% in the enoxaparin group (p = 0.014), and the incidence of total deep vein thrombosis was similarly reduced from 25% to 12.5% (p = 0.03). There were two major bleeding episodes and one minor bleed in the enoxaparin group compared to two minor bleeds in the unfractionated heparin group. Patients who received enoxaparin required fewer red blood cell transfusions and had a significantly higher hemoglobin on postoperative days 3 and 4. Thus prophylaxis with enoxaparin, 40 mg once daily, is simple, safe and more effective than standard low dose unfractionated heparin in preventing deep vein thrombosis in patients undergoing elective hip replacement.     

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

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

细胞黏附分子血浆E-选择素水平与下肢深静脉血栓形成

背景：研究表明，深静脉内白细胞参与的炎症反应在深静脉血栓形成中起了很重要的作用，而E-选择素的主要作用是介导炎症过程中白细胞与血管内皮细胞黏附的起始过程。 目的：拟观察细胞黏附分子E-选择素水平与下肢深静脉血栓形成的关系。 设计、时间及地点：配对设计，直线相关分析，于2007-09/12在重庆医科大学附属第一医院血管外科及重庆医科大学临床检验诊断学实验室完成。 对象：选择发病在3 d 内或病情加重的27例下肢深静脉血栓形成患者，男16例，女11例，平均年龄(57±15)岁。 方法：入院时采集第1次血液标本，经过溶栓，抗凝治疗72 h 后采集第2次血液标本。用ELISA法测定血浆中E-选择素的质量浓度，同时测定第1次采血样本的血小板计数及其凝血功能，包括部分激活凝血活酶时间、凝血酶原时间、血浆纤维蛋白原。 主要观察指标：治疗前后患者E-选择素的水平，治疗前凝血功能、血小板计数及与E-选择素相关性分析。 结果：27例下肢深静脉血栓形成患者在治疗期间均未发生急性肺栓塞，1例行Forgart导管取栓术，其余26例患者72 h 后，15例患者临床症状明显好转，11例临床症状未见好转。①下肢深静脉血栓形成患者经过溶栓、抗凝治疗临床缓解者血浆E-选择素水平明显下降(P=0.001)，而临床未缓解者血浆E-选择素水平则呈上升表现(P=0.003)。②下肢深静脉血栓形成患者治疗前E-选择素水平与血小板计数无相关性(r=-0.113，P=0.576)，与纤维蛋白原含量无相关性(r=-0.050，P=0.802)，与部分激活凝血活酶时间无相关性(r=-0.046，P=0.822)，与凝血酶原时间亦无相关性(r=-0.080，P=0.690)。 结论：血浆E-选择素水平与深静脉血栓形成症状严重程度呈正相关性。     

Prevention of deep vein thrombosis after hip replacement--comparison between two low-molecular heparins, tinzaparin and enoxaparin.

Consecutive patients undergoing total hip replacement in 43 centres were randomly assigned to receive blindly either enoxaparin (40 mg) or tinzaparin (4,500 anti-Factor IU Xa), as once daily subcutaneous injections. The first injection was administered 12 h preoperatively. Efficacy was assessed by bilateral venography performed 12-14 days postoperatively. Efficacy and safety were blindly and centrally adjudicated. Among the 499 patients included, 440 had a venogram. The total incidence of DVTs was 44 (20.1%) of the 219 patients of the enoxaparin group and 48 (21.7%) of the 221 patients of the tinzaparin group. The upper limit of the 80% confidence interval of the difference between the two treatment groups was less than 5.0%. Therefore according to the protocol's specifications equivalence was shown. Proximal DVTs occurred in 10.5% of the enoxaparin group (23 patients) and in 9.5% (21 patients) of the tinzaparin group. No overt major bleeding was observed. One patient in the enoxaparin group developed severe thrombocytopenia and died. The LMWH tinzaparin appears clinically to be as effective and safe as enoxaparin in the prophylaxis of deep vein thrombosis after total hip replacement, at the doses used and under the conditions of this study.     

Thrombophilic abnormalities and recurrence of venous thromboembolism in patients treated with standardized anticoagulant treatment

INTRODUCTION: Whether patients with hereditary or acquired thrombophilia have an increased risk for recurrence of venous thromboembolism (deep vein thrombosis and/or pulmonary embolism) is still controversial. The aim of this study was to evaluate the incidence of recurrence of venous thromboembolism in patients with and without thrombophilic abnormalities treated with standardized anticoagulant treatment. MATERIAL AND METHODS: Database was from a prospective multicenter randomized study aimed at evaluating the long-term clinical benefit of extending to 1 year the 3-month oral anticoagulant treatment after a first episode of idiopathic proximal deep vein thrombosis. The screening for thrombophilia included antithrombin, protein C, protein S deficiencies, resistance to activated protein C and/or factor V R506Q mutation, the mutation 20210GA of the prothrombin gene, hyperhomocysteinemia and antiphospholipid antibodies. The diagnosis of venous thromboembolism recurrence was done by objective tests and adjudicated by a panel unaware of the results of the thrombophilia screening. RESULTS: A screening for thrombophilic abnormalities was performed in 195 patients. Twenty of 57 (35.1%) thrombophilic patients experienced a recurrence of venous thromboembolism as compared with 29 of 138 (21.0%) patients without thrombophilia (HR=1.78, 95% CI 1.002-3.140, p=0.046). The difference in VTE recurrence between patients with and without thrombophilia was accounted for by those who received 3 months of oral anticoagulation (HR=3.21, 95% CI 1.349-7.616, p=0.008). No difference between thrombophilic and non-thrombophilic patients was observed in the time interval from the index episode to recurrent venous thromboembolism (29.1+/-23.9 and 30.6+/-19.8 months, respectively). CONCLUSIONS: Thrombophilic abnormalities are associated with an increased risk of venous thromboembolism recurrence. The role of thrombophilia in the long-term management of venous thromboembolism should be addressed in prospective management studies.