Distal DVT: worth diagnosing? Yes

Emergency medicine residents' learning curve in diagnosing deep vein thrombosis with 3-point venous point-of-care ultrasound

BACKGROUND

Many cases of deep vein thrombosis (DVT) are diagnosed in the emergency department, and abbreviated lower extremity venous point-of-care ultrasound (POCUS) has already shown an accuracy comparable to that of specialists. This study aimed to identify the learning curve necessary for emergency medicine (EM) residents to achieve expertise-level accuracy in diagnosing DVT through a 3-point lower extremity venous POCUS.

METHODS

This prospective study was conducted at an emergency department between May 2021 and October 2022. Four EM residents underwent a one-hour POCUS training session and performed DVT assessments in participants with DVT symptoms or confirmed pulmonary embolism. POCUS was performed at three proximal lower extremity sites to evaluate the thrombi presence and vein compressibility, with results validated by specialized radiology ultrasound. Cumulative sum (CUSUM) and the Bush and Mosteller models were used to analyze the learning curve, while generalized estimating equations were used to identify factors affecting diagnostic accuracy.

RESULTS

91 POCUS scans were conducted in 49 patients, resulting in 22% DVT confirmed by specialized venous ultrasound. In the CUSUM analysis, all four EM residents attained a 90% success rate at the common femoral vein, whereas only half achieved this rate when all three sites were considered. According to Bush and Mosteller models, 13-18 cases are required to attain 90-95% diagnostic accuracy. After 10-16 cases, the examination time for each resident decreased, and a 20% increase in examiner confidence was linked to a 2.506-fold increase in the DVT diagnosis accuracy.

CONCLUSION

EM residents generally required 13-18 cases for 90-95% DVT diagnostic accuracy, but proficiency varied among individuals, particularly requiring more cases for regions outside the common femoral vein.

Management of isolated distal deep vein thrombosis

Isolated distal deep vein thrombosis (DVT) represents up to 50% of all lower limb DVT in ultrasound series and is a frequent medical condition, which management is not well established. Data arising from registries and non-randomized studies suggest that most distal DVTs do not extend to the proximal veins and have an uneventful follow-up when left untreated. This data had some impact on international recommendations like the American College of Chest Physicians (ACCP), whose last version stated that ultrasound surveillance might be an option for selected low-risk patients. However, robust data arising from randomized studies are scarce. Indeed, only seven randomized trials assessing the need for anticoagulation for calf DVT have been published. Many of these trials had an open-label design and were affected by methodological limitations. When considering randomized placebo-controlled trials, one included low-risk patients and was hampered by a limited statistical power (CACTUS study). Nevertheless, data from this trial tend to confirm that the use of therapeutic anticoagulation in low-risk patients with symptomatic calf DVT is not superior to placebo in reducing VTE but is associated with a higher risk of bleeding. A second randomized placebo-controlled trial did not assess the necessity of anticoagulant treatment but rather the long-term risk of recurrence and compared 6 weeks versus 12 weeks of treatment with rivaroxaban (RIDTS study). Finally, the last available randomized trial compared a 3-month versus a 12-month edoxaban treatment in patients with cancer and mainly asymptomatic distal DVT, detected by systematic compression ultrasonography. Overall, available data suggest that the use of therapeutic anticoagulation in low-risk patients with symptomatic calf DVT is not superior to placebo in reducing VTE. High risk patients (previous VTE, active cancer, inpatients) might benefit from a course of anticoagulant treatment. However, the optimal anticoagulant intensity and duration are uncertain and further studies are needed.

Risk factors and prediction model of nomogram for preoperative calf muscle vein thrombosis in geriatric hip fracture patients

Introduction

Calf muscular vein thrombosis (CMVT) is a common complication in geriatric hip fracture patients. Despite its high incidence, prior research on the topic is limited. The occurrence of CMVT in patients will prolong the preoperative waiting time and even lead to serious thromboembolic events, which can be detrimental to the patient's prognosis. Therefore, this study aimed to identify the risk factors for preoperative CMVT in geriatric hip fracture patients and construct a nomogram model to predict the risk of preoperative CMVT in patients.

Materials and methods

Geriatric hip fracture patients who underwent surgery between January 2019 and January 2022 were included. The patients were categorized into two groups depending on whether they had preoperative CMVT, confirmed through Color Doppler ultrasound or venography examination. Univariate and multivariate logistic regression analyses were used to analyze demographic characteristics, medical history, comorbidities, and laboratory tests. A nomogram was constructed to predict preoperative CMVT in geriatric hip fracture patients based on the results of the multivariate logistic regression.

Results

Three hundred and eighty-eight geriatric hip fracture patients, including one hundred and thirty-four patients with CMVT and two hundred and fifty-four patients without CMVT, were ultimately included in our study. After multivariable logistic regression analysis, the time from injury to admission, smoking history, serum albumin levels, and D-dimer levels was identified as independent risk factors and was entered into a nomogram model. The nomogram showed robust discrimination, with an area under the receiver operating characteristic curve of 0.805. The calibration curve showed strong agreement between the CMVT probabilities predicted by the nomogram and the actual probabilities. The decision curve analysis illustrates the excellent clinical utility of the model.

Conclusion

We have constructed a new nomogram prediction model that can effectively predict the risk of preoperative CMVT in geriatric hip fracture patients based on their medical history and blood test results. This model can help clinicians make individualized predictions of CMVT that are tailored to each patient's unique circumstances.

Isolated distal deep vein thrombosis: What have we learnt from the OPTIMEV study?

The OPTIMEV (OPTimisation de l'Interrogatoire dans l'évaluation du risque throMbo-Embolique Veineux) study has provided some important and innovative information for the management of lower extremity isolated distal deep vein thrombosis (distal DVT). Indeed, if distal deep-vein thrombosis (DVT) therapeutic management is nowadays still debated, before the OPTIMEV study, the clinical relevance of these DVT itself was questioned. Via the publication of 6 articles, between 2009 and 2022, assessing risk factors, therapeutic management, and outcomes of 933 patients with distal DVT we were able to demonstrate that: - When distal deep veins are systematically screened for suspicion of DVT, distal DVT are the most frequent clinical presentation of the venous thromboembolic disease (VTE). This is also true in case of combined oral contraceptive related VTE. - Distal DVT share the same risk factors as proximal DVT and constitute two different clinical expressions of the same disease: the VTE disease. However, the weight of these risk factors differs: distal DVT are more often associated with transient risk factors whereas proximal DVT are more associated with permanent risk factors. - Deep calf vein and muscular DVT share the same risk factors, short and long-term prognoses. - In patients without history of cancer, risk of unknown cancer is similar in patients with a first distal or proximal DVT. - After 3years and once anticoagulation has been stopped, distal DVT recur twice less as proximal DVT and mainly as distal DVT; However, in cancer patients, prognosis of distal and proximal DVT appear similar in terms of death and VTE recurrence.

The Risk Factors for New-Onset Calf Muscle Venous Thrombosis after Hip Fracture Surgery

BACKGROUND

Calf muscle venous thrombosis (CMVT) is among the most important medical complications after hip surgery. CMVT has been known for many years, but many opinions about the incidence and risk factors of CMVT are still controversial. The objective of this retrospective study was to investigate the incidence and associated risk factors of postoperative CMVT in patients with hip fractures.

METHODS

Patients with hip fractures from January 2020 to April 2022 (n = 320) at Shenzhen Second People's Hospital were recruited in this study. The personal characteristics and clinical data of CMVT and no-CMVT patients were compared and analyzed. Binary logistic regression analyses were performed to identify potential risk factors of CMVT in patients with hip fractures. Finally we performed a receiver operating characteristic (ROC) curve analysis to compare the diagnostic values of different variables.

RESULTS

The overall incidence of new-onset CMVT in patients with hip fractures was 18.75% (60 of 320). Among the 60 CMVT patients, 70% (42 of 60) were diagnosed with femoral neck fractures, 28.3% (17 of 60) with intertrochanteric fractures, and 1.7% (1 of 60) with subtrochanteric fractures. No pulmonary embolism (PE) occurred. High preoperative D-dimer (OR = 1.002, 95%CI 0.97-1.03), sex (OR = 1.22, 95%CI 0.51-2.96), the caprini score (OR = 2.32, 95%CI 1.05-5.16) and the waterlow score (OR = 1.077, 95%CI 0.35-3.36) significantly increased the risk of developing postoperative new-onset CMVT.

CONCLUSIONS

CMVT has become a common clinical disease, and its harm should not be underestimated. Our study found that D-dimer, sex, the caprini score and the waterlow score were independent risk factors for postoperative CMVT. According to our clinical work, we should pay attention to identifying the risk factors of CMVT formation and targeted intervention measures to prevent new-onset CMVT.

Construction and Validation of a Nomogram for Predicting the Risk of Deep Vein Thrombosis in Hepatocellular Carcinoma Patients After Laparoscopic Hepatectomy: A Retrospective Study

Background

The incidence of deep vein thrombosis (DVT) in hepatocellular carcinoma (HCC) patients after laparoscopic hepatectomy (LH) is unclear, and there is no effective method for DVT risk assessment in these patients.

Methods

The data from the total of 355 consecutive HCC patients who underwent LH were included. A DVT risk algorithm was developed using a training set (TS) of 243 patients, and its predictive performance was evaluated in both the TS and a validation set (VS) of 112 patients. The model was then used to develop a DVT risk nomogram (TRN).

Results

The incidence of DVT in the present study was 18.6%. Age, sex, body mass index (BMI), comorbidities and operative position were independent risk factors for DVT in the TS. The model based on these factors had a good predictive ability. In the TS, it had an area under the receiver operating characteristic (AUC) curve of 0.861, Hosmer-Lemeshow (H-L) goodness of fit p value of 0.626, sensitivity of 44.4%, specificity of 96.5%, positive predictive value (PPV) of 74.1%, negative predictive value (NPV) of 88.4%, and accuracy of 86.8%. In the VS, it had an AUC of 0.818, H-L p value of 0.259, sensitivity of 38.1%, specificity of 98.9%, PPV of 88.9%, NPV of 87.4%, and accuracy of 87.5%. The TRN performed well in both the internal and the external validation, indicating a good clinical application value. The TRN had a better predictive value of DVT than the Caprini score (p < 0.001).

Conclusion

The incidence of DVT after LH was high, and should not be neglected in HCC patients. The TRN provides an efficacious method for DVT risk evaluation and individualized pharmacological thromboprophylaxis.

Profile of Patients with Isolated Distal Deep Vein Thrombosis versus Proximal Deep Vein Thrombosis or Pulmonary Embolism: RE-COVERY DVT/PE Study

Isolated distal deep vein thrombosis (IDDVT) is presumed to be more benign than proximal DVT (PDVT) or pulmonary embolism (PE), suggesting a need for different management approaches. This subgroup analysis of the RE-COVERY DVT/PE global, observational study investigated patient characteristics, hospitalization details, and anticoagulant therapy in patients with IDDVT in real-world settings in 34 countries enrolled from January 2016 to May 2017. Data were analyzed descriptively according to the type and location of the index venous thromboembolism (VTE): IDDVT, PDVT ± distal DVT (DDVT), and PE ± DVT. Of the 6,095 eligible patients, 323 with DVT located outside the lower limb and no PE were excluded. Of the remaining 5,772 patients, 17.6% had IDDVT, 39.9% had PDVT ± DDVT, and 42.5% had PE ± DVT. IDDVT patients were younger and had fewer risk factors for VTE than the other groups. Other comorbidities were less frequent in the IDDVT group, except for varicose veins, superficial thrombophlebitis, and venous insufficiency. IDDVT patients were less likely to be diagnosed in an emergency department (22.3 vs. 29.7% for PDVT ± DDVT and 45.4% for PE ± DVT) or hospitalized for VTE (29.2 vs. 48.5% for PDVT ± DDVT and 75.0% for PE ± DVT). At hospital discharge or 14 days after diagnosis (whichever was later), non-vitamin K antagonist oral anticoagulants were the most commonly used anticoagulants (55.6% for IDDVT, 54.7% for PDVT ± DDVT, and 52.8% for PE ± DVT). Although differences in patient characteristics, risk factors, and clinical management were identified, anticoagulant treatment of IDDVT was almost equal to that of PDVT or PE. Prospective studies should investigate whether, in a global perspective, this is an appropriate use of anticoagulants. TRIAL REGISTRATION NUMBER:  ClinicalTrials.gov NCT02596230.

Calf deep vein thrombosis – clinical relevance, diagnostic approaches and therapeutic options

Summary. Isolated distal deep vein thromboses (IDDVT) represent up to 50 % of legs deep vein thromboses (DVT). However, since their natural history is to date unknown, the need to diagnose and treat them is a matter of debate. The diagnostic strategy based on the assessment of pre-test probability and D-dimer demonstrated a scarse efficiency for IDDVT. The choice between a proximal and a complete ultrasonographic approach should be guided by the clinical context, the local expertise and the patient characteristics. Randomized and observational studies have analyzed the need of therapy and compared different regimens of anticoagulation, with conflicting results. Systematic reviews and meta-analyses tend to support the usefulness of an anticoagulant treatment, even if the optimal dose and duration are not still defined. A careful stratification of the patient’s profile, taking into account risk factors for proximal extension, recurrence and bleeding should address the therapeutic approach, which must always be discussed with an adequately informed patient. Further studies aimed to clarify the natural history of IDDVT, and to assess safety and efficacy of lower intensity and shorter duration protocols are urgently needed.

Deep venous thrombosis after Achilles tendon rupture is associated with poor patient-reported outcome

PURPOSE

The aim of this study was to investigate whether patient subjective and functional outcomes after Achilles tendon rupture (ATR) are related to deep venous thrombosis (DVT) during leg immobilization.

METHODS

A cohort study with prospectively collected randomized data was conducted between 2010 and 2017. Two-hundred and fifty-one Patients with an Achilles tendon rupture (mean age = 41 ± 8), treated with uniform surgical techniques, were retrospectively analyzed. DVT incidence at 2 and 6 weeks was assessed using compression duplex ultrasound. At 12 months patient-reported outcomes were assessed using the Achilles tendon Total Rupture Score (ATRS), Foot- and Ankle Outcome Score (FAOS), Physical Activity Scale (PAS) and functional outcome with the calf-muscle endurance test. ANOVA analyses were used and adjusted for assumed confounding factors (patient age, sex, BMI and rehabilitation).

RESULTS

The total DVT incidence was 122 out of 251 (49%). Patients suffering a DVT exhibited significantly lower ATRS at 1 year compared to patients without DVT (mean 76 vs 83, 95% CI 71-79 vs 80-87; p < 0.01). Sixty-seven percent (95% CI 57-77%) of the patients devoid of DVT reported a good outcome (ATRS > 80) compared to 51% (95% CI 41-61%) of the patients sustaining a DVT (p < 0.05). Quality of life displayed significantly better outcome in the non-DVT versus DVT patients (mean = 75 (95% CI 71-79) vs. mean = 68 (95% CI 64-72); p < 0.05). A significant difference in total concentric work was observed between non-DVT and DVT patients (median = 1.9 kJ (IQR = 0.9 kJ) vs. median = 1.6 kJ (IQR = 1.0 kJ); p < 0.01).

CONCLUSION

Sustaining a DVT during leg immobilization significantly impairs patient-reported outcome at 1 year after surgical repair of ATR.

LEVEL OF EVIDENCE

III.

Incidence and Risk Factors Associated with Venous Thromboembolism After Orthopaedic Below-knee Surgery

INTRODUCTION

Among patients undergoing below-knee orthopaedic surgery, no consensus exists regarding the need for or type of postoperative prophylaxis to prevent venous thromboembolic (VTE) events. The purpose of this study was to assess the incidence and risk factors associated with symptomatic VTE among orthopaedic patients undergoing below-knee surgery who were subject to different types of pharmacologic thromboprophylactic strategies.

METHODS

A total of 20,043 adult patients who underwent surgery for a below-knee orthopaedic condition between August 2005 and August 2015 were identified. Retrospective chart review recorded patient demographics, comorbid data, and anatomic location of any procedures performed. Multivariable logistic regression analysis was used to determine factors associated with postoperative development of symptomatic VTE among patients receiving various thromboprophylactic regimens.

RESULTS

The incidence of symptomatic VTE in patients who underwent below-knee surgery was 2.5% (492/20,043). For patients who did not receive thromboprophylaxis, the incidence was 1.5% (134/9,127 patients). In this group, risk factors for developing VTE were male sex; nonwhite race; surgery performed below the knee but above the ankle; combination procedures of the forefoot/midfoot, hindfoot/ankle, and/or lower leg; history of VTE; and Charlson Comorbidity Index score greater than 2. Among patients who received an antiplatelet agent, the VTE incidence was 1.7% (33/1,992 patients). The incidence of VTE among patients who received an oral or injectable anticoagulant was 3.6% (325/8,924 patients). In this group, risk factors for developing VTE were male sex; surgery performed below the knee but above the ankle; combination procedures of the forefoot/midfoot, hindfoot/ankle, and/or lower leg; and history of VTE.

CONCLUSION

Allowing for different types of thromboprophylactic strategies, the results of this study demonstrate a higher rate of symptomatic thromboembolic disease compared with previously reported <1% VTE incidence rates among orthopaedic patients undergoing below-knee surgery. Certain patients are at higher risk for thromboembolic disease after below-knee orthopaedic surgery. This risk was not found to be lowered by thromboprophylaxis as performed in patients in this database. Future research should be directed at determining what the best thromboprophylactic strategies are for lowering this risk.

LEVEL OF EVIDENCE

Therapeutic study level III.

Effect of anticoagulant treatment on pain in distal deep vein thrombosis: an ancillary analysis from the cactus trial

Essentials Management of patients with calf deep vein thrombosis remains controversial. We conducted a post-hoc analysis of a placebo controlled LMWH randomized clinical trial. Pain was assessed using visual analogue scale at inclusion, one and six weeks. There was no difference in pain control between the two arms. SUMMARY: Background The optimal management of distal deep vein thrombosis (DVT) is highly debated. The only available placebo-controlled trial suggested the absence of clear benefit of anticoagulation. Many physicians feel that, beyond preventing thromboembolic complications, anticoagulation with low-molecular-weight heparin (LMWH) has the potential to improve pain control. Objectives To analyze whether LMWHs decrease pain in patients with distal deep vein thrombosis. Patients and methods Two-hundred and fifty-two patients included in a multicenter, placebo-controlled, randomized clinical trial of LMWH in patients with acute distal DVT and who were asked to rate their pain at inclusion and at each medical visit, using a visual analogue pain scale (VAS). Results One hundred and thirty patients were randomized in the therapeutic nadroparin arm and 122 patients were randomized in the placebo arm. Mean VAS values were 4.6 (standard deviation [SD] 2.5) at inclusion, 2.1 (SD 2.0) at 1 week and 0.4 (SD 1.2) at 6 weeks. We calculated the individual variation in VAS between inclusion and 1 week in patients in whom VAS was available at the two study time-points. There was no difference in the mean VAS reduction between patients treated with therapeutic nadroparin (n = 106) and with placebo (n = 109): -2.6 (SD 2.4) vs. -2.3 (SD 2.0) after 1 week and -4.4 (SD 2.8) vs. -4.0 (SD 2.4) after 6 weeks, respectively. The use of compression stockings was associated with a reduction in pain. Conclusion These data suggests that LMWH use does not improve pain control as compared with placebo in patients with acute distal DVT.

[Analysis of the Incidence of Lower Extremity Venous Thrombosis and Its Related Risk Factors in Admitted Patients with Lung Cancer]

背景与目的

静脉血栓栓塞症（venous thromboembolism, VTE）是一种公认的在肺癌患者中有较高发病率和死亡率的并发症。本研究目的是明确我们中心肺癌患者入院时下肢深静脉血栓（lower extremity venous thrombosis, LEDVT）的发生率，并揭示其入院时LEDVT发生的危险因素。

方法

选择天津医科大学总医院肺部肿瘤外科在2017年7月-2017年12月收治的231例肺癌患者，入院时即行双下肢静脉彩超检查，以分析肺癌患者LEDVT的发生率；同时，对肺良性疾病患者入院时LEDVT的发生率进行比较。在肺癌患者中，进一步分析LEDVT发生与其临床特征的关系，寻找LEDVT发生的可能危险因素；同时，亦分析这些患者的血浆D-二聚体（D-Dimmer）、纤维蛋白原（fibrinogen, FIB）、凝血酶时间（thrombin time, TT）、活化部分凝血酶时间（activated partial thrombin time, APTT）、凝血酶原时间（prothrombin time, PT）及血小板（platelet, PLT）之间的差异。

结果

在231例肺癌患者中，入院时发生LEDVT者12例，其发生率为5.2%（12/231）；而77例肺良性疾病患者入院时均未查见LEDVT的发生，提示肺癌患者入院时LEDVT的发生率明显高于肺良性疾病（P < 0.05）。在肺癌患者中进一步分析发现，伴有远处转移（包括N3淋巴结转移）的肺癌患者较不伴有转移者更易发生LEDVT（11.29%, 7/62 vs 2.96%, 5/169）（P < 0.05）。肺癌LEDVT组患者入院时的D-Dimer的中位值为1, 534mg/L（369 mg/L-10, 000 mg/L），明显高于非LEDVT组患者(539 mg/L, 126 mg/L-1, 000 mg/L)（P < 0.05）；而FIB、TT、APTT、PT和PLT在两组患者之间无明显统计学差异（P > 0.05）。

结论

我们中心肺癌患者入院时LEDVT总体发生率约为5%，明显高于肺良性疾病患者。入院时伴有远处转移（包括N3淋巴结转移）的肺癌患者更易发生LEDVT，其中，D-Dimer值较高的患者应考虑到VTE事件发生的可能。

[Occurrence of Venous Thromboembolism in Patients with Lung Cancer and Its Anticoagulant Therapy]

目前，肺癌的发病率和死亡率在全世界范围内居首位。静脉血栓栓塞症（venous thromboembolism, VTE）是一种公认的肺癌并发症，也是肺癌患者的主要死因之一。癌症自身因素、患者自身因素以及治疗相关因素都是导致肺癌患者发生VTE的主要原因。肿瘤细胞可产生组织因子（tissue factor, TF）、癌性促凝物质（cancer procoagulant, CP）、炎症因子和细胞因子，从而直接激活凝血；其中TF过度表达是肿瘤患者血栓形成的主要机制之一。2016年美国胸外科医师协会（American College of Chest Physicians, ACCP）发布的第10版肿瘤患者VTE防治指南（AT-10）指出，抗凝治疗是肺癌患者合并VTE的基本治疗措施；其中低分子肝素（low molecular-weight-heparin, LWMH）被认为是首选的抗凝药物，但要注意出血风险。

Effects of Natural Hirudin and Low Molecular Weight Heparin in Preventing Deep Venous Thrombosis in Aged Patients with Intertrochanteric Fracture

Our objective was to evaluate the efficacy and safety of natural hirudin and low molecular weight heparin (LMWH) in the prevention of perioperative deep venous thrombosis (DVT) in elderly patients with intertrochanteric fracture. From June 2014 to June 2017, 96 patients with intertrochanteric fractures were treated with proximal femoral nail antirotation (PFNA) were randomly divided into two groups. For DVT prevention, 45 patients were treated with oral natural hirudin and subcutaneous LMWH-calcium (test group) and 51 patients were treated with subcutaneous LMWH-calcium (control group). The mean intraoperative bleeding, wound drainage and incisional hematoma were higher in the test group, with no significant differences between the groups. There were significant differences in distal intramuscular venous thrombosis (P = 0.043). Both activated partial thromboplastin time (APTT), thrombin time (TT), and prothrombin time (PT) lengthened in both groups postoperatively, and there was a significant difference between the two groups two weeks postoperatively. D-dimer were significantly different and platelet count (PLT) did not differ between groups two weeks postoperatively. In elderly patients with unilateral intertrochanteric fracture after PFNA on anticoagulant therapy, the combination of natural hirudin and LMWH was more effective than that of LMWH-calcium alone, with no significant difference with regard to safety.

Ultrasound for Lower Extremity Deep Venous Thrombosis

Venous ultrasound is the standard imaging test for patients suspected of having acute deep venous thrombosis (DVT). There is variability and disagreement among authoritative groups regarding the necessary components of the test. Some protocols include scanning the entire lower extremity, whereas others recommend scans limited to the thigh and knee supplemented with serial testing. Some protocols use gray-scale ultrasound alone, whereas others include Doppler interrogation. Point-of-care ultrasound is recommended in some settings, and there is heterogeneity of these protocols as well. Heterogeneity of recommendations can lead to errors including incorrect application of guidelines, confusion among requesting physicians, and incorrect follow-up. In October 2016, the Society of Radiologists in Ultrasound convened a multidisciplinary panel of experts to evaluate the current evidence to develop recommendations regarding ultrasound protocols for DVT and the terminology used to communicate results to clinicians. Recommendations were made after open discussion and by unanimous consensus.

The panel recommends a comprehensive duplex ultrasound protocol from thigh to ankle with Doppler at selected sites rather than a limited or complete compression-only examination. This protocol is currently performed in many facilities and is achievable with standard ultrasound equipment and personnel. The use of these recommendations will increase the diagnosis of calf DVT and provide better data to explain the presenting symptoms. The panel recommends a single point-of-care protocol that minimizes underdiagnoses of proximal DVT.

The panel recommends the term chronic postthrombotic change to describe the residual material that persists after the acute presentation of DVT to avoid potential overtreatment of prior thrombus.

Adoption of a single standardized comprehensive duplex ultrasound and a single point-of-care examination will enhance patient safety and clinicians’ confidence.

Missed Massive Pulmonary Embolism and the Hidden Threat of a Distal Deep Vein Thrombosis

A 47-year-old woman presented to her GP (general practitioner) surgery with a left leg pain of 4 days duration after a recent 4-hour flight. She was taking the oral combined contraceptive pill and had no past medical history. She had a low predictive Wells score for deep vein thrombosis, but her D-dimer was positive, so she had a proximal lower limb vein ultrasound scan as per the National Institute for Clinical Excellence guidelines, which was negative. Two days later, she presented to the emergency department with a collapse and dyspnea. Her blood pressure was unrecordable in the ambulance, and she was severely peripherally cyanosed with a blood pressure of 64/40 mm Hg in the emergency department. She had a computed tomography pulmonary angiogram, which confirmed extensive bilateral pulmonary emboli with right ventricular strain. She had 2 cardiac arrests while in hospital and is now on long-term anticoagulation.

Should we diagnose and treat distal deep vein thrombosis?

Ultrasound series report that isolated distal deep vein thrombosis (DVT), also known as calf DVT, represents up to 50% of all lower-limb DVTs and, therefore, is a frequent medical condition. Unlike proximal DVT and pulmonary embolism, which have been studied extensively and for which management is well standardized, much less is known about the optimal management of isolated calf DVT. Recent data arising from registries and nonrandomized studies have suggested that most distal DVTs do not extend to the proximal veins and have an uneventful follow-up when left untreated. These data had some impact on the international recommendations that recently stated that ultrasound surveillance instead of systematic therapeutic anticoagulation might be an option for selected low-risk patients. However, robust data from randomized studies are scarce. Only 5 randomized trials assessing the need for anticoagulation for calf DVT have been published. Many of these trials had an open-label design and were affected by methodological limitations. The only randomized placebo-controlled trial included low-risk patients (outpatients without cancer or previous venous thromboembolism [VTE]) and was hampered by limited statistical power. Nevertheless, data from this trial confirmed that the use of therapeutic anticoagulation in low-risk patients with symptomatic calf DVT is not superior to placebo in reducing VTE but is associated with a significantly higher risk of bleeding. Further randomized studies are needed to define the best therapy for high-risk patients (inpatients, patients with active cancer, or patients with previous VTE) and the optimal dose and duration of treatment.

Efficacy and safety of thromboprophylaxis with low-molecular-weight heparin or rivaroxaban in hip and knee replacement surgery

Prospective trials have shown that rivaroxaban thromboprophylaxis is superior over low-molecular-weight heparin (LMWH) in patients undergoing hip and knee replacement surgery. However, patients treated under trial conditions are different from unselected routine patients, which may affect efficacy and safety of thromboprophylaxis. The objective was to evaluate the efficacy and safety of rivaroxaban or LMWH thromboprophylaxis in unselected patients undergoing hip and knee replacement surgery in daily care. In a monocentric, retrospective cohort study in 5,061 consecutive patients undergoing hip and knee replacement surgery a comparison of LMWH (hospital standard in 2006–2007) and rivaroxaban (since 2009) was made with regard to rates of symptomatic VTE, bleeding and surgical complications and length of hospital stay. Rates of symptomatic VTE were 4.1 % (LMWH) and 2.1 % (rivaroxaban; p=0.005) with rates for distal DVT 2.5 vs. 1.1 % (p<0.001). Rates of major VTE were numerically higher with LMWH (1.7 vs. 1.1%, not statistically significant). Rates of major bleeding (overt bleeding leading to surgical revision or death, occurring in a critical site, or transfusion of at least two units of packed red blood cells) were statistically lower with rivaroxaban (2.9 vs. 7.0%; p<0.001). Rivaroxaban patients had fewer surgical complications (1.1 vs. 3.7%; p<0.001) and a shorter length of hospitalisation (8.3 days; 95% CI 8.1– 8.5 vs. 11.1 days; 10.7– 11.5; p< 0.001). We conclude that rivaroxaban thromboprophylaxis is more effective than LMWH in unselected patients undergoing hip and knee replacement surgery in daily care and that switching from LMWH to rivaroxaban could be beneficial. Prospective comparisons are warranted to confirm our findings.

Release of the tourniquet immediately after the implantation of the components reduces the incidence of deep vein thrombosis after primary total knee arthroplasty

Objectives

The length of the tourniquet time during total knee arthroplasty (TKA) is related to the incidence of post-operative deep vein thrombosis (DVT). Our aim in this study was to investigate the effect of the early release of the tourniquet on the incidence of DVT in patients undergoing TKA.

Methods

A total of 200 patients who underwent TKA between November 2015 and November 2016 were prospectively enrolled. The tourniquet was inflated before surgery and released immediately after the introduction of the components (early release group). This group was compared with a retrospective cohort of 200 primary TKAs, in which the tourniquet was released after the dressings had been applied (late release group). The presence of a DVT was detected using bilateral lower limb ultrasonography. Peri-operative clinical and follow-up data were collected for analysis.

Results

The incidence of DVT in the early release group (9 of 196, 4.6%) was significantly lower compared with the late release group (24 of 200, 12%; odds ratio (OR) 0.35, 95% confidence interval (CI) 0.16 to 0.78, p = 0.008). The incidence of proximal DVT in the early release group (1 of 196 (0.5%)) was significantly lower than in the late release group (8 of 196, 4%; OR 0.12, 95% CI 0.02 to 0.99, p = 0.020). Although the mean intra-operative blood loss was higher in the early release group, the mean post-operative drainage, total blood loss, transfusion requirements and complications were not significantly different in the two groups.

Conclusion

In patients who undergo TKA, releasing the tourniquet early is associated with a decreased incidence of DVT, without increasing the rate of complications.

Cite this article: Bone Joint Res 2017;6:535–541.

Low molecular weight heparin for prevention of venous thromboembolism in patients with lower-limb immobilization

BACKGROUND

Immobilization of the lower limb is a risk factor for venous thromboembolism (VTE). Low molecular weight heparins (LMWHs) are anticoagulants, which might be used in adult patients with lower-limb immobilization to prevent deep venous thrombosis (DVT) and its complications. This is an update of the review first published in 2008.

OBJECTIVES

To assess the effectiveness of low molecular weight heparin for the prevention of venous thromboembolism in patients with lower-limb immobilization in an ambulatory setting.

SEARCH METHODS

For this update, the Cochrane Vascular Information Specialist searched the Specialised Register, CENTRAL, and three trials registers (April 2017).

SELECTION CRITERIA

Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that described thromboprophylaxis by means of LMWH compared with no prophylaxis or placebo in adult patients with lower-limb immobilization. Immobilization was by means of a plaster cast or brace.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed risk of bias and extracted data. The review authors contacted the trial authors for additional information if required. Statistical analysis was carried out using Review Manager 5.

MAIN RESULTS

We included eight RCTs that fulfilled our criteria, with a total of 3680 participants. The quality of evidence, according GRADE, varied by outcome and ranged from low to moderate. We found an incidence of DVT ranging from 4.3% to 40% in patients who had a leg injury that had been immobilized in a plaster cast or a brace for at least one week, and who received no prophylaxis, or placebo. This number was significantly lower in patients who received daily subcutaneous injections of LMWH during immobilization, with event rates ranging from 0% to 37% (odds ratio (OR) 0.45, 95% confidence interval (CI) 0.33 to 0.61; with minimal evidence of heterogeneity: I² = 26%, P = 0.23; seven studies; 1676 participants, moderate-quality evidence). Comparable results were seen in the following groups of participants: patients with below-knee casts, conservatively treated patients (non-operated patients), operated patients, patients with fractures, patients with soft-tissue injuries, and patients with distal or proximal thrombosis. No clear differences were found between the LMWH and control groups for pulmonary embolism (OR 0.50, 95% CI 0.17 to 1.47; with no evidence of heterogeneity: I² = 0%, P = 0.56; five studies, 2517 participants; low-quality evidence). The studies also showed less symptomatic VTE in the LMWH groups compared with the control groups (OR 0.40, 95% CI 0.21 to 0.76; with minimal evidence of heterogeneity: I² = 16%, P = 0.31; six studies; 2924 participants; low-quality evidence). One death was reported in the included studies, but no deaths due to pulmonary embolism were reported. Complications of major adverse events were rare, with minor bleeding the main adverse events reported.

AUTHORS' CONCLUSIONS

Moderate-quality evidence showed that the use of LMWH in outpatients reduced DVT when immobilization of the lower limb was required, when compared with no prophylaxis or placebo. The quality of the evidence was reduced to moderate because of risk of selection and attrition bias in the included studies. Low-quality evidence showed no clear differences in PE between the LMWH and control groups, but less symptomatic VTE in the LMWH groups. The quality of the evidence was downgraded due to risk of bias and imprecision.

Lower-extremity venous ultrasound - past, present and future

Deep vein thrombosis is a frequent clinical concern and imaging request in the pediatric population. There has been increased awareness of deep venous thrombosis in the pediatric population and sonography is now utilized more liberally and frequently to evaluate for thrombosis in the extremities. In this review the author discusses various aspects of deep vein thrombosis in the lower extremity including the pathophysiology, background, and morbidity in children. The current ultrasound guidelines and techniques, and the controversy over treatment are discussed as well.

Prevalence of Venous Thromboembolic Events Is Low in Asians After Total Knee Arthroplasty Without Chemoprophylaxis

BACKGROUND

This retrospective cohort study was designed to establish the prevalence of clinically significant venous thromboembolic events (VTE) in our patients undergoing total knee arthroplasty (TKA) without chemoprophylaxis.

METHODS

A single-surgeon cohort of patients who underwent TKA from 2006 to 2014 were included. All patients had a pneumatic tourniquet applied and a drain inserted postoperatively. Tranexamic acid was not used perioperatively. All patients were under a standardized postoperative protocol with routine mechanical prophylaxis against VTE. None of the patients received prophylactic anticoagulation. All patients ambulated on the second postoperative day. Only symptomatic patients were referred for radiological examination to exclude VTE. We evaluated the patient demographics and calculated the prevalence of VTE in our cohort.

RESULTS

A total of 966 patients were reviewed. Mean age was 66.1 ± 7.8 years. Mean body mass index was 28.2 ± 4.7 kg/m². Mean tourniquet time was 53 ± 23 minutes. Patients stayed in hospital for a mean of 5.4 ± 3.1 days. There was 100% compliance to mechanical prophylaxis. And 11.1% of our patients were on concomitant antiplatelet or anticoagulant use. There were 8 patients with clinically significant VTE. This translates to a prevalence of 0.82%. Seven patients developed deep vein thrombosis and 1 patient died from massive pulmonary embolism.

CONCLUSION

The prevalence of clinically significant VTE in our patients who underwent TKA without routine chemoprophylaxis is 0.82%. With proper patient selection, risk stratification, and stringent perioperative protocols, routine chemoprophylaxis may not be necessary in Asians undergoing TKA.

Management of distal deep vein thrombosis

Isolated distal deep vein thrombosis (DVT), also known as calf DVT, represents up to 50% of all lower limb DVT in ultrasound series and is therefore a frequent medical condition. Unlike proximal DVT and pulmonary embolism (PE), which have been extensively studied and for which management is well standardized, much less is known on the optimal management of isolated calf DVT. Recent data arising from registries and non-randomized studies suggest that most distal DVTs do not extend to the proximal veins and have an uneventful follow-up when left untreated. This data had some impact on the international recommendations which recently stated that ultrasound surveillance instead of systematic therapeutic anticoagulation might be an option for selected low-risk patients. However, robust data arising from randomized studies are scarce. Indeed, only five randomized trials assessing the need for anticoagulation for calf DVT have been published. Many of these trials had an open-label design and were affected by methodological limitations. The only randomized placebo-controlled trial included low-risk patients (outpatients without cancer or previous venous thromboembolic events (VTE)) and was hampered by a limited statistical power. Nevertheless, data from this trial tend to confirm that the use of therapeutic anticoagulation in low-risk patients with symptomatic calf DVT is not superior to placebo in reducing VTE, but is associated with a significantly higher risk of bleeding. Further randomized studies are needed to define the best therapy for high-risk patients (inpatients, patients with active cancer or previous VTE), and the optimal dose and duration of treatment.

Current and future perspectives in imaging of venous thromboembolism

Several thrombus imaging techniques for the diagnosis of venous thromboembolism (VTE) are available. The most prevalent forms of VTE are deep vein thrombosis of the lower extremities and pulmonary embolism. However, VTE may also occur at unusual sites such as deep veins of the upper extremity and the splanchnic and cerebral veins. Currently, the imaging techniques most widely used in clinical practice are compression ultrasonography and computed tomography (CT) pulmonary angiography. Moreover, single-photon emission CT, CT venography, positron emission tomography, and different magnetic resonance imaging (MRI) techniques, including magnetic resonance direct thrombus imaging, have been evaluated in clinical studies. This review provides an overview of the technique, diagnostic accuracy and potential pitfalls of these established and emerging imaging modalities for the different sites of venous thromboembolism.

Venous Thromboembolism in Cancer: An Update of Treatment and Prevention in the Era of Newer Anticoagulants

Cancer patients are at major risk of developing venous thromboembolism (VTE), resulting in increased morbidity and economic burden. While a number of theories try to explain its pathophysiology, its risk stratification can be broadly done in cancer-related, treatment–related, and patient-related factors. Studies report the prophylactic use of thrombolytic agents to be safe and effective in decreasing VTE-related mortality/morbidity especially in postoperative cancer patients. Recent data also suggest the prophylactic use of low molecular weight Heparins (LMWHs) and Warfarin to be effective in reducing VTEs related to long-term central venous catheter use. In a double-blind, multicenter trial, a new ultra-LMWH Semuloparin has shown to be efficacious in preventing chemotherapy-associated VTE’s along with other drugs, such as Certoparin and Nadoparin. LMWHs are reported to be very useful in preventing recurrent VTEs in advanced cancers and should be preferred over full dose Warfarin. However, their long-term safety beyond 6 months has not been established yet. Furthermore, this paper discusses the safety and efficacy of different drugs used in the treatment and prevention of recurrent VTEs, including Bemiparin, Semuloparin, oral direct thrombin inhibitors, parenteral and direct oral factor Xa inhibitors.

Calf muscle venous thrombosis: a review of the clinical implications and therapy

Calf muscle veins have been demonstrated to be one of the most frequent areas that develop deep venous thrombosis (DVT), both as an isolated finding and in combination with proximal DVT. Calf muscle venous thrombosis (CMVT) has been shown to be more frequently associated with localized calf tenderness, and when left untreated, a proportion tend to propagate proximally and may lead to pulmonary embolism. Imaging with duplex venous scanning is fairly sensitive in the diagnosis of CMVT. Treatment recommendations for CMVT are variable with some studies showing clear clinical benefit of anticoagulation therapy and others showing no benefit.

Guidelines in Emergency Medicine Network (GEMNet): guideline for the use of thromboprophylaxis in ambulatory trauma patients requiring temporary limb immobilisation

The Guidelines in Emergency Medicine Network (GEMNet) has been created to promote best medical practice in a range of conditions presenting to emergency departments (EDs) in the UK. This guideline presents a summary of the best available evidence to guide the use of thromboprophylaxis in adult ambulatory outpatients who present to the ED following acute limb trauma and require temporary immobilisation. The document has been developed following discussion among emergency physicians and collegiate fellows to decide which topics would benefit from the development of clinical guidelines. The document is intended as a guideline for use in the ED by emergency physicians and is based on the review of the best existing evidence for treatments used in this setting. The document is summarised as a Clinical Decision Support Guideline that has been presented as an easy to follow algorithm. The intention is for each guideline to be updated and reviewed as further evidence becomes available. The formal revision date has been set at 5 years from publication, though the guideline is subject to continuous informal review.

Low molecular weight heparin for prevention of venous thromboembolism in patients with lower-leg immobilization

BACKGROUND

Immobilization of the lower leg is associated with venous thromboembolism (VTE). Low molecular weight heparin (LMWH) is an anticoagulant treatment which might be used in adult patients with lower-leg immobilization to prevent deep venous thrombosis (DVT) and its complications. This is an update of the review first published in 2008.

OBJECTIVES

To assess the effectiveness of low molecular weight heparin for the prevention of venous thromboembolism in patients with lower-leg immobilization in an ambulant setting.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched June 2013) and CENTRAL (2013, Issue 5).

SELECTION CRITERIA

Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) that described thromboprophylaxis by means of LMWH compared with no prophylaxis or placebo in adult patients with lower-leg immobilization. Immobilization was by means of a plaster cast or brace.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. The review authors contacted the trial authors for additional information if required. Statistical analysis was carried out using Review Manager (RevMan 5).

MAIN RESULTS

We included six RCTs fulfilling the above criteria with a total of 1490 patients. We found an incidence of VTE ranging from 4.3% to 40% in patients who had a leg injury that had been immobilized in a plaster cast or a brace for at least one week and who received no prophylaxis, or placebo. This number was significantly lower in patients who received daily subcutaneous injections of LMWH during immobilization (event rates ranging from 0% to 37%; odds ratio (OR) 0.49; fixed 95% confidence interval (CI) 0.34 to 0.72; with minimal evidence of heterogeneity with an I(2) of 20%, P = 0. 29). Comparable results were seen in the following subcategories: operated patients, conservatively treated patients, patients with fractures, patients with soft-tissue injuries, patients with proximal thrombosis, patients with distal thrombosis and patients with below-knee casts. Complications of major bleeding events were extremely rare (0.3%) and there were no reports of heparin-induced thrombocytopenia.

AUTHORS' CONCLUSIONS

Use of LMWH in outpatients significantly reduces VTE when immobilization of the lower leg is required.

Incidence and predictors of venous thromboembolism recurrence after a first isolated distal deep vein thrombosis

BACKGROUND

Isolated distal deep vein thrombosis (iDDVT) (i.e. without proximal DVT or pulmonary embolism) represents half of all cases of lower limb DVT. Its clinical significance and management are controversial. Data on long-term follow-up are scarce, especially concerning risk and predictors of venous thromboembolism (VTE) recurrence.

METHODS

Using data from the OPTIMEV (OPTimisation de l'Interrogatoire dans l'évaluation du risque throMbo-Embolique Veineux) study, a prospective, observational, multicenter study, we compared, 3 years after an index VTE event and after discontinuation of anticoagulants, (i) the incidence and type of recurrence in patients without cancer with a first iDDVT vs. a first isolated proximal DVT (iPDVT) and (ii) predictors of recurrence after iDDVT.

RESULTS

Compared with patients with iPDVT (n = 259), patients with an iDDVT (n = 490) had a lower annualized incidence of overall VTE recurrence (5.2% [95% confidence interval 3.6-7.6] vs. 2.7% [1.9-3.8], respectively; P = 0.02) but a similar incidence of pulmonary embolism recurrence (1.0% [0.5-2.3] vs. 0.9% [0.5-1.6], respectively; P = 0.83). An age of > 50 years, unprovoked character of index iDDVT, and involvement of more than one vein in one or both legs each independently tripled the risk of recurrence, with the latter then being ≥ 3% per patient-year. Neither muscular vein nor deep-calf vein location of iDDVT nor clot diameter with compression influenced the risk of recurrence.

CONCLUSIONS

After stopping anticoagulants, patients with iDDVT have a significantly lower risk of overall VTE recurrence than did patients with iPDVT but a similar risk of serious recurrent VTE. Age > 50 years, unprovoked iDDVT, and number of thrombosed veins (more than one) influenced the risk of recurrence and may help to define patients at significant risk of recurrence.

Variations in ultrasound scanning protocols in the UK for suspected deep vein thrombosis in outpatients

Aims

To assess current ultrasound scanning protocol in outpatients with suspected deep vein thrombosis (DVT), in particular whether practitioners routinely scanned calf veins.

Methods

A standard questionnaire was sent out via post to all radiology departments in the United Kingdom (UK) and via the British Medical Ultrasound Society (BMUS) website in 2010. Responses were entered into Access® and database queries were run to analyse responses. Free-text comments were taken into account in our analysis.

Results

A total of 277 responses (50 through the BMUS website) were received (46% postal response rate). Of them, six were excluded as these were incomplete. Thus, 97 (36%) were consultants, 13 (5%) accredited vascular scientists (AVSs), 153 (56%) sonographers and six (2%) higher radiology trainees. All AVSs scanned the whole limb and used all three modalities of compression, colour and pulse wave Dopplers. Practice across other healthcare professionals varied. In all, 120/176 (68%) of other health-care professionals trained in vascular ultrasound scanned the whole limb routinely and 82/120 of these used all three scanning modalities. Trained sonographers scanned the whole limb significantly more than the medical cohort (P = 0.017). The use of all three modalities varied significantly between AVS and the non-AVS trained professionals (P = 0.0194), the trained medical cohort of consultants and sonographers (P = 0.0001), and trained and non-trained respondents (P = 0.0113). The commonly chosen reason for not scanning the whole limb was that it had poor sensitivity for calf vein DVTs. Free-text reasons for not scanning the whole limb routinely included local protocols prohibiting it.

Conclusions

There is a discrepancy between the scanning protocols of medically trained and allied health-care professionals, trained or otherwise in vascular ultrasound, and between these groups and AVSs. This is likely to have an impact on clinical governance.

Postural abnormality as a risk marker for leg deep venous thrombosis in Parkinson's disease

BACKGROUND

Pulmonary thromboembolism is a common cause of death in patients with autopsy-confirmed Parkinsonism. This study investigated the incidence of leg deep vein thrombosis in Parkinson's disease and relationships between deep vein thrombosis and clinical/laboratory findings, including postural abnormalities as assessed by photographic measurements.

METHODS

This cross-sectional study assessed the presence of deep vein thrombosis using bilateral leg Doppler ultrasonography in 114 asymptomatic outpatients with Parkinson's disease.

RESULTS

Deep vein thrombosis was detected in 23 patients (20%) with Parkinson's disease. Deep vein thrombosis was located in the distal portion in 18 patients and in the proximal portion in 5 patients. No significant differences in age, sex, body mass index, disease duration, Hoehn-Yahr stage, anti-Parkinson's drugs, or daily levodopa-equivalent dose were seen between deep vein thrombosis-positive and -negative groups. Univariate analysis for developing deep vein thrombosis in patients with Parkinson's disease identified the following markers: long-term wheelchair use, bent knee, bent spine, and D-dimer elevation. Bending angles were significantly greater in the deep vein thrombosis-positive group at the knee and spine than in the deep vein thrombosis-negative group. Half of Parkinson's disease patients with camptocormia had deep vein thrombosis. Among diabetes mellitus cases, long-term wheelchair use, bent knee over 15°, camptocormia, D-dimer elevation, the more risk markers were associated with a higher incidence of DVT. The presence of risk markers contributed to the development of deep vein thrombosis. On multivariate logistic regression analysis, a bent knee posture was strongly associated with an increased risk of deep vein thrombosis.

CONCLUSION

Presence of leg deep vein thrombosis correlated with postural abnormalities in Parkinson's disease. We recommend non-invasive ultrasonographic screening for leg deep vein thrombosis in these high-risk patients with Parkinson's disease.

Diagnosis of recurrent deep vein thrombosis

Deep vein thrombosis is a chronic disease with a continuing risk of recurrence. In a patient with recurrence long term prognosis and treatment are significantly altered both carrying their own risks not only in the acute phase but mainly in the long term perspective. Thus, accurate diagnosis of recurrence is of utmost importance for the fate of the patient. Diagnosis of a first DVT episode is well established and follows an algorithm including clinical prediction rules, D-Dimer testing and compression ultrasound. Due to the previous episode the efficiency of all three elements is impaired in a patient with suspected recurrence. This opens up areas of uncertainty which have to be filled by individual clinical judgement. Guidelines reflect this difficulty by providing mainly weak recommendations based on sparse data. The present review summarizes what is known about the performance of tools for DVT diagnosis, discusses recent guidelines, and finally gives personally weighed recommendations how to deal with this peculiar diagnostic situation. In conclusion, it will turn out that the well accepted diagnostic algorithm for a first DVT may be applied as well if the lower efficiency is regarded. Compression ultrasound largely benefits from a baseline assessment at the end of the previous episode. The order of tests may be discussed according to local and regional attitudes.

Efficacy and safety of venous thromboembolism prophylaxis with fondaparinux or low molecular weight heparin in a large cohort of consecutive patients undergoing major orthopaedic surgery - findings from the ORTHO-TEP registry

AIMS

In large randomized trials, thromboprophylaxis with fondaparinux in major orthopaedic surgery (MOS) has been shown to be superior to low molecular weight heparin (LMWH) prophylaxis with comparable safety. However, patients treated under trial conditions are different from unselected patients and efficacy and safety outcomes may be different in unselected patients in daily practice. We performed a retrospective cohort study to compare the efficacy and safety of venous thromboembolism (VTE) prophylaxis with fondaparinux or LMWH in 3896 consecutive patients undergoing major orthopaedic surgery at our centre.

METHODS

All patients undergoing MOS between January 2006 and December 2009 were retrospectively analyzed using patient charts, hospital admission and discharge database, quality management database, transfusion unit database and VTE event documentation. VTE standard prophylaxis at our institution was LMWH (3000-6000 aXa units once daily) from January 2006 to December 2007 or fondaparinux 2.5 mg from January 2008 to December 2009. In these two large cohorts of unselected consecutive patients, in-hospital incidences of VTE, surgical complications, severe bleeding and death were evaluated.

RESULTS

Symptomatic VTE was found in 4.1% of patients in the LMWH group (62/1495 patients; 95% CI 0.032, 0.052) compared with 5.6% of patients receiving fondaparinux (112/1994 patients, 95% CI 0.047, 0.067; P= 0.047). Distal deep vein thrombosis (DVT) was significantly more frequent in the fondaparinux group (3.9%, 95% CI 0.031, 0.048; vs. 2.5%; 95% CI 0.018, 0.034; P= 0.021). No significant differences in the rates of major VTE or death were found. Rates of severe bleeding, transfusion of RBC concentrates, plasma and platelet concentrates were comparable between both treatment groups. However, patients receiving fondaparinux had significantly lower rates of surgical revisions (1.6%, 95% CI 0.011, 0.022 vs. 3.7%, 95% CI 0.028, 0.047; P < 0.001). Multivariate analysis revealed previous VTE (HR 18.2, 95% CI 11.6, 28.5; P < 0.001) and female gender (HR 1.9, 95% CI 1.3, 2.7; P < 0.001), but not fondaparinux prophylaxis (HR1.3, 95% CI 0.9, 1.7; P= 0.184) to be associated with significantly increased VTE risk.

DISCUSSION

Thromboprophylaxis with fondaparinux is less effective to prevent distal VTE than LMWH in unselected patients undergoing MOS, but is equally effective with regard to rates of major VTE and death. However, differences in efficacy of LMWH or fondaparinux are of little relevance compared with a history of VTE or female gender, which were found to be the main VTE risk factors in MOS. The safety profile of fondaparinux was comparable with LMWH with regard to rates of severe bleeding complications, but patients receiving fondaparinux had significantly less surgical complications requiring surgical revisions. Both our efficacy and safety findings differ from data derived from large phase III trials testing fondaparinux against LMWH in MOS, where overall rates of symptomatic VTE were lower and the safety profile of fondaparinux was different.

CONCLUSION

We conclude that the strict patient selection and surveillance in phase-III trials results in lower VTE and bleeding event rates compared with unselected routine patients. Consequently, the efficacy and safety profile of thromboprophylaxis regimens needs to be confirmed in large registries or phase IV trials of unselected patients.

Efficacy and safety of rivaroxaban or fondaparinux thromboprophylaxis in major orthopedic surgery: findings from the ORTHO-TEP registry

BACKGROUND

Thromboprophylaxis with rivaroxaban (R) is superior to enoxaparin in patients undergoing major orthopedic surgery (MOS). However, rivaroxaban has never been directly compared with fondaparinux (F), which also shows superior efficacy over enoxaparin. The clinical impact of switching from fondaparinux to rivaroxaban thromboprophylaxis is unclear.

OBJECTIVES

To evaluate the efficacy and safety of rivaroxaban or fondaparinux thromboprophylaxis in unselected patients undergoing MOS.

PATIENTS/METHODS

This is a monocentric, retrospective cohort study in 5061 consecutive patients undergoing MOS at our centre, comparing rates of symptomatic VTE, bleeding and surgical complications, length of hospital stay and risk factors for VTE.

RESULTS

Rates of symptomatic VTE were 5.6% (F) and 2.1% (R; P < 0.001), with rates for distal DVT being 3.9 vs. 1.1% (P < 0.001). Rates of major VTE were numerically higher with fondaparinux (1.8 vs. 1.1%), but not statistically significant. Rates of severe bleeding (bleeding leading to surgical revision or death, occurring in a critical site, or transfusion of at least two units of packed red blood cells) were statistically lower with rivaroxaban compared with fondaparinux (2.9 vs. 4.9%; P = 0.010). The mean length of hospital stay was significantly shorter in the rivaroxaban group (8.3 days, 95% CI 8.1-8.5 vs. 9.3 days, 9.1-9.5; P < 0.001).

CONCLUSION

Based on an indirect comparison of two consecutive cohorts, our data suggest that thromboprophylaxis with rivaroxaban is associated with less VTE and bleeding events than fondaparinux in unselected patients undergoing MOS. Prospective comparisons are warranted to confirm our findings.

[Epidemiology and management of isolated distal deep venous thrombosis]

Isolated distal deep-vein thromboses (DVT) are infra-popliteal DVT without involvement of proximal veins or pulmonary embolism (PE). They can affect deep calf (tibial anterior, tibial posterior, or peroneal) or muscular (gastrocnemius or soleal) veins. They represent half of all lower limbs DVT. Proximal and distal DVTs differ in terms of risk factor profile, proximal DVT being more frequently associated with chronic risk factors and distal DVT with transient ones. Their natural history (rate of spontaneous proximal extension) is debated leading to uncertainties on the need to diagnose and treat them with anticoagulant drugs. In the long term, the risk of venous thromboembolic recurrence is lower than that of proximal DVT and their absolute risk of post-thrombotic syndrome is unknown. French national guidelines suggest treating with anticoagulants for 6 weeks a first episode of isolated distal DVT provoked by a transient risk factor and treating for at least 3 months unprovoked or recurrent or active cancer-related distal DVT. The use of compression stockings use is suggested in case of deep calf vein thrombosis. Ongoing therapeutic trials should provide important data necessary to establish an evidence-based mode of care, especially about the need to treat distal DVT at low risk of extension with anticoagulants.

Incidence of clinically significant venous thromboembolic events in Asian patients undergoing total knee arthroplasty without anticoagulation

This study aimed to evaluate the incidence of clinically significant venous thromboembolic events (VTE) in Asian patients undergoing total knee arthroplasty (TKA) without anticoagulation. All patients who underwent TKA by a single surgeon from 2006 to 2010 in Singapore General Hospital were reviewed. Only symptomatic patients were referred for ultrasonography. Of the 531 patients reviewed, 3 patients developed symptoms of deep vein thrombosis with subsequent ultrasonographic confirmation, whereas 1 patient developed fatal pulmonary embolism without any clinical or radiologic evidence of deep vein thrombosis. Hence, the incidence of clinically significant VTE was 0.75%. Given the low incidence of clinically significant VTE, there is a need to review the current practice of routine chemoprophylaxis in Asian patients undergoing TKA.

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.