Is it worth diagnosing and treating distal deep vein thrombosis? No

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.

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.

Validation of risk assessment models predicting venous thromboembolism in inpatients with AECOPD: a multicenter cohort study

BACKGROUND

As inpatients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) are at increased risk for venous thromboembolism (VTE), identifying high-risk patients requiring thromboprophylaxis is critical to reduce the mortality and morbidity associated with VTE. This study aimed to evaluate and compare the validities of the Padua Prediction Score and Caprini risk assessment model (RAM) in predicting the risk of VTE in inpatients with AECOPD.

METHODS

The inpatients with AECOPD were prospectively enrolled from seven medical centers of China between September 2017 and January 2020. Caprini and Padua scores were calculated on admission, and the incidence of 3-month VTE was investigated.

RESULTS

Among the 3277 eligible patients with AECOPD, 128 patients (3.9%) developed VTE within 3 months after admission. The distribution of the study population by the Caprini risk level was as follows: high, 53.6%; moderate, 43.0%; and low, 3.5%. The incidence of VTE increased by risk level as high, 6.1%; moderate, 1.5%; and low, 0%. According to the Padua RAM, only 10.9% of the study population was classified as high risk and 89.1% as low risk, with the corresponding incidence of VTE 7.9% and 3.4%, respectively. The Caprini RAM had higher area under curve (AUC) compared with the Padua RAM (0.713  0.021 vs 0.644 ± 0.023, P = 0.029).

CONCLUSION

The Caprini RAM was superior to the Padua RAM in predicting the risk of VTE in inpatients with AECOPD and might better guide thromboprophylaxis in these patients.

Isolated calf deep venous thrombosis: frequency on venous ultrasound and clinical characteristics

Background

It remains controversial whether to include calf veins in the initial ultrasound evaluation of suspected deep venous thrombosis (DVT). We sought to investigate the frequency and clinical characteristics of isolated calf DVT.

Materials and methods

In this retrospective analysis, we investigated a cohort of 596 patients (median age 69 years, 52.3% women) who had been imaged with complete lower extremity venous duplex ultrasound for suspected acute DVT. Radiology reports were analyzed for the presence and localization of DVT. Clinical information was collected from patients’ electronic charts.

Results

DVT was found in 157 patients (26.3%), of which 74 patients (47.1%) had isolated calf DVT. Isolated calf DVTs were located in the posterior tibial veins (22 patients, 29.7%), peroneal veins (41 patients, 55.4%) and muscle veins (19 patients, 25.7%). There were no differences in age or sex between patients with isolated calf DVT and patients with proximal DVT. Isolated calf DVT was more commonly associated with leg pain (52.7% vs. 33.7%, p = 0.0234) and less commonly associated with subjective leg swelling (35.1% vs. 55.4%, p = 0.0158) and objectively measured difference in leg circumference (23% vs. 39.8%, p = 0.0268). D-Dimers were significantly lower in patients with isolated lower leg DVT (median 2.3 vs. 6.8 mg/L, p < 0.0001) compared to patients with proximal DVT.

Conclusions

Isolated calf DVT represents approximately half of DVT cases and has different clinical characteristics than proximal DVT.

Incremental value of compression ultrasound sonography in the emergency department

The quick evaluation of venous thromboembolism is a key point of modern medicine since the delayed diagnosis is associated with a worse prognosis. Venous ultrasound (VU) is a sensitive and rapidly performed test in cases of suspected deep venous thrombosis. Various protocols have been proposed for its execution, such as the study of the whole deep venous circulation of the lower limb or the analysis of the femoral-popliteal area. The aim is to detect a vessel thrombus and the most sensitive element is the non-compressibility with the probe. Initially, the thrombus is hypoechogenic and adherent to the vessel; later, it tends to organize and recanalize. Usually, in the early stages, the risk of embolism is higher. The role of studying the iliac axis and calf veins is still uncertain. VU is not useful for assessing response to anticoagulation therapy and it is unclear whether the persistence of thrombotic abnormalities can guide on a possible prolongation of therapy.

Significance and management of isolated distal deep vein thrombosis

PURPOSE OF REVIEW

Management of isolated distal deep vein thrombosis (IDDVT) remains controversial. We summarize recent studies regarding the natural history of IDDVT as well as pertinent therapeutic trials. We also provide our management approach.

RECENT FINDINGS

IDDVT is more commonly associated with transient risk factors and less often associated with permanent, unmodifiable risk factors than proximal DVT. IDDVT has a significantly lower risk of proximal extension and recurrence than proximal DVT. Cancer-associated IDDVT has a similar natural history to cancer-associated proximal DVT, with substantially less favourable outcomes than noncancer-associated IDDVT. Anticoagulant treatment reduces the risk of proximal extension and recurrence in IDDVT at the cost of increased bleeding risk. Intermediate dosing of anticoagulation may be effective for treating noncancer-associated IDDVT in patients without prior DVT.

SUMMARY

IDDVT with a transient risk factor can be treated for 6 weeks in patients without a prior DVT. Unprovoked IDDVT in patients without malignancy can be treated for 3 months. Outpatients without malignancy or a prior DVT can be left untreated and undergo surveillance compression ultrasound in one week to detect proximal extension, but few patients opt for this in practice. Cancer-associated IDDVT should be treated analogously to cancer-associated proximal DVT.

Incidence of venous thromboembolism in Asian patients undergoing anterior cruciate ligament reconstruction without the use of mechanical or chemical prophylaxis

Background:

Venous thromboembolism (VTE) is a clinically relevant complication of major orthopedic surgeries. The prevalence of VTE and the indications for VTE thromboprophylaxis in Asian patients undergoing arthroscopic anterior cruciate ligament (ACL) reconstruction are not clear. This study aims to evaluate the prevalence of clinically significant venous thromboembolic events (VTE) in Asian patients undergoing arthroscopic ACL reconstruction without mechanical or chemical thromboprophylaxis.

Methods:

All patients who underwent ACL reconstruction by a single surgeon from 2006 to 2018 in a single tertiary institution were reviewed. The inclusion criteria for the study included Asian patients of common ethnic groups in Singapore (Chinese, Malay, Indian) and underwent primary or revision ACL reconstruction, or ACL reconstruction combined with meniscal surgery. The exclusion criteria were patients with incomplete medical records, pre-existing anticoagulant treatment within 1 year prior to the surgery and additional procedures that altered the standard rehabilitation protocol, less than 6 months of follow-up duration. All patients received general anesthesia. The single-bundle ACL technique with autologous hamstring tendon reconstruction was performed. No chemical DVT prophylaxis was given. The patients were screened for clinically for VTE. Symptomatic patients were referred for ultrasonography.

Results:

Of the 581 patients reviewed, 3 patients had a clinical suspicion of deep vein thrombosis, but subsequent ultrasonography showed no thrombosis. Hence, the prevalence of clinically significant VTE was 0%.

Conclusion:

Given the low prevalence of clinically significant VTE, there is no need for routine mechanical or chemical thromboprophylaxis or radiologic screening in Asian patients undergoing arthroscopic ACL reconstruction.

Systematic Screening for Deep Vein Thrombosis in Critically Ill Inpatients With COVID-19: Impact on the Incidence of Venous Thromboembolism

Background: Several studies suggest an increased incidence of thrombosis in COVID-19 patients. However, evidence on how to prevent and even treat it is scarce. The aim of this study was to compare the cumulative incidence of venous thromboembolism (VTE) of two different methods for lower extremity deep vein thrombosis (LE-DVT) diagnosis: systematic vs. clinically guided complete compression venous ultrasonography (CCUS). We conducted a monocentric, prospective, open-label, non-randomized study. All consecutive patients admitted in three intensive care units (ICUs) of University Hospital of Toulouse for COVID-19 pneumonia were included: one performed systematic screening for LE-DVT, the others did not. The primary outcome was the 21-day cumulative incidence of VTE. The secondary end points were the 21-day cumulative incidences of major bleeding and death.

Results: Among the 78 patients included, 27 (34.6%) underwent systematic screening for DVT 7 ± 2 days after ICU admission. Thirty-two patients (41.0%) were diagnosed with VTE, with a 21-day cumulative incidence of 42.3% (95% CI, 31.4–55.2), without difference between screened and non-screened patients (hazard ratio 1.45, 95% CI, 0.72–2.93). In the screened group, the frequency of isolated DVT was higher (25.9 vs. 5.9%, p-value = 0.027), but the frequency of pulmonary embolism was not reduced (25.9 vs. 29.4%, p-value = 0.745). The 21-day cumulative incidences of major bleeding and death were 9.6% (95% CI, 4.7–19.2) and 10.3% (95% CI, 5.0–20.8), respectively, without difference between the two groups.

Conclusions: A systematic screening for DVT in patients hospitalized in ICU was not associated with a higher diagnosis of VTE or a reduced diagnosis of PE.

Comparison Between the Diagnostic Performance of 1.5 T and 3.0 T field Strengths for Detecting Deep Vein Thrombosis Using Magnetic Resonance Black-Blood Thrombus Imaging

BACKGROUND

Magnetic resonance (MR) black-blood thrombus imaging (BTI) is an accurate diagnostic technique for detecting deep vein thrombosis (DVT) but to date there have been no studies comparing the diagnostic performance and consistency of this technique at different field strengths. In this study, we evaluated and compared the diagnostic performance of BTI for detecting DVT at 1.5 T and 3.0 T field strengths.

METHODS

A total of 40 patients with DVT were enrolled in this study from November 2015 up to October 2018. All patients underwent BTI, a contrast-free T1-weighted MR imaging technique for detecting DVT, and contrast-enhanced MR venography (CE-MRV) at 1.5 T or 3.0 T field strengths. The MR data analyses used 1160 segments from the venous lumen of the 40 patients. The signal-to-noise ratio and contrast-to-noise ratio between thrombus and muscle/lumen were calculated to compare BTI at 1.5 T or 3.0 T to determine the image performance for thrombus detection at 1.5 T or 3.0 T. Two physicians blinded to the study evaluated all BTI images and calculated the overall sensitivity (SE), specificity (SP), positive predictive value (PPV) and negative predictive value (NPV), accuracy, and diagnostic consistency at 1.5 T and 3.0 T. These images and values were compared to control CE-MRV images that had been obtained by 2 senior physicians and used as reference standards. In addition, the reliability and consistency of diagnoses between observers were also evaluated.

RESULTS

Two study-blind physicians reviewed all BTI images to diagnose thrombus and to determine SE, SP, PPV, NPV, and accuracy. There were no statistical differences in SE, SP, PPV, NPV, or accuracy between the 1.5 T and 3.0 T groups.

CONCLUSIONS

Black-blood thrombus imaging has high SE, SP, and accuracy for DVT diagnosis both at 1.5 T and 3.0 T field strengths. This noninvasive diagnostic technique, which does not require the use of contrast agents, can be widely used in the clinical screening of DVT and follow-up after treatment.

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.

Validation of risk assessment models predicting venous thromboembolism in acutely ill medical inpatients: A cohort study

BACKGROUND

Because hospital-acquired venous thromboembolism (VTE) represents a frequent cause of preventable deaths in medical inpatients, identifying at-risk patients requiring thromboprophylaxis is critical. We aimed to externally assess the Caprini, IMPROVE, and Padua VTE risk scores and to compare their performance to advanced age as a stand-alone predictor.

METHODS

We performed a retrospective analysis of patients prospectively enrolled in the PREVENU trial. Patients aged 40 years and older, hospitalized for at least 2 days on a medical ward were consecutively enrolled and followed for 3 months. Critical ill patients were not recruited. Patients diagnosed with VTE within 48 hours from admission, or receiving full dose anticoagulant treatment or who underwent surgery were excluded. All suspected VTE and deaths occurring during the 3-month follow-up were adjudicated by an independent committee. The three scores were retrospectively assessed. Body mass index, needed for the Padua and Caprini scores, was missing in 44% of patients.

RESULTS

Among 14 910 eligible patients, 14 660 were evaluable, of which 1.8% experienced symptomatic VTE or sudden unexplained death during the 3-month follow-up. The area under the receiver operating characteristic curves (AUC) were 0.60 (95% confidence interval [CI] 0.57-0.63), 0.63 (95% CI 0.60-0.66) and 0.64 (95% CI 0.61-0.67) for Caprini, IMPROVE, and Padua scores, respectively. None of these scores performed significantly better than advanced age as a single predictor (AUC 0.61, 95% CI 0.58-0.64).

CONCLUSION

In our study, Caprini, IMPROVE, and Padua VTE risk scores have poor discriminative ability to identify not critically ill medical inpatients at risk of VTE, and do not perform better than a risk evaluation based on patient's age alone.

Clinical outcomes of isolated distal deep vein thrombosis versus proximal venous thromboembolism in cancer patients: The Cleveland Clinic experience

BACKGROUND

Previous studies suggest isolated distal deep vein thrombosis (IDDVT) has a self-limited clinical course. However, these studies excluded cancer patients, who remain a high-risk population. In addition, studies to evaluate the long-term clinical outcomes of IDDVT in cancer patients have been limited. Here, we report outcomes from our experience in treating cancer-associated IDDVT versus proximal venous thromboembolism (VTE).

METHODS

We prospectively evaluated a cohort of patients referred to our cancer-associated thrombosis clinic from August 2014 through May 2018. We compared clinical characteristics, anticoagulation prescription, VTE recurrence, overall survival, major bleeding, and subsequent hospital admission between cancer patients with IDDVT and proximal VTE. A propensity score matching method was used to reduce bias from confounding variables.

RESULTS

Of 1100 patients referred to the clinic, 124 IDDVT and 178 proximal VTE events were analyzed. After propensity score matching, 96 patients were included in each cohort. There was no difference in the rate of recurrent VTE between cancer patients with proximal VTE vs IDDVT, with or without matching (matched: hazard ratio [HR], 0.77; 95% confidence interval [CI], 0.31-1.92; P = .58). There was no difference in overall survival between cancer patients with proximal VTE vs. IDDVT with or without matching (matched: HR, 1.18; 95% CI, 0.77-1.82; P = .45). Furthermore, subsequent hospital admissions and major bleeding events were similar between patients with proximal VTE events versus IDDVT.

CONCLUSIONS

Cancer patients with IDDVT have similar outcomes as their proximal counterparts, including rate of recurrence and overall survival. These findings suggest treatment of cancer-associated IDDVT should mirror treatment of proximal events.

Should we use dabigatran or aspirin thromboprophylaxis in total hip and knee arthroplasty? A natural experiment

Background

Despite long clinical experience some authorities recommend against the use of aspirin for perioperative VTE prophylaxis and favour alternatives such as dabigatran. A change from Dabigatran to an Aspirin based protocol in a British district general hospital created the conditions of a natural experiment.

Methods

We conducted a single centre, retrospective study of 6-months using a dabigatran based protocol (THA n = 191, TKA n = 155) and 6-months using and aspirin based protocol (THA n = 165, TKA n = 136). Outcomes addressed include: VTE used, VTE events within 90-days, 30-day return to theatre (RTT) rates, and 90-day mortality.

Results

Pre-intervention, the dabigatran prescription rate was 73% (n = 139) and 78% (n = 123) with aspirin prescription post-intervention in 67% (n = 110) and 70% (n = 90) for THA and TKA respectively. We found a similar VTE rate when comparing dabigatran and aspirin groups for THA (2.2% vs. 0%, p = 0.17) and TKA (0.64% vs. 0%, p = 0.32). Similarly, no difference in the RTT rate was seen for THA (0.7% vs.2.7%, p = 0.23) or TKA (1.6% vs. 3.2%, p = 0.38).

Conclusion

No significant differences in safety were found comparing aspirin to dabigatran for VTE prophylaxis for lower limb arthroplasty which, has not been previously reported and represents significant cost saving implications.

Systemic and Local Factors’ Influence on the Topological Differences in Deep Vein Thrombosis

Background and Objectives: Deep vein thrombosis (DVT) is a common cause of intra-hospital morbidity and mortality, and its most severe complication is pulmonary thromboembolism. The risk factors that influence the apparition of DVT are generally derived from Virchow’s triad. Since the most severe complications of DVT occur in proximal rather than distal deep vein thrombosis, the aim of this study was to identify the factors influencing the apparition of proximal DVT. Materials and Methods: This was a transversal, cohort study. The study included 167 consecutive patients with lower limb DVT over a two-year period. The following data were recorded or determined: general data, conditions that are known to influence DVT, medical history and coagulation or thrombophilia-related genetic variations. Results: In the univariate analysis, male gender, neoplasia, previous DVT and mutated factor V Leiden were all associated with proximal DVT, while bed rest was associated with distal DVT. In the multivariate analysis, male gender, previous DVT and factor V Leiden mutation were independently correlated with proximal DVT, while bed rest was independently associated with distal deep vein thrombosis. Conclusion: Our observations point out that the factors indicating a systemic involvement of coagulation were correlated with proximal DVT, while local factors were associated with distal DVT.

Global guidelines trends and controversies in lower limb venous and lymphatic disease: Narrative literature revision and experts' opinions following the vWINter international meeting in Phlebology, Lymphology & Aesthetics, 23-25 January 2019

Guidelines are fundamental in addressing everyday clinical indications and in reporting the current evidence-based data of related scientific investigations. At the same time, a spatial and temporal issue can limit their value. Indeed, variability in the recommendations can be found both among the same nation different scientific societies and among different nations/continents. On the other side, Garcia already published in 2014 data showing how, after three years in average, one out of five recommendations gets outdated (Martinez Garcia LM, Sanabria AJ, Garcia Alvarez E, et al. The validity of recommendations from clinical guidelines: a survival analysis. CMAJ 2014;186(16):1211–1219). The present document reports a narrative literature revision on the major international recommendations in lower limb venous and lymphatic disease management, focusing on the different countries’ guidelines, trends and controversies from all the continents, while identifying new evidence-based data potentially influencing future guidelines. World renowned experts’ opinions are also provided. The document has been written following the recorded round tables scientific discussions held at the vWINter international meeting (22–26 January 2019; Cortina d’Ampezzo, Italy) and the pre- and post-meeting literature search performed by the leading experts.

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.

Cardiovascular magnetic resonance black-blood thrombus imaging for the diagnosis of acute deep vein thrombosis at 1.5 Tesla

BACKGROUND

The aim was to investigate the feasibility of a cardiovascular magnetic resonance (CMR) black-blood thrombus imaging (BBTI) technique, based on delay alternating with nutation for tailored excitation black-blood preparation and a variable flip angle turbo-spin-echo readout, for the diagnosis of acute deep vein thrombosis (DVT) at 1.5 T.

METHODS

BBTI was conducted in 15 healthy subjects and 30 acute DVT patients. Contrast-enhanced CMR venography (CE-CMRV) was conducted for comparison and only performed in the patients. Apparent contrast-to-noise ratios between the thrombus and the muscle/lumen were calculated to determine whether BBTI could provide an adequate thrombus signal for diagnosis. Two blinded readers assessed the randomized BBTI images from all participants and made independent decisions on the presence or absence of thrombus at the segment level. Images obtained by CE-CMRV were also randomized and assessed by the two readers. Using the consensus CE-CMRV as a reference, the sensitivity, specificity, positive and negative predictive values, and accuracy of BBTI, as well as its diagnostic agreement with CE-CMRV, were calculated. Additionally, diagnostic confidence and interobserver diagnostic agreement were evaluated.

RESULTS

The thrombi in the acute phase exhibited iso- or hyperintense signals on the BBTI images. All the healthy subjects were correctly identified from the participants based on the segment level. The diagnostic confidence of BBTI was comparable to that of CE-CMRV (3.69 ± 0.52 vs. 3.70 ± 0.47). High overall sensitivity (95.2%), SP (98.6%), positive predictive value (96.0%), negative predictive value (98.3%), and accuracy (97.7%), as well as excellent diagnostic and interobserver agreements, were achieved using BBTI.

CONCLUSION

BBTI is a reliable, contrast-free technique for the diagnosis of acute DVT at 1.5 T.

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.

Doppler ultrasound and D-dimer

The diagnosis of venous thromboembolism has evolved considerably with the development of standardized diagnostic algorithms that include clinical probability assessment, D-dimer measurement and the use of non-invasive imaging modalities such as compression ultrasonography and computed tomography angiography. The implementation of these strategies aims to improve resource allocation and patient outcome. The judicious use of these diagnostic tools requires a thorough knowledge of the appropriate clinical setting in which every test and strategy is efficient and can be used safely. For this purpose, D-dimer measurement and compression ultrasonography are complementary: the former is mainly used to exclude VTE in selected patients, while the latter is used to confirm the presence of an underlying DVT.

This review provides an appraisal of the features and use of D-dimer and compression ultrasonography in the context of suspected venous thromboembolism.

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.

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.

Clinical implications of the anatomical variation of deep venous thrombosis

Introduction

Little is known about the anatomic variation and its implication in patients with lower limb deep venous thrombosis (DVT). We studied the clinical presentation, site of thrombosis and risk factors based on the anatomic distribution of lower limb DVT.

Methods

A retrospective analysis of clinically suspected DVT cases was conducted between 2008 and 2012. DVT was categorized by the location of the thrombosed segment and limb involved. The DVT anatomic segments were assessed according to left-to-right ratio, predisposing factors and clinical presentations.

Results

A total of 637 patients with DVT were included with a mean age of 50 ± 17 years (51%; females). The most frequently thrombosed segments were popliteal, posterior tibial and profunda femoris veins. DVT was more common at the left side, with a left-to-right ratio of 1.5:1. Bilateral DVT cases (38.5%) had more prior history of DVT as compared to left- (20.3%) and right-sided DVTs (22.6%); p = 0.01. Bilateral DVT was complicated more with post-thrombotic syndrome (leg ulcer) ( p = 0.02). The rates of pulmonary embolism (25%) and mortality (23.1%) were significantly higher for bilateral DVT in comparison to left- and right-sided DVT. Abnormal coagulation profile was significantly associated with posterior tibial DVT (81% vs. 71.4%; p = 0.01) as compared to patients with normal coagulation profile.

Conclusion

Lower limb DVTs are more common at the left side; however, patients with bilateral DVT have higher frequency of recurrence, post-thrombotic syndrome, pulmonary embolism and mortality. The anatomic segments of DVT show specific distribution depending on the predisposing factors. These findings could improve our understanding of the pathophysiology and management of DVT patients.

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.

Controversies in venous thromboembolism: the unique case of isolated distal deep vein thrombosis

Venous thromboembolism (VTE) represents the third leading cause of cardiovascular mortality, and it is the main cause of preventable mortality in hospitalized patients. Among VTE, there is the unique case of isolated distal deep vein thrombosis (IDDVT), which still lacks an agreement in terms of optimal therapeutic strategy. Although most IDDVTs are self-limiting and associated with a very low risk of embolic complications, still not all IDDVTs can be safely identified as stable. Lack of strong scientific evidence, fear of thromboembolic complications, and risk of bleeding upon initiation of anticoagulant treatment result in very heterogeneous therapeutic strategies among physicians. Here, we provide a comprehensive review of the literature, highlight the many controversial issues regarding IDDVTs, and call for a consensus of experts aimed to shed new light on the gray areas of IDDVT management and therapy.

Thromboprophylaxis using combined intermittent pneumatic compression and pharmacologic prophylaxis versus pharmacologic prophylaxis alone in critically ill patients: study protocol for a randomized controlled trial

BACKGROUND

Venous thromboembolism (VTE) remains a common problem in critically ill patients. Pharmacologic prophylaxis is currently the standard of care based on high-level evidence from randomized controlled trials. However, limited evidence exists regarding the effectiveness of intermittent pneumatic compression (IPC) devices. The Pneumatic compREssion for preventing VENous Thromboembolism (PREVENT trial) aims to determine whether the adjunct use of IPC with pharmacologic prophylaxis compared to pharmacologic prophylaxis alone in critically ill patients reduces the risk of VTE.

METHODS/DESIGN

The PREVENT trial is a multicenter randomized controlled trial, which will recruit 2000 critically ill patients from over 20 hospitals in three countries. The primary outcome is the incidence of proximal lower extremity deep vein thrombosis (DVT) within 28 days after randomization. Radiologists interpreting the scans are blinded to intervention allocation, whereas the patients and caregivers are unblinded. The trial has 80 % power to detect a 3 % absolute risk reduction in proximal DVT from 7 to 4 %.

DISCUSSION

The first patient was enrolled in July 2014. As of May 2015, a total of 650 patients have been enrolled from 13 centers in Saudi Arabia, Canada and Australia. The first interim analysis is anticipated in July 2016. We expect to complete recruitment by 2018.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT02040103 (registered on 3 November 2013). Current controlled trials: ISRCTN44653506 (registered on 30 October 2013).

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.

Emergency Department Management of Suspected Calf-Vein Deep Venous Thrombosis: A Diagnostic Algorithm

Introduction

Unilateral leg swelling with suspicion of deep venous thrombosis (DVT) is a common emergency department (ED) presentation. Proximal DVT (thrombus in the popliteal or femoral veins) can usually be diagnosed and treated at the initial ED encounter. When proximal DVT has been ruled out, isolated calf-vein deep venous thrombosis (IC-DVT) often remains a consideration. The current standard for the diagnosis of IC-DVT is whole-leg vascular duplex ultrasonography (WLUS), a test that is unavailable in many hospitals outside normal business hours. When WLUS is not available from the ED, recommendations for managing suspected IC-DVT vary. The objectives of the study is to use current evidence and recommendations to (1) propose a diagnostic algorithm for IC-DVT when definitive testing (WLUS) is unavailable; and (2) summarize the controversy surrounding IC-DVT treatment.

Discussion

The Figure combines D-dimer testing with serial CUS or a single deferred FLUS for the diagnosis of IC-DVT. Such an algorithm has the potential to safely direct the management of suspected IC-DVT when definitive testing is unavailable. Whether or not to treat diagnosed IC-DVT remains widely debated and awaiting further evidence.

Conclusion

When IC-DVT is not ruled out in the ED, the suggested algorithm, although not prospectively validated by a controlled study, offers an approach to diagnosis that is consistent with current data and recommendations. When IC-DVT is diagnosed, current references suggest that a decision between anticoagulation and continued follow-up outpatient testing can be based on shared decision-making. The risks of proximal progression and life-threatening embolization should be balanced against the generally more benign natural history of such thrombi, and an individual patient’s risk factors for both thrombus propagation and complications of anticoagulation.

Direct Oral Anticoagulants and Their Use in Treatment and Secondary Prevention of Acute Symptomatic Venous Thromboembolism

Direct oral anticoagulants (DOACs) have been compared with standard therapy in large phase III studies to assess their safety and efficacy in the treatment of deep vein thrombosis and/or pulmonary embolism and in the secondary prevention of recurrent venous thromboembolism. Although the mean population age and the gross inclusion and exclusion criteria were similar across these studies, they differed in other aspects such as overall study design and acute treatment strategies. The 4 DOACs examined in phase III trials (apixaban, edoxaban, rivaroxaban, and dabigatran) showed noninferiority compared with standard therapy for the treatment of deep vein thrombosis and/or pulmonary embolism and for the prevention of recurrent venous thromboembolism. Furthermore, these DOACs exhibited a similar safety profile to standard therapy, with the risk of major bleeding significantly reduced in some of these studies. Rivaroxaban and apixaban were tested as a single-drug approach, whereas in the dabigatran and edoxaban studies, initial bridging with parenteral agents was employed. The purpose of this review is to compare the phase III studies of DOACs in this indication, to highlight the differences, and to discuss a series of clinically relevant issues, including the management of key patient subgroups (eg, fragile patients, those with cancer or renal impairment), extended treatment, use of comedications, heparin pretreatment versus a single-drug approach, and the bleeding profiles of the DOACs.

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.

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.