Proximal Distal Deep Vein Thrombosis Research Articles

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.

Rivaroxaban treatment for six weeks versus three months in patients with symptomatic isolated distal deep vein thrombosis: randomised controlled trial

ObjectiveTo compare two different treatment durations of rivaroxaban in patients with symptomatic isolated distal deep vein thrombosis (DVT).DesignRandomised, double blind, placebo controlled clinical trial.Setting28 outpatient clinics specialising in venous thromboembolism.Participants402...

Derivation and Validation of Natural Language Processing Algorithms to Identify and Classify Venous Thrombotic Events from Lower Extremity Duplex Ultrasound Reports

Background: The precise anatomic location and extent of most venous thromboembolism (VTE) is not captured through diagnostic codes and is a major limitation to research. Correctly identifying the specific site of thrombosis, whether proximal or distal deep vein thrombosis (DVT) or superficial vein thrombosis (SVT) is critical.An accurate natural language processing (NLP) tool would make analysis of large datasets from electronic medical records possible and could be an significant improvement compared to analyses using the International Classification of Diseases codes. Using an open-source NLP tool, we evaluated existing algorithms and then created and validated new NLP algorithms to classify lower extremity thrombosis as not only a DVT or SVT, but also to identify more precise anatomic locations.Methods: A random sample of deidentified ultrasound reports were extracted from electronic medical records, manually reviewed, and classified as either positive or negative for a DVT or SVT (any chronicity). Reports with DVT were further classified into proximal (popliteal, femoral, deep femoral, common femoral, iliac veins, or vena cava) and distal (posterior tibial, anterior tibial, peroneal, soleal, or gastrocnemius veins) DVT. SVT was further classified into greater saphenous vein, small saphenous vein, or other site. Thrombosis near the junction of deep and superficial veins was only designated as involving specific vein segments if there was intraluminal thrombosis at that site. Initial sets of 100 ultrasound reports were used for derivation and reiterative testing of the algorithm, consisting of 50 that were positive for DVT/SVT and 50 that were negative for DVT/SVT. Text from radiology reports underwent cleaning to remove extraneous punctuation, text outside of the “findings” and “impression” section, and all text matches for “superficial femoral vein” were replaced with “femoral vein”. Using target phrases, the simple NLP tool either classified the reports as present or absent, signifying either positive or negative for thrombosis at the site of interest. After maximizing accuracy in the derivation cohorts, each NLP algorithm was tested in the complete, manually reviewed dataset. Sensitivity (Sn) and specificity (Sp) were calculated and confidence intervals were determined by the binomial exact method.Results: A total of 1206 ultrasounds were reviewed, among which there was 687 positives for DVT (503 had proximal DVT and 378 had distal DVT involvement). A total of 176 had SVT, 114 with involvement of the great saphenous vein (GSV) and 65 with involvement of the small saphenous vein (SSV). The previously published NLP (designed to identify DVT) had a poor Sn 45.0%, but reasonable Sp (91.0%) for DVT. Among the incorrect positive determinations (n=47), 33 were incorrectly positive due to presence of SVT (in the absence of DVT). Our newly developed NLP algorithm correctly identified DVT at any site (Sn: 96.2% 95% CI 94.5-97.5; 661/687 and Sp: 93.8% 95% CI 91.4-95.7; 487/519). Among ultrasounds positive for DVT, the NLP algorithm to determine proximal DVT site had a 96.0% Sn (95% CI 93.9-97.6; 483/503) and a 97.8% Sp (95% CI 94.5-99.4; 179/183). The algorithm for distal DVT had a 96.8% Sn (95% CI 94.5-98.4; 366/378) and a 96.1% Sp (95% CI 93.3-98.0; 296/308). The algorithm to identify SVT was also highly accurate (Sn 97.7%, 95% CI 94.3-99.4; 172/176 and Sp 95.5%, 95% CI 94.1-96.7; 984/1030). Among ultrasounds positive for SVT, the Sn to determine GSV site was 94.7% (95% CI 88.9-98.0; 108/114) and Sp was 95.1% (95% CI 86.3-99.0; 58/61). The algorithm to identify SSV site had a Sn of 98.5% (95% CI 91.7-99.9; 64/65) and a Sp of 100% (95% CI 96.7-100.0; 110/110).Conclusion: Using a previously published, open source, simple NLP program, we have improved the sensitivity and specificity for identification of DVT and created an algorithm to accurately identify SVT. Using a multifaceted analysis approach, we were able to accurately further subclassify the anatomic location of thrombosis on ultrasound reports. This tool and the developed algorithms will allow analysis of large data sets with minimal effort and great accuracy, capitalizing on the power of large electronic datasets to offer new insights on pathophysiology and clinical prognosis. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Risk of Clinically Relevant Venous Thromboembolism in Critically Ill Patients With COVID-19: A Systematic Review and Meta-Analysis

Background: Early during the course of the ongoing COVID-19 pandemic, reports suggested alarmingly high incidences for thromboembolic events in critically ill patients with COVID-19. However, the clinical relevance of these events was not reported in several studies. Additionally, more recent research showed contradictory results and suggested substantially lower rates of venous thromboembolism. Thus, the aim of the present study was to summarize evidence on the incidence of clinically relevant venous thromboembolism (VTE)—defined as VTE excluding isolated subsegmental pulmonary embolism (PE) and distal deep vein thrombosis (DVT)—in adult critically ill patients with COVID-19.Methods: We performed a systematic review of studies reporting the incidence of clinically relevant PE and/or DVT in critically ill patients with COVID-19. Scientific reports published in the English language between January and October 2020 were included. We conducted a random-effects model meta-analysis to calculate incidence estimates of clinically relevant VTE and bleeding events. We also performed exploratory meta-regression and subgroup analyses of different diagnostic approaches and additional factors that possibly influenced the incidence of these outcomes.Results: Fifty-four articles (5,400 patients) fulfilled the predefined inclusion criteria, of which 41 had a high risk of bias. The majority of included patients were male, > 60 years, and overweight. Twenty-one studies reported the use of prophylactic doses of heparin. Pooled incidences for clinically relevant PE were estimated at 8% (95% CI, 4–11%), for proximal DVT at 14% (95% CI, 9–20%), and—after exclusion of studies with a high risk of bias—for the composite outcome of VTE at 18% (95% CI, 13–24%). Clinically relevant bleeding occurred at a rate of 6% (95% CI, 2–9%).Conclusions: We summarized currently available data on the rate of clinically relevant VTE in critically ill patients with COVID-19. Pooled incidence estimates were lower than those reported by previous review articles. In the absence of evidence-based anticoagulation guidelines for critically ill patients with COVID-19, the results of our study provide clinically important information for an individual risk-benefit assessment in this context.Registration: The study protocol was prospectively registered in PROSPERO on June 22, 2020 (CRD42020193353; https://www.crd.york.ac.uk/prospero).

Reduced Calf Muscle Pump Function Is a Risk Factor for Venous Thromboembolism and Mortality

Background: Venous return from the lower extremities is pumped upwards to the right side of the heart in a process that is facilitated by one-way valves and the venous muscle pump, of which the calf muscle pump is a major contributor1-3. Venous plethysmography can quantitatively assess calf pump function (CPF). The association between the CPF and venous thromboembolism (VTE) has not been investigated. Methods: Venous plethysmography (VP) data (strain gauge or air plethysmography) from the Mayo Clinic Vascular Lab database (1998-2015) of CPF (bilaterally reduced, unilaterally reduced, and bilateral normal) were examined in Olmsted County Residents. The Rochester Epidemiology Project (REP) captures the population of Olmsted County and contains demographic information, medical diagnoses, hospital admissions, and surgical procedures as well as validated VTE events and death. Patients with signs of obstructed outflow in either extremity on the venous plethysmography (a possible sign of acute or chronic deep vein thrombosis) study were excluded. Patients with a history of VTE diagnosed before the physiologic study were also excluded. If more than one measurement of calf muscle pump function was performed, only the first measurement was used. The primary outcome was a composite of any VTE, including proximal and distal deep vein thrombosis (DVT) and pulmonary embolism (PE). Results: 1703 Olmsted County residents had venous plethysmography studies performed. MN research authorization was denied in 64 patients and 107 were excluded for any documented VTE preceding index VP study. 1532 patients with recorded CPF (28% air and 72% strain gauge plethysmography) were studied: 591 (38.5%) had normal CPF, 353 (23.0%) had unilateral reduced CPF (rCPF), and 588 (38.3%) had bilateral rCPF. The mean age was 64.4 (SD 18.4), 68.9% were female, and the mean BMI was 29.5 (SD 6.4). Any VTE occurred in 87 patients (5.7%) after a mean follow up of 10.9 years (range 0-22.0 years). Isolated lower extremity DVT (excluding concurrent PE) occurred in 49 patients and PE+/-DVT occurred in 38 patients. Death occurred in 352 patients (23%). Bilateral rCPF compared to bilateral normal CPF was associated with VTE (p=0.007), DVT only (p=0.02) and death (p<0.001) but not PE+/-DVT (p=0.13). Unilateral rCPF compared to bilateral normal CPF was not associated with VTE, but was associated with death (p<0.001). Kaplan-Meier curves for VTE and death are shown in Figure 1. The hazard ratio for bilateral rCPF compared to bilateral normal CPF for VTE was 2.0 (95% CI 1.2-3.4) and for DVT only was 2.2 (95% CI 1.1-4.2). A sensitivity analysis for the main outcome of VTE did not show significant interaction based on the type of plethysmography (strain vs. air), by age stratified at 65 years, sex, or BMI stratified at 30 (p>0.1 for each comparison). Conclusion: In this population-based study of Olmsted County residents with no prior VTE, rCPF function as measured by venous plethysmography is associated with increased risk for VTE, particularly lower extremity proximal DVT. More research is required to understand what additional measures of venous physiology influence these findings and whether CPF could be used in VTE risk stratification. Disclosures No relevant conflicts of interest to declare.

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.

The long‐term recurrence risk of patients with unprovoked venous thromboembolism: an observational cohort study

Background The long-term recurrence risk (ltRR) of venous thromboembolism (VTE) is uncertain. Objective To assess the ltRR of patients with first unprovoked VTE. Patients/methods Patients were classified into three categories: distal deep vein thrombosis (DVT), proximal DVT or pulmonary embolism (PE), that is, PE associated with DVT or isolated PE. Patients with major thrombophilia or antithrombotic therapy were excluded. The endpoint was recurrent symptomatic VTE. Results A total of 839 patients were followed for a median of 7.7 years. VTE recurred in 263 patients (31%). After 10 and 20 years, the cumulative ltRR was 32% (95% confidence interval [CI], 29-36) and 44% (95% CI, 38-49) with 3.9 (95% CI, 3.3-4.6) and 3.3 (95% CI, 2.7-4.0) events per 100 patient-years, respectively. The adjusted hazard ratio was 2.1 (95% CI, 1.4-3.2) and 2.1 (95% CI, 1.4-3.2) for patients with proximal DVT or PE compared with patients with distal DVT and was 2.1 (95% CI, 1.6-2.9) for men compared with women. At 10 years, 4.7 (95% CI, 3.8-5.8) events per 100 patient-years occurred in men with proximal DVT or PE, 2.4 (95% CI, 1.2-4.4) in men with distal DVT, 1.9 (95% CI, 1.2-2.8) in women with proximal DVT or PE and 0.9 (95% CI, 0.2-1.9) in women with distal DVT. Conclusion The ltRR of patients with first unprovoked VTE is high and dependent upon sex and VTE site.

Stacked Modalities' Thromboprophylactic Therapy for Patients Undergoing Total Knee Replacement Surgery

Thromboprophylaxis is a controversial and challenging topic in joint replacement surgery. Mechanical prophylaxis in combination with the use of anticoagulants have been shown to have greater efficacy than single modalities. But the early use of anticoagulants has the potential to increases the risk of postoperative bleeding. The purpose of this study was to evaluate the thromboprophylactic effects of sequential combined method using early-mechanical compression with delayed rivaroxaban in total knee arthroplasty. A retrospective cohort study, including 369 patients receiving simultaneous combined mechanical and pharmacological thromboprophylactic modality and 385 patients receiving sequential combined modality with early-mechanical compression treatment followed by rivaroxaban 2 days later after primary total knee arthroplasty surgery was conducted. The incidence rates of proximal and distal deep vein thrombosis (DVT) on the 2nd day and the 5th week and the volume of wound drainage were compared postoperatively. On the 2nd postoperative day, the incidence rates of proximal and distal DVT in the sequential group (1.56, 4.16%) had no significant difference compared with those (1.08, 3.25%) in the simultaneous group (p = 0.569, 0.507, respectively). No difference was found in the incidence rate of proximal and distal DVT on the 5th week between groups. No pulmonary embolism occurred. The mean volume of wound drainage in the sequential group was 343 mL which was 98 mL lesser than in the simultaneous group (p < 0.001). The sequential combined method as called "stacked modalities" thromboprophylactic therapy following total knee arthroplasty was safe and effective. The use of the mechanical compression method alone during the early-postoperative 48 hours, then followed by rivaroxaban then until the 5th week had the same antithrombotic effects and reduced the postoperative wound drainage volume as compared with simultaneous combined modalities.

Individually Tailored Prophylaxis Using a Risk Score for the Management of Pregnant Women with Increased Risk of Venous Thromboembolism

Patients with thrombophilia and/or a history of venous thromboembolism (VTE) exhibit a high risk of thrombosis during pregnancy. A risk score for pregnancies with increased risk of VTE was previously described by our group (1,2). The present work reports the results of a prospective study, evaluating the efficacy and the safety of the prophylaxis strategy based on the same risk score, in 542 pregnancies at high risk of VTE, managed between 2005 and 2015 in Lyon University Hospitals.Among 445 patients included in the study, 26 had several pregnancies during the study period. The mean age of the study population was 33±4.8 years, 132 women (29.7%) were older than 35 years. Fifty three women had a BMI of 30 or over and 61 were smokers. Among these 445 patients, 279 had a personal history of VTE (62.7%), 299 patients (67.2%) had a thrombophilia marker and 131 (29.4%) thrombophilic women had a personal history of VTE.During pregnancy, patients were assigned to one of three prophylaxis strategies according to the risk scoring system. Compression stockings were worn by the majority of the patients throughout the pregnancy and during the postpartum. In antepartum, LMWH prophylaxis was prescribed to 64.5% of patients with high risk of VTE. Among them, 34.4% were treated in the third trimester only and 30.1% were treated throughout pregnancy. In postpartum, all patients received low molecular weight heparin (LMWH) prophylaxis for at least 6 weeks.In this cohort, two antepartum-related VTE (0.37%) and four postpartum-related VTE (0.73%) occurred. One of the ante-partum related VTE was occurred in a patient who was on LMWH prophylaxis with enoxaparin 40mg/day for a personal history of spontaneous pulmonary embolism and homozygous prothrombin G20210A mutation. Despite well conducted LMWH prophylaxis, the patient had a distal deep vein thrombosis (DVT) at week 28. The second VTE was a proximal DVT during a bed resting in the eighth month of pregnancy in a patient with heterozygous FV Leiden mutation and a history of proximal DVT. According to the risk score, LMWH prophylaxis was required during bed-resting but it was not prescribed by the obstetrician. Among four postpartum-related VTE, 3 occurred after the 6 weeks of LMWH prophylaxis, between weeks 8 and 12 of the postpartum period and one was a ovarian vein thrombosis. No case of pulmonary embolism was observed during the study period. The rate of bleeding was 0.37%, no serious bleeding requiring transfusions or surgery was occurred during the study period. There was no evidence of heparin-induced thrombocytopenia or osteoporosis.The use of a risk score may provide a rational decision process to implement safe and effective antepartum thromboprophylaxis in pregnant women at high risk of VTE1.Dargaud, Y., Rugeri, L., Ninet, J., Negrier, C. & Trzeciak, M.C. Management of pregnant women with increased risk of venous thrombosis. International Journal of Gynaecology and Obstetrics 2005, 90,203-2072.Dargaud, Y., Rugeri, L., Vergnes MC, Arnuti B, Miranda P, Negrier, C., Ninet, J., Trzeciak, M.C. A risk score for the management of pregnant women with increased risk of venous thrombomebolism: a multicenter prospective study. Br J Haematol 2009;145:825-35 DisclosuresNo relevant conflicts of interest to declare.

Risk factors and early outcomes of patients with symptomatic distal vs. proximal deep-vein thrombosis

Isolated distal deep-vein thrombosis (iDDVT) is a distal deep-vein thrombosis (DVT) without proximal DVT or pulmonary embolism. Although its clinical significance is uncertain, its prevalence is increasing with the use of whole leg compression ultrasonography. Epidemiological data giving reported rates of venous thromboembolism (VTE) are scarce, and there is potential conflict regarding the need to treat with anticoagulant drugs. Therefore, iDDVT management varies widely from one country/physician to another. Data are available from two large multicenter observational studies of iDDVT and proximal DVT without pulmonary embolism (iPDVT), comparing risk factor profiles and early prognosis, and also from clinical trials on iDDVT. iDDVT and iPDVT differ in terms of risk factor profile, iPDVT being more associated with chronic risk factors and iDDVT with transient ones. In the short term, case fatality rates associated with iDDVT suggest that it is a clinically relevant entity and should at least be diagnosed. From a therapeutic point of view, differences in population profile and outcomes between iPDVT and iDDVT, and results from recent clinical trials in favor of a modest VTE potential of iDDVT indicate that specific randomized double-blind trials are necessary to determine an appropriate and accepted mode of care for iDDVT.

Inconsistencies in the planning of the duration of anticoagulation among outpatients with acute deep-vein thrombosis

Three-month anticoagulation is recommended to treat provoked or first distal deep-vein thrombosis (DVT), and indefinite-duration anticoagulation should be considered for patients with unprovoked proximal, unprovoked recurrent, or cancer-associated DVT. In the prospective Outpatient Treatment of Deep Vein Thrombosis in Switzerland (OTIS-DVT) Registry of 502 patients with acute objectively confirmed lower extremity DVT (59% provoked or first distal DVT; 41% unprovoked proximal, unprovoked recurrent, or cancer-associated DVT) from 53 private practices and 11 hospitals, we investigated the planned duration of anticoagulation at the time of treatment initiation. The decision to administer limited-duration anticoagulation therapy was made in 343 (68%) patients with a median duration of 107 (interquartile range 91-182) days for provoked or first distal DVT, and 182 (interquartile range 111-184) days for unprovoked proximal, unprovoked recurrent, or cancer-associated DVT. Among patients with provoked or first distal DVT, anticoagulation was recommended for < 3 months in 11%, ≥ 3 months in 63%, and for an indefinite period in 26%. Among patients with unprovoked proximal, unprovoked recurrent, or cancer-associated DVT, anticoagulation was recommended for < 6 months in 22%, 6-12 months in 38%, and for an indefinite period in 40%. Overall, there was more frequent planning of indefinite-duration therapy from hospital physicians as compared with private practice physicians (39% vs. 28%; p=0.019). Considerable inconsistency in planning the duration of anticoagulation therapy mandates an improvement in risk stratification of outpatients with acute DVT.

Venous thromboembolism following prolonged cast immobilisation for injury to the tendo Achillis

We report an audit of 208 patients with a mean age of 39 years (16 to 65) attending the Orthopaedic Assessment Unit at the Wellington Hospital between January 2006 and December 2007 with an injury of the tendo Achillis requiring immobilisation in a cast. Information on assessment of venous thromboembolism (VTE) risk, prophylactic measures and VTE events for all patients was obtained from the medical records. A VTE risk factor was documented in the records of three (1%) patients. One of the 208 patients received aspirin prophylaxis; none received low molecular weight heparin. In all, 13 patients (6.3%, 95% confidence interval 3.4 to 10.5) developed symptomatic VTE during immobilisation in a cast, including six with a distal deep-vein thrombosis (DVT), four with a proximal DVT, and three with a confirmed pulmonary embolus. This incidence of symptomatic VTE is similar to that reported following elective hip replacement. We propose that consideration is given to VTE prophylaxis during prolonged immobilisation of the lower limbs in a cast, to ensure that the same level of protection is provided as for patients undergoing elective hip replacement.

Comparative study on risk factors and early outcome of symptomatic distal versus proximal deep vein thrombosis: Results from the OPTIMEV study

There is a lack of consensus on the value of detecting and treating symptomatic isolated distal deep-vein thrombosis (DVT) of the lower limbs. In our study, we compared the risk factors and outcomes in patients with isolated symptomatic distal DVT with those with proximal symptomatic DVT. We analysed the data of patients with objectively confirmed symptomatic isolated DVT enrolled in the national (France), multicenter, prospective OPTIMEV study. This sub-study outcomes were recurrent venous thromboembolism, major bleeding and death at three months. Among the 6141 patients with suspicion of isolated DVT included between November 2004 and January 2006, DVT was confirmed in 1643 patients (26.8%). Isolated distal DVT was more frequent than proximal DVT (56.8% vs. 43.2%, respectively; p = 0.01). Isolated distal DVT was significantly more often associated with transient risk factors (recent surgery, recent plaster immobilisation, recent travel), whereas proximal DVT was significantly more associated with more chronic states (active cancer, congestive heart failure or respiratory insufficiency, age >75 years). Most patients (96.8%) with isolated distal DVT received anticoagulant therapies. There was no difference in the percentage of recurrent venous thromboembolism and major bleeding in patients with proximal DVT and isolated distal DVT. However, the mortality rate was significantly higher (p < 0.01) in patients with proximal DVT (8.0%) than in those with isolated distal DVT (4.4%). Symptomatic isolated distal DVT differs from symptomatic proximal DVT both in terms of risk factors and clinical outcome. Whether these differences should influence the clinical management of these two events remains to be determined.

Are isolated distal deep-vein thromboses clinically significant?

The authors consider isolated distal deep-vein thrombosis (DVT) to be significant and recommend treating isolated symptomatic distal DVT in the same way as proximal lower-limb DVT. There is no guidance for the treatment of asymptomatic isolated distal DVT; however, certain triggers could be used to guide therapy. Our policy is as follows: all patients with distal DVT (asymptomatic and symptomatic) are given graduated compression stockings and early ambulation. We use anticoagulant therapy to treat asymptomatic distal DVT greater than 10 cm in length, or more proximal ones that are near the confluence of the venous trifurcation that forms the popliteal vein. Those patients with asymptomatic thrombi of 5–10 cm and with ongoing risk factors for propagation, for example immobilization or malignancy, generally receive treatment. We generally do not anticoagulate asymptomatic soleal vein and other small isolated distal DVT. We empirically watch untreated patients more closely, with repeat compression ultrasound...

Mortality rates and risk factors for asymptomatic deep vein thrombosis in medical patients

The clinical importance of asymptomatic proximal and distal deep vein thrombosis (DVT) remains uncertain and controversial. The aim of this retrospective, post-hoc analysis was to examine mortality and risk factors for development of proximal DVT in hospitalized patients with acute medical illness who were recruited into a randomized, prospective clinical trial of thromboprophylaxis with dalteparin (PREVENT). We analyzed 1738 patients who had not sustained a symptomatic venous thromboembolic event by Day 21 and who had a complete compression ultrasound of the proximal and distal leg veins on Day 21. We examined the 90-day mortality rates in patients with asymptomatic proximal DVT (Group I, N=80), asymptomatic distal DVT (Group II, N=118) or no DVT (Group III, N=1540). The 90-day mortality rates were 13.75%, 3.39%, and 1.92% for Groups I-III, respectively. The difference in mortality between Group I and Group III was significant (hazard ratio 7.63, 95% CI=3.8-15.3; p <0.0001), whereas the difference between Groups II and III did not reach significance (hazard ratio 1.36, 95% CI=0.41-4.45). The association of asymptomatic proximal DVT with increased mortality remained highly significant after adjusting for differences in baseline demographics and clinical variables. Risk factors significantly associated with the development of proximal DVT included advanced age (p=0.0005), prior DVT (p=0.001), and varicose veins (p=0.04). In conclusion, the high mortality rate in patients with asymptomatic proximal DVT underscores its clinical relevance and supports targeting of asymptomatic proximal DVT as an appropriate endpoint in clinical trials of thromboprophylaxis.

Complete compression ultrasound for the diagnosis of venous thromboembolism.

Since its first appearance in the 1980s, venous ultrasound has increasingly gained interest of both clinicians and researchers. However, a majority of authors currently are convinced that venous ultrasound has inherent limitations that preclude it from safely ruling out distal deep vein thrombosis (DVT) in symptomatic patients and from detecting proximal and distal DVT accurately in asymptomatic patients. The aim of this review is to present recent lines of evidence indicating that venous ultrasound has developed beyond these limitations. The major development does not arise from technical progress of imaging but from standardizing the examination procedure. The most efficient protocols now focus on B-mode sonography only but extend the examination to the paired deep calf veins and the calf muscle veins. For such an examination protocol, the term complete compression ultrasound (CCUS) has been coined. Interobserver variability of CCUS resembles that of venography, as do the technical failure rates. By means of a CCUS protocol, the diagnostic work-up of patients with suspected DVT can be simplified significantly. Studies in asymptomatic patients indicate that CCUS has the potential to generate valid data in prevalence and incidence studies and in intervention trials. Complete compression ultrasound protocols are ready for implementation into clinical practice for diagnosing patients with symptomatic DVT. Research has already benefited from CCUS and benefits further with an increasing number of CCUS-driven trial designs. However, the value of a CCUS protocol critically depends on sound training and on strict compliance with all its details.