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.

Management of isolated distal deep-vein thrombosis with direct oral anticoagulants in the RIETE registry.

Isolated distal deep-vein thrombosis (DVT, infra-popliteal DVT without pulmonary embolism) is a common presentation of venous thromboembolism (VTE), but was an exclusion criterion from the pivotal trials that validated the use of direct oral anticoagulants (DOACs) for VTE management. Using data from the international RIETE registry, we analyzed and compared trends in DOACs prescription between January 2011 and June 2019 in patients with distal vs. proximal DVT. We also assessed DOACs' prescriptions and compared the outcomes (VTE recurrence, bleeding and death) of distal DVT patients treated with DOACs vs. those on vitamin K antagonists (VKAs). 2308 patients with distal DVT and 11,364 patients with proximal DVT were included in the current analysis. DOACs were more frequently prescribed in patients with distal than proximal DVT (25% vs. 16%, p < 0.001). DOACs use increased sharply during the observation period (P < 0.001 for trend). In 2018, 56% of patients with distal DVT received DOACs. Distal DVT patients treated with rivaroxaban or edoxaban received the dose recommended for VTE management in most (> 85%) cases. Patients treated with apixaban were older, more likely to have underlying conditions than patients treated with rivaroxaban and, in most cases (> 75%), did not receive the recommended 1-week loading dose for acute VTE management. Outcomes between distal DVT patients treated with VKAs or DOACs appeared to be similar. In patients with distal DVT, DOACs have become the most common anticoagulant regimen. Specific trials are needed to determine the optimal DOACs dose regimen for treatment of distal DVT.

Dalteparin or vitamin K antagonists to prevent recurrent venous thromboembolism in cancer patients: a patient-level economic analysis for France and Austria.

BACKGROUND: International guidelines recommend extended duration secondary prophylaxis in cancer patients who develop primary venous thromboembolism (VTE). Agent selection is guided in part by one large randomized trial (i.e., CLOT; Lee et al., N Engl J Med 349:146-53, 2003) which demonstrated that dalteparin reduced the relative risk of recurrence by 52% compared with oral vitamin K antagonists (VKA; HR = 0.48, 95% CI, 0.30 to 0.77). In a subgroup analysis from that same trial, patients with renal impairment also derived benefit with dalteparin (VTE rates = 3% vs. 17%; p = 0.011). To measure the economic value of secondary VTE prophylaxis with dalteparin, a patient-level pharmacoeconomic analysis was conducted from the Austrian and French healthcare system perspectives. METHODS: Chapter 1 Healthcare resource use collected during the CLOT trial was extracted and converted into direct cost estimates. Incremental cost differences between the dalteparin and VKA groups were then combined with health state utilities to measure the cost per quality-adjusted life year (QALY) gained. RESULTS: The dalteparin group had significantly higher costs than the VKA group in both countries (Austria: dalteparin = €2687 vs. VKA = €2012; France: dalteparin = €2053 vs. VKA = €1352: p < 0.001). However, when the incremental costs were combined with the utility gain, dalteparin had a cost of €6600 and €4900 per QALY gained in Austria and France, respectively. The analyses in patients with renal impairment suggested an even better economic profile, with the cost per QALY gained being less than €4000 in both countries. CONCLUSIONS: Secondary prophylaxis with dalteparin is a cost-effective alternative to VKA for the prevention of recurrent VTE in patients with cancer.

Guidance for the prevention and treatment of the post-thrombotic syndrome.

The post-thrombotic syndrome (PTS) is a frequent, potentially disabling complication of deep vein thrombosis (DVT) that reduces quality of life and is costly. Clinical manifestations include symptoms and signs such as leg pain and heaviness, edema, redness, telangiectasia, new varicose veins, hyperpigmentation, skin thickening and in severe cases, leg ulcers. The best way to prevent PTS is to prevent DVT with pharmacologic or mechanical thromboprophylaxis used in high risk patients and settings. In patients whose DVT is treated with a vitamin K antagonist, subtherapeutic INRs should be avoided. We do not suggest routine use of elastic compression stockings (ECS) after DVT to prevent PTS, but in patients with acute DVT-related leg swelling that is bothersome, a trial of ECS is reasonable. We suggest that selecting patients for catheter-directed thrombolytic techniques be done on a case-by-case basis, with a focus on patients with extensive thrombosis, recent symptoms onset, and low bleeding risk, who are seen at experienced hospital centers. For patients with established PTS, we suggest prescribing 20-30 mm Hg knee-length ECS to be worn daily. If ineffective, a stronger pressure stocking can be tried. We suggest that intermittent compression devices or pneumatic compression sleeve units be tried in patients with moderate-to-severe PTS whose symptoms are inadequately controlled with ECS alone. We suggest that a supervised exercise training program for 6 months or more is reasonable for PTS patients who can tolerate it. We suggest that management of post-thrombotic ulcers should involve a multidisciplinary approach. We briefly discuss upper extremity PTS and PTS in children.

Comparative incidence of a first thrombotic event in purely obstetric antiphospholipid syndrome with pregnancy loss: the NOH-APS observational study.

The incidence of thrombosis in the purely obstetric form of antiphospholipid syndrome is uncertain. We performed a 10-year observational study of 1592 nonthrombotic women who had experienced 3 consecutive spontaneous abortions before the 10th week of gestation or 1 fetal death at or beyond the 10th week of gestation. We compared the frequencies of thrombotic events among women positive for antiphospholipid Abs (n = 517), women carrying the F5 6025 or F2 rs1799963 polymorphism (n = 279), and women with negative thrombophilia screening results (n = 796). The annual rates of deep vein thrombosis (1.46%; range, 1.15%-1.82%), pulmonary embolism (0.43%; range, 0.26%-0.66%), superficial vein thrombosis (0.44%; range, 0.28%-0.68%), and cerebrovascular events (0.32%; range, 0.18%-0.53%) were significantly higher in aPLAbs women than in the other groups despite low-dose aspirin primary prophylaxis. Women carrying 1 of the 2 polymorphisms did not experience more thrombotic events than women who screened negative for thrombophilia. Lupus anticoagulant was a risk factor for unprovoked proximal and distal deep and superficial vein thrombosis and women in the upper quartile of lupus anticoagulant activity had the highest risk. Despite data suggesting that aPLAbs may induce pregnancy loss through nonthrombotic mechanisms, women with purely obstetric antiphospholipid syndrome are at risk for thrombotic complications.

Postthrombotic syndrome: a 2014 update.

PURPOSE OF REVIEW: Postthrombotic syndrome (PTS) is the most frequent complication of deep vein thrombosis. Its pathophysiology is incompletely understood and therapeutic options are limited. This review aims to present and discuss recently published studies that have improved our knowledge related to PTS. RECENT FINDINGS: From a prognostic point of view, some polymorphisms of plasminogen activator inhibitor-1 and platelet endothelial cell adhesion molecule 1 influence the degree of thrombus resolution after deep vein thrombosis and the subsequent rate of PTS, and could help in predicting the risk of PTS. From a therapeutic point of view, the results of a large multicenter placebo-controlled trial suggest an absence of effectiveness of elastic compression stockings to prevent PTS. In addition, although the Cavent trial of catheter-directed thrombolysis to treat ilio-femoral deep vein thrombosis showed significant reduction in the incidence of PTS that was cost-effective, secondary analyses did not show dramatic improvements in quality of life associated with use of catheter-directed thrombolysis. SUMMARY: Choice of anticoagulant to treat deep vein thrombosis may represent a new cornerstone of PTS therapeutic management. Studies are needed to assess the impact of new oral anticoagulants and the benefit of extended courses of low molecular weight heparins on the risk of PTS.

Clinical Presentation and Outcomes of Patients With Cancer-Associated Isolated Distal Deep Vein Thrombosis.

PURPOSE: Patients with isolated distal deep vein thrombosis (DVT) have lower rates of adverse outcomes (death, venous thromboembolism [VTE] recurrence or major bleeding) than those with proximal DVT. It is uncertain if such findings are also observed in patients with cancer. METHODS: Using data from the international Registro Informatizado de la Enfermedad TromboEmbolica venosa registry, we compared the risks of adverse outcomes at 90 days (adjusted odds ratio [aOR]; 95% CI) and 1 year (adjusted hazard ratio [aHR; 95% CI]) in 886 patients with cancer-associated distal DVT versus 5,196 patients with cancer-associated proximal DVT and 5,974 patients with non-cancer-associated distal DVT. RESULTS: More than 90% of patients in each group were treated with anticoagulants for at least 90 days. At 90 days, the adjusted risks of death, VTE recurrence, or major bleeding were lower in patients with non-cancer-associated distal DVT than in patients with cancer-associated distal DVT (reference): aOR = 0.16 (0.11-0.22), aOR = 0.34 (0.22-0.54), and aOR = 0.47 (0.27-0.80), respectively. The results were similar at 1-year follow-up: aHR = 0.12 (0.09-0.15), aHR = 0.39 (0.28-0.55), and aHR = 0.51 (0.32-0.82), respectively. Risks of death, VTE recurrence, and major bleeding were not statistically different between patients with cancer-associated proximal versus distal DVT, both at 90 days: aOR = 1.11 (0.91-1.36), aOR = 1.10 (0.76-1.62), and aOR = 1.18 (0.76-1.83), respectively, and 1 year: aHR = 1.01 (0.89-1.15), aHR = 1.02 (0.76-1.35), and aHR = 1.10 (0.76-1.61), respectively. However, more patients with cancer-associated proximal DVT, compared with cancer-associated distal DVT, developed fatal pulmonary embolism (PE) during follow-up: The risk difference was 0.40% (95% CI, 0.23 to 0.58). CONCLUSION: Cancer-associated distal DVT has serious and relatively comparable outcomes compared with cancer-associated proximal DVT. The lower risk of fatal PE from cancer-associated distal DVT needs further investigation.

Venous recanalisation in the setting of post-thrombotic syndrome: An expert consensus from the French Society of Vascular Medicine (SFMV) and the French Society of Cardiovascular Imaging and Interventional Radiology (SFICV).

Several aspects of the management of post-thrombotic syndrome (PTS) are still a matter of debate, or not yet addressed in international guidelines. The objective of this expert consensus from the French Society of Vascular Medicine (SFMV) and the French Society of Cardiovascular Imaging (SFICV) was to define the main elements of diagnosis and treatment of this syndrome, and to develop a proposal for its preoperative, procedural and follow-up management. In this consensus, the following issues were addressed: clinical and ultrasound diagnosis; pre-procedural workup; indications and contraindications to venous recanalisation; procedures; clinical and duplex ultrasound reports; follow-up; long-term treatment; management of great saphenous vein incompetency; anticoagulant and antiplatelet therapy after venous stenting.

Very long-term risk of moderate-to-severe postthrombotic syndrome after deep vein thrombosis.

BACKGROUND: Postthrombotic syndrome (PTS) refers to manifestations of chronic venous insufficiency after a deep vein thrombosis (DVT). The risk of developing moderate-to-severe PTS in the very long term is largely unknown and particularly in case of distal DVT. Furthermore, the impact of DVT vs other causes of chronic venous insufficiency on long-term manifestations of PTS is also unknown. OBJECTIVES: To assess the very long-term risk of moderate-to-severe PTS after DVT and the role that DVT plays in PTS symptoms. METHODS: Patients with lower-limb DVT enrolled in the multicenter Optimisation de l'interrogatoire dans l'evaluation du risque thromboembolique veineux (OPTIMEV) study underwent a very long-term telephone follow-up. We assessed i) the proportion of moderate-to-severe PTS (assessed with the patient-reported Villalta score) according to DVT extent and ii) the population attributable fraction that DVT plays in patients' moderate-to-severe PTS manifestations. RESULTS: Fourteen years after DVT, moderate-to-severe PTS developed in 35 of 185 patients with distal DVT (18.9%; 95% CI, 13.5%-25.3%), 11 of 47 patients with popliteal DVT (23.4%; 95% CI, 12.3%-38.0%), and 27 of 74 patients with iliofemoral DVT (36.5%; 95% CI, 25.6%-48.5%). The population attributable fraction of DVT in moderate-to-severe symptoms of PTS was 25.7% (-18.1% to 53.3%) in patients with distal DVT, 27.3% (-63.7% to 67.7%) in patients with popliteal DVT, and 43.1% (+0.7%-67.4%) in patients with iliofemoral DVT. CONCLUSION: In the very long term after DVT, a quarter of patients have moderate-to-severe PTS manifestations. However, the impact of the DVT on these manifestations appears nonpredominant and varies according to DVT extent. Distal DVT does not significantly increase the risk of developing moderate-to-severe PTS.

TILE pilot trial study protocol: Tinzaparin Lead-in to Prevent the Post-Thrombotic syndrome study protocol.

INTRODUCTION: The post-thrombotic syndrome (PTS) is a form of chronic venous insufficiency due to a prior ipsilateral deep venous thrombosis (DVT). This is a frequent complication that develops in 20%-50% of patients after a proximal DVT and is associated with significant healthcare, economic and societal consequences. In the absence of effective and well-tolerated treatment options for established PTS, effective preventative measures are needed. Anticoagulation itself reduces the risk of PTS, and low-molecular-weight heparin may reduce this further through anti-inflammatory properties targeting the initial acute inflammatory phase of DVT. METHODS AND ANALYSIS: The Tinzaparin Lead-In to Prevent the Post-Thrombotic syndrome pilot trial is an investigator-initiated, multicentre, open-label assessor-blinded trial that will randomise patients with first acute symptomatic common femoral or iliac DVT to receive either a 3-week lead-in course of tinzaparin, followed by rivaroxaban (experimental arm) or rivaroxaban alone (control arm). Its primary objectives are to assess: (1) proportion of PTS at 6 months using the Villalta scale and (2) study feasibility, which consists of (a) the proportion of screened patients eligible for the study, (2) the proportion of eligible patients recruited and (c) the proportion of recruited patients adherent to treatment (defined as at least 80% of drug taken). This study will determine the feasibility of a subsequent larger definitive trial. Secondary outcomes include change of quality of life scores, PTS severity, global improvement, patient satisfaction, bleeding, recurrent venous thromboembolism, leg pain, death and lost to follow-up. Target recruitment will be a total of 60 participants, recruited at 5-6 centres. ETHICS AND DISSEMINATION: Primary ethics approval was received from the Sunnybrook Health Sciences Center Research Ethics Board (approval ID 3315). Results of the study will be disseminated via peer-reviewed presentation at scientific conferences and open access publication. TRIAL REGISTRATION NUMBER: NCT04794569.

Exploring the Villalta scale to capture postthrombotic syndrome using alternative approaches: A subanalysis of the ATTRACT trial.

Background: Clinical trials that evaluated interventions to prevent postthrombotic syndrome (PTS) used the Villalta scale (VS) to define PTS, but there is a lack of consistency in its use. Objectives: This study aimed to improve the ability to identify patients with clinically meaningful PTS after DVT in participants of the ATTRACT trial. Methods: We conducted a post hoc exploratory analysis of 691 patients from the ATTRACT study, a randomized trial evaluating the effectiveness of pharmacomechanical thrombolysis to prevent PTS in proximal deep vein thrombosis. We compared 8 VS approaches to classify patients with or without PTS in terms of their ability to discriminate between those with poorer vs better venous disease-specific quality of life (Venous Insufficiency Epidemiological and Economic Study Quality of Life [VEINES-QOL]) between 6- and 24-months follow-up. The difference in the average area under the fitted curve of VEINES-QOL scores between PTS and no PTS ( Δ A U C ¯ ) were compared among approaches. Results: For any PTS (a single VS score ≥5), approaches 1 to 3 had similar Δ A U C ¯ (-21.2, -23.7, -22.0, respectively). Adjusting the VS for contralateral chronic venous insufficiency (CVI) or restricting to patients without baseline CVI (approaches 7 and 8) did not improve Δ A U C ¯ (-13.6, -19.9, respectively; P >.01). For moderate-to-severe PTS (a single VS score ≥10), approaches 5 and 6 requiring 2 positive assessments had greater but not statistically significant Δ A U C ¯ than approach 4, using one single positive assessment (-31.7, -31.0, -25.5, respectively; P >.01). Conclusion: A single VS score of ≥ 5 reliably distinguishes patients with clinically meaningful PTS as assessed by impact on QOL and is preferred because of greater convenience (only one assessment needed). Alternative methods to define PTS (ie, adjusting for CVI) do not improve the scale's ability to identify clinically meaningful PTS.

Implementation of the YEARS algorithm to optimise pulmonary embolism diagnostic workup in the emergency department.

BACKGROUND: Excessive use of CT pulmonary angiography (CTPA) to investigate pulmonary embolism (PE) in the emergency department (ED) contributes to adverse patient outcomes. Non-invasive D-dimer testing, in the context of a clinical algorithm, may help decrease unnecessary imaging but this has not been widely implemented in Canadian EDs. AIM: To improve the diagnostic yield of CTPA for PE by 5% (absolute) within 12 months of implementing the YEARS algorithm. MEASURES AND DESIGN: Single centre study of all ED patients >18 years investigated for PE with D-dimer and/or CTPA between February 2021 and January 2022. Primary and secondary outcomes were the diagnostic yield of CTPA and frequency of CTPA ordered compared with baseline. Process measures included the percentage of D-dimer tests ordered with CTPA and CTPAs ordered with D-dimers <500 µg/L Fibrinogen Equivalent Units (FEU). The balancing measure was the number of PEs identified on CTPA within 30 days of index visit. Multidisciplinary stakeholders developed plan- do-study-act cycles based on the YEARS algorithm. RESULTS: Over 12 months, 2695 patients were investigated for PE, of which 942 had a CTPA. Compared with baseline, the CTPA yield increased by 2.9% (12.6% vs 15.5%, 95% CI -0.06% to 5.9%) and the proportion of patients that underwent CTPA decreased by 11.4% (46.4% vs 35%, 95% CI -14.1% to -8.8%). The percentage of CTPAs ordered with a D-dimer increased by 26.3% (30.7% vs 57%, 95% CI 22.2% 30.3%) and there were two missed PE (2/2695, 0.07%). IMPACT: Implementing the YEARS criteria may safely improve the diagnostic yield of CTPAs and reduce the number of CTPAs completed without an associated increase in missed clinically significant PEs. This project provides a model for optimising the use of CTPA in the ED.

Superficial venous thrombosis and compression ultrasound imaging.

BACKGROUND: A current debate concerning suspected superficial vein thrombosis (SVT) focuses on the need of performing a compression ultrasound (CUS) exploration for confirming the diagnosis of SVT. This study was conducted to determine the clinical relevance and optimal CUS exploration in patients with symptomatic SVT. METHODS: We analyzed the characteristics of SVT and concomitant deep vein thrombosis (DVT) in patients included in the Prospective Observational Superficial Thrombophlebitis (POST) multicenter, observational prospective study. All patients underwent complete bilateral lower limb CUS, exploring both the superficial and deep venous systems. RESULTS: A total of 844 patients with clinical symptoms of SVT were recruited, of which 99 isolated SVTs (21.4%) had saphenofemoral/popliteal junction involvement, and 198 (23.5%) had a concomitant DVT, with 41.8% of them proximal DVTs. In 83 patients (41.9%), DVT and SVT were not contiguous. Five of 639 patients (1%) had an isolated contralateral DVT (ie, not bilateral). Age ≥ 75 years (odds ratio [OR], 2.3; 95% confidence interval [CI], 1.6-3.4), inpatient status (OR, 5.4; 95% CI, 3.4-8.7), a personal history of DVT or pulmonary embolism (OR, 1.8; 95% CI, 1.2-2.8), and SVT on nonvaricose veins (OR, 3.3; 95% CI, 2.1-5.0) were significantly and independently associated with an increased risk of concomitant DVT. Half of the patients exhibited none of these risk factors, and the prevalence of concomitant DVT dropped to 11%. CONCLUSIONS: In patients with symptomatic SVT, a CUS exploration screening the whole venous system of the affected limb is useful because it provides information that has important consequences for the management of these patients.

Prevention of the Postthrombotic Syndrome with Anticoagulation: A Narrative Review.

The postthrombotic syndrome (PTS) is chronic venous insufficiency secondary to a prior deep vein thrombosis (DVT). It is the most common complication of venous thromboembolism (VTE) and, while not fatal, it can lead to chronic, unremitting symptoms as well as societal and economic consequences. The cornerstone of PTS treatment lies in its prevention after DVT. Specific PTS preventative measures include the use of elastic compression stockings and pharmacomechanical catheter-directed thrombolysis. However, the efficacy of these treatments has been questioned by large randomized controlled trials (RCTs). So far, anticoagulation, primarily prescribed to prevent DVT extension and recurrence, appears to be the only unquestionably effective treatment for the prevention of PTS. In this literature review we present pathophysiological, biological, radiological, and clinical data supporting the efficacy of anticoagulants to prevent PTS and the possible differential efficacy among available classes of anticoagulants (vitamin K antagonists [VKAs], low molecular weight heparins [LMWHs] and direct oral anticoagulants [DOACs]). Data suggest that LMWHs and DOACs are superior to VKAs, but no head-to-head comparison is available between DOACs and LMWHs. Owing to their potentially greater anti-inflammatory properties, LMWHs could be superior to DOACs. This finding may be of interest particularly in patients with extensive DVT at high risk of moderate to severe PTS, but needs to be confirmed by a dedicated RCT.

Clinical Presentation and Short- and Long-term Outcomes in Patients With Isolated Distal Deep Vein Thrombosis vs Proximal Deep Vein Thrombosis in the RIETE Registry.

Importance: Insufficient data exist about the clinical presentation, short-term, and long-term outcomes of patients with isolated distal deep vein thrombosis (IDDVT), that is, thrombosis in infrapopliteal veins without proximal extension or pulmonary embolism (PE). Objective: To determine the clinical characteristics, short-term, and 1-year outcomes in patients with IDDVT and to compare the outcomes in unadjusted and multivariable adjusted analyses with patients who had proximal DVT. Design, Setting, and Participants: This was a multicenter, international cohort study in participating sites of the Registro Informatizado Enfermedad Tromboembólica (RIETE) registry conducted from March 1, 2001, through February 28, 2021. Patients included in this study had IDDVT. Patients with proximal DVT were identified for comparison. Patients were excluded if they had a history of asymptomatic DVT, upper-extremity DVT, coexisting PE, or COVID-19 infection. Main Outcomes and Measures: Primary outcomes were 90-day and 1-year mortality, 1-year major bleeding, and 1-year venous thromboembolism (VTE) deterioration, which was defined as subsequent development of proximal DVT or PE. Results: A total of 33 897 patients were identified with isolated DVT (without concomitant PE); 5938 (17.5%) had IDDVT (mean [SD] age, 61 [17] years; 2975 male patients [50.1%]), and 27 959 (82.5%) had proximal DVT (mean [SD] age, 65 [18] years; 14 315 male patients [51.2%]). Compared with individuals with proximal DVT, those with IDDVT had a lower comorbidity burden but were more likely to have had recent surgery or to have received hormonal therapy. Patients with IDDVT had lower risk of 90-day mortality compared with those with proximal DVT (odds ratio [OR], 0.47; 95% CI, 0.40-0.55). Findings were similar in 1-year unadjusted analyses (hazard ratio [HR], 0.52; 95% CI, 0.46-0.59) and adjusted analyses (HR, 0.72; 95% CI, 0.64-0.82). Patients with IDDVT had a lower 1-year hazard of VTE deterioration (HR, 0.83; 95% CI, 0.69-0.99). In 1-year adjusted analyses of patients without an adverse event within the first 3 months, IDDVT was associated with lower risk of VTE deterioration (adjusted HR, 0.48; 95% CI, 0.24-0.97). By 1-year follow-up, symptoms or signs of postthrombotic syndrome were less common in patients with IDDVT (47.6% vs 60.5%). Conclusions and Relevance: Results of this cohort study suggest that patients with IDDVT had a less ominous prognosis compared with patients with proximal DVT. Such differences were likely multifactorial, including the differences in demographics, risk factors, comorbidities, particularly for all-cause mortality, and a potential association of thrombus location with VTE deterioration and postthrombotic syndrome. Randomized clinical trials are needed to assess the optimal long-term management of IDDVT.

25 mm Hg versus 35 mm Hg elastic compression stockings to prevent post-thrombotic syndrome after deep vein thrombosis (CELEST): a randomised, double-blind, non-inferiority trial.

BACKGROUND: The optimal strength of compression needed to prevent post-thrombotic syndrome (PTS) after a proximal deep vein thrombosis (DVT) is debated. We aimed to assess whether 25 mm Hg elastic compression stockings (ECS) are non-inferior to 35 mm Hg ECS in preventing PTS after a DVT. METHODS: In this multicentre, double-blind, non-inferiority, randomised controlled trial, we enrolled adults (≥18 years) with a first ipsilateral proximal DVT attending 46 French vascular medicine hospital departments or private practices. Participants were randomly allocated (1:1, stratified by centre, age, and sex; with varying block sizes of two and four) to wear 25 mm Hg or 35 mm Hg ECS for 2 years. The primary outcome was the cumulative rate of PTS 2 years after inclusion, defined by a Villalta scale (≥5). Efficacy was assessed by intention-to-treat and in eligible participants who had complete primary outcome data. A per-protocol analysis was also conducted among compliant patients as a secondary outcome measure. Safety was assessed in all participants who used ECS at least once, and for which we have at least some tolerance information during follow-up. The margin for non-inferiority was 12·5%. This study is registered with ClinicalTrials.gov, NCT01578122, and has been completed. FINDINGS: Between June 28, 2012, and July 21, 2017, we enrolled 341 eligible participants who consented to randomisation. 233 (68%) were men and median age was 59 years (IQR 45-70). Collection of ethnicity and race as a routine research variable is not authorised in France. Median follow-up was 735 days (IQR 721-760). 249 (73%) had complete data at 2 years. For the primary analysis, 40 (31%) of 129 participants with complete data in the 25 mm Hg ECS group and 40 (33%) of 120 in the 35 mm Hg group had PTS (absolute difference -2·3% [90% CI -12·1 to 7·4], pnon-inferiority=0·0062; relative risk 0·93, 95% CI 0·65 to 1·33). Results remained similar after imputation of missing data in patients we were authorised to do so: the cumulative proportion of PTS was 45 (29%) of 154 in the 25 mm Hg ECS group versus 52 (35%) of 148 in the 35 mm Hg ECS group (relative risk 0·83, 95% CI 0·60 to 1·16). Absolute difference was -5·9%, (90% CI -14·7 to 2·9), p=0·0003 for non-inferiority. Adherence was optimal (>80% and modified GIRERD score of 0-2) for 75 (51%) of 146 patients assigned to 25 mm Hg ECS and for 56 (42%) of 134 patients assigned to 35 mm Hg ECS (p=0·11). Regarding major adverse events related to ECS, there were no between-group differences in rates of deep vein thrombosis (0 vs 1 [0·6%]), ipsilateral leg ulcer (0 vs 1 [0·6%]), infection (0 vs 0), or death (0 vs 0) between the 169 patients evaluated in the 25 mm Hg ECS group and the 159 patients in the 35 mm Hg ECS group. Two (1%) of 328 patients who ever wore ESC developed ECS-related serious adverse events, one distal DVT and one leg ulcer (both in the 35 mm Hg ECS group). In the 25 mm Hg group, 6 patients died, 14 had a venous thromboembolic recurrence (proximal DVT or pulmonary embolism), and 7 had a major bleed. In the 35 mm Hg group, 5 patients died, 10 had a venous thromboembolic recurrence (proximal DVT or pulmonary embolism), and 6 had a major bleed. INTERPRETATION: Although we did not reach the prespecified sample size, our results suggest that 25 mm Hg ECS are non-inferior to 35 mm Hg ECS in preventing PTS. Larger more powerful studies are needed. FUNDING: Laboratoires Innothera, France.

Development of an international standard set of outcome measures for patients with venous thromboembolism: an International Consortium for Health Outcomes Measurement consensus recommendation.

The International Consortium for Health Outcomes Measurement assembled an international working group of venous thromboembolism experts and patient representatives to develop a standardised minimum set of outcomes and outcome measurements for integration into clinical practice and potentially research to support clinical decision making and benchmarking of quality of care. 15 core outcomes important to patients and health-care professionals were selected and categorised into four domains: patient-reported outcomes, long term consequences of the disease, disease-specific complications, and treatment-related complications. The outcomes and outcome measures were designed to apply to all patients with venous thromboembolism aged 16 years or older. A measurement tool package was selected for inclusion in the core standard set, with a minimum number of items to be measured at predefined timepoints, which capture all core outcomes. Additional measures can be introduced to the user by a cascade opt-in system that allows for further assessment if required. This set of outcomes and measurement tools will facilitate the implementation of the use of patient-centred outcomes in daily practice.

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

PURPOSE OF REVIEW: 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. RECENT FINDINGS: 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. SUMMARY: 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.

Initiation of anticoagulation in atrial fibrillation by primary care physicians: Results of a telephone survey.

BACKGROUND: Direct oral anticoagulants (DOACs) are prescribed for over 80% of patients who start anticoagulant therapy for a new diagnosis of atrial fibrillation (AF). Inappropriate DOAC prescriptions are associated with increased mortality. However, limited data exist as to what proportion of primary care physicians (PCPs) initiate anticoagulation in patients with new AF and the extent of their DOAC knowledge. MATERIAL AND METHODS: We conducted a telephone survey of randomly selected PCPs in Ontario, Canada. Our primary objective was to determine the percentage of PCPs who initiate anticoagulation in new AF patients and the proportion of patients they initiate on DOACs. Our secondary objectives were to assess PCPs' knowledge about DOACs and to identify educational opportunities to address any knowledge gaps. RESULTS: Our survey included 50 respondents. After making a new AF diagnosis, 66% of PCPs stated that they usually initiate anticoagulation themselves and 84% prescribed a DOAC at least 75% of the time. Potential DOAC knowledge gaps included: administration considerations, off-label dosing, concomitant use of acetylsalicylic acid (ASA) in stable coronary artery disease (CAD) and use in valvular AF. CONCLUSION: Most PCPs initiate anticoagulants for AF and prescribe DOACs for the vast majority of new patients. PCPs were well versed in certain aspects of DOAC prescribing, however, a number of knowledge gaps were identified. PCPs may benefit from targeted education in these areas to improve patient outcomes in AF.

Micronized purified flavonoid fraction for the treatment of chronic venous insufficiency, with a focus on postthrombotic syndrome: A narrative review.

INTRODUCTION: Postthrombotic syndrome (PTS) is a form of secondary chronic venous insufficiency (CVI) that occurs after deep vein thrombosis (DVT). Effective treatments for PTS are lacking. Micronized purified flavonoid fraction (MPFF) is a venoactive drug used in the treatment of CVI. OBJECTIVE: To determine whether MPFF is a good candidate to explore as a therapeutic agent for PTS. METHODS: We performed a narrative review in which we identified 14 systematic reviews, 33 randomized controlled trials, and 19 observational studies that discussed the use of MPFF in CVI, as well as studies that reported on the mechanistic action of MPFF in relation to the pathophysiology of PTS. RESULTS: MPFF targets a number of pathophysiologic components of PTS. Based on animal models and human studies investigating objective vascular and lymphatic measures, MPFF promotes venous recanalization after DVT, decreases venous remodeling and reflux, inhibits inflammatory processes, improves venous tone and stasis, improves lymphatic circulation, improves capillary hyperpermeability, and decreases tissue hypoxia. Furthermore, MPFF shows promise in improving clinical manifestations, quality of life, and objective venous parameters of CVI. Studies suggest good patient acceptability and tolerability with the use of MPFF in CVI. CONCLUSION: MPFF is a good candidate to explore as a potential therapy for PTS. Confirmatory high-quality studies are still needed to reinforce the evidence supporting the use of MPFF in CVI. Double-blind randomized controlled trials with clinical endpoints are needed to assess the clinical efficacy of MPFF in the treatment of PTS.