Pulmonary embolism in patients with COVID-19 pneumonia: When we have to search for it?

BACKGROUND: COVID-19 is still a global challenge in regard for management and therapy. Pulmonary embolism (PE) seems to have a higher prevalence in COVID-19 instead of non-COVID patients. Clinical and laboratory parameters related with PE are still unknown. METHODS: We conducted a retrospective unicentre study in Alto Vicentino Hospital between March 1st, 2020, and January 31st, 2021 in patients admitted for COVID-19 tested with a RT-PCR nasal swab. Data about patients studied with computed tomography pulmonary angiogram (CTPA) because of PE suspicion were collected, as their clinical and laboratory parameters too. RESULTS: 2621 patients were admitted for COVID-19 in Alto Vicentino Hospital between March 1st, 2020, and January 31st, 2021 and in 267 of them a CTPA was performed finding 50 PE (18.7%). Only non-Caucasian race (OR = 5.44; 95% CI 1.22-24.35; p = 0.027) and previous VTE (OR = 5.3; 95% CI 1.09-26.17; p = 0.039) were found to be independently associated with PE. CONCLUSION: PE is a frequent complication of COVID-19 and clinician need high degree of suspicion because clinical and laboratoristic parameters cannot drive diagnosis.

Measuring functional limitations after venous thromboembolism: Optimization of the Post-VTE Functional Status (PVFS) Scale.

INTRODUCTION: We recently proposed a scale for assessment of patient-relevant functional limitations following an episode of venous thromboembolism (VTE). Further development of this post-VTE functional status (PVFS) scale is still needed. METHODS: Guided by the input of VTE experts and patients, we refined the PVFS scale and its accompanying manual, and attempted to acquire broad consensus on its use. RESULTS: A Delphi analysis was performed involving 53 international VTE experts with diverse scientific and clinical backgrounds. In this process, the number of scale grades of the originally proposed PVFS scale was reduced and descriptions of the grades were improved. After these changes, a consensus was reached on the number/definitions of the grades, and method/timing of the scale assessment. The relevance and potential impact of the scale was confirmed in three focus groups totaling 18 VTE patients, who suggested additional changes to the manual, but not to the scale itself. Using the improved manual, the κ-statistics between PVFS scale self-reporting and its assessment via the structured interview was 0.75 (95%CI 0.58-1.0), and 1.0 (95%CI 0.83-1.0) between independent raters of the recorded interview of 16 focus groups members. CONCLUSION: We improved the PVFS scale and demonstrated broad consensus on its relevance, optimal grades, and methods of assessing among international VTE experts and patients. The interobserver agreement of scale grade assignment was shown to be good-to-excellent. The PVFS scale may become an important outcome measure of functional impairment for quality of patient care and in future VTE trials.

Relationship between type of unprovoked venous thromboembolism and cancer location: An individual patient data meta-analysis.

BACKGROUND: Unprovoked venous thromboembolism (VTE) may be the first manifestation of an underlying cancer. We aimed to assess the period prevalence of occult cancer detection stratified by VTE location (deep vein thrombosis [DVT], pulmonary embolism [PE] or both) and the anatomical relationship between occult cancer and VTE. METHODS: Post-hoc analysis of a systematic review and individual patient data meta-analysis of adults with unprovoked VTE with at least 12 months of follow-up. Cancer types were grouped according to thoracic, abdomino-pelvic, or other locations. RESULTS: A total of 2300 patients were eligible including 1218 with DVT only (53%), 719 with PE only (31%), and 363 with both PE and DVT (16%). The pooled 12-month period prevalence of cancer in DVT only, PE only, and DVT + PE was 5.6% (95% CI, 4.4 to 7.2), 4.3% (95% CI, 2.7 to 6.9), and 5.6% (95% CI, 1.7 to 15.5), respectively. Most occult cancers were located in the abdomen (68.4%). The proportion of patients with an abdomino-pelvic cancer was not different in patients with DVT + PE (81%; 95% CI, 54 to 96) than in those with DVT (68%; 95% CI, 57 to 78) or PE alone (65%; 95% CI, 48 to 79). CONCLUSION: The 12-month prevalence of occult cancer was similar in patients with DVT only, PE only, or both. Most cancers were located in the abdomen, and there was no relationship between VTE type and cancer location.

The American College of Chest Physician score to assess the risk of bleeding during anticoagulation in patients with venous thromboembolism.

Essentials The risk of bleeding influences the duration of anticoagulation (AC) after venous thromboembolism. We assessed the ACCP bleeding risk score in an inception-cohort of patients receiving AC. 53% were categorized at high-risk, but their bleeding rate was low during long-term AC. ACCP score had low predictive value for bleeding. SUMMARY: Background The American College of Chest Physicians (ACCP) guideline proposes a score to decide on extended anticoagulation after an unprovoked venous thromboembolism (VTE). Methods We investigated the ACCP score to predict bleeding risk in an inception cohort of 2263 patients on long-term anticoagulation (1522 treated with vitamin K antagonists [VKAs] and the remaining with direct oral anticoagulants [DOACs]) belonging to the Italian START2 Register. Results More than half the patients were categorized as high risk; nevertheless, a higher proportion received anticoagulation for > 1 year compared with those in the low-risk category. For 3130 years (median 12 [interquartile range 6, 24] months), 48 bleeding outcomes occurred (1.53%/year) in the cohort (1.7%/year and 0.95%/year in high- and low-risk categories, respectively). The c-statistic of the ACCP score was 0.55 (0.48-0.63), 0.50 (0.42-0.58) and 0.56 (0.48-0.64) in low-, moderate- and high-risk categories, respectively. The bleeding incidence was higher during the first 90 days of treatment (3.0%/year) than afterwards (1.2%/year; relative risk (RR), 2.5 [1.3-4.7]), and similar among the three categories. The bleeding rate was not different during the initial 3 months of treatment in patients receiving VKAs or DOACs; it was, however, lower in the latter patients in the subsequent period (0.5%/year vs. 1.4%/year, respectively). Conclusion The bleeding rate during extended treatment was rather low in our patients. ACCP score had insufficiently predictive value for bleeding and cannot be used to guide decisions on extended treatment. New prediction tools for bleeding risk during anticoagulant treatments (including DOACs) are required.

Clinical and economic impact of compression in the acute phase of deep vein thrombosis.

Essentials The value of compression therapy in acute phase of deep vein thrombosis is still unclear. Patients with deep vein thrombosis received acute compression hosiery, bandaging, or none. Acute compression reduces irreversible skin signs related to post thrombotic syndrome. Compression hosiery may be the preferred choice for the acute phase SUMMARY: Background The effectiveness of compression therapy in the acute phase of deep vein thrombosis (DVT) is not yet determined. Objectives To investigate the impact of compression therapy in the acute phase of DVT on determinants of the Villalta score, health-related quality of life (HRQOL), and costs. Patients/Methods Eight hundred and sixty-five patients with proximal DVT (substudy of the IDEAL DVT study) received, immediately after DVT diagnosis, either no compression, multilayer bandaging, or hosiery. In the acute phase and 3 months after diagnosis, HRQOL was determined by use of the EQ-5D, SF6D, and VEINES-QoL intrinsic method (VEINES-QoLint ). At 3 months, signs and symptoms were assessed for the total and separate items of the Villalta score, and healthcare costs were calculated. Results The compression groups had lower overall objective Villalta scores than the no-compression group (1.47 [standard deviation (SD) 1.570] and 1.59 [SD 1.64] versus 2.21 [SD 2.15]). The differences were mainly attributable to irreversible skin signs (induration, hyperpigmentation, and venectasia) and pain on calf compression. Subjective and total Villalta scores were similar across groups. Differences in HRQOL were only observed at 1 month; HRQOL was better for hosiery (EQ-5D 0.86 [SD 0.18]; VEINES-QoLint  0.66 [SD 0.18]) than for multilayer compression bandaging (EQ-5D 0.81 [SD 0.23; VEINES-QoLint  0.62 [SD 0.19]). Mean healthcare costs per patient were €417.08 (€354.10 to €489.30) for bandaging, €114.25 (€92.50 to €198.43) for hosiery, and €105.86 (€34.63 to €199.30) for no compression. Conclusions Initial compression reduces irreversible skin signs, edema, and pain on calf compression. Multilayer bandaging is slightly more effective than hosiery, but has substantially higher costs, without a gain in HRQOL. From a patient and economic perspective, compression hosiery would be preferred when initial compression is applied. TRIAL REGISTRATION: IDEAL DVT study ClinicalTrials.gov number, NCT01429714.

Age-adjusted D-dimer to rule out deep vein thrombosis: findings from the PALLADIO algorithm.

Essentials The accuracy of the age-adjusted D-dimer in suspected venous thromboembolism is still debated. We assessed the performance of age-adjusted D-dimer combined with the PALLADIO algorithm. The age-adjusted threshold can reduce the need for imaging tests compared to the fixed cut-off. The safety of this approach should be confirmed in large management studies. SUMMARY: Background Age-adjusted D-dimer has been proposed to increase specificity for the diagnosis of venous thromboembolism (VTE). However, the accuracy of this threshold has been recently questioned. Objectives To assess the diagnostic performance of age-adjusted D-dimer combined with clinical pretest probability (PTP) in patients with suspected deep vein thrombosis (DVT). Methods PALLADIO (NCT01412242) was a multicenter management study that validated a new diagnostic algorithm, incorporating PTP, D-dimer (using the manufacturer's cut-off) and limited or extended compression ultrasonography (CUS) in outpatients with clinically suspected DVT. Patients with unlikely PTP and negative D-dimer had DVT ruled out without further testing (group 1); patients with likely PTP or positive D-dimer underwent limited CUS (group 2); patients with likely PTP and positive D-dimer underwent extended CUS (group 3). Patients with DVT ruled out at baseline had a 3-month follow-up. In this post-hoc analysis we evaluated age-adjusted D-dimer cut-off (defined as age times 10 µg L-1 , or age times 5 µg L-1 for D-dimers with a lower manufacturer's cut-off, in patients > 50 years). Results In total, 1162 patients were enrolled. At initial visit, DVT was detected in 4.0% of patients in group 2 and 53.0% in group 3. The age-adjusted D-dimer, compared with the fixed cut-off, resulted in 5.1% (95% CI, 4.0-6.5%) reduction of CUS. The incidence of symptomatic VTE during follow-up was: 0.24% (95% CI, 0.04-1.37) in group 1; 1.12% (95% CI, 0.44-2.85) in group 2; and 1.89% (95% CI, 0.64-5.40) in group 3. Conclusions The PALLADIO algorithm using age-adjusted D-dimer slightly decreased the number of required imaging tests, but this approach should be confirmed in large management studies.

OC-15 - Risk factors for cancer development after idiopathic venous thromboembolism.

INTRODUCTION: Idiopathic venous thromboembolism (VTE) is associated with the risk of cancer but the risk factors for cancer development in such patients are still uncertain. AIM: To assess risk factors for the development of cancer after a standard course of anticoagulation in patients with first episode of idiopathic VTE. MATERIALS AND METHODS: Subjects were enrolled in the three large prospective multicentre studies: PROLONG (NEJM 2006) PROLONG II (Blood 2010) and DULCIS (Blood 2014). Women whose index event was hormone related were excluded from the analysis. The development of cancer was recorded during a 2-year follow-up. RESULTS: 1,805 patients were enrolled (M/F: 510/453), mean age: 62, median: 67; range:18-87 years). Cancer developed in 55 patients (3% ; 1.7% pt-years) of whom 15 (2.0%; 1.1% pt-years) had PE with or without DVT and 40 (3.8%; 2.1% pt-years) had DVT without PE (p=0.03). The development of cancer was associated with DVT without PE (HR:1.8; 95% CI: 1.1-3.3) and age >65 (HR: 2.5; 95%: 1.3-4.9). Among patients with DVT, with or without PE, the development of cancer was associated with the presence of residual vein obstruction>4mm (RVO) at compression ultrasound (HR: 1.8, 95% CI: 1.1-3.3) and age>65 (HR: 2.8; 95% CI: 1.3-6.2). CONCLUSIONS: Age>65 years, DVT without PE and the presence of RVO are significantly associated with the risk of developing cancer after a first episode of idiopathic VTE over a two-year follow-up.

Systematic Review and Meta-Analysis of Utility of Graduated Compression Stockings in Prevention of Post-Thrombotic Syndrome.

BACKGROUND: Up to 50% of patients develop post-thrombotic syndrome (PTS) following their first proximal deep vein thrombosis (DVT). This meta-analysis aims to evaluate the effectiveness of graduated compression stockings (GCS) in preventing PTS. METHOD: Medline, Embase, Cochrane Database of Systematic Reviews, and ClinicalTrials.gov were electronically searched from inception to January 2015 for studies investigating the effect of GCS in preventing PTS. All randomised control trials were considered for inclusion if they compared the efficacy of GCS (30-40 mmHg at the ankle) with either placebo or no stockings in adults with new proximal lower limb DVT. Methodological assessment, using the Cochrane Risk of Bias Tool, and data extraction was performed by two independent reviewers. The effect of GCS was expressed as the risk difference (RD). RESULTS: A total of 686 articles were screened. Three randomised controlled trials inclusive of 1,177 patients were eligible for inclusion. PTS developed in 49-70% of control patients at 5 years. High statistical heterogeneity was observed between trials (all PTS: I(2) = 0.94; severe PTS: I(2) = 0.79). The risk difference in PTS incidence between control and GCS arms varied from 0% to 39% between trials. In trials with a higher baseline prevalence of PTS, a visual trend towards more benefit with GCS was noted. CONCLUSION: Uncertainty because of sampling variability and heterogeneity was too high to conclude in favour or against an effect of wearing compression stockings in preventing PTS. An effect may be present for higher values of baseline risk. Further evidence is needed. Article history.

Biosimilars of low-molecular-weight heparin products: fostering competition or reducing 'biodiversity'?

The term 'biosimilars' is used to qualify products developed to be similar to an original biological drug. Biosimilars are much more complicated to develop than a generic version of small-molecule drugs and this is especially true for low-molecular-weight heparins (LMWHs). Evidence on the antithrombotic management of acute coronary syndromes (ACS) showed that the introduction into the market of biosimilars approved on the basis of simple biological criteria, without robust data from comparative clinical trials, may be hazardous. Moreover, the mixtures of LMWH polysaccharide chains, some immunoallergic properties and potential contamination during the extraction process raise safety concerns. As was the case for the biosimilar erythropoietin, there is the risk that only copies of the most commercially successful LMWHs will be marketed, thus jeopardizing the 'biodiversity' now ensured by the presence of several LMWHs, each with unique features that support the use of an individual LMWH as first-choice therapy in certain categories of patients.

Association between thrombophilia and the post-thrombotic syndrome: a systematic review and meta-analysis.

BACKGROUND: The postthrombotic syndrome (PTS) is a frequent chronic complication of deep vein thrombosis (DVT), occurring in 20-40% of patients. Identifying risk factors for PTS may be useful to provide patients with prognostic information and target prevention strategies. OBJECTIVE: To conduct a systematic review to assess whether, among patients with DVT, inherited and acquired thrombophilias are associated with a risk of PTS. METHODS: We searched the electronic databases PubMed, EMBASE, Scopus, and Web of Science for studies published from 1990 to 2013 that assessed any thrombophilia in adult DVT patients and its association with the development of PTS. We calculated odds ratios and 95% confidence intervals for PTS according to the presence of thrombophilia. Meta-analysis was performed using the random-effects model. RESULTS: Sixteen studies were included: 13 assessed factor V Leiden (FVL), 10 assessed prothrombin mutation, five assessed protein S and C deficiencies, three assessed antithrombin deficiency, four assessed elevated FVIII levels, and six assessed antiphospholipid antibodies. None of the meta-analyses identified any thrombophilia to be predictive of PTS. Both FVL and prothrombin mutation appeared protective among studies including patients with both first and recurrent DVT and studies in which more than 50% of patients had an unprovoked DVT. CONCLUSIONS: Our meta-analysis did not demonstrate a significant association between any of the thrombophilias assessed and the risk of PTS in DVT patients. Other biomarkers in the pathophysiological pathway may be more predictive of PTS.

Aspirin and recurrent venous thromboembolism.

While there is conclusive evidence that aspirin plays a role in reducing the risk of clinically relevant venous thromboembolism (VTE) arising in a number of surgical and non-surgical situations at risk, little is known of the potential of aspirin for the long/term prevention of recurrent VTE. In two recent multicentre, double-blind studies (WARFASA and ASPIRE), the efficacy and safety of a low dose of aspirin (100 mg per day) were assessed in patients with unprovoked VTE who had completed an initial period of conventional treatment with vitamin K antagonists. The two studies used identical aspirin regimens and had similar enrollment criteria and outcome measures. When data from these two trials were pooled, there was a 32% reduction in the rate of recurrence of VTE (hazard ratio [HR], 0.68; 95% confidence interval [CI], 0.51-0.90) and a 34% reduction in the rate of major vascular events (HR, 0.66; 95% CI, 0.51-0.86). Moreover, these benefits were achieved with a low risk of bleeding. As patients with previous symptomatic atherosclerosis were not enrolled in these two studies, whether these results apply also to this category of patients is uncertain. We recently had the opportunity to review the clinical charts of 1919 consecutive patients presented with a first episode of VTE, which was either unprovoked or triggered by transient risk factors, and were followed up for an average period of four years after discontinuing anticoagulation. The rate of recurrent VTE in the 256 patients with a history of symptomatic atherosclerosis who had been given 80-160 mg of aspirin once daily (17.2%) did not differ from that (19.9%) observed in those without atherosclerosis who were left without any antithrombotic treatments. The implication of this observation is that whenever patients with symptomatic atherosclerosis are deemed to require long-term protection against recurrent VTE, they are unlikely to benefit from (resuming) aspirin. Conversely, aspirin in low doses offers an appealing, safe and highly cost-effective option for the long-term prevention of recurrent events in patients with unprovoked VTE who are free from symptomatic atherosclerotic lesions.

New anticoagulants for the treatment of venous thromboembolism.

In recent years, the significant limitations associated with the use of vitamin K antagonists (VKA) have encouraged the development of new agents. Based upon the central roles played by the serine proteases thrombin and Factor Xa in the blood coagulation cascade, direct thrombin inhibitors and direct Factor Xa inhibitors have been developed. These agents, which include the direct thrombin inhibitor dabigatran etexilate and the Factor Xa inhibitors rivaroxaban and idrabiotaparinux are free from many of the limitations of VKAs. According to the results of available phase III randomized clinical trials, both dabigatran and rivaroxaban are effective and safe enough to qualify as ideal oral anticoagulants for the initial and long-term treatment of patients with acute venous thromboembolism (VTE). Rivaroxaban does not require an initial parenteral treatment and can be given in once daily administrations after the first three weeks. Both of them have limitations for the treatment of patients with severe renal failure, and require further investigations in cancer patients and in pregnant patients with VTE. Both of them lack an antidote.

International clinical practice guidelines for the treatment and prophylaxis of venous thromboembolism in patients with cancer.

BACKGROUND: Guidelines addressing the management of venous thromboembolism (VTE) in cancer patients are heterogeneous and their implementation has been suboptimal worldwide. OBJECTIVES: To establish a common international consensus addressing practical, clinically relevant questions in this setting. METHODS: An international consensus working group of experts was set up to develop guidelines according to an evidence-based medicine approach, using the GRADE system. RESULTS: For the initial treatment of established VTE: low-molecular-weight heparin (LMWH) is recommended [1B]; fondaparinux and unfractionated heparin (UFH) can be also used [2D]; thrombolysis may only be considered on a case-by-case basis [Best clinical practice (Guidance)]; vena cava filters (VCF) may be considered if contraindication to anticoagulation or pulmonary embolism recurrence under optimal anticoagulation; periodic reassessment of contraindications to anticoagulation is recommended and anticoagulation should be resumed when safe; VCF are not recommended for primary VTE prophylaxis in cancer patients [Guidance]. For the early maintenance (10 days to 3 months) and long-term (beyond 3 months) treatment of established VTE, LMWH for a minimum of 3 months is preferred over vitamin K antagonists (VKA) [1A]; idraparinux is not recommended [2C]; after 3-6 months, LMWH or VKA continuation should be based on individual evaluation of the benefit-risk ratio, tolerability, patient preference and cancer activity [Guidance]. For the treatment of VTE recurrence in cancer patients under anticoagulation, three options can be considered: (i) switch from VKA to LMWH when treated with VKA; (ii) increase in LMWH dose when treated with LMWH, and (iii) VCF insertion [Guidance]. For the prophylaxis of postoperative VTE in surgical cancer patients, use of LMWH o.d. or low dose of UFH t.i.d. is recommended; pharmacological prophylaxis should be started 12-2 h preoperatively and continued for at least 7-10 days; there are no data allowing conclusion that one type of LMWH is superior to another [1A]; there is no evidence to support fondaparinux as an alternative to LMWH [2C]; use of the highest prophylactic dose of LMWH is recommended [1A]; extended prophylaxis (4 weeks) after major laparotomy may be indicated in cancer patients with a high risk of VTE and low risk of bleeding [2B]; the use of LMWH for VTE prevention in cancer patients undergoing laparoscopic surgery may be recommended as for laparotomy [Guidance]; mechanical methods are not recommended as monotherapy except when pharmacological methods are contraindicated [2C]. For the prophylaxis of VTE in hospitalized medical patients with cancer and reduced mobility, we recommend prophylaxis with LMWH, UFH or fondaparinux [1B]; for children and adults with acute lymphocytic leukemia treated with l-asparaginase, depending on local policy and patient characteristics, prophylaxis may be considered in some patients [Guidance]; in patients receiving chemotherapy, prophylaxis is not recommended routinely [1B]; primary pharmacological prophylaxis of VTE may be indicated in patients with locally advanced or metastatic pancreatic [1B] or lung [2B] cancer treated with chemotherapy and having a low risk of bleeding; in patients treated with thalidomide or lenalidomide combined with steroids and/or chemotherapy, VTE prophylaxis is recommended; in this setting, VKA at low or therapeutic doses, LMWH at prophylactic doses and low-dose aspirin have shown similar effects; however, the efficacy of these regimens remains unclear [2C]. Special situations include brain tumors, severe renal failure (CrCl<30 mL min(-1) ), thrombocytopenia and pregnancy. Guidances are provided in these contexts. CONCLUSIONS: Dissemination and implementation of good clinical practice for the management of VTE, the second cause of death in cancer patients, is a major public health priority.

International clinical practice guidelines for the treatment and prophylaxis of thrombosis associated with central venous catheters in patients with cancer.

BACKGROUND: Although long-term indwelling central venous catheters (CVCs) may lead to pulmonary embolism (PE) and loss of the CVC, there is lack of consensus on management of CVC-related thrombosis (CRT) in cancer patients and heterogeneity in clinical practices worldwide. OBJECTIVES: To establish common international Good Clinical Practices Guidelines (GCPG) for the management of CRT in cancer patients. METHODS: An international working group of experts was set up to develop GCPG according to an evidence-based medicine approach, using the GRADE system. RESULTS: For the treatment of established CRT in cancer patients, we found no prospective randomized studies, two non-randomized prospective studies and one retrospective study examining the efficacy and safety of low-molecular-weight heparin (LMWH) plus vitamin K antagonists (VKAs). One retrospective study evaluated the benefit of CVC removal and two small retrospective studies were on thrombolytic drugs. For the treatment of symptomatic CRT, anticoagulant treatment (AC) is recommended for a minimum of 3 months; in this setting, LMWHs are suggested. VKAs can also be used, in the absence of direct comparisons of these two types of anticoagulants in this setting [Guidance]. The CVC can be kept in place if it is functional, well-positioned and non-infected and there is good resolution under close surveillance; whether the CVC is kept or removed, no standard approach in terms of AC duration has been established [Guidance]. For the prophylaxis of CRT in cancer patients, we found six randomized studies investigating the efficacy and safety of VKA vs. placebo or no treatment, one on the efficacy and safety of unfractionnated heparin, six on the value of LMWH, one double-blind randomized and one non randomized study on thrombolytic drugs and six meta-analyses of AC and CVC thromboprophylaxis. Type of catheter (open-ended like the Hickman(®) catheter vs. closed-ended catheter with a valve like the Groshong(®) catheter), its position (above, below or at the junction of the superior vena cava and the right atrium) and method of placement may influence the onset of CRT on the basis of six retrospective trials, four prospective non-randomized trials, three randomized trials and one meta-analysis. In light of these data: use of AC for routine prophylaxis of CRT is not recommended [1A]; a CVC should be inserted on the right side, in the jugular vein, and distal extremity of the CVC should be located at the junction of the superior vena cava and the right atrium [1A]. CONCLUSION: Dissemination and implementation of these international GCPG for the prevention and treatment of CRT in cancer patients at each national level is a major public health priority, needing worldwide collaboration.

Prevention and treatment of venous thromboembolism--International Consensus Statement.

The aim of this document is to provide a clear and concise account of the evidence regarding efficacy or harm for various methods available to prevent and manage venous thromboembolism (VTE).

The optimal duration of anticoagulation in patients with venous thromboembolism: how long is long enough?

The risk of recurrent venous thromboembolism (VTE) approaches 40% of all patients after 10 years of follow-up. This risk is higher in patients with permanent risk factors of thrombosis such as active cancer, prolonged immobilization from medical diseases, and antiphospholipid syndrome; in carriers of several thrombophilic abnormalities, including deficiencies of natural anticoagulants; and in patients with unprovoked presentation. Patients with permanent risk factors of thrombosis should receive indefinite anticoagulation, consisting of subtherapeutic doses of low-molecular-weight heparin in cancer patients, and oral anticoagulants in all other conditions. Patients whose VTE is triggered by major surgery or trauma should be offered three months of anticoagulation. Patients with unprovoked VTE, including carriers of thrombophilia, and those whose thrombotic event is associated with minor risk factors (such as hormonal treatment, minor injuries, long travel) should receive at least three months of anticoagulation. The decision as to go on or discontinue anticoagulation after this period should be individually tailored and balanced against the haemorrhagic risk. Post-baseline variables, such as the D-dimer determination and the ultrasound assessment of residual thrombosis can help identify those patients in whom anticoagulation can be safely discontinued. As a few emerging anti-Xa and anti-IIa compounds seem to induce fewer haemorrhagic complications than conventional anticoagulation, while preserving at least the same effectiveness, they have the potential to open new scenarios for decisions regarding the duration of anticoagulation in patients with VTE.