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This guidance document focuses on the diagnosis and treatment of venous thromboembolism (VTE). Efficient, cost effective diagnosis of VTE is facilitated by combining medical history and physical examination with pre-test probability models, D dimer testing and selective use of confirmatory imaging. Clinical prediction rules, biomarkers and imaging can be used to tailor therapy to disease severity. Anticoagulation options for acute VTE include unfractionated heparin, low molecular weight heparin, fondaparinux and the direct oral anticoagulants (DOACs). DOACs are as effective as conventional therapy with LMWH and vitamin K antagonists. Thrombolytic therapy is reserved for massive pulmonary embolism (PE) or extensive deep vein thrombosis (DVT). Inferior vena cava filters are reserved for patients with acute VTE and contraindications to anticoagulation. Retrievable filters are strongly preferred. The possibility of thoracic outlet syndrome and May-Thurner syndrome should be considered in patients with subclavian/axillary and left common iliac vein DVT, respectively in absence of identifiable triggers. The optimal duration of therapy is dictated by the presence of modifiable thrombotic risk factors. Long term anticoagulation should be considered in patients with unprovoked VTE as well as persistent prothrombotic risk factors such as cancer. Short-term therapy is sufficient for most patients with VTE associated with transient situational triggers such as major surgery. Biomarkers such as D dimer and risk assessment models such the Vienna risk prediction model offer the potential to customize VTE therapy for the individual patient. Insufficient data exist to support the integration of bleeding risk models into duration of therapy planning.

No consensus exists as to who should be tested for thrombophilia, mainly due to the lack of good quality clinical outcome data in relationship to presence or absence of a given thrombophilia. Testing may be considered if (a) finding a thrombophilia predicts recurrent thrombosis and, thus, influences length of anticoagulation treatment decisions; (b) identifying a thrombophilia has implications on management of asymptomatic family members who are carriers of the detected thrombophilia; (c) a patient wishes to better understand why a thrombotic event occurred. Testing may be helpful in patients with venous thromboembolism at intermediate risk of recurrence in whom the finding of a strong thrombophilia can be one of the arguments for long-term anticoagulation - the “risk-of-recurrence-triangle” may be a useful aid in this decision process. Patients whose venous thromboembolism was provoked by a major transient risk factor should not be tested for thrombophilia. Thrombophilia tests should only be ordered by health care professionals who can provide the “4P”: (a) appropriately select which patient to test, (b) provide pre-test counseling, (c) properly interpret the test results, and (d) provide education and advice to the patient. If testing is embarked on in patients with venous thromboembolism, it is advisable to be done at the time of decision making whether to stop or continue anticoagulation, i.e. typically after 3 months of anticoagulant therapy. Thrombophilia testing is best not done at the time of an acute thrombotic event and while a patient is on an anticoagulant.

Coronavirus disease 2019 (COVID‐19) is associated with high rates of thromboembolic events in hospitalized patients. It remains to be determined if this risk persists following hospital discharge. We conducted a retrospective cohort study of outpatients recently hospitalized for COVID‐19 to determine the incidence of vascular thromboembolic events within 30 days of discharge. We investigated the risk factors associated with these events, including intensive care admission, age, and anticoagulation. Among 447 patients hospitalized for COVID‐19, 2.0% experienced a vascular thromboembolic event within 30 days of discharge. No risk factor variable was significantly associated with an increased risk for these events. The incidence of vascular thromboembolic events following hospital discharge for COVID‐19 is low. These findings suggest against the routine use of postdischarge thromboprophylaxis in patients with COVID‐19.

Nearly 1 million patients undergo knee arthroscopy in the United States every year. 1 The incidence of symptomatic venous thromboembolism in this patient population is approximately 0.6%, or nearly 4000 patients per year. 1 , 2 Published evidence for the benefit of prophylactic anticoagulation in patients undergoing knee arthroscopy has been of low or moderate quality, and on the basis of this evidence, the 2012 American College of Chest Physicians (ACCP) guidelines do not recommend the use of thromboprophylaxis in patients who do not have a history of venous thromboembolism. 3 The National Institute for Health and Care Excellence (NICE) recommendations for hospitalized patients . . .

An obstructive jugular-vein thrombosis developed in an astronaut 2 months into a 6-month space mission, a clinical scenario with no evidence base to support the choice of a management approach. The thrombosis was managed with enoxaparin, followed by apixaban, which was discontinued 4 days before Earth landing. No adverse sequelae were noted.

IntroductionParenteral anticoagulants may improve outcomes in patients with cancer by reducing risk of venous thromboembolic disease and through a direct antitumour effect. Study-level systematic reviews indicate a reduction in venous thromboembolism and provide moderate confidence that a small survival benefit exists. It remains unclear if any patient subgroups experience potential benefits.Methods and analysisFirst, we will perform a comprehensive systematic search of MEDLINE, EMBASE and The Cochrane Library, hand search scientific conference abstracts and check clinical trials registries for randomised control trials of participants with solid cancers who are administered parenteral anticoagulants. We anticipate identifying at least 15 trials, exceeding 9000 participants. Second, we will perform an individual participant data meta-analysis to explore the magnitude of survival benefit and address whether subgroups of patients are more likely to benefit from parenteral anticoagulants. All analyses will follow the intention-to-treat principle. For our primary outcome, mortality, we will use multivariable hierarchical models with patient-level variables as fixed effects and a categorical trial variable as a random effect. We will adjust analysis for important prognostic characteristics. To investigate whether intervention effects vary by predefined subgroups of patients, we will test interaction terms in the statistical model. Furthermore, we will develop a risk-prediction model for venous thromboembolism, with a focus on control patients of randomised trials.Ethics and disseminationAside from maintaining participant anonymity, there are no major ethical concerns. This will be the first individual participant data meta-analysis addressing heparin use among patients with cancer and will directly influence recommendations in clinical practice guidelines. Major cancer guideline development organisations will use eventual results to inform their guideline recommendations. Several knowledge users will disseminate results through presentations at clinical rounds as well as national and international conferences. We will prepare an evidence brief and facilitate dialogue to engage policymakers and stakeholders in acting on findings.Trial registration numberPROSPERO CRD42013003526.

Chronic leg ulceration is a debilitating manifestation of hemoglobinopathies, and best management is uncertain. Livedoid vasculopathy (LV) is a cutaneous non-inflammatory thrombotic vasculopathy treated with anticoagulation that has been identified in hemoglobinopathy-associated chronic leg ulceration. However, most patients with hemoglobinopathy-associated ulcers do not undergo workup for secondary causes, and the prevalence and relevance of LV is unclear. Outcomes of secondary workup were examined retrospectively in this study. 108 patients with hemoglobinopathy-associated chronic leg ulcers were identified. 15% of patients underwent skin biopsy, and 97% of biopsies showed non-specific findings. Two patients had LV and neither responded to anticoagulants. Livedoid vasculopathy is a rare cause of ulceration in hemoglobin gene disorders and the benefit of anticoagulation in these cases is unclear.

VITT is caused by antibodies to PF4 that recognize the heparin-binding site. Thrombocytopenia and thrombosis associated with VITT-like antibody specificity developed in a child and an adult after adenovirus infection.