External validation of the DASH prediction rule: a retrospective cohort study

Hemostasis and complement in allogeneic hematopoietic stem cell transplantation: clinical significance of two interactive systems

Hematopoietic stem cell transplantation (HCT) represents a curative treatment option for certain malignant and nonmalignant hematological diseases. Conditioning regimens before HCT, the development of graft-versus-host disease (GVHD) in the allogeneic setting, and delayed immune reconstitution contribute to early and late complications by inducing tissue damage or humoral alterations. Hemostasis and/or the complement system are biological regulatory defense systems involving humoral and cellular reactions and are variably involved in these complications after allogeneic HCT. The hemostasis and complement systems have multiple interactions, which have been described both under physiological and pathological conditions. They share common tissue targets, such as the endothelium, which suggests interactions in the pathogenesis of several serious complications in the early or late phase after HCT. Complications in which both systems interfere with each other and thus contribute to disease pathogenesis include transplant-associated thrombotic microangiopathy (HSCT-TMA), sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD), and GVHD. Here, we review the current knowledge on changes in hemostasis and complement after allogeneic HCT and how these changes may define clinical impact.

A Prediction Rule for Occurrence of Chronic Thromboembolic Disease After Acute Pulmonary Embolism

BACKGROUND

Occurrence of chronic thromboembolic disease (CTED) after 3 or 6 months of standard and effective anticoagulation is not uncommon in patients with acute pulmonary embolism (PE). To date, there has been no scoring model for the prediction of CTED occurrence.

METHODS

A Prediction Rule for CTED (PRC) was established in the establishment cohort (n=1,124) and then validated in the validation cohort (n=211). Both original and simplified versions of the PRC score were provided by using different scoring and cut-offs.

RESULTS

The PRC score included 10 items: active cancer (3.641; 2.338-4.944; p<0.001), autoimmune diseases (2.218; 1.545-2.891; p=0.001), body mass index >30 kg/m2 (2.186; 1.573-2.799; p=0.001), chronic immobility (2.135; 1.741-2.529; p=0.001), D-dimer >2,000 ng/mL (1.618; 1.274-1.962; p=0.005), PE with deep vein thrombosis (3.199; 2.356-4.042; p<0.001), previous venous thromboembolism (VTE) history (5.268; 3.472-7.064; p<0.001), thromboembolism besides VTE (4.954; 3.150-6.758; p<0.001), thrombophilia (3.438; 2.573-4.303; p<0.001), and unprovoked VTE (2.227; 1.471-2.983; p=0.001). In the establishment cohort, the sensitivity, specificity, Youden index (YI), and C-index were 85.5%, 79.7%, 0.652, and 0.821 (0.732-0.909) when using the original PRC score, whereas they were 87.9%, 74.6%, 0.625, and 0.807 (0.718-0.897) when using the simplified one, respectively (Kappa coefficient 0.819, p-value of McNemar's test 0.786). In the validation cohort, the sensitivity, specificity, YI, and C-index were 86.3%, 76.3%, 0.626, and 0.815 (0.707-0.923) when using the original PRC score, whereas they were 85.0%, 78.6%, 0.636, and 0.818 (0.725-0.911) when using the simplified one, respectively (Kappa coefficient 0.912, p-value of McNemar's test 0.937); both were better than that of the DASH score (72.5%, 69.5%, 0.420, and 0.621 [0.532-0.710]).

CONCLUSIONS

A prediction score for CTED occurrence, termed PRC, predicted the likelihood of CTED occurrence after 3 or 6 months of standard anticoagulation in hospitalised patients with a diagnosis of acute PE.

D-dimer and risk of venous thromboembolism recurrence: Comparison of two studies with similar designs but different laboratory and clinical results

BACKGROUND

D-dimer testing may help deciding the duration of anticoagulation in subjects at high risk of venous thromboembolism (VTE) recurrence. Two management studies on this issue have been published (DULCIS in 2014 and APIDULCIS in 2022). They had similar designs but had important different results. Aim of this article is to compare their results.

METHODS

Both studies were finalized to extend anticoagulation [with vitamin K anticoagulants (VKAs) in DULCIS or apixaban 2.5 mg BID (kindly provided by BMS-Pfizer Collaboration) in APIDULCIS] only in patients with positive D-dimer results.

RESULTS

More D-dimer assays resulted positive in APIDULCIS than in DULCIS (61.1 % vs 47.7 %, respectively; p < 0.0001). While only 4 (0.5 %) refused low dose apixaban in APIDULCIS, the 22.6 % of patients with positive D-dimer refused to resume VKAs in DULCIS; their rates of recurrence were 187 and 8.8 per 100 person-years, respectively (incidence rate ratio [IRR]: 21.2). The incidence of bleeding was low in those receiving apixaban vs those who resumed VKAs (0.4 vs 2.3 per 100 person-years, respectively; IRR 0.17;). While the recurrence rate was low and similar in the studies in subjects who resumed anticoagulation, it was significantly higher in APIDULCIS than in DULCIS in those who stopped anticoagulation for negative D-dimer (5.6 vs 3.0 per 100 person-years, respectively; IRR 1.9).

CONCLUSION

The low dose Apixaban for extended VTE treatment is effective and safe, and well accepted by patients. Why subjects who stopped anticoagulation for negative D-dimer had a higher recurrence rate in APIDULCIS than in DULCIS remains to be explained.

Anticoagulation in venous thromboembolism for the general physician

Venous thromboembolism (VTE) is frequently encountered across various specialties. The management of VTE has become more nuanced, requiring consideration of several factors when deciding on the choice and duration of anticoagulation. This evidence-based review article summarises the current practice and evidence behind anticoagulation in VTE, incorporating national and international guidelines. Factors influencing decision-making around the choice and duration of anticoagulation, along with special circumstances such as cancer and antiphospholipid syndrome, are discussed. The clinical utility of thrombophilia screening is also addressed.

International Normalized Ratio Predicts Recurrence and Bleeding in Patients With Acute Venous Thromboembolism Who Undergo Direct Oral Anticoagulants

Prothrombin time/international normalized ratio (PT/INR) is related to both antithrombotic effect and risk of bleeding. Its role in the prediction of venous thromboembolism (VTE) recurrence and bleeding for patients with acute VTE who undergo direct oral anticoagulants (DOACs) treatment is unclear, despite previous studies revealed some association between them. The predictive efficiency of INR for VTE recurrence and bleeding were analyzed in a retrospective cohort with VTE patients who underwent DOACs treatment. Then its predictive efficiency for VTE recurrence and bleeding were validated in a prospective cohort with the acquired cutoffs range, and compared with anti-Xa level, DASH and VTE-BLEED scores. In the retrospective cohort (n = 1083), the sensitivity and specificity of INR for the prediction of VTE recurrence were 79.4% and 92.8%, respectively. The area under the curve (AUC) was 0.881 (0.803-0.960)(P = .025). The cutoff value of INR was 0.9. The sensitivity and specificity of INR for the prediction of bleeding were 85.7% and 77.9%, respectively. The AUC was 0.876 (0.786-0.967)(P < .001). The cutoff value of INR was 2.1. In the prospective cohort (n = 202), the calibration showed that there were 4 (50%) patients with VTE recurrence, 156 (97.5%) patients with non-recurrence and bleeding (non-R&B), and 20 (58.8%) patients with bleeding in the low (INR < 0.9)(n = 8), intermediate (0.9 ≤ INR ≤ 2.1)(n = 160), and high (INR > 2.1)(n = 34) groups, respectively. The baseline PT/INR value at the initiation of DOACs treatment is an independent predictor for VTE recurrence and bleeding in patients with acute VTE who undergo DOACs treatment.

Risk Scores in Venous Thromboembolism Guidelines of ESC, ACCP, and ASH: An Updated Review

Venous thromboembolism (VTE) is associated with high morbidity and mortality. Risk scores associated with VTE have been widely used in clinical practice. Among numerous scores published, those included in guidelines are usually typical risk scores which have been extensively validated and globally recognized. This review provides an updated overview of the risk scores associated with VTE endorsed by 3 guidelines which are highly recognized in the field of VTE including the European Society of Cardiology, American College of Chest Physicians, and American Society of Hematology, focusing on the development, modification, validation, and comparison of these scores, to provide a comprehensive and updated understanding of all the classic risk scores associated with VTE to medical readers including but not limited to cardiologists, pulmonologists, hematologists, intensivists, physicians, surgeons, and researchers. Although each score recommended by these guidelines was more or less validated, there may still be room for further improvement. It may still be necessary to seek simpler, more practical, and more universally applicable VTE-related risk scores in the future.

Chinese expert consensus on antithrombotic management of high-risk elderly patients with chronic coronary syndrome

The prevalence and mortality of coronary artery disease (CAD) in China are still at an increasing stage. CAD can be classified as acute coronary syndrome (ACS) or chronic coronary syndrome (CCS). CCS is the main manifestation type of elderly patients with CAD, with a large number of patients, long course of disease, and poor prognosis, leading to decreased quality of life and heavy disease burden and economic burden. Especially in patients with high-risk CCS, the case fatality rate and total mortality are high. In order to better standardize the antithrombotic treatment of elderly patients with high-risk CCS, the Geriatrics Branch of the Chinese Medical Association organizes domestic experts to develop this consensus for clinicians' reference based on published clinical research evidence, combined with relevant guidelines, consensus, and expert recommendations in China and abroad.

Changes in Heme Levels During Acute Vaso-occlusive Crisis in Sickle Cell Anemia

OBJECTIVE/BACKGROUND

Sickle cell anemia (SCA) is associated with increased levels of extracellular heme, which is a key mediator of inflammation in this condition. Despite abundant evidence supporting this concept in cell and animal models, few studies addressed the association between heme levels and the development and severity of acute vasoocclusive crises (VOC) in humans.

METHODS

A cross-sectional study was conducted in patients with acute VOC. Total extracellular heme levels were measured in both plasma and serum at admission and after convalescence, and correlated with other clinical and laboratory markers of SCA severity.

RESULTS

A total of 28 episodes of VOC in 25 patients were included. Heme levels were similar between admission and convalescence, and correlated with the difference between pre and post hemoglobin, and SCA severity estimated by a composite score of clinical and laboratory markers. Heme levels were neither associated with VOC severity nor with markers of hemostasis activation, and were similar to those reported in an independent population of SCA patients at steady state.

DISCUSSION

Acute VOC are not characterized by significant increases in total extracellular heme levels. Studies measuring the fraction of free extracellular heme unbound to proteins are warranted to further refine our understanding of the role of heme in acute VOC.

Overall haemostatic potential (OHP) assay can risk stratify for venous thromboembolism recurrence in anticoagulated patients

Assessing the risk of recurrent venous thromboembolism (VTE), particularly when patients are anticoagulated, remains a major challenge largely due to the lack of biomarkers. Blood was sampled from adult VTE patients recruited between January 2018 and September 2020, while receiving therapeutic anticoagulation. Results were compared to 144 healthy subjects (34.7% male, median age 42 years). Overall haemostatic potential (OHP) assay, a spectrophotometric assay, was performed on platelet-poor plasma, in which fibrin formation (triggered by small amounts of thrombin (overall coagulation potential, OCP)) and fibrinolysis (by the addition of thrombin and tissue plasminogen activator (OHP)) are simultaneously measured. Results were obtained from 196 patients (52.6% male, mean age 57.1 years). Compared to healthy subjects, VTE patients displayed significantly higher OCP (39.6 vs 34.5 units, p < 0.001) and OHP (9.3 vs 6.4 units, p < 0.001) as well as lower overall fibrinolytic potential (75.6 v s81.1%, p < 0.001). All 16 VTE recurrences, including 11 unprovoked, occurred above an OCP cut-off of 40^th percentile (recurrence rate 4.32/100 patient-years (100PY), 95% confidence interval (CI) 2.39-7.80, p = 0.002). Of 97 patients who subsequently discontinued anticoagulation, all unprovoked VTE recurrences (n = 9) occurred above the 40^th OCP percentile (recurrence rate 9.10/100PY, 95% CI 4.74-17.49, p = 0.005) and the 40^th OHP percentile (recurrence rate 8.46/100PY, 95% CI 4.40-16.25, p = 0.009). Our pilot study demonstrates that the OHP assay can detect a hypercoagulable and hypofibrinolytic state in anticoagulated VTE patients and may be able to risk stratify VTE recurrence, allowing for more individualised decision on long-term anticoagulation. Further larger prospective studies are required.

D-dimer and reduced-dose apixaban for extended treatment after unprovoked venous thromboembolism: the Apidulcis study

D-dimer assay is used to stratify patients with unprovoked venous thromboembolism (VTE) for the risk of recurrence. However, this approach was never evaluated since direct oral anticoagulants are available. With this multicenter, prospective cohort study, we aimed to assess the value of an algorithm incorporating serial D-dimer testing and administration of reduced-dose apixaban (2.5 mg twice daily) only to patients with a positive test. A total of 732 outpatients aged 18 to 74 years, anticoagulated for ≥12 months after a first unprovoked VTE, were included. Patients underwent D-dimer testing with commercial assays and preestablished cutoffs. If the baseline D-dimer during anticoagulation was negative, anticoagulation was stopped and testing repeated after 15, 30, and 60 days. Patients with serially negative results (286 [39.1%]) were left without anticoagulation. At the first positive result, the remaining 446 patients (60.9%) were given apixaban for 18 months. All patients underwent follow-up planned for 18 months. The study was interrupted after a planned interim analysis for the high rate of primary outcomes (7.3%; 95% confidence interval [CI], 4.5-11.2), including symptomatic proximal deep vein thrombosis (DVT) or pulmonary embolism (PE) recurrence, death for VTE, and major bleeding occurring in patients off anticoagulation vs that in those receiving apixaban (1.1%; 95% CI, 0.4-2.6; adjusted hazard ratio [HR], 8.2; 95% CI, 3.2-25.3). In conclusion, in patients anticoagulated for ≥1 year after a first unprovoked VTE, the decision to further extend anticoagulation should not be based on D-dimer testing. The results confirmed the high efficacy and safety of reduced-dose apixaban against recurrences. This trial was registered at www.clinicaltrials.gov as #NCT03678506.

Recurrence after stopping anticoagulants in women with combined oral contraceptive-associated venous thromboembolism: A systematic review and meta-analysis

The risk of recurrence after discontinuation of anticoagulation for a combined oral contraceptive (COC)-associated venous thromboembolism (VTE) is unclear. Therefore, we conducted a systematic review and meta-analysis to estimate the incidence of recurrent VTE among women with COC-associated VTE, unprovoked VTE and to compare the incidence of recurrent VTE between the two groups. The Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Embase Classic +Embase and Medline ALL to July 2020 and citations from included studies were searched. Randomized controlled trials, prospective cohort studies and meta-analyses of these study types were selected. The analysis was conducted by random-effects model. Nineteen studies were identified including 1537 women [5828 person-years (PY)] with COC-associated VTE and 1974 women (7798 PY) with unprovoked VTE. Studies were at low risk of bias. The incidence rate of VTE recurrence was 1.22/100 PY [95% confidence interval (CI) 0.92-1.62, I²  = 6%] in women with COC-associated VTE, 3.89/100 PY (95% CI 2.93-5.17, I²  = 74%) in women with unprovoked VTE and the unadjusted incidence rate ratio was 0.34 (95% CI 0.26-0.46, I²  = 3%). The recurrence risk in women after COC-associated VTE is low and lower than after an unprovoked VTE.

Incident thrombus location and predicting risk of recurrent venous thromboembolism

Background

Understanding venous thromboembolism (VTE) recurrence risk is central to determining the appropriate treatment course. Whether this risk varies after discontinuing anticoagulation or overall by type of incident event (pulmonary embolism [PE] vs deep vein thrombosis [DVT]) and by the detailed location of the DVT needs further clarification.

Methods

In this population-based inception cohort of incident VTE cases with follow-up by electronic health record review, incident DVT was categorized as distal, popliteal, or iliofemoral. We used the Fine-Gray regression model to describe the predictive association of the thrombus location with the risk of recurrence before death.

Results

Among 2766 participants with an incident event from 2002 to 2010, 1713 (62%) ceased anticoagulation and were followed for recurrent events; 301 events were observed during the 4.5 years of follow-up. Relative to participants with an incident thrombus in an iliofemoral location and no PE, those with a thrombus in a popliteal location and no PE had a similar risk of recurrence (adjusted subdistribution hazard ratio [aSHR], 0.82 [95% confidence interval (CI), 0.57-1.19]), while those with a thrombus in a distal location and no PE and those with a thrombus that included a PE had lower risk of recurrence: aSHR, 0.34 (95% CI, 0.20-0.57); and aSHR, 0.58 (95% CI 0.45-0.76), respectively.

Conclusions

The findings of this population-based inception cohort confirm that the risk of recurrent VTE after discontinuing anticoagulants is similar after iliofemoral and popliteal DVT but is lower after distal DVT. Recurrence may be lower after PE than proximal DVT.

D-dimers: a most misunderstood test

The role of D-dimers in the management of venous thromboembolism is well established and testing for D-dimers has become common in most acute settings. Although it has been validated for the purpose of excluding venous thromboembolism, the test is increasingly ordered to 'diagnose' venous thromboembolism. Furthermore, in the COVID-19 pandemic, heavy reliance has been put on this test with the inclusion of D-dimers to guide treatment pathways. This review summarises the appropriateness of D-dimer tests in these different clinical settings.

Outpatient treatment of emergency department patients diagnosed with venous thromboembolism

Venous thromboembolism (VTE) includes the diagnosis of either deep venous thrombosis (DVT) and/or pulmonary embolism (PE). This review discusses an evidence-based approach to the outpatient treatment of VTE in the emergency care setting. Main findings: The majority of patients diagnosed with VTE in the acute care setting are at low risk for an adverse event. Outpatient treatment for patients deemed low-risk by validated clinical decision tools leads to safe, efficacious, patient-centered, and cost-effective care. From a patient perspective, outpatient treatment of VTE can been simplified by the use of direct oral anticoagulant (DOACs) medications, and is supported by clinical trial evidence, and clinical practice guidelines from international societies. Outpatient treatment of patients with DVT has been more widely accepted as a best practice, while adoption of outpatient treatment of low-risk patients with acute PE has lagged. Many acute care clinicians remain wary of discharging patients with PE, concerned about drug access, adherence, and follow-up. Patients with VTE should be risk stratified identically as emerging evidence has demonstrated efficacy and safety in the interdependence of acute care protocols for the outpatient treatment of low-risk DVT and PE. Clinicians who practice in the acute care setting should be comfortable with risk stratification, anticoagulation, and discharge of low-risk VTE.

Predicting Recurrent Venous Thromboembolism in Patients With Deep-Vein Thrombosis: Development and Internal Validation of a Potential New Prediction Model (Continu-8)

Background: Previous prediction models for recurrent thromboembolism (VTE) are often complicated to apply and have not been implemented widely.

Aim: To develop and internally validate a potential new prediction model for recurrent VTE that can be used without stopping anticoagulant treatment for D-dimer measurements in patients with provoked and unprovoked DVT.

Methods: Cohort data of 479 patients treated in a clinical care pathway at Maastricht University Medical Center were used. Predictors for the Cox proportional hazards model (unprovoked DVT, male gender, factor VIII levels) were derived from literature and using forward selection procedure. The scoring rule was internally validated using bootstrapping techniques and the predictive ability was compared to existing prediction models.

Results: Patients were followed for a median of 3.12 years after stopping anticoagulation treatment (IQR 0.78, 3.90). Sixty-four of 479 patients developed recurrent VTE (13%). The scoring rule consisted of unprovoked DVT (yes: 2 points), male sex (yes: 1 point), and factor VIII > 213 % (yes: 2 points) and was categorized into three groups [i.e., low risk (score 0), medium risk (scores 1, 2, or 3) and high risk (scores 4 and 5)]. The concordance statistic was 0.68 (95% CI: 0.61, 0.75).

Conclusion: The discriminative ability of the new Continu-8 score was adequate. Future studies shall verify this score in an independent setting without stopping anticoagulation treatment.

Design and rationale of a randomized, placebo-controlled trial on the efficacy and safety of sulodexide for extended treatment in elderly patients after a first venous thromboembolism

How to prevent recurrences after a first venous thromboembolic (VTE) event in elderly patients is still an open issue, especially because of the high bleeding risk of anticoagulation in these patients. The placebo-controlled "Jason" study aims at assessing the efficacy and safety for secondary VTE prevention in elderly patients of oral Sulodexide (Vessel^®) administration, a mixture of glycosaminoglycans (Alfasigma, Bologna, Italy) which proved effective against recurrences in a general population (SURVET study) without major bleeding (MB) complications. 1450 patients, aged ≥ 75 years, after at least 3 months of anticoagulation treatment for a first VTE episode, are double-blind randomized to receive for 12 months either sulodexide 500 lipasemic units (LSUs) twice daily, or sulodexide 250 LSU twice daily + indistinguishable placebo, or indistinguishable placebo. Primary outcomes for efficacy are the composite of death for VTE and recurrent VTE, and occurrence of MB for safety. Secondary outcomes include stroke, cardiovascular death and other thromboembolic events, and MB + clinically relevant non-MB. The first patient is scheduled to be randomized in May 2020. The study protocol has been approved by AIFA (Agenzia Italiana del Farmaco) and the Ethics Committee of the coordinating center. Written informed consent will be obtained from all patients prior to study participation. Jason study is an investigator-initiated trial, promoted by "Arianna Anticoagulazione" Foundation, Bologna, Italy, and supported by Alfasigma, Bologna, Italy. Study findings will be disseminated to participant centers, at research conferences and in peer-reviewed journals. Trial registration numbers NCT04257487; EudraCT (2019-000570-33).

Advances in the Management of Acute Venous Thromboembolism and New Therapeutic Agents

Important advances in the understanding and management of venous thromboembolism (VTE) have enhanced our ability to diagnose, prevent, and treat VTE. In this narrative review, we discuss how recent advances in the understanding and management of VTE are changing practice, highlight ongoing unmet needs in VTE management, and outline how novel therapeutic targets with little or no influence on hemostasis may help address these unmet needs.

Prediction models for recurrence and bleeding in patients with venous thromboembolism: A systematic review and critical appraisal

INTRODUCTION

Prediction models for recurrence and bleeding are infrequently used when deciding on anticoagulant treatment duration after venous thromboembolism (VTE) due to concerns about performance and validity. Our aim was to critically appraise these models by systematically summarizing data from derivation and validation studies.

MATERIALS AND METHODS

MEDLINE and CENTRAL were searched until November 15th, 2019. Studies on prediction models for recurrence or bleeding after at least 3 months of anticoagulation in adult patients with VTE were included. The PROBAST, ROBINS-I and RoB2 tools were used to assess risk of bias and applicability.

RESULTS

Selection yielded 18 studies evaluating 8 models for recurrence (7 on development; 9 on validation; 1 update). Generally, models for recurrent VTE appeared to perform poorly to moderately in external validation studies (C-statistics 0.39-0.66, one 0.83). However, impact studies show that HERDOO2 and Vienna prediction model may identify patients with unprovoked VTE at low recurrence risk. Sixteen studies evaluating 14 models for anticoagulation-related bleeding were identified (7 on development; 9 on validation). Although some models seemed promising in development studies, their predictive performance was poor to moderate in external validation (C-statistics 0.52-0.71). All but 3 studies were considered at high risk of bias, mainly due to limitations in the statistical analysis.

CONCLUSIONS

Prognostic models for recurrence and anticoagulation-related bleeding risk often have important methodological limitations and insufficient predictive accuracy. These findings do not support their use in clinical practice to weigh risks of recurrence and bleeding when deciding on continuing anticoagulation after initial treatment of VTE.

Individualised Risk Assessments for Recurrent Venous Thromboembolism: New Frontiers in the Era of Direct Oral Anticoagulants

Venous thromboembolism (VTE) is a leading cause of morbidity and mortality and is associated with high recurrence rates. The introduction of direct oral anticoagulants (DOACs) in the 2010s has changed the landscape of VTE management. DOACs have become the preferred anticoagulant therapy for their ease of use, predictable pharmacokinetics, and improved safety profile. Increasingly, guidelines have recommended long term anticoagulation for some indications such as following first unprovoked major VTE, although an objective individualised risk assessment for VTE recurrence remains elusive. The balance of preventing VTE recurrence needs to be weighed against the not insignificant bleeding risk, which is cumulative with prolonged use. Hence, there is a need for an individualised, targeted approach for assessing the risk of VTE recurrence, especially in those patients in whom the balance between benefit and risk of long-term anticoagulation is not clear. Clinical factors alone do not provide the level of discrimination required on an individual level. Laboratory data from global coagulation assays and biomarkers may provide enhanced risk assessment ability and are an active area of research. A review of the prediction models and biomarkers for assessing VTE recurrence risk is provided, with an emphasis on contemporary developments in the era of DOACs and global coagulation assays.

Anticoagulation for Patients with Venous Thromboembolism: When is Extended Treatment Required?

The need for extended venous thromboembolism (VTE) treatment beyond 3 to 6 months is usually determined by balancing the risk of recurrence if treatment is stopped against the risk of bleeding from continuing treatment. The risk of recurrence, and in turn the decision to extend, can be determined through the nature of the index event. Patients with VTE provoked by surgery or trauma (major transient risk factors) are recommended to receive 3 months of anticoagulation therapy because their risk of recurrence is low, whereas patients with VTE provoked by a major persistent risk factor, such as cancer, or those considered to have “unprovoked” VTE, are recommended to receive an extended duration of therapy based on an established high risk of recurrence. Nonetheless, recent evidence and new guidance identify that this approach fails to consider patients with risk factors classed as minor transient (e.g., impaired mobility and pregnancy) or minor persistent (e.g., inflammatory bowel disease and congestive heart disease). Indeed, the risk of recurrence with respect to VTE provoked by minor persistent risk factors has been demonstrated to be not dissimilar to that of VTE without identifiable risk factors. This review provides an overview of the available data on the risk of recurrence according to the underlying cause of VTE, a critical evaluation of evidence from clinical studies on the available anticoagulants for extended VTE treatment, models of risk prediction for recurrent VTE and bleeding, and guidance on how to apply the evidence in practice.

Epidemiology and 3-year outcomes of combined oral contraceptive-associated distal deep vein thrombosis

BACKGROUND

Distal deep vein thrombosis (infrapopliteal DVT without proximal DVT or pulmonary embolism [PE]) generally shares the same triggering risks factors as proximal DVT. In women of childbearing age, a frequent triggering risk factor is the use of combined oral contraceptive (COC) pills. However, data on the epidemiology and long-term outcomes of COC-associated distal DVT are lacking.

OBJECTIVES

To assess the epidemiology and long-term outcomes of COC-associated distal DVT.

METHODS

Using data from the OPTIMEV (Optimisation de l'Interrogatoire dans l'évaluation du risque thrombo-Embolique Veineux [Optimization of Interrogation in the Assessment of Thromboembolic Venous Risk]) multicenter cohort study of patients with objectively confirmed venous thromboembolism (VTE) enrolled between 2004 and 2006, we assessed in nonpregnant or postpartum women aged ≤ 50 years without cancer or history of VTE (i) proportion of COC-associated distal DVTs among women with distal DVTs and among women with COC-associated VTEs (distal DVT, proximal DVT, or PE) and (ii) 3-year incidence of death, bleeding, and VTE recurrence.

RESULTS

COC-associated distal DVTs (n = 54) represented 43.9% of all distal DVTs and 51.9% of COC-associated VTEs. All but one woman with a COC-associated distal DVT received therapeutic anticoagulation for a median of 3 months. At 3-year follow-up, all women with COC-associated distal DVTs were alive, and none had bled during anticoagulant treatment or had experienced a DVT or PE recurrence after stopping anticoagulants. Similar results were found in patients with COC-associated proximal DVT and PE: The VTE recurrence rate was 1.7% per patient-year (PY) and 0% PY, respectively, and there were no deaths or major bleeds in either group.

CONCLUSIONS

Distal DVT was the most frequent clinical presentation of COC-associated VTE and had similarly favorable long-term outcomes as other COC-associated VTE.

Predicting the Risk of Recurrent Venous Thromboembolism: Current Challenges and Future Opportunities

Acute venous thromboembolism (VTE) is a commonly diagnosed condition and requires treatment with anticoagulation to reduce the risk of embolisation as well as recurrent venous thrombotic events. In many cases, cessation of anticoagulation is associated with an unacceptably high risk of recurrent VTE, precipitating the use of indefinite anticoagulation. In contrast, however, continuing anticoagulation is associated with increased major bleeding events. As a consequence, it is essential to accurately predict the subgroup of patients who have the highest probability of experiencing recurrent VTE, so that treatment can be appropriately tailored to each individual. To this end, the development of clinical prediction models has aided in calculating the risk of recurrent thrombotic events; however, there are several limitations with regards to routine use for all patients with acute VTE. More recently, focus has shifted towards the utility of novel biomarkers in the understanding of disease pathogenesis as well as their application in predicting recurrent VTE. Below, we review the current strategies used to predict the development of recurrent VTE, with emphasis on the application of several promising novel biomarkers in this field.

D-dimer testing, with gender-specific cutoff levels, is of value to assess the individual risk of venous thromboembolic recurrence in non-elderly patients of both genders: a post hoc analysis of the DULCIS study

Male patients, especially the young, are at a higher risk of recurrent venous thromboembolism (RVTE) than females. Recent scientific reports show the use of D-dimer does not help predict RVTE risk in males. In the present report, we reviewed the data obtained in the DULCIS study (main report published in Blood 2014), focusing on D-dimer results recorded in non-elderly patients of both genders included in the study, and their relationship with RVTE events occurring during follow-up. Using specifically designed cutoff values for positive/negative interpretation, serial D-dimer measurements (performed during warfarin treatment and up to 3 months after discontinuation of anticoagulation) in 475 patients (males 57.3%) aged ≤ 65 years were obtained. D-dimer resulted positive in 46.3% and 30.5% of males and females, respectively (p = 0.001). Following management procedure, anticoagulation was stopped in 53.7% of males and 69.5% of females, who had persistently negative D-dimer results. The rate of subsequent recurrent events was 1.7% (95% CI 0.5-4.5%) and 0.4% (95% CI 0-2.5%) patient-years in males and females, respectively, with upper limits of confidence intervals always below the level of risk considered acceptable by international scientific societies for stopping anticoagulation (< 5%). In conclusion, using sensitive quantitative assays with specifically designed cutoff values and serial measurements during and after discontinuation of anticoagulation, D-dimer testing is useful to predict the risk of RVTE and is of help in deciding the duration of anticoagulation in both male and female adult patients aged up to 65 years.

From Classical Laboratory Parameters to Novel Biomarkers for the Diagnosis of Venous Thrombosis

Venous thrombosis is a common and potentially fatal disease, because of its high morbidity and mortality, especially in hospitalized patients. To establish the diagnosis of venous thrombosis, in the last years, a multi-modality approach that involves not only imaging modalities but also serology has been evolving. Multiple studies have demonstrated the use of some biomarkers, such as D-dimer, selectins, microparticles or inflammatory cytokines, for the diagnosis and treatment of venous thrombosis, but there is no single biomarker available to exclusively confirm the diagnosis of venous thrombosis. Considering the fact that there are some issues surrounding the management of patients with venous thrombosis and the duration of treatment, recent studies support the idea that these biomarkers may help guide the length of appropriate anticoagulation treatment, by identifying patients at high risk of recurrence. At the same time, biomarkers may help predict thrombus evolution, potentially identifying patients that would benefit from more aggressive therapies. This review focuses on classic and novel biomarkers currently under investigation, discussing their diagnostic performance and potential benefit in guiding the therapy for venous thrombosis.

Which patients with unprovoked venous thromboembolism should receive extended anticoagulation with direct oral anticoagulants? A systematic review, network meta-analysis, and decision analysis

INTRODUCTION

Direct oral anticoagulants (DOACs) effectively prevent recurrent venous thromboembolism (VTE). However, it is unknown which agents should be used to prevent recurrent VTE and which patients with unprovoked VTE should receive extended anticoagulation. We therefore sought to compare the efficacy and safety among DOACs for secondary prevention of VTE. We also determined a risk-adapted threshold for initiating extended anticoagulation based on the likelihood of VTE recurrence (without treatment) and bleeding (with treatment) in patients with unprovoked VTE.

METHODS

Our systematic review of randomized controlled trials compares extended anticoagulation with DOACs to another DOAC, aspirin, or placebo for the prevention of recurrent VTE. We searched PubMed, EMBASE, and Cochrane Registry of Controlled Trials (CENTRAL) in October 2018. Our outcomes of interest were VTE recurrence, major bleeding, and all clinically relevant bleeding. We used network meta-analysis to make indirect comparisons among DOACs. We populated the threshold decision-analytic model with data from our meta-analysis to determine the risk of VTE recurrence above which the benefits of extended anticoagulation outweigh the harms compared with no treatment.

RESULTS

We included four, high-quality, randomized trials comprising 8386 participants. Low-dose apixaban, full-dose apixaban, low-dose rivaroxaban, full-dose rivaroxaban, and dabigatran reduce VTE recurrence compared with placebo (RR = 0.19, 95% CI, 0.12-0.31; RR = 0.20, 95% CI, 0.12-0.32; RR = 0.08, 95% CI, 0.03-0.27; RR = 0.14, 95% CI, 0.06-0.35; RR = 0.19, 95% CI, 0.09-0.40, respectively). No DOACs increased major bleeding risk compared with placebo. A VTE recurrence risk above 0.3% to 0.4% at approximately 1 year is the threshold to treat a patient with unprovoked VTE with extended anticoagulation (with any DOAC).

CONCLUSIONS

All DOACs exhibit comparable efficacy for the prevention of recurrent VTE. Given that the risk of VTE recurrence is much higher than the calculated threshold for treatment, extended thromboprophylaxis should be considered in all patients with unprovoked VTE who do not have increased bleeding risk.

Predicting venous thromboembolism in multiple myeloma: development and validation of the IMPEDE VTE score

Venous thromboembolism (VTE) is a common cause of morbidity and mortality among patients with multiple myeloma (MM). The International Myeloma Working Group (IMWG) developed guidelines recommending primary thromboprophylaxis, in those identified at high-risk of VTE by the presence of risk factors. The National Comprehensive Cancer Network (NCCN) has adopted these guidelines; however, they lack validation. We sought to develop and validate a risk prediction score for VTE in MM and to evaluate the performance of the current IMWG/NCCN guidelines. Using 4446 patients within the Veterans Administration Central Cancer Registry, we used time-to-event analyses to develop a risk score for VTE in patients with newly diagnosed MM starting chemotherapy. We externally validated the score using the Surveillance, Epidemiology, End Results (SEER)-Medicare database (N = 4256). After identifying independent predictors of VTE, we combined the variables to develop the IMPEDE VTE score (Immunomodulatory agent; Body Mass Index ≥25 kg/m2 ; Pelvic, hip or femur fracture; Erythropoietin stimulating agent; Dexamethasone/Doxorubicin; Asian Ethnicity/Race; VTE history; Tunneled line/central venous catheter; Existing thromboprophylaxis). The score showed satisfactory discrimination in the derivation cohort, c-statistic = 0.66. Risk of VTE significantly increased as score increased (hazard ratio 1.20, P = <.0001). Within the external validation cohort, IMPEDE VTE had a c-statistic of 0.64. For comparison, when evaluating the performance of the IMWG/NCCN guidelines, the c-statistic was 0.55. In summary, the IMPEDE VTE score outperformed the current IMWG/NCCN guidelines and could be considered as the new standard risk stratification for VTE in MM.

Prediction of recurrent venous thrombosis in all patients with a first venous thrombotic event: The Leiden Thrombosis Recurrence Risk Prediction model (L-TRRiP)

BACKGROUND

Recurrent venous thromboembolism (VTE) is common. Current guidelines suggest that patients with unprovoked VTE should continue anticoagulants unless they have a high bleeding risk, whereas all others can stop. Prediction models may refine this dichotomous distinction, but existing models apply only to patients with unprovoked first thrombosis. We aimed to develop a prediction model for all patients with first VTE, either provoked or unprovoked.

METHODS AND FINDINGS

Data were used from two population-based cohorts of patients with first VTE from the Netherlands (Multiple Environment and Genetic Assessment of Risk Factors for Venous Thrombosis [MEGA] follow-up study, performed from 1994 to 2009; model derivation; n = 3,750) and from Norway (Tromsø study, performed from 1999 to 2016; model validation; n = 663). Four versions of a VTE prediction model were developed: model A (clinical, laboratory, and genetic variables), model B (clinical variables and fewer laboratory markers), model C (clinical and genetic factors), and model D (clinical variables only). The outcome measure was recurrent VTE. To determine the discriminatory power, Harrell's C-statistic was calculated. A prognostic score was assessed for each patient. Kaplan-Meier plots for the observed recurrence risks were created in quintiles of the prognostic scores. For each patient, the 2-year predicted recurrence risk was calculated. Models C and D were validated in the Tromsø study. During 19,201 person-years of follow-up (median duration 5.7 years) in the MEGA study, 507 recurrences occurred. Model A had the highest predictive capability, with a C-statistic of 0.73 (95% CI 0.71-0.76). The discriminative performance was somewhat lower in the other models, with C-statistics of 0.72 for model B, 0.70 for model C, and 0.69 for model D. Internal validation showed a minimal degree of optimism bias. Models C and D were externally validated, with C-statistics of 0.64 (95% CI 0.62-0.66) and 0.65 (95% CI 0.63-0.66), respectively. According to model C, in 2,592 patients with provoked first events, 367 (15%) patients had a predicted 2-year risk of >10%, whereas in 1,082 patients whose first event was unprovoked, 484 (45%) had a predicted 2-year risk of <10%. A limitation of both cohorts is that laboratory measurements were missing in a substantial proportion of patients, which therefore were imputed.

CONCLUSIONS

The prediction model we propose applies to patients with provoked or unprovoked first VTE-except for patients with (a history of) cancer-allows refined risk stratification, and is easily usable. For optimal individualized treatment, a management study in which bleeding risks are also taken into account is necessary.

Risk prediction of recurrent venous thrombosis; where are we now and what can we add?

BACKGROUND

Several models are available to predict recurrent venous thrombosis (VT) in patients with unprovoked first events.

OBJECTIVES

To validate these prediction models externally.

METHODS

Within the MEGA follow-up study (n = 3750), we externally validated the Vienna and DASH score. These models were validated (a) by using the original study's criteria for patients with unprovoked VT and (b) by using our own criteria for unprovoked VT. In addition, absolute recurrence risks based on individual VT risk factors were calculated.

RESULTS

The recurrence rate was 5.2 (95% CI, 4.6-5.9) per 100 patient-years in those who had a first unprovoked VT according to our definition. For the Vienna model it was 3.4 per 100 patient-years and for DASH 3.8 per 100 patient-years. The C-statistic was 0.62 for Vienna and 0.65 for DASH. The C-statistic declined to 0.58 for both Vienna and DASH when we used our own definition of "unprovoked VT." Within the provoked group a strong gradient in risk was found dependent on the presence of traditional risk factors or biomarkers in a patient.

CONCLUSIONS

The ability to distinguish patients' recurrence risks is lower than proposed in the original prediction model studies and dependent on the definition that is used for an unprovoked first event. Furthermore, our results suggest that a more-refined risk estimation is possible, also in patients with a provoked first event, who are currently all classified as low risk.

D-dimer: Preanalytical, analytical, postanalytical variables, and clinical applications

D-dimer is a soluble fibrin degradation product deriving from the plasmin-mediated degradation of cross-linked fibrin. D-dimer can hence be considered a biomarker of activation of coagulation and fibrinolysis, and it is routinely used for ruling out venous thromboembolism (VTE). D-dimer is increasingly used to assess the risk of VTE recurrence and to help define the optimal duration of anticoagulation treatment in patients with VTE, for diagnosing disseminated intravascular coagulation, and for screening medical patients at increased risk of VTE. This review is aimed at (1) revising the definition of D-dimer; (2) discussing preanalytical variables affecting the measurement of D-dimer; (3) reviewing and comparing assay performance and some postanalytical variables (e.g. different units and age-adjusted cutoffs); and (4) discussing the use of D-dimer measurement across different clinical settings.

Risk Of Recurrence After Withdrawal Of Anticoagulation In Patients With Unprovoked Venous Thromboembolism: External Validation Of The Vienna Nomogram And The Dash Prediction Score

INTRODUCTION

Scales for predicting venous thromboembolism (VTE) recurrence are useful for deciding the duration of the anticoagulant treatment. Although there are several scales, the most appropriate for our setting has not been identified. For this reason, we aimed to validate the DASH prediction score and the Vienna nomogram at 12 months.

METHODS

This was a retrospective study of unselected consecutive VTE patients seen between 2006 and 2014. We compared the ability of the DASH score and the Vienna nomogram to predict recurrences of VTE. The validation was performed by stratifying patients as low-risk or high-risk, according to each scale (discrimination) and comparing the observed recurrence with the expected rate (calibration).

RESULTS

Of 353 patients evaluated, 195 were analyzed, with an average age of 53.5 ± 19 years. There were 21 recurrences in 1 year (10.8%, 95% CI: 6.8%-16%). According to the DASH score, 42% were classified as low risk, and the rate of VTE recurrence in this group was 4.9% (95% CI: 1.3%-12%) vs. the high-risk group that was 15% (95% CI: 9%-23%) (p <.05). According to the Vienna nomogram, 30% were classified as low risk, and the rate of VTE recurrence in the low risk group vs. the high risk group was 4.2% (95% CI:0.5%-14%) vs. 16.2% (95% CI: 9.9%-24.4%) (p <.05).

CONCLUSIONS

Our study validates the DASH score and the Vienna nomogram in our population. The DASH prediction score may be the most advisable, both because of its simplicity and its ability to identify more low-risk patients than the Vienna nomogram (42% vs. 30%).

Anticoagulation risk assessment for patients with non-valvular atrial fibrillation and venous thromboembolism: A clinical review

Non-valvular atrial fibrillation and venous thromboembolism anticoagulation risk assessment tools have been increasingly utilized to guide implementation and duration of anticoagulant therapy. Anticoagulation significantly reduces stroke and recurrent venous thromboembolism risk, but comes at the cost of increased risk of major and clinically relevant non-major bleeding. The decision for anticoagulation in high-risk patients is complicated by the fact that many risk factors associated with increased thromboembolic risk are simultaneously associated with increased bleeding risk. Traditional risk assessment tools rely heavily on age, sex, and presence of cardiovascular comorbidities, with newer tools additionally taking into account changes in risk factors over time and novel biomarkers to facilitate more personalized risk assessment. These tools may help counsel and inform patients about the risks and benefits of starting or continuing anticoagulant therapy and can identify patients who may benefit from more careful management. Although the ability to predict anticoagulant-associated hemorrhagic risk is modest, ischemic and bleeding risk scores have been shown to add significant value to therapeutic management decisions. Ultimately, further work is needed to optimally implement accurate and actionable risk stratification into clinical practice.

The prevention of venous thromboembolism recurrence in the elderly: a still open issue

INTRODUCTION

Venous thromboembolism (VTE) is frequent in the elderly, with an unclear recurrence risk. After the initial and early maintenance anticoagulant treatment, the decision about its extension versus recurrences is difficult because of the high risk of bleeding in this population. Areas covered: This paper analyzes recent literature on VTE recurrence and risk of bleeding associated with extended anticoagulation in elderly patients with VTE, focusing on available data regarding efficacy and safety of old anticoagulant or recent direct oral anticoagulant (DOACs). Expert commentary: The following are clinically important and still unmet needs in elderly patients with VTE: the current real risks for recurrence or for bleeding are still uncertain; the available clinical predictive rules for recurrence are of less use; in general, the phase III trials on DOACs proved less satisfactory in the elderly than in the general population; low dose DOACs use for extended treatment seems promising and data on long periods of therapy are needed; low dose aspirin does not seem an appropriate therapeutic alternative to anticoagulants due to the high rate of bleeding in the elderly; antithrombotic drugs, with low risk of bleeding should be assessed as alternative therapeutic options for extended treatment in the elderly.

The secondary prevention of venous thromboembolism: Towards an individual therapeutic strategy

After the anticoagulant withdrawal, a substantial proportion of patients with venous thromboembolism will develop recurrent events. Whether to consider an extended treatment depends on the risk of recurrence and bleeding risk. The assessment of the individual risk profile remains a difficult task. Several basal and post-basal factors modulate the risk of recurrence and may help clinicians to select patients who can benefit from the extended therapy. During the year 2017, new evidence regarding the post-basal factors was provided by the Morgagni and Scope studies. Another interesting novelty was the VTE-BLEED score, the first bleeding risk score that obtained the external validation in venous thromboembolism setting. In secondary prevention, the use of direct oral anticoagulants is growing instead of vitamin K antagonist. Even at lower doses, direct oral anticoagulants showed to be effective and safe, to reduce all-cause mortality and seemed to be superior to placebo for the composite outcome of fatal bleeding and fatal recurrence. After the recently published Einstein-Choice trial, the role of aspirin has become truly marginal as rivaroxaban 10 mg showed a bleeding risk similar to aspirin 100 mg but a greater effectiveness reducing the relative risk of recurrence by about 70%. Another option for secondary prevention could be sulodexide, with a lower protective effect than direct oral anticoagulants but an interesting safety profile. In conclusion, in our opinion, an individual strategy taking into account the risk of recurrence, bleeding risk, therapeutic options and patient preferences is the most appropriate approach to secondary prevention of venous thromboembolism.

A Review of the Role of Non-Vitamin K Oral Anticoagulants in the Acute and Long-Term Treatment of Venous Thromboembolism

Venous thromboembolism (VTE), which includes both deep vein thrombosis and pulmonary embolism (PE), is a very common disorder with high risk for recurrence and is associated with significant morbidity and mortality. The non-vitamin K oral anticoagulants (NOACs), which include dabigatran, rivaroxaban, apixaban, and edoxaban, have been shown to be noninferior to conventional anticoagulant therapy for the prevention of recurrent VTE and are associated with more favorable bleeding risk. Evidence from the treatment of VTE with traditional therapy (low molecular weight heparin and vitamin K antagonists) implies that extended or indefinite treatment reduces risk of recurrence. Recently, mounting evidence suggests a role for the extended use of NOACs to reduce the risk of VTE recurrence. This review summarizes the existing evidence for the extended use of NOACs in the treatment of VTE from phase III extension studies with dabigatran, rivaroxaban, and apixaban. Additionally, it examines and discusses the major society guidelines and how these recommendations may change physician practices in the near future.

Risk factors for recurrent venous thromboembolism after unprovoked pulmonary embolism: the PADIS-PE randomised trial

We aimed to identify risk factors for recurrent venous thromboembolism (VTE) after unprovoked pulmonary embolism.

Analyses were based on the double-blind randomised PADIS-PE trial, which included 371 patients with a first unprovoked pulmonary embolism initially treated during 6 months who were randomised to receive an additional 18 months of warfarin or placebo and followed up for 2 years after study treatment discontinuation. All patients had ventilation/perfusion lung scan at inclusion (i.e. at 6 months of anticoagulation).

During a median follow-up of 41 months, recurrent VTE occurred in 67 out of 371 patients (6.8 events per 100 person-years). In main multivariate analysis, the hazard ratio for recurrence was 3.65 (95% CI 1.33–9.99) for age 50–65 years, 4.70 (95% CI 1.78–12.40) for age >65 years, 2.06 (95% CI 1.14–3.72) for patients with pulmonary vascular obstruction index (PVOI) ≥5% at 6 months and 2.38 (95% CI 1.15–4.89) for patients with antiphospholipid antibodies. When considering that PVOI at 6 months would not be available in practice, PVOI ≥40% at pulmonary embolism diagnosis (present in 40% of patients) was also associated with a 2-fold increased risk of recurrence.

After a first unprovoked pulmonary embolism, age, PVOI at pulmonary embolism diagnosis or after 6 months of anticoagulation and antiphospholipid antibodies were found to be independent predictors for recurrence.