Risk Assessment of Recurrence in Patients With Unprovoked Deep Vein Thrombosis or Pulmonary Embolism

Is Pulmonary Embolism a Chronic Disease?

Pulmonary embolism (PE) is often regarded as an acute disorder, yet emerging evidence underscores its chronic trajectory. Many survivors endure long-term complications, including recurrent thrombosis, persistent dyspnoea, and psychosocial challenges. These sequelae impair functional capacity and quality of life long after the initial event. To address these issues, we suggest that clinicians should adopt an integrated, multidisciplinary model that includes risk stratification for recurrence, structured follow-up, exercise rehabilitation, and support for psychological challenges. Recognising the potential chronic sequalae of PE ultimately fosters comprehensive care aimed at reducing morbidity and improving long-term outcomes for surviv.

Prediction of Recurrent Venous Thromboembolism and Arterial Cardiovascular Events after Discontinuation of Anticoagulation: The R-VTE-predict and MACE-predict Risk Scores

Patients who had venous thromboembolism (VTE) are not only at increased risk of recurrent VTE but also of major adverse cardiovascular events (MACEs) than the general population. Therefore, the prediction of the risk of these events is important for a tailored prevention and mitigation strategy. We aimed to develop simple scores to estimate recurrent VTE and MACE risks after the discontinuation of anticoagulation in a large cohort of individuals who suffered VTE (EDITH cohort). The primary endpoints were recurrent symptomatic VTE and MACE (composite of non-fatal acute coronary syndrome, stroke and cardiovascular death). Arterial thrombotic event (ATE) exclusively was also considered. Independent predictors of main outcomes were derived from multivariable Cox regression models. Weighted integer points based on the effect estimate of identified predictors were used to derive the final risk scores. A total of 1,999 participants (mean age: 54.78 years, 46.4% male, 43.6% unprovoked VTE) were included in the derivation cohort and 10,000 in the validation cohort (built using bootstrapping). During a median post-anticoagulation follow-up of 6.9 years, recurrent VTE occurred in 29.5% of participants and MACE in 14.8%. Independent predictors of recurrent VTE were male sex, age >65 years, cancer-associated VTE, and unprovoked VTE (vs. transient risk factor-associated VTE). Independent predictors of MACE were age >65 years, cancer-associated VTE, hypertension, renal insufficiency, and atrial fibrillation. The risk of recurrent VTE (moderate vs. low: hazard ratio [HR]: 2.62, 95% confidence interval [CI]: 2.06-3.34; high vs. low: HR: 3.78, 95% CI: 2.91-4.89), MACE (moderate vs. low: HR: 6.37, 95% CI: 3.19-12.69; high vs. low: HR: 12.32, 95% CI: 6.09-24.89), and ATE (based on MACE-predict risk score) increased gradually from the lowest to highest of the respective prediction risk score groups. These results were confirmed in the validation cohort with overall reasonable models' discrimination performance (recurrent VTE C-statistic: 0.62-0.63, MACE and ATE C-statistic: 0.72-0.77). Contemporary simple risk scores based on readily available clinical characteristics can reasonably predict the risk of recurrent VTE and MACE after the discontinuation of anticoagulation. These findings may influence the choice of anticoagulation strategy after the acute phase of VTE and, therefore, need confirmation by further studies.

Role of Artificial Intelligence in the Diagnosis and Management of Pulmonary Embolism: A Comprehensive Review

Pulmonary embolism (PE) remains a critical condition with significant mortality and morbidity, necessitating timely detection and intervention to improve patient outcomes. This review examines the evolving role of artificial intelligence (AI) in PE management. Two primary AI-driven models that are currently being explored are deep convolutional neural networks (DCNNs) for enhanced image-based detection and natural language processing (NLP) for improved risk stratification using electronic health records. A major advancement in this field was the FDA approval of the Aidoc© AI model, which has demonstrated high specificity and negative predictive value in PE diagnosis from imaging scans. Additionally, AI is being explored for optimizing anticoagulation strategies and predicting PE recurrence risk. While further large-scale studies are needed to fully establish AI's role in clinical practice, its integration holds significant potential to enhance diagnostic accuracy and overall patient management.

Fibrinogen genotypes and their impact on recurrence of venous thromboembolism and family history: A prospective population-based study

Venous thromboembolism (VTE) involves blood clot formation in veins, resulting in serious health issues. Fibrinogen, a crucial clotting protein, consists of three polypeptides encoded by the fibrinogen genes: alpha (FGA), beta (FGB) and gamma (FGG). We genotyped most common missense variants in the fibrinogen genes in relation to VTE, recurrence and family history in Malmö Thrombophilia Study, including 1465 VTE patients followed for ~10 years and 429 healthy donors. FGG (rs6063) was significantly associated with increased odds of primary VTE (odds ratio [OR] = 8.2; 95% confidence interval [CI] = 1.05-63.6) after adjusting for age and sex. For recurrent VTE, Cox-regression analysis indicated a higher risk associated with FGA (rs6050) (hazard ratio [HR] = 1.8; 95% CI = 1.1-2.8), with even greater risk for unprovoked recurrent VTE (HR = 2.3; 95% CI = 1.3-4.2), surpassing the well-known factor V Leiden (FVL) (HR = 1.9; 95% CI = 1.2-3.0). Combining risk alleles from FVL and FGA (rs6050) significantly raised the risk for unprovoked recurrent VTE: ≥3 risk alleles (HR = 4.6; 95% CI = 1.9-11.3), two risk alleles (HR = 2.6; 95% CI = 1.4-4.8) and one risk allele (HR = 1.5; 95% CI = 0.8-2.7) compared to 0 risk allele. Prevalence of FGA (rs6050) risk allele was significantly higher in cases with a family history of VTE. We propose FGA (rs6050) as a novel predictor for unprovoked recurrent VTE and it may contribute to the familial occurrence of VTE.

Exploration of the plasma proteomic profile of patients at risk of thromboembolic events

Background

The elevated health burden of thromboembolic events necessitates development of blood-based risk monitoring tools.

Objectives

We explored the potential of mass spectrometry-based plasma proteomics to provide insights into underlying plasma protein signatures associated with treatment and occurrence of thromboembolic events.

Methods

Utilizing a high-throughput, data-independent acquisition, discovery-based proteomics workflow, we analyzed 434 plasma proteomes from different groups of individuals with elevated risk of thromboembolic events, including individuals I) on vitamin K antagonists (VKAs; n = 130), II) with a prior venous thromboembolism (n = 10), III) with acute cerebral venous sinus thrombosis (n = 10, and IV) with SARS-CoV-2 infection (n = 67). Plasma protein levels measured with mass spectrometry were correlated with international normalized ratio and conventional clinical laboratory measurements. Plasma profile differences between different groups were assessed using principal component analysis, moderated t-test, and clustering analysis.

Results

Plasma protein levels were in agreement with conventional clinical laboratory parameters, including albumin and fibrinogen. Levels of vitamin K-dependent proteins inversely correlated with international normalized ratio. In the individual studies, we found decreased levels of vitamin K-dependent coagulation proteins in patients on VKAs, alterations in inflammatory signatures among CVST patients and a distinctive signature indicative of SARS-CoV-2 infection. However, no protein signature associated with a thromboembolic event could be identified neither in individual nor combined studies.

Conclusion

Although VKA treatment-specific and disease-specific signatures were captured, our study highlights that the challenges of discovering biomarkers in patients at risk of thromboembolic events lie in the heterogeneity of individual plasma profiles in relation to treatment and etiology.

Management of patients with venous thromboembolism and a high recurrence risk estimated by the Vienna Prediction Model: a prospective cohort study

Background

The Vienna Prediction Model (VPM) identifies patients with a first unprovoked deep vein thrombosis of the leg and/or pulmonary embolism who have a low recurrence risk and may, therefore, not benefit from extended-phase anticoagulation.

Objectives

The aim of this study was to evaluate patients with a predicted high risk of recurrent venous thromboembolism (VTE).

Methods and Results

We prospectively followed 266 patients in whom the VPM had predicted a recurrence risk of more than 5.5% at 1 year for a median of 13.5 months. Their median age was 56 years, and 96% were men. After the VPM risk assessment, 196 patients restarted anticoagulation. While on anticoagulation, none of the patients experienced recurrent VTE, whereas 4 patients had nonmajor clinically relevant bleeding (absolute bleeding rate, 1.8 [95% CI, 0.5-4.5] events per 100 patient-years). Seventy patients were left untreated after VPM risk assessment for various reasons. Among patients not using anticoagulation, 15 had recurrence (absolute recurrence rate, 18.1 [95% CI, 10.1, 29.9] events per 100 person-years). According to the extended Kaplan-Meier analysis, the probability of VTE recurrence in patients not on anticoagulation was 10.1% and 17.9% at 6 and 12 months after VPM risk assessment, respectively.

Conclusion

Anticoagulant therapy is effective and safe in patients with an unprovoked VTE, in whom the VPM had predicted a high risk of recurrent VTE. If these patients are left untreated, the risk of recurrence is high.

Genomic Landscape of Thrombosis Recurrence Risk Across Venous Thromboembolism Subtypes

Venous thromboembolism (VT) is a frequent (annual incidence of 1 to 2 per 1,000) and potentially life-threatening (case-fatality rate up to 10%) disease. VT is associated with serious short-term and long-term complications including a recurrence rate of approximately 20% within five years. Anticoagulant therapy, the mainstay of VT treatment, drastically reduces the risk of early VT recurrence, but it exposes patients to a substantial risk of bleeding. We analysed the genomic architecture of VT recurrence using data from 6,571 patients across eight cohorts, 1,816 of whom experienced recurrence, with a particular focus on the clinical manifestation of the type of first VT event. Through genome-wide association studies (GWAS), we identified three loci significantly associated (P<5×10-8) with VT recurrence in the general VT population: GPR149/MME, L3MBTL4, and THSD7B. Protein Quantitative Trait Locus and Mendelian Randomization analyses further identified elevated plasma levels of coagulation factor XI and GOLM2 as risk factors for recurrence, while decreased levels of PCSK9 and pro-IL16 were linked to reduced VT recurrence risk. Subgroup analyses revealed 18 loci associated with VT recurrence, with notable differences between pulmonary embolism (PE) and deep vein thrombosis (DVT). For example, the exonic variant SLC4A1 p.Glu40Lys was significantly associated with recurrence in PE patients (Hazard Ratio (HR)=3.23, P=9.7×10-12) but showed no effect in DVT (HR=1.00, P=0.98). These findings emphasize the role of specific genetic loci and protein pathways in influencing VT recurrence and provide valuable insights into potential therapeutic targets. Further research is needed to clarify the biological mechanisms driving these associations.

Long-term monitoring and treatment of venous thromboembolic disease: recommendations of the Thromboembolic Disease Group of the Spanish Society of Internal Medicine 2024

Venous thromboembolim (VTE) is a highly prevalent condition that requires long-term monitoring and treatment. This monitoring includes: 1) completing the etiological study and determining the risk of VTE recurrence; 2) establishing the optimal duration of anticoagulant treatment, as well as the type of therapy and its dosage; 3) estimating the risk of bleeding, and 4) identifying the occurrence of chronic complications. This consensus document, prepared by the VTE Group of the Spanish Society of Internal Medicine (SEMI), aims to update and establish consensus recommendations on these aspects. The document focuses on four aspects of management: the first includes risk factors for VTE recurrence after an unprovoked VTE episode and describes the predictive scores of VTE recurrence; the second focuses on risk factors for bleeding; the third provides recommendations for long-term follow-up in VTE, addressing specific considerations for screening chronic thromboembolic pulmonary hypertension and post-thrombotic syndrome of the lower limbs; and the fourth provides guidance on the optimal duration of extended anticoagulant treatment, as well as the type of therapy and its dosage. For each area, an exhaustive literature review was conducted, analyzing the updated VTE clinical guidelines and recent studies. This document is intended to be a guide in the long-term management of VTE based on the most current knowledge.

Urgent Reversal of Direct Oral Anticoagulants in Critical and Life-Threatening Bleeding: A Multidisciplinary Expert Consensus

Direct oral anticoagulants (DOACs) are increasingly being used due to their improved efficacy/safety ratio and lower clinical and economic burden when compared to vitamin K antagonists. However, bleeding is still the most frequent complication associated with DOACs, and although rare, bleeding episodes can be life-threatening or critical. The impact of DOAC anticoagulation activity during a bleeding event must be evaluated according to patient clinical assessment, dosage and time from last intake, the presence of comorbidities (especially kidney and liver dysfunction), and, whenever possible, coagulation tests. Unfortunately, DOACs' anticoagulation activity is not easily or usually detectable in routine common coagulation testing. Specific DOAC tests allow for specific drug monitoring, but they are too time consuming, and are usually unavailable in routine emergency practice. If a clinically relevant DOAC plasma concentration is assumed or proven in a severe bleeding scenario, DOAC reversal is needed to restore hemostasis. This experts' consensus provides a narrative review about DOAC reversal and practical life-threatening bleeding management in several scenarios (trauma, intracranial hemorrhage and gastrointestinal bleeding), focusing on the selection of patients to whom specific reversal agents should be given.

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.

Duration of anticoagulation of venous thromboembolism

Venous thromboembolism (VTE) is a common, serious condition that requires anticoagulation for at least three months to prevent recurrence and long-term complications. After this initial period, the decision to continue or stop anticoagulation depends on the balance between the risk of recurrent VTE and the risk of bleeding. Established guidelines suggest short-term anticoagulation for VTE caused by transient factors and indefinite anticoagulation for recurrent or cancer-associated VTE. However, for a first unprovoked VTE, decision-making remains challenging. Current predictive scores for recurrence and bleeding are not sufficiently reliable, and the safety and efficacy of reduced-dose anticoagulation remain unclear. In the future, precision and patient-centred medicine may improve treatment decisions in this area.

Optimal long-term anticoagulation after acute pulmonary embolism: current state of the art and a look into the near future

PURPOSE OF REVIEW

This review aims to summarize the current state of the art and future directions in optimal long-term anticoagulation following acute pulmonary embolism (PE).

RECENT FINDINGS

Actual studies and guidelines underscore the preference for direct oral anticoagulants (DOAC) in standard therapeutic doses for maintenance therapy post-PE, while considering patient-specific factors and dose-reduction criteria. Risk stratification should always include the assessment of concomitant trigger- or risk factors regarding their strength and persistence. The use of tools like specific scores can facilitate the identification of optimal candidates for long-term therapy, emphasizing once more personalized approaches and strategies. Special patient groups, such as cancer associated thrombosis, chronic thromboembolic pulmonary hypertension or antiphospholipid syndrome require even more tailored therapy approaches.

SUMMARY

Optimal long-term anticoagulation post-PE should be guided by straightforward and individual risk assessment strategies. The array of indications for DOACs has gotten wider in last years, also within special patient groups. Still, chronic thromboembolic pulmonary hypertension and antiphospholipid syndrome remains domain of vitamin K agonists.

Anticoagulation and compression therapy for proximal acute deep vein thrombosis

The treatment of proximal deep vein thrombosis (DVT) of the lower limbs includes an initial management phase, covering the first 1 to 3 weeks, a primary treatment phase, lasting a minimum of 3 months, and a secondary treatment phase for those patients requiring continuing anticoagulation beyond the first 3 to 6 months. During the initial phase most patients with DVT can be managed as outpatients. Exclusion criteria for home treatment include high risk of bleeding, limb threatening DVT or other conditions requiring hospitalisation. Anticoagulant drugs represent the mainstay of treatment and include parenteral drugs such as unfractionated heparin or low molecular weight heparin, and oral drugs such as the vitamin K antagonists and the direct oral anticoagulants (DOACs). DOACs are currently recommended as the first line of treatment for proximal DVT of the lower limbs, with no preference for one DOAC over another. Factors to consider when choosing the anticoagulant strategy include, among others, renal and liver function, underlying diseases such as cancer or the antiphospholipid syndrome, and patient preferences. Indefinite duration of anticoagulation beyond the first 3 to 6 months is recommended for patients with unprovoked DVT and patients with permanent, chronic risk factors. Two DOACs, namely apixaban and rivaroxaban, can be administered at low doses for the secondary prevention of DVT. Elastic compression stockings (ECS) have been used for decades in patients with proximal DVT with the aim of counteracting the venous hypertension generated by the vascular disorder and reducing leg edema and to prevent the post-thrombotic syndrome.

Clinical outcomes after discontinuing anticoagulant therapy in patients with first unprovoked venous thromboembolism

BACKGROUND

The duration of anticoagulation for a first episode of unprovoked venous thromboembolism (VTE) should balance the likelihood of VTE recurrence against the risk of major bleeding.

OBJECTIVES

Analyze rates and case-fatality rates (CFRs) of recurrent VTE and major bleeding after discontinuing anticoagulation in patients with a first unprovoked VTE after at least 3 months of anticoagulation.

METHODS

We compared the rates and CFRs in patients of the Registro Informatizado Enfermedad Trombo Embólica (RIETE) and Contemporary management and outcomes in patients with venous thromboembolism registries. We used logistic regression models to identify predictors for recurrent pulmonary embolism (PE) and major bleeding.

RESULTS

Of 8261 patients with unprovoked VTE in RIETE registry, 4012 (48.6%) had isolated deep vein thrombosis (DVT) and 4250 had PE. Follow-up (median, 318 days) showed 543 recurrent DVTs, 540 recurrent PEs, 71 major bleeding episodes, and 447 deaths. The Contemporary management and outcomes in patients with venous thromboembolism registry yielded similar results. Corresponding CFRs of recurrent DVT, PE, and major bleeding were 0.4%, 4.6%, and 24%, respectively. On multivariable analyses, initial PE presentation (hazard ratio [HR], 3.03; 95% CI, 2.49-3.69), dementia (HR, 1.47; 95% CI, 1.01-2.13), and anemia (HR, 0.72; 95% CI, 0.57-0.91) predicted recurrent PE, whereas older age (HR, 2.11; 95% CI, 1.15-3.87), inflammatory bowel disease (HR, 4.39; 95% CI, 1.00-19.3), and anemia (HR, 2.24; 95% CI, 1.35-3.73) predicted major bleeding. Prognostic scores were formulated, with C statistics of 0.63 for recurrent PE and 0.69 for major bleeding.

CONCLUSION

Recurrent DVT and PE were frequent but had low CFRs (0.4% and 4.6%, respectively) after discontinuing anticoagulation. On the contrary, major bleeding was rare but had high CFR (24%). A few clinical factors may predict these outcomes.

Poor patients' knowledge about venous thromboembolism and its therapy is associated with increased risk of major bleeding and discontinuation of anticoagulation: A cohort study

It has been shown that patients' knowledge about venous thromboembolism (VTE) and its therapy is suboptimal, which might reduce compliance and worsen prognosis. We investigated whether low VTE patients' knowledge affects their clinical outcomes during long-term follow-up. We evaluated 151 consecutive patients (51.8 ± 15.7 years) after unprovoked VTE, who were recruited from the outpatient clinic (Krakow, Poland). All patients received anticoagulant treatment, mostly with direct oral anticoagulants (n = 113, 74.8%). The modified Jessa Atrial fibrillation Knowledge Questionnaire (JAKQ-VTE; 16 questions) was used to assess the knowledge of VTE and anticoagulant therapy. During a median follow-up of 58.0 months, VTE recurrence, major bleeding, and anticoagulation withdrawal were recorded. The median percentage of correct responses was 62.5% (12.5-100%) and was inversely correlated with age (P < .01). Diabetic patients and those with positive family history of VTE had lower overall scoring compared to the remainder (both P < .05). Major bleeding (n = 10, 6.6%) and anticoagulation withdrawal (n = 28, 18.5%), but not VTE recurrence (n = 12, 7.9%), were associated with lower overall scoring compared to the remainder (48.8% ± 12.5% vs 63.8% ± 16.3%, P = .003 and 55.3% ± 14.7% vs 64.4% ± 16.3%, P = .040, respectively). Major bleeding was independently associated with the female sex (hazard ratio [HR] 6.18; 95% confidence interval [CI] 1.15-33.19, P = .034), younger age (HR per 10 years 0.55; 95% CI 0.34-0.90, P = .016), OAC therapy discontinuation (HR 6.69; 95% CI 1.62-27.70), and lower overall scoring of JAKQ-VTE (HR 0.60 per 10 percentage points; 95% CI 0.40-0.92, P = .019). Insufficient knowledge about VTE and anticoagulant treatment predisposes to a higher risk of major bleeding and therapy discontinuation, but not VTE recurrence in unprovoked VTE patients during long-term follow-up.

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.

Overall haemostatic potential assay for prediction of outcomes in venous and arterial thrombosis and thrombo-inflammatory diseases

Thromboembolic diseases including arterial and venous thrombosis are common causes of morbidity and mortality globally. Thrombosis frequently recurs and can also complicate many inflammatory conditions through the process of 'thrombo-inflammation,' as evidenced during the COVID-19 pandemic. Current candidate biomarkers for thrombosis prediction, such as D-dimer, have poor predictive efficacy. This limits our capacity to tailor anticoagulation duration individually and may expose lower risk individuals to undue bleeding risk. Global coagulation assays, such as the Overall Haemostatic Potential (OHP) assay, that investigate fibrin generation and fibrinolysis, may provide a more accurate and functional assessment of hypercoagulability. We present a review of fibrin's critical role as a central modulator of thrombotic risk. The results of our studies demonstrating the OHP assay as a predictive biomarker in venous thromboembolism, chronic renal disease, diabetes mellitus, post-thrombotic syndrome, and COVID-19 are discussed. As a comprehensive and global measurement of fibrin generation and fibrinolytic capacity, the OHP assay may be a valuable addition to future multi-modal predictive tools in thrombosis.

Identifying novel biomarkers using proteomics to predict cancer-associated thrombosis

Comprehensive protein analyses of plasma are made possible by high-throughput proteomic screens, which may help find new therapeutic targets and diagnostic biomarkers. Patients with cancer are frequently affected by venous thromboembolism (VTE). The limited predictive accuracy of current VTE risk assessment tools highlights the need for new, more targeted biomarkers. Although coagulation biomarkers for the diagnosis, prognosis, and treatment of VTE have been investigated, none of them have the necessary clinical validation or diagnostic accuracy. Proteomics holds the potential to uncover new biomarkers and thrombotic pathways that impact the risk of thrombosis. This review explores the fundamental methods used in proteomics and focuses on particular biomarkers found in VTE and cancer-associated thrombosis.

Inconsistency in UK Biobank Event Definitions From Different Data Sources and Its Impact on Bias and Generalizability: A Case Study of Venous Thromboembolism

The UK Biobank study contains several sources of diagnostic data, including hospital inpatient data and data on self-reported conditions for approximately 500,000 participants and primary-care data for approximately 177,000 participants (35%). Epidemiologic investigations require a primary disease definition, but whether to combine data sources to maximize statistical power or focus on only 1 source to ensure a consistent outcome is not clear. The consistency of disease definitions was investigated for venous thromboembolism (VTE) by evaluating overlap when defining cases from 3 sources: hospital inpatient data, primary-care reports, and self-reported questionnaires. VTE cases showed little overlap between data sources, with only 6% of reported events for persons with primary-care data being identified by all 3 sources (hospital, primary-care, and self-reports), while 71% appeared in only 1 source. Deep vein thrombosis-only events represented 68% of self-reported VTE cases and 36% of hospital-reported VTE cases, while pulmonary embolism-only events represented 20% of self-reported VTE cases and 50% of hospital-reported VTE cases. Additionally, different distributions of sociodemographic characteristics were observed; for example, patients in 46% of hospital-reported VTE cases were female, compared with 58% of self-reported VTE cases. These results illustrate how seemingly neutral decisions taken to improve data quality can affect the representativeness of a data set.

Tutorial: dos and don'ts in clinical prediction research for venous thromboembolism

Clinical prediction modeling has become an increasingly popular domain of venous thromboembolism research in recent years. Prediction models can help healthcare providers make decisions regarding starting or withholding therapeutic interventions, or referrals for further diagnostic workup, and can form a basis for risk stratification in clinical trials. The aim of the current guide is to assist in the practical application of complicated methodological requirements for well-performed prediction research by presenting key dos and don'ts while expanding the understanding of predictive research in general for (clinical) researchers who are not specifically trained in the topic; throughout we will use prognostic venous thromboembolism scores as an exemplar.

Thrombosis recurrence and major bleeding in non-anticoagulated thrombotic antiphospholipid syndrome patients: Prospective study from antiphospholipid syndrome alliance for clinical trials and international networking (APS ACTION) clinical database and repository ("Registry")

BACKGROUND

Long-term anticoagulant therapy is generally recommended for thrombotic antiphospholipid syndrome (TAPS) patients, however it may be withdrawn or not introduced in routine practice.

OBJECTIVES

To prospectively evaluate the risk of thrombosis recurrence and major bleeding in non-anticoagulated TAPS patients, compared to anticoagulated TAPS, and secondly, to identify different features between those two groups.

PATIENTS/METHODS

Using an international registry, we identified non-anticoagulated TAPS patients at baseline, and matched them with anticoagulated TAPS patients based on gender, age, type of previous thrombosis, and associated autoimmune disease. Thrombosis recurrence and major bleeding were prospectively analyzed using Kaplan-Meier method and compared using a marginal Cox's regression model.

RESULTS

As of June 2022, 94 (14 %) of the 662 TAPS patients were not anticoagulated; and 93 of them were matched with 181 anticoagulated TAPS patients (median follow-up 5 years [interquartile range 3 to 8]). The 5-year thrombosis recurrence and major bleeding rates were 12 % versus 10 %, and 6 % versus 7 %, respectively (hazard ratio [HR] 1.38, 95 % confidence interval [CI] 0.53 to 3.56, p = 0.50 and HR 0.53; 95 % CI 0.15 to 1.86; p = 0.32, respectively). Non-anticoagulated patients were more likely to receive antiplatelet therapy (p < 0.001), and less likely to have more than one previous thrombosis (p < 0.001) and lupus anticoagulant positivity (p = 0.01).

CONCLUSION

Fourteen percent of the TAPS patients were not anticoagulated at recruitment. Their recurrent thrombosis risk did not differ compared to matched anticoagulated TAPS patients, supporting the pressing need for risk-stratified secondary thrombosis prevention trials in APS investigating strategies other than anticoagulation.

Tailored anticoagulant treatment after a first venous thromboembolism: protocol of the Leiden Thrombosis Recurrence Risk Prevention (L-TRRiP) study - cohort-based randomised controlled trial

INTRODUCTION

Patients with a first venous thromboembolism (VTE) are at risk of recurrence. Recurrent VTE (rVTE) can be prevented by extended anticoagulant therapy, but this comes at the cost of an increased risk of bleeding. It is still uncertain whether patients with an intermediate recurrence risk or with a high recurrence and high bleeding risk will benefit from extended anticoagulant treatment, and whether a strategy where anticoagulant duration is tailored on the predicted risks of rVTE and bleeding can improve outcomes. The aim of the Leiden Thrombosis Recurrence Risk Prevention (L-TRRiP) study is to evaluate the outcomes of tailored duration of long-term anticoagulant treatment based on individualised assessment of rVTE and major bleeding risks.

METHODS AND ANALYSIS

The L-TRRiP study is a multicentre, open-label, cohort-based, randomised controlled trial, including patients with a first VTE. We classify the risk of rVTE and major bleeding using the L-TRRiP and VTE-BLEED scores, respectively. After 3 months of anticoagulant therapy, patients with a low rVTE risk will discontinue anticoagulant treatment, patients with a high rVTE and low bleeding risk will continue anticoagulant treatment, whereas all other patients will be randomised to continue or discontinue anticoagulant treatment. All patients will be followed up for at least 2 years. Inclusion will continue until the randomised group consists of 608 patients; we estimate to include 1600 patients in total. The primary outcome is the combined incidence of rVTE and major bleeding in the randomised group after 2 years of follow-up. Secondary outcomes include the incidence of rVTE and major bleeding, functional outcomes, quality of life and cost-effectiveness in all patients.

ETHICS AND DISSEMINATION

The protocol was approved by the Medical Research Ethics Committee Leiden-Den Haag-Delft. Results are expected in 2028 and will be disseminated through peer-reviewed journals and during (inter)national conferences.

TRIAL REGISTRATION NUMBER

NCT06087952.

Choice and Duration of Anticoagulation for Venous Thromboembolism

Venous thromboembolism (VTE) is a prevalent medical condition with high morbidity, mortality, and associated costs. Anticoagulation remains the main treatment for VTE, though the decision on when, how, and for how long to administer anticoagulants is increasingly complex. This review highlights the different phases of VTE management, with special circumstances for consideration such as antiphospholipid syndrome, coronary artery disease, cancer-associated thrombus, COVID-19, and future anticoagulation options. Anticoagulation management will continue to be a complex decision, applying evidence-based medicine to individual patients with the hope of maximizing effectiveness while minimizing risks.

The Vienna Prediction Model for identifying patients at low risk of recurrent venous thromboembolism: a prospective cohort study

BACKGROUND AND AIMS

Patients with unprovoked venous thromboembolism (VTE) have a high recurrence risk, and guidelines suggest extended-phase anticoagulation. Many patients never experience recurrence but are exposed to bleeding. The aim of this study was to assess the performance of the Vienna Prediction Model (VPM) and to evaluate if the VPM accurately identifies these patients.

METHODS

In patients with unprovoked VTE, the VPM was performed 3 weeks after anticoagulation withdrawal. Those with a predicted 1-year recurrence risk of ≤5.5% were prospectively followed. Study endpoint was recurrent VTE over 2 years.

RESULTS

A total of 818 patients received anticoagulation for a median of 3.9 months. 520 patients (65%) had a predicted annual recurrence risk of ≤5.5%. During a median time of 23.9 months, 52 patients had non-fatal recurrence. The recurrence risk was 5.2% [95% confidence interval (CI) 3.2-7.2] at 1 year and 11.2% (95% CI 8.3-14) at 2 years. Model calibration was adequate after 1 year. The VPM underestimated the recurrence risk of patients with a 2-year recurrence rate of >5%. In a post-hoc analysis, the VPM's baseline hazard was recalibrated. Bootstrap validation confirmed an ideal ratio of observed and expected recurrence events. The recurrence risk was highest in men with proximal deep-vein thrombosis or pulmonary embolism and lower in women regardless of the site of incident VTE.

CONCLUSIONS

In this prospective evaluation of the performance of the VPM, the 1-year rate of recurrence in patients with unprovoked VTE was 5.2%. Recalibration improved identification of patients at low recurrence risk and stratification into distinct low-risk categories.

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.

Acute myocardial infarction after initially diagnosed with unprovoked venous thromboembolism: A case report

BACKGROUND

Protein C deficiency is typically associated with venous thromboembolism; however, arterial thrombosis has been reported in several cases. We report the case of a patient with pulmonary thromboembolism and deep vein thrombosis following acute myocardial infarction with high thrombus burden.

CASE SUMMARY

A 40-year-old man was diagnosed with pulmonary thromboembolism and deep vein thrombosis without any provoking factors. The patient was treated with anticoagulants for six months, which were then discontinued. Three months after the discontinuation of anticoagulant therapy, the patient was hospitalized with chest pain and diagnosed with acute myocardial infarction with high thrombus burden. Additional tests revealed protein C deficiency associated with thrombophilia. The patient was treated with anticoagulants combined with dual antiplatelet agents for 1 year after percutaneous coronary intervention, and no recurrent events were reported during a follow-up period of 5 years.

CONCLUSION

Recurrent thromboembolic events including acute myocardial infarction with thrombus should be considered an alarming sign of thrombophilia.

Sex differences in long-term outcomes of patients with deep vein thrombosis

OBJECTIVE

Sex differences in short-term outcomes of patients with deep vein thrombosis (DVT) have been reported, but differences in long-term outcomes remain poorly characterized. This study aimed to evaluate sex differences in long-term mortality, venous thromboembolism (VTE)-related mortality, and bleeding-related mortality in patients with DVT at a tertiary care center.

METHODS

A retrospective chart review from 2012 to 2018 of all consecutive patients diagnosed with DVT was performed. Patients were grouped by sex, and baseline characteristics and treatment modalities were compared. Long-term outcomes of recurrent VTE, bleeding, and related mortalities were analyzed. Multivariable regression analysis was performed to determine factors associated with overall mortality.

RESULTS

A total of 1043 (female = 521 and male = 522) patients with DVT were captured in this study period. Female patients were older (64.7 vs 61.6 years old, p = 0.01) and less likely to be obese (68.2% vs. 71.1%, p = 0.04),but had a higher average Caprini score (6.73 vs 6.35, p = 0.04). There was no difference in anatomic extent of DVT, association with PE, and severity of PE between sexes. Most patients (80.5%) were treated with anticoagulation, with no differences in choice of anticoagulant or duration of anticoagulation between females and males. Male patients were more likely to undergo catheter-directed thrombolysis (CDT) for DVT (4.2% vs 1.7%, p = 0.02) and PE (2.7% vs 0.9%, p = 0.04). Female patients were more likely to receive systemic thrombolysis for PE (2.9% vs 1.1%, p = 0.05). After an average 2.3 years follow-up, there was significantly higher bleeding complications among females (22.2% vs 16.7%, p = 0.027). The overall mortality rate was 33.5% and not different between males and females. Females were more likely to experience VTE-related mortality compared to males (3.3% vs 0.6%, p = 0.002). On regression analysis, older age (OR = 1.04 [1.03-1.06]), cancer (OR = 7.64 [5.45-10.7]), and congestive heart failure (OR = 3.84 [2.15-6.86]) were independently associated with overall mortality.

CONCLUSIONS

In this study, there was no difference in overall long-term mortality between sexes for patients presenting with DVT. However, females had increased risk of long-term bleeding and VTE-related mortality compared to males.

Predictors of Recurrent Venous Thromboembolism or Arterial Thrombotic Events during and after Anticoagulation for a First Venous Thromboembolism

After first episodes of venous thromboembolism (VTE), patients are at increased risk of recurrent VTE and arterial thrombotic events (ATE) compared with the general population, two disorders that are influenced by anticoagulation. However, risk factors of these conditions occurring during and after anticoagulation are little described. Using cause-specific hazard regression models, we aimed to determine risk factors of the composite outcome recurrent VTE/ATE, and separately recurrent VTE or ATE, during and after anticoagulation in patients with first episodes of VTE from a prospective cohort. Hazard ratios (HRs) are given with 95% confidence intervals (CIs). A total of 2,011 patients treated for at least 3 months were included. A total of 647 patients had recurrent VTE/ATE (incidence: 4.69% per patient-years) during overall follow-up (median: 92 months). Of these events, 173 occurred during anticoagulation (incidence: 3.67% per patient-years). Among patients free of events at the end of anticoagulation, 801 had a post-anticoagulation follow-up ≥3 months; and 95 had recurrent VTE/ATE (incidence: 1.27% per patient-years). After adjustment for confounders, cancer-associated VTE (HR: 2.64, 95% CI: 1.70-4.11) and unprovoked VTE (HR: 1.95, 95% CI: 1.35-2.81) were the identified risk factors of recurrent VTE/ATE during anticoagulation (vs. transient risk factor-related VTE). Risk factors of recurrent VTE/ATE after anticoagulation included 50 to 65 years of age (vs. < 50, HR: 1.99, 95% CI: 1.04-3.81), older than 65 years (vs. < 50, HR: 5.28, 95% CI: 3.03-9.21), and unprovoked VTE (vs. transient risk factor-related VTE, HR: 2.06, 95% CI: 1.27-3.34). Cancer-associated VTE and unprovoked VTE are the main risk factors of recurrent VTE/ATE during anticoagulation, while older age and unprovoked VTE mainly predict the risk of these events after anticoagulation.

Low D-dimer levels at diagnosis of venous thromboembolism are associated with reduced risk of recurrence: data from the TROLL registry

BACKGROUND

Venous thromboembolism (VTE) is a frequent disease with a high risk of recurrence. It has been suggested that the D-dimer level at the time of VTE diagnosis can be used to identify patients at a low risk of recurrence.

OBJECTIVES

We aimed to investigate the impact of D-dimer levels measured at the time of VTE diagnosis on the risk of recurrence in a large cohort of patients with a first-time VTE.

METHODS

The study included 2585 patients with first symptomatic non-cancer-associated VTE from the Venous Thrombosis Registry in Østfold Hospital (TROLL) (2005-2020). All recurrent events during the follow-up were recorded, and cumulative incidences of recurrence were estimated according to D-dimer levels of ≤1900 ng/mL (≤25th percentile) and >1900 ng/mL.

RESULTS

During a median follow-up of 3.3 years, 395 patients experienced a recurrent VTE. The 1- and 5-year cumulative incidences of recurrence were 2.9% (95% CI: 1.8-4.6) and 11.4% (95% CI: 8.7-14.8), respectively, in those with a D-dimer concentration of ≤1900 ng/mL and 5.0% (95% CI, 4.0-6.1) and 18.3% (95% CI: 16.2-20.6), respectively, in those with a D-dimer concentration of >1900 ng/mL, respectively. In patients with unprovoked VTE, the 5-year cumulative incidence was 14.3% (95% CI: 10.3-19.7) in the ≤1900-ng/mL category, and 20.2% (95% CI: 17.3-23.5) in the >1900-ng/mL category.

CONCLUSIONS

D-dimer levels within the lowest quartile, measured at the time of VTE diagnosis, were associated with lower recurrence risk. Our findings imply that D-dimer levels measured at the time of diagnosis may be used to identify patients with VTE at a low risk of recurrent VTE.

Elevated plasma complement factor H related 5 protein is associated with venous thromboembolism

Venous thromboembolism (VTE) is a common, multi-causal disease with potentially serious short- and long-term complications. In clinical practice, there is a need for improved plasma biomarker-based tools for VTE diagnosis and risk prediction. Here we show, using proteomics profiling to screen plasma from patients with suspected acute VTE, and several case-control studies for VTE, how Complement Factor H Related 5 protein (CFHR5), a regulator of the alternative pathway of complement activation, is a VTE-associated plasma biomarker. In plasma, higher CFHR5 levels are associated with increased thrombin generation potential and recombinant CFHR5 enhanced platelet activation in vitro. GWAS analysis of ~52,000 participants identifies six loci associated with CFHR5 plasma levels, but Mendelian randomization do not demonstrate causality between CFHR5 and VTE. Our results indicate an important role for the regulation of the alternative pathway of complement activation in VTE and that CFHR5 represents a potential diagnostic and/or risk predictive plasma biomarker.

Massive DVT from the proximal IVC to the pedal vein: Our approach using aspiration mechanical thrombectomy and open surgery thrombectomy

Deep venous thrombosis might present in an acute condition requiring early thrombus removal. Several endovascular and surgical approaches are available with a short treatment time and minimal complications compared to pharmacotherapies. However, due to a lack of evidence, these are not the first treatment choice for deep vein thrombosis. Our case report showed a successful multimodality treatment for an acute-on-chronic massive deep vein thrombosis from the inferior vena cava to the pedal vein. A 47-year-old with chief complaints of cold, significant swelling, and severe pain in her left leg was diagnosed with deep vein thrombosis through Doppler ultrasound and contrast-enhanced computed tomography. The patient received aspiration mechanical thrombectomy with the "kissing catheter" technique, adjunctive stent, percutaneous transluminal angioplasty, and open surgical thrombectomy by Fogarty catheter without recurrence and complication.

Prevention, Diagnostics and Treatment of Deep Vein Thrombosis. Russian Experts Consensus

The guidelines are developed in accordance with the requirements of the Ministry of Health of the Russian Federation by the all-Russian public organization «Association of Phlebologists of Russia» with participation of the Association of Cardiovascular Surgeons of Russia, the Russian Society of Surgeons, the Russian Society of Angiologists and Vascular Surgeons, the Association of Traumatologists and Orthopedists of Russia, the Association of Oncologists of Russia, the Russian Society of Clinical Oncology, Russian Society of Oncohematologists, Russian Society of Cardiology, Russian Society of Obstetricians and Gynecologists.

Surgical Prevention of Thromboembolic Complications in Transfascial Thrombosis

The aim. To evaluate the effectiveness of surgical methods of prevention of venous thromboembolic complications in transfascial thrombosis of the lower extremities. Materials and methods. The paper analyzes the results of examination and surgical or conservative treatment of 417 patients with transfascial thrombosis treated at the Vascular Surgery Department of the Zakarpattia Regional Clinical Hospital named after A. Novak from 1995 to March 2020 and at the Surgical Department of the Central City Clinical Hospital of Uzhhorod from September 2020 to September 2022. The main (I) group consisted of 349 (83.7%) patients who were operated for transfascial thrombosis. The control (II) group consisted of 68 (16.3%) patients with transfascial thrombosis who received conservative treatment. Results. In case of acute varicothrombophlebitis complicated by transfascial thrombosis, the scope of surgery should be expanded in order to surgically prevent thromboembolism of the pulmonary artery. All the patients with transfascial thrombosis were treated as for deep vein thrombosis. The approach to the removal of the small saphenous vein should be differentiated depending on the extent of thrombotic occlusion and the confluence of the sural veins. Surgical treatment of patients with transfascial thrombosis made it possible to prevent recurrence of the thrombotic process in the superficial and deep veins of the lower extremities, thromboembolism of the pulmonary artery, while with conservative treatment their frequency was 5.1%, 3.4% and 3.4%, respectively. Active surgical tactics in patients of the I group made it possible to reduce the frequency of manifestations of decompensated chronic venous insufficiency from 27.1% to 7.0%, and manifestations of postthrombotic syndrome in the deep veins of the lower extremities from 100% to 3.7%. Conclusions. Implementation of operative treatment of acute varicothrombophlebitis complicated by transfascial thrombosis allows to effectively prevent venous thromboembolic complications, eliminate manifestations of chronic venous insufficiency and prevent the development of post-thrombotic changes in superficial and deep veins.

Derivation and External Validation of a Risk Assessment Model of Venous Thromboembolism in Hospitalized Chinese Patients

AIM

To develop and validate a risk assessment model (RAM) of venous thromboembolism (VTE) in hospitalized Chinese patients.

METHODS

We reviewed data from 300 patients with VTE and 300 non-VTE patients at Beijing Shijitan Hospital. The risk factors related to VTE were analyzed, and the VTE RAM (Shijitan (SJT) version) was developed according to the weight of each risk factor. A total of 407 patients with VTE and 533 non-VTE patients were enrolled for external validation. The sensitivity, specificity, Youden index, receiver operating curve (ROC), and area under the ROC curve (AUC) were used to evaluate the performance of VTE RAM (SJT version) compared with Caprini RAM and Padua RAM.

RESULTS

The VTE RAM (SJT version) contained six risk factors (age >60 years, lower limb edema, chronic obstructive pulmonary disease (COPD), central venous catheterization (CVC), VTE history, and D dimer). In the external validation group, for medical patients, the AUC value of SJT RAM (0.82 ± 0.03) is significantly higher than Caprini RAM (0.76 ± 0.04; P < 0.05), SJT RAM has a higher sensitivity, specificity, and Youden index than Caprini RAM (P < 0.05), which means that the SJT RAM has a much better predictive value than Caprini RAM. While SJT RAM and Padua RAM have the similar predictive value for medical patients (P > 0.05). For surgical patients, the AUC value of SJT RAM (0.72 ± 0.04) is significantly higher than the value of Padua RAM (0.66 ± 0.04; P < 0.05), SJT RAM has a higher sensitivity, specificity, and Youden index than Padua RAM (P < 0.05), which shows that the VTE RAM has better predictive value than Padua RAM. While SJT RAM and Caprini RAM have the similar predictive value for surgical patients (P > 0.05).

CONCLUSION

The SJT RAM derived from general hospitalized Chinese patients will be time-saving for physicians and has a better predictive ability for patients at risk of VTE.

C-reactive protein, immunothrombosis and venous thromboembolism

C-reactive protein (CRP) is a member of the highly conserved pentraxin superfamily of proteins and is often used in clinical practice as a marker of infection and inflammation. There is now increasing evidence that CRP is not only a marker of inflammation, but also that destabilized isoforms of CRP possess pro-inflammatory and pro-thrombotic properties. CRP circulates as a functionally inert pentameric form (pCRP), which relaxes its conformation to pCRP* after binding to phosphocholine-enriched membranes and then dissociates to monomeric CRP (mCRP). with the latter two being destabilized isoforms possessing highly pro-inflammatory features. pCRP* and mCRP have significant biological effects in regulating many of the aspects central to pathogenesis of atherothrombosis and venous thromboembolism (VTE), by directly activating platelets and triggering the classical complement pathway. Importantly, it is now well appreciated that VTE is a consequence of thromboinflammation. Accordingly, acute VTE is known to be associated with classical inflammatory responses and elevations of CRP, and indeed VTE risk is elevated in conditions associated with inflammation, such as inflammatory bowel disease, COVID-19 and sepsis. Although the clinical data regarding the utility of CRP as a biomarker in predicting VTE remains modest, and in some cases conflicting, the clinical utility of CRP appears to be improved in subsets of the population such as in predicting VTE recurrence, in cancer-associated thrombosis and in those with COVID-19. Therefore, given the known biological function of CRP in amplifying inflammation and tissue damage, this raises the prospect that CRP may play a role in promoting VTE formation in the context of concurrent inflammation. However, further investigation is required to unravel whether CRP plays a direct role in the pathogenesis of VTE, the utility of which will be in developing novel prophylactic or therapeutic strategies to target thromboinflammation.

Pathophysiological Aspects of Aging in Venous Thromboembolism: An Update

The aim of this review is to highlight all the factors that associate venous thromboembolism (VTE) with aging. Elderly people are characterized by a higher incidence of thrombosis taking into account the co-existing comorbidities, complications and fatality that arise. Based on the Virchow triad, pathophysiological aspects of venous stasis, endothelium injury and hypercoagulability in elderly people (≥65 years) are described in detail. More precisely, venous wall structure, nitric oxide (NO) and endothelin-1 expression are impaired in this age group. Furthermore, an increase in high-molecular-weight kininogen (HMWK), prekallikrein, factors V, VII, VIII, IX and XI, clot lysis time (CLT) and von Willebrand factor (vWF) is observed. Age-dependent platelet dysfunction and changes in anticoagulant factors are also illustrated. A “low-grade inflammation stage” is delineated as a possible risk factor for thrombosis in the elderly. Consequently, clinical implications for frail elderly people related to diagnosis, treatment, bleeding danger and VTE recurrence emerge. We conclude that aging is an acquired thrombotic factor closely related to pathophysiological changes.

Extended Anticoagulation After Pulmonary Embolism: A Multicenter Observational Cohort Analysis

Background Pulmonary embolism (PE) has a long-term risk of adverse events, which can be prevented by extended anticoagulation. We compared clinical characteristics and outcomes between patients treated with 2-year extended anticoagulation and those who were not, in a population who had completed an initial phase of 3 to 6 months of anticoagulant therapy after acute PE. Methods and Results Observational cohort analysis of patients with PE who survived an initial phase of 3 to 6 months anticoagulation. Primary efficacy outcome was all-cause death or recurrent venous thromboembolism. Primary safety outcome was major bleeding. In total, 858 (71.5%) patients were treated with and 341 (28.5%) were treated without extended anticoagulant therapy during the active study period. Age <65 years, intermediate-high or high-risk index PE, normal platelet count, and the absence of concomitant antiplatelet treatment were independently associated with the prescription of extended anticoagulation. The mean duration of the active phase was 2.1±0.3 years. The adjusted rate of the primary efficacy outcome was 2.1% in the extended group and 7.7% in the nonextended group (P<0.001) for patients treated with extended anticoagulant therapy. Rate of bleeding were similar between the extended anticoagulant group and the nonextended group. Conclusions Extended oral anticoagulation over 2 and a half years after index PE seems to provide a net clinical benefit compared with no anticoagulation in patients with PE selected to receive extended anticoagulation. Randomized clinical trials are warranted to explore the potential benefit of extended anticoagulation in patients with PE, especially those with transient provoking factors but residual risk.

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.

Apixaban Use in Obese Patients: A Review of the Pharmacokinetic, Interventional, and Observational Study Data

Abstract

Relatively little is known about the influence of extreme body weight on the pharmacokinetics (PK), pharmacodynamics (PD), efficacy, and safety of drugs used in many disease states. While direct oral anticoagulants (DOACs) have an advantage over warfarin in that they do not require routine drug monitoring, some may regard this convenience as less compelling in obese patients. Some consensus guidelines discourage using DOACs in patients weighing > 120 kg or with a body mass index > 35–40 kg/m², given a sparsity of available data in this population and the concern that fixed dosing in obese patients might lead to decreased drug exposure and lower efficacy. Per the prescribing information, apixaban does not require dose adjustment in patients weighing above a certain threshold (e.g., ≥ 120 kg). Data from healthy volunteers and patients with nonvalvular atrial fibrillation (NVAF) or venous thromboembolism (VTE) have shown that increased body weight has a modest effect on apixaban’s PK. However, the paucity of exposure data in individuals > 120 kg and the lack of guideline consensus on DOAC use in obese patients continue to raise concerns about potential decreased drug exposure at extreme weight. This article is the first to comprehensively review the available PK data in obese individuals without NVAF or VTE, and PK, PD, efficacy, effectiveness, and safety data for apixaban in obese patients with either NVAF or VTE, including subgroup analyses across randomized controlled trials and observational (real-world) studies. These data suggest that obesity does not substantially influence the efficacy, effectiveness, or safety of apixaban in these patients.

Trial Registration ARISTOTLE: NCT00412984; AVERROES: NCT00496769; AMPLIFY: NCT00643201; AMPLIFY-EXT: NCT00633893; ADVANCE-1: NCT00371683; ADVANCE-2: NCT00452530; ADVANCE-3: NCT00423319

Video abstract

Extended Anticoagulation for Venous Thromboembolism: A Survey of the American Venous Forum and the European Venous Forum

OBJECTIVE

Extended anticoagulation should always be considered after standard treatment for an unprovoked episode of venous thromboembolism (VTE). It may also be considered in selected patients with provoked VTE. However, evidence-based protocols suggested by some clinical guidelines and risk assessment tools to guide this practice are limited and ambiguous. The goal of this survey research was to analyze current practices in applying extended anticoagulation therapy in patients with VTE among members of the American Venous Forum (AVF) and the European Venous Forum (EVF).

METHODS

An online survey was created by the AVF Research Committee. The survey consisted of sixteen questions to identify the country of practice, specialty, experience of participating physicians, and their clinical practice patterns in applying extended anticoagulation in VTE patients. The survey was distributed over email to the members of the AVF and EVF.

RESULTS

A total of 144 practitioners, 48 (33%) AVF members and 96 (66%) EVF members, participated in the survey. The majority of respondents identified themselves as vascular specialists with primary certification in vascular surgery (70%), vascular medicine/angiology (9%), and venous disease/phlebology (3%). Seventy-two percent of participants believe that the risk of VTE recurrence generally overweighs the risk of bleeding in patients with unprovoked VTE. Extended anticoagulation may be utilized by 97% of providers. Different patterns in real world clinical practice were identified. More than half of practitioners estimated VTE recurrence and bleeding risk subjectively. The antithrombotic drugs most commonly used for secondary prophylaxis were rivaroxaban, apixaban, warfarin, dabigatran, and aspirin, in decreasing order of frequency. Among the reasons selected for not considering extended anticoagulation on a regular basis were the lack of specific clinical practice guidelines (24%), the lack of published evidence (9%), and the absence of valid VTE/bleeding risk prediction calculators (8%). Twelve participants (8%) stated that extended anticoagulation was not beneficial for the majority of patients with VTE. Ten participants (7%) indicated that prescribing extended anticoagulation was outside the scope of their specialty.

CONCLUSIONS

There are different practice patterns in extending anticoagulation beyond the standard treatment in patients with VTE. Major gaps in knowledge remain a serious challenge at least partially explaining inaccuracy and inconsistency in long-term VTE management. Appropriately designed studies are needed to evaluate risk stratification tools when contemporary best medical therapy is used, accurately predict VTE recurrence and its long-term outcomes, and to tailor safe and effective secondary prophylaxis.

Proteomics in thrombosis research

A State of the Art lecture titled “Proteomics in Thrombosis Research” was presented at the ISTH Congress in 2021. In clinical practice, there is a need for improved plasma biomarker‐based tools for diagnosis and risk prediction of venous thromboembolism (VTE). Analysis of blood, to identify plasma proteins with potential utility for such tools, could enable an individualized approach to treatment and prevention. Technological advances to study the plasma proteome on a large scale allows broad screening for the identification of novel plasma biomarkers, both by targeted and nontargeted proteomics methods. However, assay limitations need to be considered when interpreting results, with orthogonal validation required before conclusions are drawn. Here, we review and provide perspectives on the application of affinity‐ and mass spectrometry‐based methods for the identification and analysis of plasma protein biomarkers, with potential application in the field of VTE. We also provide a future perspective on discovery strategies and emerging technologies for targeted proteomics in thrombosis research. Finally, we summarize relevant new data on this topic, presented during the 2021 ISTH Congress.

Current Knowledge on Factor V Leiden Mutation as a Risk Factor for Recurrent Venous Thromboembolism: A Systematic Review and Meta-Analysis

Background

Thrombophilia screening is widely done in clinical practice, and it is claimed that the extent of venous thromboembolism (VTE) recurrence risk in patients with common defects is still not fully understood.

Aim

We aimed to summarize data of all observational studies prospectively assessing the association of heterozygous factor V Leiden (FVL) mutation and recurrent VTE in patients with VTE, and to calculate pooled relative risks (RR), overall and in various subgroups.

Methods

We searched MEDLINE and EMBASE databases for cohort studies prospectively assessing VTE recurrence in patients with and without FVL mutation (PROSPERO: CRD42021182800). Data were extracted on cohort and study-level. The methodological quality was assessed using the Newcastle-Ottawa Scale (NOS). RR were calculated overall and in subgroups using a random-effects model.

Results

From 31 cohorts, 24 studies were finally included summarizing 13,571 patients. Heterozygous FVL mutation was identified in 2,840 individuals (21%). The methodological quality was estimated to be high in 20 studies (83%). The overall RR was 1.46 (95% CI: 1.31, 1.64), consistent across subgroups.

Conclusions

Pooling all high-quality epidemiological data, the risk of recurrent VTE was increased by 46% in patients with heterozygous FVL mutation. Against the background of established risk factors, the FVL mutation plays only a marginal role in the risk assessment for recurrent VTE.