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Background: Frailty influences the effectiveness and safety of anticoagulant therapy in patients with atrial fibrillation (AF). The age-weighted Charlson comorbidity index may offer a valuable tool to assess the risk of adverse events in AF patients treated with direct oral anticoagulants (DOACs). This sub-analysis of MAS trial data aimed to assess whether using the Charlson index, instead of the standard criteria, would have led to different dosing and improved adverse event occurrence during treatment., Methods: The MAS study looked for a relationship between DOAC levels assessed at baseline and adverse events during follow-up. The study is described in detail elsewhere., Results: Among the 1,657 patients studied, 832 (50.2 %) had a relatively low Charlson index (up to 6, general median class), of whom 132 (15.9 %) were treated with reduced doses. Conversely, among the 825 patients with a high Charlson index (≥7), 257 (31.1 %) received standard doses. A weak but statistically significant positive correlation (r = 0.1413, p < 0.0001 by ANOVA) was observed between increasing Charlson classes and DOAC levels standardized to allow comparability among drug results. However, no significant differences were found in the incidence or number of adverse events during follow-up, or in other parameters, between patients with low and high Charlson's scores., Conclusions: Utilizing the Charlson index would have led to notable differences in DOAC dosing compared to standard criteria. However, we found no evidence that its use would have improved the prediction of adverse events in AF patients enrolled in the MAS study., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: PALARETI GUALTIERO reports financial support was provided by Fondazione Cassa di Risparmio di Bologna. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Anti-Phospholipid Antibodies (aPL) are autoantibodies predisposing to an increased risk of thrombotic events. The net clinical benefit of antithrombotic prophylaxis in aPL carriers is still unclear. We performed a systematic review to assess the efficacy and safety of antiplatelet drugs for the primary prevention of thrombotic events in aPL carriers., Methods: Studies were identified by electronic search of MEDLINE and EMBASE database until May 2023. The differences in the outcomes among groups were estimated as pooled odds ratio (OR) and corresponding 95 % confidence interval (CI). Statistical heterogeneity was evaluated using the I2 statistic., Results: 1056 participants were included in 10 studies, 2 RCTs and 8 cohorts. Low-dose acetylsalicylic acid (LDA) was the antiplatelet drug in treated patients. Thrombotic events were significantly reduced in the LDA group compared to the control group [OR 0.46 (95 % CI 0.30-0.71), I2 27%, fixed-effects model]. Arterial thrombotic events were significantly reduced in the LDA group compared to the control group [OR 0.47 (95 % CI 0.26-0.86), I2 0%, fixed-effects model]. Venous thrombotic events were significantly reduced in the LDA group compared to the control group [OR 0.44 (95 % CI 0.21-0.89, I2 1%, fixed-effects model]. No major bleedings occurred in the five studies reporting them., Conclusions: aPL carriers receiving long-term LDA had a significant reduction of thrombotic events, without a significant increase of the risk of major bleeding. It remains unclear if LDA has the same benefit/risk profile in all aPL profile, i.e. single, double, or triple positivity., Competing Interests: Declaration of competing interest Alessandro Squizzato reports a relationship with Daiichi Sankyo, Bayer, Pfizer, Bristol-Myers Squibb, Boehringer-Ingelheim, Sanofi, Werfen, Alexion, Roche, and Viatris that includes: speaking and lecture fees. Vittorio Pengo reports a relationship with Werfen that includes: speaking and lecture fees. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Introduction: The recently published ACR/EULAR classification criteria score (3 points or more) both clinical and laboratory criteria to define the presence of antiphospholipid syndrome (APS). The clinical criteria have been better defined while laboratory criteria remain the same [lupus anticoagulant (LA), anticardiolipin (aCL) and anti ß2-Glycoprotein I (aß2GPI) antibodies] but with different impact (points) on the classification of patients. APS is excluded if more than 3 years separate positive test for antiphospholipid antibodies (aPL) and clinical manifestation., Methods: The present study evaluates how many patients would be excluded by the new criteria among those enrolled as APS in the START 2 antiphospholipid registry. The analysis includes 380 patients (274 APS and 106 carriers)., Results: Of 274 patients classified as APS, 118 (43%) did not match the new ACR/EULAR criteria for various reasons. First, the determination of aCL and aß2GPI antibodies was performed by automated instrumentations not allowed in the new criteria. Second, laboratory test score was less than 3 and this was due to an isolated IgM aCL or IgM aß2GPI in most cases and to isolated LA unconfirmed after 12 weeks in few cases. Third, 2 patients had a positive laboratory tests more than 3 years after the clinical event. Of the 106 carriers, 62% had aCL and aß2GPI determined by ELISA thus meeting the ACL/EULAR laboratory criteria but were negative for clinical criteria., Discussion: This study shows that many patients classified as APS in the START 2 registry do not match the classification using the new ACR/EULAR criteria., (© 2024 John Wiley & Sons Ltd.)

Background: Lupus anticoagulant hypoprothrombinemia syndrome (LAHPS) is a rare autoimmune condition characterized by acquired prothrombin (FII) deficiency associated with antiphospholipid syndrome (APS) and life-threatening bleeding. We present the case of a 34-year-old woman with heavy menstrual bleeding (HMB), positive Lupus anticoagulant (LA) test, and high titer anticardiolipin antibodies Immunoglobulin G (ACA IgG) and anti-β2 glycoprotein I antibodies IgG (antiB2GPI IgG). Severe iron deficiency anemia necessitated recurrent blood transfusions and intravenous iron infusions from 2018 to 2021., Results: In January 2022, she was admitted to our clinic. Von Willebrand disease screening and platelet function analysis (PFA100) were normal. FII and FIX deficiencies were detected, without factor IX inhibitors. Anti-phosphatidylserine/prothrombin antibodies were confirmed by Padua University lab. To reduce antibody titers and menstrual bleeding, immunosuppressive therapy (Rituximab 375 mg/m2 weekly ×4 weeks) and hormonal therapy (desogestrel 75 mcg/day) were initiated., Conclusion: After 1-year, complete remission of clinical symptoms was achieved, with normalization of FII and FIX values and moderate reduction of aPS/PT titers, especially IgM isotype., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: The MAS study (Blood Advances 2024) showed that a high proportion of Italian AF patients treated with direct oral anticoagulants (DOACs) receive reduced doses. This sub-analysis of MAS data aimed to analyze the effects of reduced (appropriate or not)- or standard-dose use on DOAC activity assessed at baseline and the occurrence of thrombotic or bleeding complications during follow-up., Methods: The MAS study design, the methods for DOAC measurement, the results, and the adverse events during follow-up, are described in detail elsewhere., Results: Seven hundred AF patients (42 % of the total 1657) received a reduced dose (considered inappropriate in 140 [20 %]). They were older, more frequently women, with lower body mass index (BMI), hemoglobin levels, and creatinine clearance. They more often had cerebral or cardiovascular diseases, were taking more medications, with higher scores for thrombotic or bleeding risk. Despite the use of low doses, 133 (19.0 %) patients had high standardized C-trough DOAC levels and experienced a high proportion of bleeding events (8.3 % per year). Conversely, some patients (4.7 %) had very low levels, resulting in a high incidence of thrombotic events (6.7 % per year). No difference was detected if the reduced dose was appropriate or not., Conclusion: The unpredictable, highly variable inter-individual anticoagulant effect of DOACs may lead to either too low or too high anticoagulant levels, increasing the risk of thrombotic or bleeding events. This is particularly relevant for patients with high-risk conditions, such as those chosen for reduced-dose treatment. Further studies are needed to investigate this important clinical issue., (Copyright © 2024. Published by Elsevier B.V.)

Antiphospholipid syndrome (APS) diagnosis is dependent on the accurate detection and interpretation of antiphospholipid antibodies (aPL). Lupus anticoagulant (LA), anticardiolipin antibodies (aCL), and anti-beta2 glycoprotein I antibodies (aβ2GPI) remain the cornerstone of the laboratory part of APS diagnosis. In the 2023 American College of Rheumatology (ACR)/European Alliance of Associations for Rheumatology (EULAR) APS classification criteria, the type of laboratory parameters remain essentially unchanged compared with the updated Sapporo classification criteria, and aCL and aβ2GPI measurement are still restricted to enzyme-linked immunosorbent assays (ELISAs) with moderate and high titer aPL thresholds defined as 40 and 80 Units, respectively, and a cutoff calculated by the 99th percentile has been abandoned. We must differentiate between classification criteria and assessment of aPLs in clinical care. Classification criteria are strict and meant for participant inclusion in studies and trials to study homogeneous populations of patients. In contrast, laboratory detection for APS diagnosis in daily practice is broader, meant to diagnose each APS patient to optimize their management. Nowadays, there is increasing use of measurement of aPLs by methods other than ELISAs , the semiquantitative reporting of titers is a matter of debate, as well as the role of the isotypes immunoglobulin (Ig)M and IgA, and the role of other aPLs, such as antiphosphatidylserine (aPS)/prothrombin (PT) antibodies. Patients diagnosed with the disease may or may not fulfill the classification criteria, and inappropriate use of classification criteria may lead to mis(under)diagnosis. The aim of this guidance, based on literature and expert opinion, is to provide guidance recommendations for laboratory workers and clinicians on routine diagnostic assessment of patients with suspected APS., Competing Interests: Declaration of competing interests K.M.J.D. has no conflicts of interest; M.L.B. is supported by the King’s British Heart Foundation Centre for Research Excellence Award RE/18/2/34213; D.W.B. reports a research award from UCB Biopharma; H.C. has no conflicts of interest and reports, outside the submitted work, consultancy fees from UCB Biopharma and lecture fees from Technoclone paid to University College London Hospitals Charity, and advisory board member at Roche and Argenx; D.E. has no conflict of interest regarding this project and reports outside this project research support from GlaxoSmithKline, American College of Rheumatology & European League Against Rheumatism, Exagen, and The National Institutes of Health, is a consultant to GlaxoSmithKline and Chugai, and is a speaker for GlaxoSmithKline; B.d.L. is an employee of Synapse Research Foundation and advisor for Diagnostica Stago; E.J.F. reports no conflicts of interest; T.L.O. has received consulting fees from Instrumentation Laboratory and Sanofi, and research support from Instrumentation Laboratory, Stago, and Siemens; V.P. reports participation in the advisory board of Daiichi-Sankyo and Bayer HealthCare and received lecture fees from Daiichi-Sankyo, Bayer HealthCare, and Werfen Group; D.W. reports personal fees, outside the submitted work, from Alexion and GlaxoSmithKline and support to attend scientific meetings from Bayer Healthcare and Leo Pharma., (Copyright © 2024 International Society on Thrombosis and Haemostasis. Published by Elsevier Inc. All rights reserved.)

Introduction: Oral anticoagulant drugs reduce the risk of stroke associated with atrial fibrillation. Vitamin K antagonists, gold standard therapy for decades, have been deposed by the direct oral anticoagulants that exhibit superior safety profiles. However, hemorrhagic complications remain a major concern to anticoagulation., Areas Covered: We searched available data in the literature to review the current knowledge on the safety profiles of available anticoagulants., Expert Opinion: Despite a relevant leap forward with the introduction of DOACs, safety concerns persist in some fields of the current pharmacotherapy for stroke prevention in atrial fibrillation. In-depth knowledge of the safety profile of available anticoagulants and dealing with safety issues in patient subgroups is of utmost importance. Bleeding risk scores should not be dichotomously used to decide anticoagulation treatment but rather to promote shared decision, identify and correct modifiable risk factors, and set monitoring frequency. Additional issues that wait to be investigated in order to improve the safety of therapy include circulating levels of direct oral anticoagulants and anticoagulation in patient sub-groups: very elderly, frail, those with advanced kidney or liver disease, and so on. Safety may be improved from the in-depth knowledge of safety concerns and therapeutic options.

Objectives: This study focused on the prevalence and impact of antinuclear antibodies (ANA) in antiphospholipid antibody (aPL)-positive patients without concomitant systemic autoimmune rheumatic diseases (SARDs)., Methods: Data from aPL-positive patients with or without Revised Sapporo APS classification criteria were retrieved from the APS ACTION Registry. Patients with concomitant SARDs were excluded., Results: 430 aPL-positive patients were included in the analysis, 56% ANA-positive and 44% negative. ANA positivity was significantly associated with history of hematologic manifestations (persistent autoimmune hemolytic anaemia, thrombocytopenia, leukopenia and/or lymphopenia) (16% of ANA-positive vs 7% of ANA-negative, p= 0.006). Triple aPL-positivity was more frequent in the ANA-positive subgroup (p= 0.02), along with low baseline C3 and C4 levels (p= 0.05 and p= 0.009, respectively), and higher frequency for extractable nuclear antigens (ENA). Among aPL-positive patients with no APS classification, ANA-positive patients showed a higher rate of arthritis (p= 0.006). Among female patients who have experienced at least one pregnancy, 113 were ANA-positive and 96 were ANA-negative; ANA-negative patients had a higher number of pregnancies (p= 0.018), and number of live births (p= 0.014). A wider proportion of ANA-positive patients were treated with hydroxychloroquine (HCQ) (p< 0.001)., Conclusion: When we analysed aPL-positive patients with no other SARDs, ANA status was not associated with thrombosis or pregnancy morbidity. Interestingly, ANA-positive patients showed higher rates of systemic autoimmune features, including hematologic manifestations, multiple aPL positivity, lower complement levels, ENA positivity, and joint involvement, and were more often treated with HCQ. Finally, aPL-positive subjects who were ANA-negative had a higher rate of pregnancies and live births., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Competing Interests: Declaration of competing interests V.P. received lecture fees from Werfen Group, Milan, Italy. All other authors have no conflicts to declare.

Competing Interests: None declared.

Several scores can predict clinical outcomes of patients with Acute Coronary Syndromes (ACS). The validated PARIS (Patterns of Non-Adherence to Anti-Platelet Regimen in Stented Patients) score is poorly used in clinical practice because it needs items that are not always easily available. The ACEF (Age, Creatinine, and Ejection Fraction) score is more attractive because it only includes three items. We compared these scores to risk-stratify ACS patients enrolled into the START (Survey on anticoagulated pAtients RegisTer)-ANTIPLATELET registry. ACS patients who completed 1-year follow-up ( n = 1171) were grouped in tertiles (low, medium, and high-risk) according to their ACEF/PARIS scores. Primary endpoints were: one-year MACCE (major adverse cardiac and cerebrovascular events: death, non-fatal myocardial infarction, stroke or target vessel revascularization) and NACE (net adverse cardiac and cerebrovascular events): MACCE plus major bleeding). MACCE incidence was higher in the high-risk tertile (15%) VS low/medium (3/7 %) risk tertiles ( P < .001). NACE incidence in the high-risk tertile was 24% VS low/medium (9/15 %) risk tertiles ( P < .001), independently of the risk score used . The ACEF score has similar accuracy as the validated PARIS score for the estimation of ischemic/bleeding risk. Thereby, we strongly suggest its use in clinical practice to risk-stratify ACS patients and select optimal therapeutic strategies., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Some previous observations suggest that a low platelet count is associated with an increased risk of adverse outcomes in patients with acute coronary syndromes (ACS). However, most of the data come from post-hoc analyses of randomized controlled trials and from studies including thrombocytopenia developed during hospital stay. Our aim was to assess the impact of low platelet count at admission on cardiovascular outcomes and treatment approach in patients hospitalized for ACS in a current real-life setting in Italy. Patients admitted to Italian coronary care units for ACS were enrolled in the START-ANTIPLATELET registry. Baseline clinical characteristics and treatment at discharge were recorded. Patients were followed-up at 6 months, 1 year and yearly thereafter. Low platelet count was defined as a count at admission < 150 > 100 k/µl or < 100 k/µL. Among 1894 enrolled patients, 157 (8.3%) had a platelet count < 150 > 100 k/µl and 30 (1.6%) < 100 k/µl. The median follow-up was 12.3 months (0.4-50.1). patients with low platelets were older (72 ± 10.4 vs 66 ± 12.4 years, p = 0.006), more frequently males (82.9 vs 72.1%, p = 0.001), hypertensive (90.0% vs 70.4%, p = 0.03), with non-valvular atrial fibrillation (NVAF) (17.1 vs 8.6%, p = 0.02), and peripheral arterial disease (11.5 vs 6.2% p = 0.01) and/or had a previous myocardial infarction (40 vs 18.7%, p = 0.008) and/or a PCI (14.6 vs 7.8%, p = 0.001) than patients with normal platelets. A slightly, but significantly, lower percentage of thrombocytopenic patients were treated with primary PCI (78.1 vs 84.4%, p = 0.04) and they were more frequently discharged on aspirin plus clopidogrel rather than aspirin plus newer P2Y 12 antagonists (51.9 vs 65.4%, p = 0.01). MACE-free survival was significantly shorter in thrombocytopenic patients compared to patients with normal platelets (< 150 > 100 k/µl: 37.6 vs 41.8 months, p = 0.002; HR = 2.7, 95% CIs 1.4-5.2; < 100 k/µl: 31.7 vs 41.8 months, p = 0.01; HR = 6.5, 95% CIs 1.5-29.1). At multivariate analysis, low platelet count, age at enrollment, low glomerular filtration rate, low ejection fraction, a previous ischemic stroke and NVAF were independent predictors of MACE. A low platelet count at admission identifies a subgroup of ACS patients with a significantly increased risk of MACE and these patients should be managed with special care to prevent excess adverse outcomes., (© 2024. The Author(s).)

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., Competing Interests: Declaration of competing interest BC declares speakers' fees from Techdow and from Werfen; all other authors declare no competing financial interests., (Copyright © 2024. Published by Elsevier Ltd.)

Abstract: Antiprothrombin antibodies are found in antiphospholipid patients, but how they interact with prothrombin remains elusive. Prothrombin adopts closed and open forms. We recently discovered type I and type II antibodies and proposed that type I recognizes the open form. In this study, we report the discovery and structural and functional characterization in human plasma of a type I antibody, POmAb (prothrombin open monoclonal antibody). Using surface plasmon resonance and single-molecule spectroscopy, we show that POmAb interacts with kringle-1 of prothrombin, shifting the equilibrium toward the open form. Using single-particle cryogenic electron microscopy (cryo-EM), we establish that the epitope targeted by POmAb is in kringle-1, comprising an extended binding interface centered at residues R90-Y93. The 3.2-Å cryo-EM structure of the complex reveals that the epitope overlaps with the position occupied by the protease domain of prothrombin in the closed state, explaining the exclusive binding of POmAb to the open form. In human plasma, POmAb prolongs phospholipid-initiated and diluted Russell's viper venom clotting time, which could be partly rescued by excess phospholipids, indicating POmAb is an anticoagulant but exerts a weak lupus anticoagulant effect. These studies reveal the structural basis of prothrombin recognition by a type I antiphospholipid antibody and uncover an exciting new strategy to achieve anticoagulation in human plasma., (© 2024 American Society of Hematology. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)

Objectives: Thrombosis in antiphospholipid syndrome (APS) involves in most cases the venous circulation . Why in some patients thrombotic APS affects the arterial circulation and in particular cerebral circulation is unknown. In previous studies, both patient characteristics and antiphospholipid antibody types and titers have been associated with arterial thrombosis. Aim of this study was to compare the clinical characteristics and laboratory findings of venous and arterial thrombotic APS from a large series of patients., Methods: Data were retrieved from the Start 2 antiphospholipid, a multicenter prospective register of long-term collected data from Thrombosis Centers in Italy., Results: Of 167 patients with thrombotic APS, 114 (68 %) had a venous and 53 (32 %) had an arterial event as first clinical manifestation. Several clinical characteristics and risk factors were different among groups in univariate analysis. Using logistic regression analysis, reduced creatinine clearance and hyperlipidemia were independent variable for the occurrence of arterial APS. Notably, no difference in antiphospholipid antibody profiles and aβ2-Glycoprotein I levels were found between groups. A higher adjusted global antiphospholipid syndrome score (aGAPSS) was found in arterial group indicating a possible high recurrence rate in arterial APS., Conclusions: These data have pathophysiological and clinical implication since associated conditions might predispose patients to arterial rather than venous events and call to a close monitoring and treatment of arterial APS due to their increased tendency to recurrence., (© 2024 the author(s), published by De Gruyter, Berlin/Boston.)

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., Competing Interests: Declaration of competing interest Authors had no conflict of interest to declare., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Direct oral anticoagulants (DOACs) are recommended for stroke prevention in non-valvular atrial fibrillation (NVAF) patients. We aimed to describe the prevalence of inappropriate DOACs dose prescription in the START2-AF Registry, the outcomes according to the appropriateness of the dosage, and the factors associated with inappropriate dose prescription. Methods: Patients' demographics and clinical data were prospectively collected as electronic files in an anonymous form on the website of the START2-Registry; DOACs dosage was determined to be appropriate when prescribed according to the European Heart Rhythm Association Guidelines. Results: We included 5943 NVAF patients on DOACs; 2572 (46.3%) were female patients. The standard dose (SD) was prescribed to 56.9% of patients and the low dose (LD) was prescribed to 43.1% of patients; 38.9% of all NVAF patients received an inappropriate LD DOAC and 0.3% received inappropriate SD. Patients treated with LD DOAC had a significantly higher rate of all bleedings (RR 1.5; 95% CI 1.2-2.0), major bleedings (RR 1.8; 95% CI 1.3-1.7), and mortality (RR 2.8; 95% CI 1.9-4.1) with respect to patients treated with SD DOAC. No difference was found among patients treated with appropriate and inappropriate LD regarding bleeding, thrombotic, and mortality rates. Age, body weight <60 kg, and renal failure were significantly associated with inappropriate LD DOAC prescription. Conclusions: Inappropriate LD DOACs in NVAF patients is not associated with a reduction in bleeding risk, nor with an increased thrombotic risk. Instead, it is associated with higher mortality rate, suggesting that, in clinical practice, underdosing is preferred for patients at particularly high risk for adverse events.

Objectives: Our primary objective was to quantify damage burden measured by Damage Index for Antiphospholipid Syndrome (DIAPS) in aPL-positive patients with or without a history of thrombosis in an international cohort (the APS ACTION cohort). Secondly, we aimed to identify clinical and laboratory characteristics associated with damage in aPL-positive patients., Methods: In this cross-sectional study, we analysed the baseline damage in aPL-positive patients with or without APS classification. We excluded patients with other autoimmune diseases. We analysed the demographic, clinical and laboratory characteristics based on two subgroups: (i) thrombotic APS patients with high vs low damage; and (ii) non-thrombotic aPL-positive patients with vs without damage., Results: Of the 826 aPL-positive patients included in the registry as of April 2020, 586 with no other systemic autoimmune diseases were included in the analysis (412 thrombotic and 174 non-thrombotic). In the thrombotic group, hyperlipidaemia (odds ratio [OR] 1.82; 95% CI 1.05, 3.15; adjusted P = 0.032), obesity (OR 2.14; 95% CI 1.23, 3.71; adjusted P = 0.007), aβ2GPI high titres (OR 2.33; 95% CI 1.36, 4.02; adjusted P = 0.002) and corticosteroid use (ever) (OR 3.73; 95% CI 1.80, 7.75; adjusted P < 0.001) were independently associated with high damage at baseline. In the non-thrombotic group, hypertension (OR 4.55; 95% CI 1.82, 11.35; adjusted P = 0.001) and hyperlipidaemia (OR 4.32; 95% CI 1.37, 13.65; adjusted P = 0.013) were independent predictors of damage at baseline; conversely, single aPL positivity was inversely correlated with damage (OR 0.24; 95% CI 0.075, 0.77; adjusted P = 0.016)., Conclusions: DIAPS indicates substantial damage in aPL-positive patients in the APS ACTION cohort. Selected traditional cardiovascular risk factors, steroids use and specific aPL profiles may help to identify patients more prone to present with a higher damage burden., (© The Author(s) 2023. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Unprovoked thrombosis (thrombosis occurring without an established environmental factor favouring the episode) is a classic feature of APS. In the general population, provoked venous thromboembolism (VTE) is clearly defined and has clinical and therapeutic differences compared with unprovoked VTE. Whether provoked VTE in the context of APS may lead to a limited treatment duration is not well established. Therefore, careful clinical and laboratory evaluation is needed to identify patients eligible for a limited duration of anticoagulation treatment after provoked VTE. Given the uncertainties of available data, the risks and benefits of treatment decisions should be clearly explained. Decisions should be shared by both the patient and physician. Cardiovascular risk factors are common in patients with APS with arterial thrombosis. There are insufficient data suggesting that cardiovascular risk factor control would allow the cessation of anticoagulation. In most instances, arterial thrombosis will require prolonged anticoagulants. A careful analysis of clinical characteristics and laboratory evaluation, particularly the aPL antibody profile, is needed to make decisions on a case-by-case basis., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Aims: We assessed the cumulative incidence of recurrent stroke, major bleeding and all-cause mortality associated with restarting antithrombotic treatment, in patients experiencing an anticoagulation-related event (stroke or major bleeding), occurred during anticoagulation therapy for AF., Methods and Results: We performed a retrospective population-based analysis on linked claims data of patients resident in the Veneto Region, treated with DOACs for AF and discharged (2013-2020) from the hospital for stroke, intracranial haemorrhage (ICH), and major bleeding. To adjust for competing risk of death and reduce confounding, we started the follow up after a 120-days blanking period, counting events in patients resuming oral anticoagulation versus those that did not. Risks of all-cause mortality, ischemic stroke (IS)intracranial haemorrhage (ICH), and other major bleeding events (MB) were estimated with multivariable Cox proportional hazard models and propensity score to adjust for differences in baseline characteristics. Overall, 1029 patients (mean age 77 years) were included in the final cohort: 23% experienced an IS, 18% an ICH, and 59% MB. Of these, 77% resumed anticoagulation. The cumulative incidence of events was significantly lower in patients resuming therapy. In the multivariable analysis considering age, sex and propensity score as covariates, resumption of anticoagulation significantly reduced the risk of a cumulative event (HR 0.45, 95%CI 0.35-0.57, p < 0.01). Stratifying for the index event, among patients with IS (92% resumed therapy), we observed a risk reduction of 81%; in patients with ICH (64% resumed therapy), we observed a risk reduction of 64% and for patients with MB (76% resuming therapy), we observed a risk reduction of 49%., Conclusions: In patients with AF who experienced an anticoagulation-related event, resuming oral anticoagulation was associated with better outcomes for all-cause mortality and subsequent events as compared with patients who did not resume treatment., Competing Interests: Conflict of interest None to declare. Authorship: VP and GD made substantial contributions to the conception and design of the study. NG, EF and MZ contributed to acquisition and interpretation of data; VP and GD made the first draft and NG, EF and MZ revised it critically; all authors gave final approval of the version to be published; authors agreed to be accountable for all aspects of the work., (Copyright © 2023. Published by Elsevier B.V.)

Unprovoked (or provoked by mild risk factors) venous thromboembolism (VTE) in young patients, VTE in uncommon sites, or cases of unexplained VTE recurrence may be positive for antiphospholipid antibodies (aPL) and thus may be diagnosed with antiphospholipid syndrome (APS). The evaluation of aPL is standardized using immunological tests for anticardiolipin and anti-β2-glycoprotein I. The determination of functional antibodies (lupus anticoagulant) is less standardized, especially in patients on anticoagulant treatment. Patients positive for all the three tests are at high risk of recurrence, which, in turn, might lead to chronic obstruction of pulmonary vessels (chronic thromboembolic pulmonary hypertension). Randomized clinical trials have shown that triple-positive patients should be treated with vitamin K antagonists maintaining an international normalized ratio between 2 and 3. Whether patients with VTE and incomplete aPL profile can be treated with direct oral anticoagulants should be further investigated., Competing Interests: None declared., (Thieme. All rights reserved.)

Background: Most of the carriers/patients triple-positive for antiphospholipid antibodies (lupus anticoagulant [LAC], immunoglobulin G [IgG]/immunoglobulin M [IgM] anticardiolipin, and anti-β2-glycoprotein I antibodies) are tetra-positive, being positive for antiphosphatidylserine/prothrombin (aPS/PT) antibodies. The relationship between aPS/PT titer, LAC potency, and resistance to activated protein C (aPC-R) has not been investigated., Objectives: The aim of this study was to clarify the mutual interdependence of these parameters in tetra-positive subjects., Methods: Twenty-three carriers and 30 patients with antiphospholipid syndrome, none of whom were being treated with anticoagulants, and 30 age- and sex-matched controls were studied. Detection of aPS/PT, LAC, and aPC-R in each individual was performed with established methods in our laboratory. Carriers and patients were positive for IgG or IgM aPS/PT or for both isotypes without significant difference. Since both IgG and IgM aPS/PT have anticoagulant activity, we used the sum of their titers (total aPS/PT) for the correlation studies., Results: Total aPS/PT in all individuals studied exceeded that in controls. There was no difference in total aPS/PT titers (P = .72), LAC potency (P = .56), and aPC-R (P = .82) between antiphospholipid antibody-carriers and patients with antiphospholipid syndrome. There was a significant correlation between total aPS/PT and LAC potency (r = 0.78; P < .0001) and between total aPS/PT titers and aPC-R (r = 0.80; P < .0001). LAC potency also was correlated significantly with aPC-R (r = 0.72; P < .0001)., Conclusion: This study shows that there is interdependence between aPS/PT, LAC potency, and aPC-R., Competing Interests: Declaration of competing interests V.P. received lecture fees from Werfen Group. The other authors have no competing interests to disclose., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: To develop new antiphospholipid syndrome (APS) classification criteria with high specificity for use in observational studies and trials, jointly supported by the American College of Rheumatology (ACR) and EULAR., Methods: This international multidisciplinary initiative included 4 phases: 1) Phase I, criteria generation by surveys and literature review; 2) Phase II, criteria reduction by modified Delphi and nominal group technique exercises; 3) Phase III, criteria definition, further reduction with the guidance of real-world patient scenarios, and weighting via consensus-based multicriteria decision analysis, and threshold identification; and 4) Phase IV, validation using independent adjudicators' consensus as the gold standard., Results: The 2023 ACR/EULAR APS classification criteria include an entry criterion of at least one positive antiphospholipid antibody (aPL) test within 3 years of identification of an aPL-associated clinical criterion, followed by additive weighted criteria (score range 1-7 points each) clustered into 6 clinical domains (macrovascular venous thromboembolism, macrovascular arterial thrombosis, microvascular, obstetric, cardiac valve, and hematologic) and 2 laboratory domains (lupus anticoagulant functional coagulation assays, and solid-phase enzyme-linked immunosorbent assays for IgG/IgM anticardiolipin and/or IgG/IgM anti-β 2 -glycoprotein I antibodies). Patients accumulating at least 3 points each from the clinical and laboratory domains are classified as having APS. In the validation cohort, the new APS criteria versus the 2006 revised Sapporo classification criteria had a specificity of 99% versus 86%, and a sensitivity of 84% versus 99%., Conclusion: These new ACR/EULAR APS classification criteria were developed using rigorous methodology with multidisciplinary international input. Hierarchically clustered, weighted, and risk-stratified criteria reflect the current thinking about APS, providing high specificity and a strong foundation for future APS research., (© 2023 American College of Rheumatology.)

Objective: To develop new antiphospholipid syndrome (APS) classification criteria with high specificity for use in observational studies and trials, jointly supported by the American College of Rheumatology (ACR) and EULAR., Methods: This international multidisciplinary initiative included four phases: (1) Phase I, criteria generation by surveys and literature review; (2) Phase II, criteria reduction by modified Delphi and nominal group technique exercises; (3) Phase III, criteria definition, further reduction with the guidance of real-world patient scenarios, and weighting via consensus-based multicriteria decision analysis, and threshold identification; and (4) Phase IV, validation using independent adjudicators' consensus as the gold standard., Results: The 2023 ACR/EULAR APS classification criteria include an entry criterion of at least one positive antiphospholipid antibody (aPL) test within 3 years of identification of an aPL-associated clinical criterion, followed by additive weighted criteria (score range 1-7 points each) clustered into six clinical domains (macrovascular venous thromboembolism, macrovascular arterial thrombosis, microvascular, obstetric, cardiac valve, and hematologic) and two laboratory domains (lupus anticoagulant functional coagulation assays, and solid-phase enzyme-linked immunosorbent assays for IgG/IgM anticardiolipin and/or IgG/IgM anti-β 2 -glycoprotein I antibodies). Patients accumulating at least three points each from the clinical and laboratory domains are classified as having APS. In the validation cohort, the new APS criteria vs the 2006 revised Sapporo classification criteria had a specificity of 99% vs 86%, and a sensitivity of 84% vs 99%., Conclusion: These new ACR/EULAR APS classification criteria were developed using rigorous methodology with multidisciplinary international input. Hierarchically clustered, weighted, and risk-stratified criteria reflect the current thinking about APS, providing high specificity and a strong foundation for future APS research., Competing Interests: Competing interests: RAL is an employee of GlaxoSmithKline., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Age and frailty are associated with underuse of anticoagulation in elderly patients with atrial fibrillation (AF)., Objectives: This study aimed at assessing major clinical outcomes in very elderly patients with AF treated with recommended dose edoxaban and look for a possible relation with frailty measured by a validated score., Methods: This prospective multicenter cohort study enrolled consecutive very elderly (age ≥80 years) anticoagulation-naïve patients starting recommended doses of edoxaban. Upon entry into the study, patients were categorized into nonfrail, prefrail and frail with the SHARE-FI (Survey of Health, Ageing, and Retirement in Europe-Frailty Index) score. The primary outcome was a composite incidence of stroke/systemic embolism, major bleeding, clinically relevant nonmajor bleeding, and death between frail and fitter patients over 2 years follow-up. Secondary outcomes were frailty-related incidence of the individual components part of the composite outcome., Results: Of the 180 screened patients, 176 were enrolled in the study. Of these, 58 (32.9%) were frail, 35 (19.8%) prefrail, and 83 (47.2%) nonfrail. The composite outcome occurred in 49 patients (18.9% per patient-year). No difference in the primary endpoint between frail and fitter patients (incidence rate ratio: 1.2; 95% CI: 0.6-2.2) was observed. On multivariable analysis, anemia was significantly related to the primary outcome (HR: 3.6; 95% CI: 1.8-7.3; P  < 0.001), while frailty was not (frail vs nonfrail HR: 0.9; 95% CI: 0.5-1.8). No difference across frailty categories of the individual components of composite events was observed, except for death., Conclusions: Anticoagulation with recommended dose edoxaban is feasible in very elderly patients with AF even if frail. (ESCAPE [Edoxaban and Frailty in Senior Individuals]; NCT03524924)., Competing Interests: Nonconditional support from Daiichi Sankyo Italy was received. The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (© 2023 The Authors.)

Objective: This study aimed to elucidate the presence, antigen specificities, and potential clinical associations of anti-neutrophil extracellular trap (anti-NET) antibodies in a multinational cohort of antiphospholipid (aPL) antibody-positive patients who did not have lupus., Methods: Anti-NET IgG/IgM levels were measured in serum samples from 389 aPL-positive patients; 308 patients met the classification criteria for antiphospholipid syndrome. Multivariate logistic regression with best variable model selection was used to determine clinical associations. For a subset of the patients (n = 214), we profiled autoantibodies using an autoantigen microarray platform., Results: We found elevated levels of anti-NET IgG and/or IgM in 45% of the aPL-positive patients. High anti-NET antibody levels are associated with more circulating myeloperoxidase (MPO)-DNA complexes, which are a biomarker of NETs. When considering clinical manifestations, positive anti-NET IgG was associated with lesions affecting the white matter of the brain, even after adjusting for demographic variables and aPL profiles. Anti-NET IgM tracked with complement consumption after controlling for aPL profiles; furthermore, patient serum samples containing high levels of anti-NET IgM efficiently deposited complement C3d on NETs. As determined by autoantigen microarray, positive testing for anti-NET IgG was significantly associated with several autoantibodies, including those recognizing citrullinated histones, heparan sulfate proteoglycan, laminin, MPO-DNA complexes, and nucleosomes. Anti-NET IgM positivity was associated with autoantibodies targeting single-stranded DNA, double-stranded DNA, and proliferating cell nuclear antigen., Conclusion: These data reveal high levels of anti-NET antibodies in 45% of aPL-positive patients, where they potentially activate the complement cascade. While anti-NET IgM may especially recognize DNA in NETs, anti-NET IgG species appear to be more likely to target NET-associated protein antigens., (© 2023 The Authors. Arthritis & Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)

Competing Interests: None declared.

Objective: The present study was undertaken to longitudinally evaluate titers of antibodies against β 2 -glycoprotein I (anti-β 2 GPI) and domain 1 (anti-D1), to identify predictors of variations in anti-β 2 GPI and anti-D1 titers, and to clarify whether antibody titer fluctuations predict thrombosis in a large international cohort of patients who were persistently positive for antiphospholipid antibodies (aPL) in the APS ACTION Registry., Methods: Patients with available blood samples from at least 4 time points (at baseline [year 1] and at years 2-4 of follow-up) were included. Detection of anti-β 2 GPI and anti-D1 IgG antibodies was performed using chemiluminescence (BIO-FLASH; INOVA Diagnostics)., Results: Among 230 patients in the study cohort, anti-D1 and anti-β 2 GPI titers decreased significantly over time (P < 0.0001 and P = 0.010, respectively). After adjustment for age, sex, and number of positive aPL tests, we found that the fluctuations in anti-D1 and anti-β 2 GPI titer levels were associated with treatment with hydroxychloroquine (HCQ) at each time point. Treatment with HCQ, but not immunosuppressive agents, was associated with 1.3-fold and 1.4-fold decreases in anti-D1 and anti-β 2 GPI titers, respectively. Incident vascular events were associated with 1.9-fold and 2.1-fold increases in anti-D1 and anti-β 2 GPI titers, respectively. Anti-D1 and anti-β 2 GPI titers at the time of thrombosis were lower compared to titers at other time points. A 1.6-fold decrease in anti-D1 titers and a 2-fold decrease in anti-β 2 GPI titers conferred odds ratios for incident thrombosis of 6.0 (95% confidence interval [95% CI] 0.62-59.3) and 9.4 (95% CI 1.1-80.2), respectively., Conclusion: Treatment with HCQ and incident vascular events in aPL-positive patients predicted significant anti-D1 and anti-β 2 GPI titer fluctuations over time. Both anti-D1 and anti-β 2 GPI titers decreased around the time of thrombosis, with potential clinical relevance., (© 2023 The Authors. Arthritis & Rheumatology published by Wiley Periodicals LLC on behalf of American College of Rheumatology.)

Several antiphospholipid antibody (aPL) profiles ("triple" and lupus anticoagulant [LA] positivity) are associated with a higher risk for clinical manifestations of antiphospholipid syndrome (APS). Further risk is correlated with higher levels of anticardiolipin antibody (aCL) and anti-β 2 glycoprotein-I antibody (aβ 2 GPI), and with aPL persistence. Given that the 3 aPL tests detect partially overlapping sets of antibodies, the primary goal of this study was to characterize the associations among aPL tests using AntiPhospholipid Syndrome Alliance for Clinical Trials and InternatiOnal Networking (APS ACTION) core laboratory data. The APS ACTION Registry includes annually followed adult patients with positive aPL based on the Revised Sapporo Classification Criteria. We analyzed baseline and prospective core laboratory data of the registry for associations among aPL tests using the Spearman rank correlation with Bonferroni-adjusted significance level for multiple comparisons. An aPL Load was calculated based on 6 tests (aCL IgG/IgM/IgA and aβ 2 GPI IgG/IgM/IgA); a receiver operating characteristic curve was used to evaluate the diagnostic performance of the aPL Load in predicting LA positivity. In 351 patients simultaneously tested for LA, aCL, and aβ 2 GPI, the frequency of moderate-to-high (≥40 U) titers of aCL and aβ 2 GPI IgG/IgM/IgA was higher in patients who were positive for LA vs those who were negative. An aPL Load was calculated for each patient to assess the overall aPL burden. For every 1-point increase in the aPL Load, the possibility of a positive LA test increased by 32% (odds ratio, 1.32; 95% CI, 1.2-1.5; P < .001). Based on core laboratory data from a large international registry, most aPL enzyme-linked immunosorbent assay ≥40 U and a high calculated aPL Load combining 6 aPL enzyme-linked immunosorbent assays were predictive of a positive LA. These data suggest that the combined quantitative burden of aPL may provide a mechanistic explanation of a positive LA., (Copyright © 2023 United States & Canadian Academy of Pathology. Published by Elsevier Inc. All rights reserved.)

Introduction: Although much progress has been made using anticoagulation for stroke prevention in patients with non-valvular atrial fibrillation, bleeding is still a major concern., Areas Covered: This article reviews current pharmacotherapeutic options in this setting. Particular emphasis is placed on the ability of the new molecules to minimize the bleeding risk in elderly patients. A systematic search of PubMed, Web of Science, and the Cochrane Library up to March 2023 was carried out., Expert Opinion: Contact phase of coagulation is a possible new target for anticoagulant therapy. Indeed, congenital or acquired deficiency of contact phase factors is associated with reduced thrombotic burden and limited risk of spontaneous bleeding. These new drugs seem particularly suitable for stroke prevention in elderly patients with non-valvular atrial fibrillation in whom the hemorrhagic risk is high. Most of anti Factor XI (FXI) drugs are for parenteral use only. A group of small molecules are for oral use and therefore are candidates to substitute direct oral anticoagulants (DOACs) for stroke prevention in elderly patients with atrial fibrillation. Doubts remain on the possibility of impaired hemostasis. Indeed, a fine calibration of inhibition of contact phase factors is crucial for an effective and safe treatment.

Acquired thrombophilia and in particular the presence of antiphospholipid antibodies (aPL) may play an important role in the development of chronic thromboembolic pulmonary hypertension (CTEPH). Young patients suffering from an episode of unprovoked pulmonary embolism (PE), or PE provoked by mild risk factors, should be tested for aPL. In case of a positive result, they should be closely followed up and lifelong anticoagulant treatment should be considered. Indeed, aPL-induced thrombophilia may favor PE recurrence with the consequence of possible CTEPH development. The aPL profiles play an important role in this pathway. Patients with PE and triple positivity (lupus anticoagulant, LAC, anti-cardiolipin, aCL, and anti-β2-glycoprotein I, aβ2GPI) are at the highest risk of recurrence and deserve maximum protection by anticoagulant treatment with warfarin., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2023 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.)

Introduction: Variable D-dimer trends during hospitalization reportedly result in distinct in-hospital mortality. In this multinational case series from the first and second waves, we show the universality of such D-dimer trends., Methods: We reviewed 405 patients with COVID-19 during the first wave admitted to three institutions in the United States, Italy, and Colombia, and 111 patients admitted to the U.S. site during the second wave and 55 patients during the third wave. D-dimer was serially followed during hospitalization., Results: During the first wave, 66 (15%) patients had a persistently-low pattern, 33 (8%) had early-peaking, 70 (16%) had mid-peaking, 94 (22%) had fluctuating, 30 (7%) had late-peaking, and 112 (26%) had a persistently-high pattern. During the second and third waves, similar patterns were observed. D-dimer patterns were significantly different in terms of in-hospital mortality similarly in all waves. Patterns were then classified into low-risk patterns (persistently-low and early-peaking), where no deaths were observed in both waves, high-risk patterns (mid-peaking and fluctuating), and malignant patterns (late-peaking and persistently-high). Overall, D-dimer trends were associated with an increased risk for in-hospital mortality in the first wave (overall: HR: 1.73) and stayed the same during the second (HR: 1.67, p < 0.001) and the third (HR: 4.4, p = 0.001) waves., Conclusion: D-dimer behavior during COVID-19 hospitalization yielded universal categories with distinct mortality risks that persisted throughout all studied waves of infection. Monitoring D-dimer behavior may be useful in the management of these patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Ronderos Botero, Omar, Pengo, Haider, Latif, Parati, Pengo, Cañas Arboleda, Díaz, Villaquirán-Torres, Contreras and Chilimuri.)

Background: The efficacy and safety of direct oral anticoagulants (DOACs) for patients with thrombotic antiphospholipid syndrome remain controversial., Objectives: The authors performed a systematic review and meta-analysis of randomized controlled trials that compared DOACs with vitamin K antagonists (VKAs)., Methods: We searched PubMed, EMBASE, and Cochrane Central Register of Controlled Trials through April 9, 2022. The 2 main efficacy outcomes were a composite of arterial thrombotic events and venous thromboembolic events (VTEs). The main safety outcome was major bleeding. Random effects models with inverse variance were used., Results: Our search retrieved 253 studies. Four open-label randomized controlled trials involving 472 patients were included (mean control-arm time-in-therapeutic-range 60%). All had proper random sequence generation and adequate allocation concealment. Overall, the use of DOACs compared with VKAs was associated with increased odds of subsequent arterial thrombotic events (OR: 5.43; 95% CI: 1.87-15.75; P < 0.001, I 2  = 0%), especially stroke, and the composite of arterial thrombotic events or VTE (OR: 4.46; 95% CI: 1.12-17.84; P = 0.03, I 2  = 0%). The odds of subsequent VTE (OR: 1.20; 95% CI: 0.31-4.55; P = 0.79, I 2  = 0%), or major bleeding (OR: 1.02; 95% CI: 0.42-2.47; P = 0.97; I 2  = 0%) were not significantly different between the 2 groups. Most findings were consistent within subgroups., Conclusions: Patients with thrombotic antiphospholipid syndrome randomized to DOACs compared with VKAs appear to have increased risk for arterial thrombosis. No significant differences were observed between patients randomized to DOACs vs VKAs in the risk of subsequent VTE or major bleeding., Competing Interests: Funding Support and Author Disclosures Dr Piazza has received research support from Bristol Myers Squibb/Pfizer Alliance, Bayer, Janssen, Alexion, Amgen, and Boston Scientific Corporation; and has received consulting fees from Bristol Myers Squibb/Pfizer Alliance, Boston Scientific Corporation, Janssen, Namsa, Prairie Education and Research Cooperative, Boston Clinical Research Institute, and Amgen. Dr Jiménez has received research support from Daiichi-Sankyo and Sanofi; and has received consulting fees from Bristol Myers Squibb/Pfizer Alliance, Daiichi-Sankyo, Leo Pharma, Rovi, and Sanofi. Dr Monreal has received research support from Sanofi, Leo, and Rovi; and has received consulting fees from Sanofi. Dr Pengo has received lecture fees from Werfen Group. Dr Cortes-Hernandez has received institutional research funding from Bayer Hispania to conduct the APS RCT. Dr Connors has received research funding to her institution from CSL Behring; has received consulting fees from Abbott; has received honoraria for lectures from Bristol Myers Squibb, Roche, and Sanofi; and has participated on the advisory board of Abbott, Alnylam, Anthos, Bristol Myers Squibb, Sanofi, and Takeda, outside of the submitted work. Dr Kanthi is an inventor on a pending patent application by the University of Michigan on the use of biogases in vascular disease (US202201670756A1); and is supported by the National Heart, Lung, and Blood Institute Intramural Research Program and the Lasker Foundation. Dr Krumholz has received (within the last 3 years) expenses and/or personal fees from UnitedHealth, Element Science, Aetna, Reality Labs, Tesseract/4Catalyst, F-Prime, the Siegfried and Jensen Law Firm, the Arnold and Porter Law Firm, and the Martin/Baughman Law Firm; is a cofounder of Refactor Health, an enterprise health care artificial intelligence–augmented data management company, and HugoHealth, a personal health information platform; and is associated with contracts through Yale University from Johnson and Johnson. Dr Middeldorp has received grants and personal fees from Daiichi-Sankyo; has received grants and personal fees from Bayer, Pfizer, and Boehringer Ingelheim; and has received personal fees from Portola/Alexion, Abbvie, Bristol Myers Squibb Pfizer, Norgine, and Viatris, all paid to her institution. Dr Falanga has received honoraria/consulting fees from Stago, Sanofi, Daiichi-Sankyo, Leo Pharma, and Pfizer. Dr Goldhaber has received research support from Bayer, Bristol Myers Squibb, Boston Scientific BTG EKOS, Janssen, National Heart, Lung, and Blood Institute, and Pfizer; and has received consulting fees from Agile, Bayer, and Pfizer. Dr Bikdeli is a consulting expert, on behalf of the plaintiff, for litigation related to 2 specific brand models of IVC filters; and is supported by the Scott Schoen and Nancy Adams IGNITE Award from the Mary Horrigan Connors Center for Women's Health and Gender Biology at Brigham and Women's Hospital and a Career Development Award from the American Heart Association and VIVA Physicians (#938814). All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. All rights reserved.)

Antiphospholipid syndrome (APS) is an autoimmune condition characterized by thrombosis (arterial, venous, and microvascular) and/or pregnancy morbidity occurring in subjects persistently positive for antiphospholipid antibodies (aPL). While the APS classification criteria are being currently updated to improve homogeneity in clinical research, patients who seek medical treatment often have a variety of laboratory and clinical characteristics that may not completely fulfill the classification criteria for overt APS. Those cases might represent a challenge in terms of treatment and overall management. We aim to present a collection of challenging scenarios of patients who tested positive for aPL and to discuss available literature to guide the therapeutic strategies., Competing Interests: Declaration of Competing Interest The authors declare they have no conflict of interest., (Copyright © 2022 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.)

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., (© 2022 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Background/purpose: APS ACTION Registry was created to study the outcomes of patients with persistently positive antiphospholipid antibodies (aPL) with or without other systemic autoimmune disease (SAIDx). Given that immunosuppression (IS) is used for certain aPL manifestations, for example, thrombocytopenia (TP), our primary objective was to describe the indications for IS in aPL-positive patients without other SAIDx. Secondly, we report the type of IS used in patients with selected microvascular or non-thrombotic aPL manifestations., Methods: An online database is used to collect clinical data. The inclusion criteria are positive aPL based on the laboratory section of the APS Classification Criteria, tested at least twice within one year prior to enrollment. Patients are followed every 12 ± 3 months. For this descriptive retrospective and prospective analysis, we included aPL-positive patients without other SAIDx and excluded those with new SAIDx classification during follow-up. For each patient, we retrieved clinical data at baseline and follow-up including selected aPL manifestations (diffuse alveolar hemorrhage [DAH], antiphospholipid-nephropathy [aPL-N], livedoid vasculopathy [LV]-related skin ulcers, TP, autoimmune hemolytic anemia [AIHA], cardiac valve disease [VD]), and IS medications., Results: Of 899 patients enrolled, 537 were included in this analysis (mean age 45 ± 13 years, female 377 [70%], APS Classification in 438 [82%], and at least one selected microvascular or non-thrombotic aPL manifestation in 141 (26%)). Of 537 patients, 76 (14%) were reported to use IS (ever), and 41/76 (54%) received IS primarily for selected aPL manifestation. In six of 8 (75%) DAH patients, 6/19 (32%) aPL-N, 4/28 (14%) LV, 25/88 (28%) TP, 6/11 (55%) AIHA, and 1/43 (2%) VD, the IS (excluding corticosteroids/hydroxychloroquine) indication was specific for selected aPL manifestation., Conclusion: In our international cohort, 14% of aPL-positive patients without other SAIDx were reported to receive IS; the indication was at least one of the selected microvascular and/or non-thrombotic aPL-related manifestations in half. Thrombocytopenia was the most frequent among those selected aPL-related manifestations; however, approximately one-third received IS specifically for that indication. Diffuse alveolar hemorrhage was frequently treated with IS followed by AIHA and aPL-N. Systematic controlled studies are urgently needed to better define the role of IS in APS.

Thrombotic antiphospholipid syndrome (APS) is a condition in which thrombosis in venous, arterial, and/or small vessels is ascribed to the presence of antiphospholipid antibodies (aPL). Among the various proposed pathogenic theories to explain thrombotic APS, those involving the interaction between aPL and the protein C system have gained much consensus. Indeed, robust data show an acquired activated protein C resistance (APC-R) in these patients. The role of aPL in this impairment is clear, but the mechanism of action is uncertain, as the type of aPL and to what extent aPL are involved remains a gray area. Lupus anticoagulant (LA) is often associated with APC-R, but antibodies generating LA comprise those directed to β2-glycoprotein I and antiphosphatidylserine/prothrombin. Moreover, the induction of APC-R by aPL requires the presence of phospholipids and is suppressed by the presence of an excess of phospholipids. How phospholipids exposed on the cell membranes work in the system in vivo is unknown. Interestingly, acquired APC-R due to aPL might explain the clinical phenotypes of thrombotic APS. Indeed, the literature reports cases of both venous and arterial thromboembolism as well as skin necrosis, the latter observed in the severe form of protein C deficiency and in catastrophic APS., Competing Interests: None declared., (Thieme. All rights reserved.)

Objectives: Studies on microparticles (MPs) in patients with antiphospholipid antibodies (aPL) are sparse and inconclusive. The relation between MPs and different aPL antibody profiles has never been tested. We evaluated the presence of platelet and endothelial microparticles in patients positive for IgG anti-β2-glycoprotein I (aβ2GPI) antibodies according to triple, double and single positive aPL profiles., Methods: Megamix (Biocytex) was used to set up the MPs gating according to the datasheet. Markers of Platelet Microparticles (PMPs) were CD41a-PE and annexin-V-FITC that was used to determine phosphatidylserine (PS) exposure. CD144-FITC was used as a marker of Endothelial Microparticles (EMPs)., Results: The number of total MPs and EMPs was significantly higher in triple positive groups with respect to single positive group and showed a significant correlation with IgG aβ2GPI titers. The number PMPs was the lowest in triple positive group and inversely correlated with IgG aβ2GPI titers., Conclusions: Elevated levels of total MPs and EMPs suggest a state of vascular activation in IgG aβ2GPI positive individuals according to the number of positive tests. PMPs may be fast cleared from circulation in high risk triple positive patients.

Background: Anti-phosphatidylserine/prothrombin (aPS/PT) antibodies are the major contributor to activated Protein C resistance (APC-R) in tetra-positive thrombotic high-risk patients with Antiphospholipid Syndrome (APS)., Objectives: To evaluate the role of phospholipids (PL) on aPS/PT mediated APC-R., Patients/methods: Total IgG were purified from plasma of 6 tetra-positive patients and IgG aPS/PT were affinity-purified from 3 of these patients. Purified material was spiked into Normal Pooled Plasma (NPP) and tested for APC-R in thrombin generation assay and in Factor Va inactivation assay using increasing amounts of phospholipids., Results and Conclusions: Total IgG showed APC-R at low PL concentration (1.5 μg/mL) that disappeared at increasing PL concentrations (5.8, 11.6 and 46.6 μg/mL). In the same way, affinity purified aPS/PT showed a robust (59 %, 52 %, 36 %) APC-R in patients #4, #5 and #6, respectively at low PL concentration (1.5 μg/mL) that was completely reversed at higher concentration (11.6 μg/mL). The inactivation of FVa by activated Protein C (aPC) was impaired in the presence of aPS/PT at low aPL concentration and reversed by increasing amounts of PL. These data point out the relevance of PL in reversing APC-R in this 'in vitro' system. The mechanism for reversal might be explained by loss of PL availability for aPC. These results may give some insight into the pathogenesis of thrombosis or suggestions for alternative treatments., Competing Interests: Declaration of competing interest Prof. Vittorio Pengo received lecture fees from Werfen Group, Milan Italy., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Objectives: Patients with APS and triple-positive for aPL are at high risk of recurrent events. As COVID-19 and COVID-19 vaccination may induce thrombotic complications, the objective of the study was to assess the course of COVID-19 and adverse events after vaccination in these patients., Methods: This is a nationwide multicentre survey conducted in nine APS referral centres by means of a questionnaire. Included patients are thrombotic APS with triple-positive aPL confirmed 12 weeks apart. Reference specialist physicians used a four-graded scale of severity for COVID-19 [from 0 (asymptomatic) to 3 (hospitalization in intensive care unit)] and a six-graded scale for adverse reactions to vaccination [from 0 (transient local injection site sign/symptoms) to 5 (potentially life-threatening reactions)]. Outcomes were considered within a 30-day period., Results: Out of 161 patients interviewed, 18 (11%) had COVID-19. All of them fully recovered without any progression to severe disease nor thromboembolic event. A total of 146 patients received the first (92%) and 129 (80%) the second dose of vaccine; side effects were minimal and, in most cases (83% after the first and 68% after the second vaccination) limited to a sore arm. Fifteen patients (9%) were unvaccinated. Most of them raised doubts on the need for vaccination, complained of poor safety and in general were reluctant about COVID-19 vaccination., Conclusion: Patients with triple-positive thrombotic APS did not suffer from severe COVID-19 outcomes. Importantly, COVID-19 vaccination was well tolerated. These data may reassure patients and physicians and contribute to reducing hesitancy in unvaccinated patients., (© The Author(s) 2022. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by the presence of antiphospholipid antibodies (aPLs) and thrombotic events. The association of aPLs with thrombotic events depends on the number of positive tests. Besides the three classical tests to classify APS, phosphatidylserine/prothrombin complex autoantibodies (aPS/PT) are increasingly used to better define this condition. The aim of this systematic review was to evaluate the prevalence of aPS/PT in general and according to antiphospholipid antibody profiles in patients with APS., Methods: A systematic search of PubMed, Web of Science, and the Cochrane Library from January 1990 to September 2021 was carried out according to PRISMA guidelines. Proportions and 95% confidence intervals (CIs) were calculated using random-effects model. Publication biases were evaluated via visualization of funnel plots along with Egger's and Begg's tests., Results: Twenty-one articles about the prevalence of aPS/PT in 1853 patients with APS were deemed eligible and analyzed according to the inclusion criteria. Pooled prevalence of aPS/PT IgG alone, IgM alone, and IgG/M were 50.0%, 45.0%, and 65.0%, respectively. No significant publication bias was detected from funnel plots or Egger's and Begg's tests. When the prevalence of aPS/PT was calculated in homogeneous aPLs, a much higher rate of pooled prevalence of aPS/PT IgG/M in patients positive for Lupus Anticoagulant (84.5%) and in those with triple positivity (83.4%) was found., Conclusions: These data show a high rate of aPS/PT positivity in patients with APS (especially in those positive for LAC) but further studies are needed to ascertain whether this test might be useful in the laboratory classification criteria of APS., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Objectives: To describe the outcomes of pregnancies in antiphospholipid antibody (aPL)-positive patients since the inception of the AntiPhospholipid Syndrome Alliance for Clinical Trials and InternatiOnal Networking Registry., Methods: We identified persistently aPL-positive patients recorded as 'pregnant' during prospective follow-up, and defined 'aPL-related outcome' as a composite of: (1) Preterm live delivery (PTLD) at or before 37th week due to pre-eclampsia (PEC), eclampsia, small-for-gestational age (SGA) and/or placental insufficiency (PI); or (2) Otherwise unexplained fetal death after the 10th week of gestation. The primary objective was to describe the characteristics of patients with and without aPL-related composite outcomes based on their first observed pregnancies following registry recruitment., Results: Of the 55 first pregnancies observed after registry recruitment among nulliparous and multiparous participants, 15 (27%) resulted in early pregnancy loss <10 weeks gestation. Of the remaining 40 pregnancies: (1) 26 (65%) resulted in term live delivery (TLD), 4 (10%) in PTLD between 34.0 weeks and 36.6 weeks, 5 (12.5%) in PTLD before 34th week, and 5 (12.5%) in fetal death (two associated with genetic anomalies); and (2) The aPL-related composite outcome occurred in 9 (23%). One of 26 (4%) pregnancies with TLD, 3/4 (75%) with PTLD between 34.0 weeks and 36.6 weeks, and 3/5 (60%) with PTLD before 34th week were complicated with PEC, SGA and/or PI. Fifty of 55 (91%) pregnancies were in lupus anticoagulant positive subjects, as well as all pregnancies with aPL-related composite outcome., Conclusion: In our multicentre, international, aPL-positive cohort, of 55 first pregnancies observed prospectively, 15 (27%) were complicated by early pregnancy loss. Of the remaining 40 pregnancies, composite pregnancy morbidity was observed in 9 (23%) pregnancies., Competing Interests: Competing interests: MAP is the chair for the Belimumab Pregnancy Registry, supported by GSK. DWB is the co-principal investigator of The TNF-alpha Blockade with Certolizumab to Prevent Pregnancy Complications in High-Risk Patients with APS, supported by a grant from the NIH/NIAMS R21AR21069189-03S1. DWB is the principal investigator of The Certolizumab to Prevent Pregnancy Complications in High-Risk Patients with APS or SLE, supported by UCB Pharma Inc., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Available evidence on left atrial (LA) thrombus dissolution in patients with atrial fibrillation (AF) largely refers to the use of vitamin K antagonist oral anticoagulants (VKAs), showing >50% thrombus resolution over a 4-week to 12-month treatment period. Available data on non-vitamin K antagonist anticoagulants (NOACs) in this setting are limited and derive from isolated case reports or observational small-sized investigations with dabigatran, rivaroxaban or apixaban. The aim of this study was to investigate the extent of thrombus resolution with edoxaban therapy in patients with AF and LA thrombosis. We conducted a prospective, observational, open-label pilot study in seven Italian institutions. We included a total of 25 patients with non-valvular AF and LA (or left atrial appendage (LAA)) thrombosis, documented by transesophageal echocardiography (TEE). All patients received edoxaban OD treatment (n = 23 on 60 mg daily; n = 2 on 30 mg daily) and underwent TEE examination after 4 weeks. The primary endpoint was the percentage of patients with complete thrombus resolution by TEE imaging at 4 weeks. The mean age of the study population was 68.3 ± 10.8 years with a female population of 16%. AF was permanent in all cases, with a mean arrhythmia duration of 4.3 ± 1.7 years. CHA2DS2-VASc and HAS-BLED scores were 3.2 ± 1.5 and 1.9 ± 1.1, respectively. We were able to demonstrate a complete thrombus resolution in 14 patients (56%) at 4 weeks. In patients with residual atrial thrombosis (n = 11), we observed a 15.4 ± 14.9% reduction in the thrombus area from baseline. As compared with patients without thrombus dissolution, those with thrombus resolution had a numerically lower-indexed LA diameter (27.9 ± 9.3 vs 34.8 ± 16.1 mm/m2), a smaller maximum thrombus area at baseline (45.5 ± 44.6 vs 63.9 ± 43.5 mm2), a higher left ventricular ejection fraction (47.4 ± 21.0% vs 38.4 ± 20.6%) and higher maximum LAA flow velocities (26.3 ± 15.2 vs 19.3 ± 10.0 cm/s). Figures on the percentage of thrombus resolution in this study are comparable to those reported in the literature for the other OACs. We conclude that, in patients with AF, the use of edoxaban is associated with a >50% resolution of atrial thrombus at 4 weeks, similar to studies using VKAs and the other NOACs (ClinicalTrials.gov identifier number: NCT034899395).

Objective: To describe the baseline characteristics of patients with positivity for antiphospholipid antibodies (aPLs) who were enrolled in an international registry, the Antiphospholipid Syndrome (APS) Alliance for Clinical Trials and International Networking (APS ACTION) clinical database and repository, overall and by clinical and laboratory subtypes., Methods: The APS ACTION registry includes adults who persistently had positivity for aPLs. We evaluated baseline sociodemographic and aPL-related (APS classification criteria and "non-criteria") characteristics of patients overall and in subgroups (aPL-positive without APS, APS overall, thrombotic APS only, obstetric APS only, and both thrombotic APS/obstetric APS). We assessed baseline characteristics of patients tested for the presence of three aPLs (lupus anticoagulant [LAC] test, anticardiolipin antibody [aCL], and anti-β 2 -glycoprotein I [anti-β 2 GPI]) antibodies by aPL profiles (LAC only, single, double, and triple aPL positivity)., Results: The 804 aPL-positive patients assessed in the present study had a mean age of 45 ± 13 years, were 74% female, and 68% White; additionally, 36% had other systemic autoimmune diseases. Of these 804 aPL-positive patients, 80% were classified as having APS (with 55% having thrombotic APS, 9% obstetric APS, and 15% thrombotic APS/obstetric APS). In the overall cohort, 71% had vascular thrombosis, 50% with a history of pregnancy had obstetric morbidity, and 56% had experienced at least one non-criteria manifestation. Among those with three aPLs tested (n = 660), 42% were triple aPL-positive. While single-, double-, and triple aPL-positive subgroups had similar frequencies of vascular, obstetric, and non-criteria events, these events were lowest in the single aPL subgroup, which consisted of aCLs or anti-β 2 GPI only., Conclusion: Our study demonstrates the heterogeneity of aPL-related clinical manifestations and laboratory profiles in a multicenter international cohort. Within single aPL positivity, LAC may be a major contributor to clinical events. Future prospective analyses, using standardized core laboratory aPL tests, will help clarify aPL risk profiles and improve risk stratification., (© 2020, American College of Rheumatology.)

Background: DOACs are characterized by a higher incidence of gastrointestinal bleeding and this may be different among males and females. Female patients were underrepresented in the DOAC pivotal trials. We aimed to assess real-world differences in gastrointestinal bleeding with oral anticoagulants (DOACs and VKAs) among males and females with atrial fibrillation. Methods: We performed a population-based retrospective analysis on linked administrative claims. Atrial fibrillation patients of 65 years and above were considered. Bleeding risk factors were assessed through HASBED and previous history of gastrointestinal disease. A time-to-event analysis compared gastrointestinal bleeding between males and females. Results: The overall cohort consisted of 15338 (55% female) DOAC and 44542 (50% female) VKA users. Most of the patients showed HASBED ≥2. Incidence rate of GI bleeding was higher in females as compared to males among DOAC users (0.90% vs 0.59%), and significant gender difference in GI bleeding was found, after adjustment, in the Cox regression analysis (HR 1.48, 95%CI 1.02-2.16). In the VKA group, no significant difference among genders was found in the time-to-event analysis. Conclusions: Our data suggest that female patients treated with DOACs have a higher risk of GI bleeding versus male patients; this difference is not observed in VKA patients.

Background: Venous thromboembolism (VTE) is a frequent and serious disease that requires immediate and long-term anticoagulant treatment, which is inevitably associated with a risk of bleeding complications. Some studies, though not all, reported a higher risk of bleeding in female patients treated with either old anticoagulants [vitamin k antagonists (VKAs)] or recent anticoagulants [direct oral anticoagulants (DOACs)]. Furthermore, analyses of clinical trials reported an abnormal vaginal bleeding in women of reproductive age treated with DOACs. This study aimed at comparing the risk of bleeding in an inception cohort of VTE women and men included in a prospective observational registry., Methods: Baseline characteristics and bleeding events occurring during anticoagulation in patients of both sexes, included in the START-Register after a first VTE, were analyzed., Results: In all, 1298 women were compared with 1290 men. Women were older and more often had renal diseases; their index events were often provoked (often by hormonal contraception and pregnancy), and more frequently presented as isolated pulmonary embolism (PE). The rate of bleeding was similar in women (2.9% patient-years) and men (2.1% patient-years), though it was higher when uterine bleeds were included (3.5% patient-years, p = 0.0141). More bleeds occurred in VKA- than DOAC-treated patients (6.4% versus 2.6%, respectively; p = 0.0013). At multivariate analysis, age ⩾ 75 years was associated with higher prevalence of bleeds., Conclusion: The occurrence of bleeding was not different between women and men during anticoagulation after VTE. Only after inclusion of vaginal/uterine bleeds, the rate of bleeding was higher in women. The incidence of bleeding was higher in women treated with VKAs., Plain Language Summary: The risk of bleeding in women anticoagulated for deep vein thrombosis or pulmonary embolism is not higher than that in men, except for vaginal bleeding: Background:: The occurrence of a venous thromboembolic event (VTE, including deep vein thrombosis and pulmonary embolism) necessarily requires a period of at least 3-6 months of treatment with anticoagulant drugs [either vitamin k antagonists (VKA) or, more recently, direct oral anticoagulants (DOACs)]. Anticoagulation therapy, however, is associated with a risk of bleeding that is influenced by several factors. Sex is one of these factors as some authors have hypothesized that women are at higher risk than men. Furthermore, some studies have recently found more vaginal bleeding in VTE women treated with a DOAC compared with those who received VKAs. Methods:: The present study aimed to compare the frequency of bleeds occurring in women and in men who were treated with DOACs or VKAs for a first VTE event and followed in real-life conditions. Since the beginning of their anticoagulant treatment, the patients were included in a prospective, multicenter, observational registry (the START-Register), and bleeding events were recorded. Results:: A total of 1298 women were compared with 1290 men. Women were older and more often were affected by renal diseases; their VTE events were often associated with risk factors (especially hormonal contraception and pregnancy) and presented as isolated pulmonary embolism. The rate of all bleeding events (including major, non-major but clinically relevant, and minor bleeds) was higher in women (3.5% patient-years) than in men (2.1% patient-years, p = 0.0141); however, the difference was no longer statistically significant after exclusion of uterine bleeds (2.9% patient years). More bleeding occurred in women receiving VKA as anticoagulant drug compared with those treated with a DOAC (6.4% versus 2.6%, respectively; p = 0.0013). At multivariate analysis, age ⩾ 75 years was associated with higher prevalence of bleeds. Conclusion:: In conclusion, we found that in real-life conditions, the rate of bleeding events occurring during anticoagulation after a VTE episode is not higher in women than in men. Only after inclusion of vaginal bleeds, the rate of bleeding was higher in women. More bleeds (including vaginal bleeding) occurred in women treated with VKA than DOACs., Competing Interests: Conflict of interest statement: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s), 2021.)