Antiphospholipid antibodies and the risk of recurrence after a first episode of venous thromboembolism: a systematic review

Standardized Data Elements for Patients With Acute Pulmonary Embolism: A Consensus Report From the Pulmonary Embolism Research Collaborative

Recent advances in therapy and the promulgation of multidisciplinary pulmonary embolism teams show great promise to improve management and outcomes of acute pulmonary embolism (PE). However, the absence of randomized evidence and lack of consensus leads to tremendous variations in treatment and compromises the wide implementation of new innovations. Moreover, the changing landscape of health care, where quality, cost, and accountability are increasingly relevant, dictates that a broad spectrum of outcomes of care must be routinely monitored to fully capture the impact of modern PE treatment. We set out to standardize data collection in patients with PE undergoing evaluation and treatment, and thus establish the foundation for an expanding evidence base that will address gaps in evidence and inform future care for acute PE. To do so, >100 international PE thought leaders convened in Washington, DC, in April 2022 to form the Pulmonary Embolism Research Collaborative. Participants included physician experts, key members of the US Food and Drug Administration, patient representatives, and industry leaders. Recognizing the multidisciplinary nature of PE care, the Pulmonary Embolism Research Collaborative was created with representative experts from stakeholder medical subspecialties, including cardiology, pulmonology, vascular medicine, critical care, hematology, cardiac surgery, emergency medicine, hospital medicine, and pharmacology. A list of critical evidence gaps was composed with a matching comprehensive set of standardized data elements; these data points will provide a foundation for productive research, knowledge enhancement, and advancement of clinical care within the field of acute PE, and contribute to answering urgent unmet needs in PE management. Evidence produced through the Pulmonary Embolism Research Collaborative, as it is applied to data collection, promises to provide crucial knowledge that will ultimately produce a robust evidence base that will lead to standardization and harmonization of PE management and improved outcomes.

Antiphospholipid antibodies as potential prognostic indicators of recurrent ischemic stroke

BACKGROUND

Immunity play a pivotal role in the risk of ischemic stroke, and studies have also shown a relationship between ischemic stroke and autoimmune diseases. In light of this we conducted a prospective cohort study to elucidate the impact of antiphospholipid antibodies (aPLs), antinuclear antibodies (ANA), and anti-extractable nuclear antigen autoantibodies (anti-ENA) on the prognosis of ischemic stroke.

METHODS

245 stroke patients were recruited in this single-center study and followed up with for 3 years. Autoantibodies, including aPLs (ACA, anti-β2GPI, LA), ANA and anti-ENA were evaluated in recurrent ischemic stroke (RIS) and nonrecurrent ischemic stroke (nonRIS). Stroke severity was judged using the National Institutes of Health Stroke Scale (NIHSS). For preventive treatment, 42 IS patients with positive aPLs + ANA/anti-ENA were randomized 1:1 into a hydroxychloroquine (HCQ) treatment group and a control group, and the prognoses were compared.

RESULTS

The positive rate of ACA IgG (p = 0.018), anti-β2GPI IgG (p = 0.047), LA (p = 0.023), and aPLs + ANA/anti-ENA (p = 0.000) were significantly higher in patients with RIS compared to patients with nonRIS, and aPLs + ANA/anti-ENA (HR2.31, 95 % CI1.02-5.25, p = 0.046) and hypertension (HR2.50, 95 % CI1.17-5.35, p = 0.018) were the independent risk factors of recurrence. There were differences in NIHSS at month 36 between those positive and negative for aPLs + ANA/anti-ENA (p = 0.001, Eta2 = 0.052), anti-ENA (p = 0.016, Eta2 = 0.030), ANA (p = 0.035, Eta2 = 0.022), and LA (p = 0.016, Eta2 = 0.028). Furthermore, the recurrence rate of the HCQ treatment group was lower than that of the control group (p = 0.024).

CONCLUSIONS

Co-positivity of aPLs and ANA/anti-ENA is an independent risk factor for RIS. However, HCQ therapy may reduce the recurrence rate of IS for these patients.

Risk Factors for Antiphospholipid Antibodies and Antiphospholipid Syndrome

Persistence of serum antiphospholipid antibodies (aPL) is associated with a high thrombotic risk, both arterial and venous, and with pregnancy complications. Due to the potential morbidity and mortality associated with the presence of aPL, identifying and recognizing risk factors for the development of aPL and thrombosis in aPL carriers may help to prevent and reduce the burden of disease. Multiple elements are involved in the pathomechanism of aPL development and aPL-related thrombosis such as genetics, malignancy, and infections. This review will address the role of both well-known risk factors and their evolution, and of emerging risk factors, including COVID-19, in the development of aPL and thrombosis in aPL carriers.

Thrombotic antiphospholipid syndrome: From guidelines to clinical management

Thrombotic manifestations, mainly venous thromboembolism (VTE) and stroke, are the most common and potentially life-threatening presentations of antiphospholipid syndrome (APS). The management of APS requires the assessment of the antiphospholipid antibodies (aPL) profile, of concurrent systemic lupus erythematosus or other systemic autoimmune diseases and the presence of risk factors for cardiovascular disease and bleeding. Anticoagulation with vitamin K antagonists (VKA) remains the cornerstone of therapy for thrombotic APS. As platelets play a central role in APS, low-dose aspirin is the first option for primary thromboprophylaxis in asymptomatic aPL carriers, and also plays a role as combination therapy with VKAs in arterial thrombosis. Treatment with direct oral anticoagulants (DOACs) could be considered in certain low-risk situations, although they are not recommended in patients with arterial thrombosis or triple positive aPL. Adjuvant therapies such as hydroxychloroquine and statins may be useful in complex settings such as thrombotic recurrences or high risk of bleeding. In this article, we review the evidence and the recommendations of the guidelines for the treatment of APS, and provide a critical and practical approach of its management from our clinical perspective.

Low recurrent thrombosis rates in single positive antiphospholipid syndrome regardless of type of anticoagulation

Thrombotic antiphospholipid syndrome (TAPS) is characterized by thrombosis and persistently positive tests for antiphospholipid antibodies or lupus anticoagulant (LAC). Triple-positive APS has the highest risk of recurrent thrombosis, but no studies have focused on recurrent thrombosis in patients with single-positive TAPS. We conducted a retrospective cohort study of patients with single-positive TAPS diagnosed at Lifespan Health System, Rhode Island, to determine the rates and risk factors for recurrent thrombosis. Between January 2001 and April 2022, 128 patients were assessed who had single-positive APS (LAC = 98, aCL = 21, aβ2GPI = 9) and who had been followed for a total of 1453.8 patient-years (median follow-up 3.04 years). The initial antithrombotic regimen was warfarin in 44 %, a direct oral anticoagulant (DOAC) in 34 %, enoxaparin in 2 %, and no antithrombotic therapy or antiplatelet therapy only in 20 %. Recurrent thrombosis occurred in 16 (12.5 %) with a recurrent thrombosis rate of 3.08 per 100 patient-years. Systemic lupus erythematosus was the only variable significantly associated with recurrent thrombosis in a model adjusted for age, sex, body mass index, and type of positive APS test. All 16 patients with recurrent thrombosis were initially treated with warfarin, and, at the time of recurrent thrombosis, 13 patients remained on warfarin and three were off anticoagulation. In conclusion, the recurrent thrombosis rate in single-positive APS is low, and not all patients with a single-positive test may need indefinite anticoagulation with warfarin. Larger prospective studies are required to confirm this finding and establish optimal anticoagulation regimens for low-risk TAPS.

Viewpoint: Lupus anticoagulant detection and interpretation in antiphospholipid syndrome

Lupus anticoagulant (LA) is a well-established risk factor for the clinical manifestations of antiphospholipid syndrome (APS). Accurate LA detection is an essential prerequisite for optimal diagnosis and management of patients with APS or aPL carriers. Variability remains a challenge in LA testing, with reliable detection influenced by multiple factors, including pre-analytical conditions, anticoagulation treatment, choice of tests and procedures performed, as well as interpretation of results, that can lead to false-positives or negatives. A standardised approach to LA testing, following current guidance, based on published data and international consensus, and with attention to detail, is required to underpin accurate detection of LA. Future work should focus on better characterisation of the nature of LA, which may ultimately lead to improved diagnosis and management of patients with APS and aPL carriers. This article reviews current practice and challenges, providing an overview on detection of LA.

Viewpoint: Provoked thrombosis in antiphospholipid syndrome

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.

Risk of venous thromboembolism in autoimmune diseases: A comprehensive review

Autoimmune diseases have specific pathophysiologic mechanisms leading to an increased risk of arterial and venous thrombosis. The risk of venous thromboembolism (VTE) varies according to the type and stage of the disease, and to concomitant treatments. In this review, we revise the most common autoimmune disease such as antiphospholipid syndrome, inflammatory myositis, polymyositis and dermatomyositis, rheumatoid arthritis, sarcoidosis, Sjogren syndrome, autoimmune haemolytic anaemia, systemic lupus erythematosus, systemic sclerosis, vasculitis and inflammatory bowel disease. We also provide an overview of pathophysiology responsible for the risk of VTE in each autoimmune disorder, and report current indications to anticoagulant treatment for primary and secondary prevention of VTE.

Antiphospholipid Syndrome in Patients with Venous Thromboembolism

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.

Anti-thrombotics and major adverse cardiovascular events in anti-phospholipid syndrome: a cross-sectional study using the 2016-2018 National Inpatient Sample database

OBJECTIVE

This study assessed the relationship between anti-thrombotics and major adverse cardiovascular events (MACE) in patients with anti-phospholipid syndrome (APS).

METHOD

We included 13 947 subjects with APS from the National (Nationwide) Inpatient Sample (NIS) database for 2016-2018, and collected relevant covariates and demographic data using ICD-10 codes. Our two primary outcomes were MACE and death. We performed multivariate logistic regression analysis to assess the impact of various anti-thrombotic regimens on MACE/death in our primary cohort and high-risk subgroups.

RESULTS

Patients on anti-coagulants had significantly reduced odds of MACE [odds ratio (OR) 0.68, 95% confidence interval (CI) 0.62-0.76, p < 0.001] as well as each of its subcomponents. Those not on any anti-coagulants had significantly increased odds of MACE (OR 1.47, 95% CI 1.24-1.72, p < 0.001). No significant association was found between anti-platelet use and the odds of MACE (p > 0.05). Patients on anti-coagulants were the only class that appeared to have a mortality benefit with reduced odds for death (OR 0.64, 95% CI 0.49-0.84, p = 0.001). In the subgroups at higher risk for MACE (those with atrial fibrillation and thrombocytopenia), full anti-coagulation therapy was also the only anti-thrombotic class that significantly affected the odds of MACE, with a protective effect on MACE, but had no mortality benefit.

CONCLUSION

Patients with APS are most likely to benefit from anti-coagulant therapy in reducing MACE. Furthermore, anti-platelets alone or in combination with anti-coagulants are probably not beneficial in MACE reduction and may even increase risk.

Antiphospholipid Syndrome: State of the Art of Clinical Management

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder clinically characterized by recurrent arterial and venous thrombosis and/or pregnancy morbidity in the presence of antiphospholipid antibodies. Currently, treatment is mainly focused on anticoagulation, but therapies targeting mechanisms involved in APS autoimmune pathogenesis could play an important role in specific settings. An evidence-based therapeutic approach is limited by the broad clinical spectrum of the syndrome and the nature of a "rare disease" that makes it difficult to carry out well-designed prospective studies. Vitamin K antagonists (AVK), notably warfarin, are the standard treatment for preventing recurrent venous thrombosis and perhaps also arterial thrombosis. Direct oral anticoagulants (DOACs) are not recommended at least in patients with triple positivity APS. Treatment options for the prevention of pregnancy complications in obstetric APS, as combined use of aspirin and heparin, low-dose prednisolone, hydroxychloroquine, intravenous immunoglobulin (IVIG), may improve pregnancy outcome. The catastrophic antiphospholipid syndrome (CAPS) is the most severe form of APS with acute multiple organ involvement and small vessel thrombosis. Glucocorticoids, heparin, plasma exchange or IVIG, rituximab, or eculizumab must be added to concurrent treatment of precipitating factors (e.g. infections) as rescue therapies. Finally, it has been observed that SARS COV2 infection may produce vascular complications mimicking the clinical and pathophysiological features of APS and particularly of CAPS. From this point of view, attention has been focused on the "protective" role of anticoagulant therapy in preventing thrombotic complication when these clinical conditions coexist.

The bridging conundrum: perioperative management of direct oral anticoagulants for venous thromboembolism

Most patients diagnosed with venous thromboembolism (VTE) are currently treated with direct oral anticoagulants (DOACs). Before an invasive procedure or surgery, clinicians face the challenging decision of how to best manage DOACs. Should the DOAC be held, for how long, and are there instances where bridging with other anticoagulants should be considered? Although clinical trials indicate that most patients taking DOACs for atrial fibrillation do not require bridging anticoagulation, the optimal strategy for patients with a history of VTE is undefined. In this review, we present a case-based discussion for DOAC interruption perioperatively in patients receiving anticoagulation for management of VTE.

Anticoagulant Therapy in Patients with Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by the persistent positivity of antiphospholipid antibodies (aPLA) together with thrombosis or obstetrical complications. Despite their recognized predominant role, aPLA are not sufficient to induce the development of thrombosis and a second hit has been proposed to be necessary. The mainstay of treatment of APS is anticoagulant therapy. However, its optimal intensity in different presentations of the disease remains undefined. Moreover, decision on which patients with aPLA would benefit from an antithrombotic prophylaxis and its optimal intensity are challenging because of the lack of stratification tools for the risk of thrombosis. Finally, decision on the optimal type of anticoagulant drug is also complex because the central pathway responsible for the development of thrombosis is so far unknown and should be carried out on an individual basis after a careful evaluation of the clinical and laboratory features of the patient. This review addresses the epidemiology, physiopathology, diagnosis and management of thrombosis and obstetrical complications in APS, with a special focus on the role of direct oral anticoagulants.

Ethnicity and Antiphospholipid Syndrome in Israel

OBJECTIVE

Antiphospholipid syndrome (APS) is an acquired coagulopathy associated with the presence of antiphospholipid antibodies. Whether ethnicity modulates APS clinical course is not known. The aim of our study was to assess the interplay of ethnicity and APS in Israel.

METHODS

We retrospectively evaluated the ethnic distribution of APS patients from 3 medical centers in Israel compared to the general population. Ethnic groups were defined according to the Israeli Bureau of Statistics as Ashkenazi (European), former Union of Soviet Socialist Republics (USSR), North African, Asian (West Asia, Greece, and Turkey), Israeli Arab individuals, and others.

RESULTS

Our cohort included 382 patients. The prevalence of Ashkenazi and Asian ethnicities was more pronounced (33% versus 12.8% and 15.4% versus 7.7%, respectively; P < 0.001), while Israeli Arabs were less represented (5.2% versus 31.1%; P < 0.001) relative to their part in the general population. Arab patients were younger at presentation (mean ± SD 28 ± 10 years versus 34 ± 13 years; P < 0.001) and were more likely to present with venous thrombosis (50% versus 35%; P = 0.037) and to suffer from venous thrombotic recurrence (45% versus 16%; P < 0.001) compared to other ethnicities. Mortality was higher among patients of Asian ethnic origin (8.8% versus 1.1%; P = 0.005); intriguingly, this group experienced cardiovascular risk factors more often (i.e., dyslipidemia and hypertension).

CONCLUSION

Ethnicity may affect the prevalence and/or natural course of APS, which is less prevalent and differs clinically in Israeli Arab patients, while mortality was linked with Asian ethnicity.

Added value of antiphosphatidylserine/prothrombin antibodies in the workup of thrombotic antiphospholipid syndrome: Communication from the ISTH SSC Subcommittee on Lupus Anticoagulant/Antiphospholipid Antibodies

BACKGROUND

Diagnosis of antiphospholipid syndrome (APS) requires persistent presence of lupus anticoagulant (LAC), anticardiolipin (aCL) IgG/IgM, or anti-β2 glycoprotein I (aβ2GPI) IgG/IgM antibodies. Other antiphospholipid antibodies (aPL) such as antiphosphatidylserine/prothrombin antibodies (aPS/PT) are promising in assessment of thrombotic APS (TAPS).

AIM

To evaluate the added value of aPS/PT IgG and IgM in TAPS.

MATERIAL AND METHODS

aPS/PT IgG/IgM, aCL IgG/IgM, aβ2GPI IgG/IgM, and LAC were determined in 757 patients (TAPS and controls). aPS/PT cut-off values were calculated, and aPS/PT titers and positivity were compared between TAPS and controls, type of thrombosis, and antibody profiles. Likelihood ratios (LR), odds ratios (OR), and aPL score were determined.

RESULTS

aPS/PT IgG and IgM were associated with TAPS and triple positivity. In-house calculated cut-offs were higher for IgM (43 units), compared to manufacturer's cut-off (30 units). Thresholds of 90 (IgG) and 200 (IgM) units were determined as high-titer cut-off. Higher aPS/PT titers were observed in triple positive patients and showed higher LR and OR for TAPS. aPS/PT was independently associated with TAPS when adjusted for aCL/aβ2GPI, but not when adjusted for LAC. In isolated LAC positive patients, aPS/PT was positive in 27.1% TAPS patients and in 77.3% patients with autoimmune disease. Diagnostic value of aPL score did not differ with and without including aPS/PT.

CONCLUSION

aPS/PT positivity, especially with high antibody titer, is associated with TAPS diagnosis. Analysis on top of current laboratory criteria is not essential in TAPS diagnosis, but aPS/PT could be useful in patients with thrombosis and a double positive aPL profile (aCL+/aβ2GPI+).

Antiphospholipid Syndrome-Related Pulmonary Embolism: Clinical Characteristics and Early Recognition

Background

Pulmonary thromboembolism is a common disease frequently encountered in the emergency room and has a high mortality rate. Antiphospholipid syndrome (APS) is a high-risk factor for recurrent pulmonary embolism (PE). It is critical to effectively administer anticoagulants to avoid the recurrence of thrombotic events. This study aims to identify the clinical characteristics of APS patients with PE (APS-PE) and to develop a risk score for determining the presence of APS in PE patients in the emergency situations.

Methods

We retrospectively enrolled 76 PE patients in this study, with 46 patients in the APS-PE group and 30 patients in the non-APS-PE group. We compared differences in demographics, laboratory parameters, and early mortality risk between the two groups. Risk factors for APS-PE were screened using logistic regression analysis. We also developed an early risk score using multivariate analysis weighted points proportional to the β- regression coefficient values and calculated the sensitivity and specificity for APS in PE patients.

Results

In the APS-PE group, we observed a higher proportion of males (43.6 vs. 20%), a higher proportion of low-risk patients (58.7 vs. 10%), lower levels of white blood cells and platelets (PLT), longer activated partial thromboplastin time (APTT), and a slight increase in D-dimer levels. Patients who were triple positive for antiphospholipid antibodies (aPLs) were younger. The APTT gradually increased as the number of positive aPLs increased. The risk factors for APS included male (OR = 5.565, 95% CI 1.176–26.341), decreased PLT (OR = 0.029, 95% CI 0.003–0.330), slightly increased D-dimer (OR = 0.089, 95% CI 0.019–0.426), and prolonged APTT (OR = 4.870, 95% CI 1.189–19.951). The risk score was named MPDA and included male, PLT, D-dimer and APTT, which can predict APS in PE patients with the AUC at 0.888 (95% CI 0.811–0.965).

Conclusion

The risk factors for APS in PE patients are male, low PLT, prolonged APTT and slightly increased D-dimer. The MPDA is a quantitative scoring system which is highly suggestive of APS in PE patients.

Lupus anticoagulant test persistence over time and its associations with future thrombotic events

Data on lupus anticoagulant (LA) test stability in patients persistently positive for LA are limited and its implications on clinical outcomes are lacking. We investigated the rate and predictors of a negative LA test and whether experiencing a negative test affected a patient's risk of future thrombotic events or death in a prospective observational study of persistently LA positive patients. We followed 164 patients (84% women) for a median of 9.2 years and a total of 1,438 follow-up visits. During the observation period, 50 thrombotic events (23 arterial and 27 venous events) occurred and 24 patients died. Forty-six of the patients had at least one negative LA test during the observation period, corresponding to a 10-year cumulative incidence of a negative LA test of 28% (95%CI: 20-35). The majority of patients with available follow-up after a negative LA test (n=41) had at least one subsequent positive test for LA (n=28/41, 68%). Vitamin K antagonist (VKA) treatment at baseline was associated with a negative LA test during follow up. Using a multistate time-to-event model with multivariable adjustment, a negative LA test had no impact on a patient's prospective risk of thrombosis or mortality. We conclude that a negative LA test during observation cannot be used clinically to stratify a patient's risk for future events.

Venous Thromboembolism for the Practicing Cardiologist

Venous thromboembolism (VTE), encompassing pulmonary embolism (PE) and deep vein thrombosis (DVT), is encountered commonly. Acute PE may present as a high-risk cardiovascular emergency, and acute DVT can cause acute and chronic vascular complications. The goal of this review is to ensure that cardiologists are comfortable managing VTE-including risk stratification, anticoagulation therapy, and familiarity with primary reperfusion therapy. Clinical assessment and determination of degree of right ventricular dysfunction are critical in initial risk stratification of PE and determination of parenteral versus oral anticoagulation therapy. Direct oral anticoagulants have emerged as preferred first-line oral anticoagulation strategy in VTE scenarios.

A systematic review of the association between anti-β-2 glycoprotein I antibodies and APS manifestations

Anti-β-2 glycoprotein I antibodies (anti-B2GPI) are often cited as the major pathogenically relevant antibody in antiphospholipid syndrome (APS), but it is unclear if there is clinical evidence to support this theory. We performed a systematic review to determine if immunoglobulin G anti-B2GPI positivity was independently associated with thrombotic and/or obstetric manifestations of APS. We searched MEDLINE, EMBASE, The Cochrane Library, and clinicaltrials.gov electronic databases through April 2020 for prospective studies that met prespecified design criteria. Of 4758 articles identified through computer-assisted search, 4 studies examining obstetric outcomes and 2 studies examining thrombotic outcomes were included for qualitative assessment. The presence of anti-B2GPI had only a weak independent association with thrombosis and was, at best, inconsistently associated with obstetric complications. A quantitative assessment could not be performed because of study heterogeneity. The overall quality of the evidence was very low. Although anti-B2GPI are commonly thought to mediate APS manifestations, clinical evidence is lacking with very low-quality data to support a weak association with thrombosis.

Loss of antiphospholipid antibody positivity post-thrombosis in SLE

Background/Purpose

Loss of positivity of antiphospholipid antibodies has been observed in clinical practice post-thrombosis in patients with SLE with secondary antiphospholipid syndrome (APS). Our study defined the frequency of this loss and the duration before positivity recurred.

Methods

In this prospective study, patients with SLE having at least two positive antiphospholipid markers prior to thrombosis and at least 1 year of follow-up after thrombosis were included. Antiphospholipid markers included lupus anticoagulant (dilute Russell viper venom test >45 s followed by mixing and confirmatory tests) and/or anticardiolipin titre (aCL IgG ≥20, aCL IgM ≥20 and/or aCL IgA ≥20). The percentage of visits with positive antiphospholipid markers after thrombosis was calculated. For patients with a negative antiphospholipid marker any time after thrombosis, survival estimates were performed to calculate the time to return of antiphospholipid positivity.

Results

In APS due to SLE, complete loss of antiphospholipid positivity post-thrombosis was up to 41% for aCL IgG, 51% for IgM and 50% for IgA, but only 20% for those with lupus anticoagulant. Of those who at some point lost aCL IgG or became negative for lupus anticoagulant, the majority (60% and 76%, respectively) reacquired the antibody within 5 years. In contrast, of those who lost aCL IgM or IgA, fewer reacquired it within 5 years (37% and 17%, respectively).

Conclusion

Intermittent positivity of antiphospholipid antibodies is present in APS due to SLE. These fluctuations make it difficult to decide on length of anticoagulation. Lupus anticoagulant is more likely to persist post-thrombosis.

Venous thromboembolism: Recent advancement and future perspective

Clinicians have been more and more often encountering patients with venous thromboembolism (VTE), including pulmonary embolism and deep vein thrombosis, leading to the increased importance of VTE in daily clinical practice. VTE is becoming a common issue in Asian countries including Japan. The management strategies of VTE have changed dramatically in the past decade including the introduction of direct oral anticoagulants (DOACs). In addition, there have been several landmark clinical trials assessing acute treatment strategies including thrombolysis and inferior vena cava (IVC) filter. The current VTE guidelines do not recommend the routine use of thrombolysis or IVC filters based on recent evidence; Nevertheless, the prevalence of thrombolysis and IVC filter use in Japan was strikingly high. The novel profiles of DOACs with rapid onset of action and potential benefit of a lower risk for bleeding compared with vitamin K antagonist could make home treatment feasible and is safer even with extended anticoagulation therapy. One of the most clinically relevant issues for VTE treatment is optimal duration of anticoagulation for the secondary prevention of VTE. Considering recent evidence, optimal duration of anticoagulation should be determined based on the risk for recurrence as well as the risk for bleeding in an individual patient. Despite the recent advances for VTE management, there are still a number of uncertain issues that challenge clinicians in daily clinical practice, such as cancer-associated VTE and minor VTE including subsegmental pulmonary embolism and distal deep vein thrombosis, warranting future research. Several clinical trials are now ongoing for these issues, globally as well as in Japan. The current review is aimed to overview the recent advances in VTE management, describe the current status including some domestic issues in Japan, and discuss the future perspective of VTE.

Investigation and management of pulmonary embolism 1: a probability-based approach

Pulmonary embolism remains a common and potentially deadly disease, despite advances in diagnostic imaging, treatment and prevention. Managing pulmonary embolism requires a multifactorial approach involving risk stratification, determining appropriate diagnostics and selecting individualised therapy. This article reviews the pathophysiology, risk factors, clinical presentation, diagnostic evaluation and therapeutic management and early outpatient management of pulmonary embolism. The second part summarises pulmonary embolism in the setting of pregnancy, COVID-19, recurrent disease and chronic thromboembolic pulmonary hypertension.

Venous thromboembolism

Venous thromboembolism, comprising both deep vein thrombosis and pulmonary embolism, is a chronic illness that affects nearly 10 million people every year worldwide. Strong provoking risk factors for venous thromboembolism include major surgery and active cancer, but most events are unprovoked. Diagnosis requires a sequential work-up that combines assessment of clinical pretest probability for venous thromboembolism using a clinical score (eg, Wells score), D-dimer testing, and imaging. Venous thromboembolism can be considered excluded in patients with both a non-high clinical pretest probability and normal D-dimer concentrations. When required, ultrasonography should be done for a suspected deep vein thrombosis and CT or ventilation-perfusion scintigraphy for a suspected pulmonary embolism. Direct oral anticoagulants (DOACs) are the first-line treatment for almost all patients with venous thromboembolism (including those with cancer). After completing 3-6 months of initial treatment, anticoagulation can be discontinued in patients with venous thromboembolism provoked by a major transient risk factor. Patients whose long-term risk of recurrent venous thromboembolism outweighs the long-term risk of major bleeding, such as those with active cancer or men with unprovoked venous thromboembolism, should receive indefinite anticoagulant treatment. Pharmacological venous thromboembolism prophylaxis is generally warranted in patients undergoing major orthopaedic or cancer surgery. Ongoing research is focused on improving diagnostic strategies for suspected deep vein thrombosis, comparing different DOACs, developing safer anticoagulants, and further individualising approaches for the prevention and management of venous thromboembolism.

A Diagnostic Solution for Lupus Anticoagulant Testing in Patients Taking Direct Oral FXa Inhibitors Using DOAC Filter

Background: Direct oral factor Xa (FXa) inhibitors interfere with lupus anticoagulant (LA) assays challenging antiphospholipid syndrome diagnosis in treated patients. We evaluated a new device, called DOAC Filter, and its usefulness in this setting. It is a single-use filtration cartridge in which FXa inhibitor compounds are trapped by non-covalent binding while plasma is filtered through a solid phase. Patient samples were analyzed before and after filtration: 38 rivaroxaban, 41 apixaban, and 68 none. Anticoagulant plasma concentrations were measured using specific anti-Xa assays and HPLC-MS/MS. LA testing was performed using dilute Russell Viper Venom Time (dRVVT) and Silica Clotting Time (SCT). Baseline median [min-max] concentrations were 64.8 [17.6; 311.4] for rivaroxaban and 92.1 ng/mL [37.1; 390.7] for apixaban (HPLC-MS/MS). They were significantly correlated with anti-Xa assay results (r = 0.98 and r = 0.94, respectively). dRVVT was positive in 92% rivaroxaban and 72% apixaban and SCT in 28 and 41% of samples, respectively. Post-filtration, median % of neutralization was 100% with rivaroxaban and apixaban concentrations of, respectively, <2 [<2-2.4] and <2 ng/mL [<2-9.6] using HPLC-MS/MS. No significant effect of DOAC Filter was observed on LA testing in controls (n = 31) and LA-positive (n = 37) non-anticoagulated samples. dRVVT and SCT remained positive in, respectively, 16 and 8% of rivaroxaban and 41 and 18% of apixaban samples. DOAC Filter would be an easy-to-use device allowing FXa inhibitor removal from plasma samples, limiting their interference with LA testing in treated patients.

How I treat anticoagulant-refractory thrombotic antiphospholipid syndrome

The standard treatment of thrombotic antiphospholipid syndrome (APS) is lifelong oral anticoagulation with a vitamin K antagonist (VKA), generally warfarin. A minority of patients with APS rethrombose despite seemingly adequate anticoagulation. These patients are deemed anticoagulant refractory. The management of anticoagulant-refractory APS is largely empirical and extrapolated from other clinically similar situations. Further options include increased VKA anticoagulation intensity or alternative antithrombotic strategies, including low-molecular-weight heparin, fondaparinux, the addition of antiplatelet therapy, and consideration of vascular options. Patients with anticoagulant-refractory thrombotic APS may have APS-associated thrombocytopenia, which necessitates balancing the risk of recurrent thrombosis vs bleeding to achieve adequate anticoagulation. The multiple mechanisms involved in the generation of the thrombotic phenotype in APS suggest that anticoagulation alone may not control thrombosis. Thus, other modalities, including adjunctive treatment (hydroxychloroquine, statins, and vitamin D) for APS-related thrombosis, merit consideration, as do immunomodulatory therapy and complement inhibition. Patients with APS may have coexistent systemic lupus erythematosus, which adds to the complexity of managing their thromboembolic disease. However, with attention to detail and judicious application of the limited data, it is possible to minimize the morbidity resulting from anticoagulant-refractory thrombotic APS. Multicenter studies are required to guide the sequence of interventions and their comparative efficacy in patients with anticoagulant-refractory thrombotic APS.

Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking (APS ACTION): 10-Year Update

Purpose of Review

APS ACTION is an international research network created to design and conduct large-scale, multicenter research in persistently antiphospholipid antibody (aPL)–positive patients. Given the expanding research activities of the network in the last decade since its creation, the purpose of this article is to review the scientific contributions of APS ACTION as well as future directions.

Recent Findings

APS ACTION has achieved increased international collaboration with internal and external investigators for outcome, interventional, and mechanistic antiphospholipid syndrome (APS) studies. This has been linked to substantial progress in Core laboratory work, which has demonstrated that laboratories can achieve good agreement in performance of aPL assays by use of the same reagents, analyzer type, and protocols.

Summary

APS ACTION will continue to identify gaps in the existing aPL/APS literature, design mechanistic studies to elucidate underlying mechanisms, and conduct prospective, large-scale clinical studies, all for the ultimate goal of early diagnosis and improved management of aPL-positive patients.

Recurrent thrombosis in patients with antiphospholipid antibodies and an initial venous or arterial thromboembolic event: A systematic review and meta-analysis

BACKGROUND

Patients with antiphospholipid antibodies (aPL) and thromboembolism (TE) are at risk for recurrent TE. Few studies, however, distinguish patients based on the initial event.

OBJECTIVES

We performed a systematic review and meta-analysis to investigate patients with aPL and venous TE (VTE), provoked or unprovoked, and patients with arterial TE (ATE).

PATIENTS/METHODS

We conducted searches in PubMed, CINAHL, Cochrane, and EMBASE. Inclusion criteria were prospective trials or cohort studies investigating patients with aPL and ATE or VTE. Excluded studies did not provide estimated recurrence rates, did not specify whether the incident event was ATE or VTE, included patients with multiple events, or included <10 patients. Two-year summary proportions were estimated using a random effects model.

RESULTS

Ten studies described patients with VTE, 2 with ATE, and 5 with VTE or ATE. The 2-year proportion for recurrent TE in patients with VTE who were taking anticoagulant therapy was 0.054 (95% confidence interval [CI], 0.037-0.079); the 2-year proportion for patients not taking anticoagulant therapy was 0.178 (95% CI, 0.150-0.209). Most studies did not distinguish whether VTE were provoked or unprovoked. The 2-year proportion for recurrent TE in patients with ATE who were taking anticoagulant therapy was 0.220 (95% CI, 0.149-0.311); the 2-year proportion for patients taking antiplatelet therapy was 0.216 (95% CI, 0.177-0.261).

CONCLUSIONS

Patients with aPL and ATE may benefit from a different antithrombotic approach than patients with aPL and VTE. Prospective studies with well-defined cohorts with aPL and TE are necessary to determine optimal antithrombotic strategies.

Use of direct oral anticoagulants in patients with thrombotic antiphospholipid syndrome: Guidance from the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis

Clarity and guidance is required with regard to the use of direct oral anticoagulants in antiphospholipid syndrome (APS) patients, within the confines of the recent European Medicines Agency recommendations, discrepant recommendations in other international guidelines and the limited evidence base. To address this, the Lupus Anticoagulant/Antiphospholipid Antibodies Scientific and Standardization Committee (SSC) chair and co-chairs together with SSC Control of Anticoagulation members propose guidance for healthcare professionals to help them manage APS patients. Uncertainty in this field will be addressed. This guidance will also serve as a call and focus for research.

Pulmonary embolism: update on management and controversies

Pulmonary embolism is a common and potentially fatal cardiovascular disorder that must be promptly diagnosed and treated. The diagnosis, risk assessment, and management of pulmonary embolism have evolved with a better understanding of efficient use of diagnostic and therapeutic options. The use of either clinical probability adjusted or age adjusted D-dimer interpretation has led to a reduction in diagnostic imaging to exclude pulmonary embolism. Direct oral anticoagulation therapies are safe, effective, and convenient treatments for most patients with acute venous thromboembolism, with a lower risk of bleeding than vitamin K antagonists. These oral therapeutic options have opened up opportunities for safe outpatient management of pulmonary embolism in selected patients. Recent clinical trials exploring the use of systemic thrombolysis in intermediate to high risk pulmonary embolism suggest that this therapy should be reserved for patients with evidence of hemodynamic compromise. The role of low dose systemic or catheter directed thrombolysis in other patient subgroups is uncertain. After a diagnosis of pulmonary embolism, all patients should be assessed for risk of recurrent venous thromboembolism to guide duration of anticoagulation. Patients with a venous thromboembolism associated with a strong, transient, provoking risk factor can safely discontinue anticoagulation after three months of treatment. Patients with an ongoing strong risk factor, such as cancer, or unprovoked events are at increased risk of recurrent events and should be considered for extended treatment. The use of a risk prediction score can help to identify patients with unprovoked venous thromboembolism who can benefit from extended duration therapy. Despite major advances in the management of pulmonary embolism, up to half of patients report chronic functional limitations. Such patients should be screened for chronic thromboembolic pulmonary hypertension, but only a small proportion will have this as the explanation of their symptoms. In the remaining patients, future studies are needed to understand the pathophysiology and explore interventions to improve quality of life.

Long-term treatment of venous thromboembolism

The most important decision in the long-term treatment of venous thromboembolism (VTE) is how long to anticoagulate. VTE provoked by a reversible risk factor, or a first unprovoked isolated distal deep vein thrombosis (DVT), generally should be treated for 3 months. VTE provoked by a persistent or progressive risk factor (eg, cancer), or a second unprovoked proximal DVT or PE, is generally treated indefinitely. First unprovoked proximal DVT or PE may be treated for 3 to 6 months or indefinitely. Male sex, presentation as PE (particularly if concomitant proximal DVT), a positive d-dimer test after stopping anticoagulation, an antiphospholipid antibody, low risk of bleeding, and patient preference favor indefinite anticoagulation. The type of indefinite anticoagulation is of secondary importance. Low-dose oral Xa inhibitors are convenient and are thought to have a lower risk of bleeding; they are less suitable if there is a higher risk for recurrence. For cancer-associated VTE, we now prefer full-dose oral Xa inhibitors over low-molecular-weight heparin, with gastrointestinal lesions being a relative contraindication. Graduated compression stockings are not routinely indicated after DVT, but are encouraged if there is persistent leg swelling or if a trial of stockings improves symptoms. Medications have a limited role in the treatment of postthrombotic syndrome. After PE, patients should have clinical surveillance for chronic thromboembolic pulmonary hypertension (CTEPH), with ventilation-perfusion scanning and echocardiography being the initial diagnostic tests if CTEPH is a concern. Patients with CTEPH and other symptomatic patients with extensive residual perfusion defects should be evaluated for endarterectomy, balloon pulmonary angioplasty, or vasodilator therapies.

Anti–Domain I β2-Glycoprotein I Antibodies and Activated Protein C Resistance Predict Thrombosis in Antiphospholipid Syndrome: TAC(I)T Study

Background

Antibodies binding to domain I of β2-glycoprotein I (aDI) and activated protein C (APC) resistance are associated with an increased risk of thrombosis in cross-sectional studies. The objective of this study was to assess their predictive value for future thromboembolic events in patients with antiphospholipid antibodies (aPL) or antiphospholipid syndrome.

Methods

This prospective multicenter cohort study included consecutive patients with aPL or systemic lupus erythematosus. We followed 137 patients (43.5 ± 15.4 year old; 107 women) for a mean duration of 43.1 ± 20.7 months.

Results

We detected aDI IgG antibodies by ELISA in 21 patients. An APC sensitivity ratio (APCsr) was determined using a thrombin generation–based test. The APCsr was higher in patients with anti–domain I antibodies demonstrating APC resistance (0.75 ± 0.13 vs 0.48 ± 0.20, P &lt; 0.0001). In univariate analysis, the hazard ratio (HR) for thrombosis over time was higher in patients with aDI IgG (3.31 [95% CI, 1.15–9.52]; P = 0.03) and patients with higher APC resistance (APCsr &gt;95th percentile; HR, 6.07 [95% CI, 1.69–21.87]; P = 0.006). A sensitivity analysis showed an increased risk of higher aDI IgG levels up to HR 5.61 (95% CI, 1.93–16.31; P = 0.01). In multivariate analysis, aDI IgG (HR, 3.90 [95% CI, 1.33–11.46]; P = 0.01) and APC resistance (HR, 4.98 [95% CI, 1.36–18.28]; P = 0.02) remained significant predictors of thrombosis over time.

Conclusions

Our study shows that novel tests for antibodies recognizing domain I of β2-glycoprotein I and functional tests identifying APC resistance are significant predictors of thrombosis over time and may be useful for risk stratification.

Recommendations of the Spanish Rheumatology Society for Primary Antiphospholipid Syndrome. Part I: Diagnosis, Evaluation and Treatment

OBJECTIVE

The difficulty in diagnosis and the spectrum of clinical manifestations that can determine the choice of treatment for primary antiphospholipid syndrome (APS) has fostered the development of recommendations by the Spanish Society of Rheumatology (SER), based on the best possible evidence. These recommendations can serve as a reference for rheumatologists and other specialists involved in the management of APS.

METHODS

A panel of four rheumatologists, a gynaecologist and a haematologist with expertise in APS was created, previously selected by the SER through an open call or based on professional merits. The stages of the work were: identification of the key areas for drafting the document, analysis and synthesis of the scientific evidence (using the Scottish Intercollegiate Guidelines Network [SIGN] levels of evidence) and formulation of recommendations based on this evidence and formal assessment or reasoned judgement techniques (consensus techniques).

RESULTS

46 recommendations were drawn up, addressing five main areas: diagnosis and evaluation, measurement of primary thromboprophylaxis, treatment for APS or secondary thromboprophylaxis, treatment for obstetric APS and special situations. These recommendations also include the role of novel oral anticoagulants, the problem of recurrences or the key risk factors identified in these subjects. This document reflects the first 21, referring to the areas of: diagnosis, evaluation and treatment of primary APS. The document provides a table of recommendations and treatment algorithms.

CONCLUSIONS

An update of the SER recommendations on APS is presented. This document corresponds to partI, related to diagnosis, evaluation and treatment. These recommendations are considered tools for decision-making for clinicians, taking into consideration both the decision of the physician experienced in APS and the patient. A partII has also been prepared, which addresses aspects related to obstetric SAF and special situations.

Catastrophic antiphospholipid syndrome: is life-long anticoagulation therapy required?

Catastrophic antiphospholipid syndrome (CAPS) is an unusual complication of antiphospholipid syndrome (APS) occurring in about 1% of patients. If left untreated, mortality can be as high as 50%. Therapy of APS and its complication CAPS is hampered by the lack of validated prospective, controlled, intervention clinical trials, although there is consensus that treatment should include anticoagulation therapy. But there are issues that need to be addressed such as duration and intensity of therapy. The present report describes our experience in 7 patients with CAPS in whom anticoagulation was discontinued after 6 months of therapy. During an average follow-up of 5.5 years, only 2 patients exhibited one episode each of recurrent venous thrombosis, but none of the patients in whom anticoagulation was discontinued experienced recurrent CAPS.Key Points• Discontinuation of long-term anticoagulation therapy in CAPS patients was not followed by recurrence of CAPS.

Lupus anticoagulant diagnosis in patients receiving direct oral FXa inhibitors at trough levels: A real-life study

INTRODUCTION

Direct oral factor Xa inhibitors (xabans) induce false positive results for lupus anticoagulant (LA) diagnosis. Consequently, it is suggested not to perform LA testing in xabans patients although it may be useful in selected patients. In this monocentric study, we evaluated xabans impact at trough levels (ie, just before the next intake) on LA diagnosis in treated patients using dilute Russell viper venom time (dRVVT) and two LA sensitive activated partial thromboplastin time (aPTT).

METHODS

Sixty patients receiving rivaroxaban (30) or apixaban (30) were included. Plasma concentrations were measured using specific anti-Xa assays. LA testing was performed using one dRVVT (LAC-Screening^® /Confirm^® ; Siemens) and two LA sensitive aPTT-based assays (Hemosil^® Silica Clotting Time (SCT) Screen/Confirm; Werfen and Dade^® Actin^® Factor Sensitivity FSL/FS (Actin F); Siemens).

RESULTS

Median [min-max] concentrations were 23 [<18-68] for rivaroxaban and 42 ng/mL [19-99] for apixaban. dRVVT was positive in 93% of rivaroxaban and 40% of apixaban samples. SCT was positive in 40 and 30% and Actin F in 17 and 20% of samples respectively. Xabans affected more significantly dRVVT than aPTT-based assays (P < .001) with less false positive results with apixaban than with rivaroxaban samples irrespective of the assay used.

CONCLUSION

lupus anticoagulant diagnosis in rivaroxaban and apixaban samples drawn at trough levels remains questionable whenever positive results are obtained. If LA testing in apixaban samples might be useful to rule-out LA using dRVVT and/or aPTT-based assays, the wide majority of rivaroxaban samples would give false positive results.

Incidence and Risk Factors of Recurrent Venous Thromboembolism after Pulmonary Embolism

Background

Information about the epidemiology of venous thromboembolism (VTE) recurrence in Korea is lacking. The purpose of this study was to investigate VTE cumulative recurrence rates and identify risk factors for VTE recurrence among Korean adults.

Methods

A retrospective cohort study was conducted on adult patients (≥18 years) admitted to a university teaching hospital for pulmonary embolism (PE) from 2005 to 2013. The main outcome of interest was a recurrence of VTE. We used Cox proportional hazard regression analyses to calculate the relative risk of VTE recurrence.

Results

Five-year cumulative incidence of recurrent VTE events was 21.5% (95% confidence interval [CI], 17.7–25.4) in all cases of PE; 17% after provoked and 27% after unprovoked PE. Multivariate analysis showed that body mass index (BMI) of ≥25 (hazard ratio [HR], 2.02; 95% CI, 1.17–3.46; p=0.01) and longer anticoagulation therapy duration (HR, 0.90; 95% CI, 0.84–0.96; p<0.01) were independently associated with risk of VTE recurrence. Risk factors not found to be statistically significant at the <0.05 level included history of VTE (HR, 1.81; 95% CI, 0.84–3.88; p=0.12), unprovoked PE (HR, 1.70; 95% CI, 0.89–3.25; p=0.10), symptomatic deep vein thrombosis (HR, 1.62; 95% CI, 0.89–2.94; p=0.10), and female sex (HR, 1.42; 95% CI, 0.78–2.55; p=0.24). We found that age, history of cancer, and other co-morbidities did not significantly affect the risk of VTE recurrence.

Conclusion

Recurrence of VTE after PE is high. Patients with BMI ≥25 or reduced anticoagulation therapy duration have a higher risk of recurrent VTE.

Prevalence of antiphospholipid (aPL) antibodies among patients with chronic thromboembolic pulmonary hypertension: a systematic review and meta-analysis

How thrombophilia may contribute to the development of chronic thromboembolic pulmonary hypertension (CTEPH) is unknown. We searched on PubMed and EMBASE (until 15 April 2018), studies on CTEPH reporting data on inherited or acquired thrombophilia. Starting from 367 articles mentioning the search terms, 347 were excluded mainly as duplicate articles or articles not in English. After reading the full text of remaining articles, ten were excluded for being reviews, editorials, letters or case reports, and two were further removed from the analysis because of the potential selection bias. All the eight considered studies provided the proportion of patients positive for antiphospholipid (aPL) antibodies. The crude rate of aPL in CTPEH patients is 11.8% (95% CI 10.09-13.8%). The meta-analysis considering the weighted mean proportion and 95% confidence intervals (CIs) yields a rate of aPL antibody-positive profile of 12.06% (95% CI 8.12-16.65%) among the patients with CTEPH in the random effects model (I² 76.33%; 95% CI 52.75-88.14%, p = 0.0001). The sensibility analysis confirms the result. No predictors of heterogeneity are found in a meta-regression analysis. Our results suggest that aPL antibodies are frequently associated with CTEPH underlining the need to test for aPL antibodies in young patients with "idiopathic" and "provoked" PE caused by mild provoking risk factors.

Six months versus two years of oral anticoagulation after a first episode of unprovoked deep-vein thrombosis. The PADIS-DVT randomized clinical trial

The optimal duration of anticoagulation after a first episode of unprovoked deep-vein thrombosis is uncertain. We aimed to assess the benefits and risks of an additional 18 months of treatment with warfarin versus placebo, after an initial 6 months of anticoagulation for a first unprovoked proximal deep-vein thrombosis. We conducted a multicenter, randomized, double-blind, controlled trial comparing an additional 18 months of warfarin with placebo in patients with a unprovoked proximal deep-vein thrombosis initially treated for 6 months (treatment period: 18 months; follow up after treatment period: 24 months). The primary outcome was the composite of recurrent venous thromboembolism or major bleeding at 18 months. Secondary outcomes were the composite at 42 months, as well as each component of the composite, and death unrelated to pulmonary embolism or major bleeding, at 18 and 42 months. All outcomes were centrally adjudicated. A total of 104 patients, enrolled between July 2007 and October 2013 were analyzed on an intention-to-treat basis; no patient was lost to follow-up. During the 18-month treatment period, the primary outcome occurred in none of the 50 patients in the warfarin group and in 16 out of 54 patients (cumulative risk, 29.6%) in the placebo group (hazard ratio, 0.03; 95% confidence interval: 0.01 to 0.09; P<0.001). During the entire 42-month study period, the composite outcome occurred in 14 patients (cumulative risk, 36.8%) in the warfarin group and 17 patients (cumulative risk, 31.5%) in the placebo group (hazard ratio, 0.72; 95% confidence interval: 0.35-1.46). In conclusion, after a first unprovoked proximal deep-vein thrombosis initially treated for 6 months, an additional 18 months of warfarin therapy reduced the composite of recurrent venous thrombosis and major bleeding compared to placebo. However, this benefit was not maintained after stopping anticoagulation. Clinical registration: this trial was registered at www.clinicaltrials.gov as #NCT00740493.

Hypercoagulable states in arterial and venous thrombosis: When, how, and who to test?

Evaluation for underlying hypercoagulable states in patients with thrombosis is a frequent clinical conundrum. Testing for thrombophilias is often reflexively performed without strategic approach nor clear appreciation of the clinical implications of such results. Guidelines vary in the appropriate utilization of thrombophilia testing. In this review, we discuss the more commonly encountered inherited and acquired thrombophilias, their association with initial and recurrent venous thromboembolism, arterial thromboembolism, and role in women's health. We suggest an approach to thrombophilia testing guided by the clinical presentation, suspected pathophysiology, and an understanding of how such results may affect patient care.

Anticoagulating patients with high-risk acquired thrombophilias

Antiphospholipid syndrome (APS), heparin-induced thrombocytopenia, and paroxysmal nocturnal hemoglobinuria are 3 acquired thrombophilias that carry a high risk of venous and arterial thromboembolism. Management of these conditions has largely included anticoagulation with a vitamin K antagonist after an initial period of a parenteral anticoagulant, for as long as the thrombotic risk is still present. The available evidence for the use of direct oral anticoagulants (DOACs) is limited and primarily consists of case series and cohort studies, which are summarized in this chapter. Randomized trials evaluating DOACs in patients with APS are reviewed. Further research is needed prior to widely adopting DOACs for use in these high-risk acquired thrombophilias; however, there may be selected low-risk subgroups where DOAC use is possible after careful consideration and patient discussion.

Anticoagulating patients with high-risk acquired thrombophilias

Antiphospholipid syndrome (APS), heparin-induced thrombocytopenia, and paroxysmal nocturnal hemoglobinuria are 3 acquired thrombophilias that carry a high risk of venous and arterial thromboembolism. Management of these conditions has largely included anticoagulation with a vitamin K antagonist after an initial period of a parenteral anticoagulant, for as long as the thrombotic risk is still present. The available evidence for the use of direct oral anticoagulants (DOACs) is limited and primarily consists of case series and cohort studies, which are summarized in this chapter. Randomized trials evaluating DOACs in patients with APS are reviewed. Further research is needed prior to widely adopting DOACs for use in these high-risk acquired thrombophilias; however, there may be selected low-risk subgroups where DOAC use is possible after careful consideration and patient discussion.

Antiphospholipid antibodies and recurrent thrombosis after a first unprovoked venous thromboembolism

It is uncertain whether antiphospholipid antibodies (APAs) increase the risk of recurrence after a first unprovoked venous thromboembolism (VTE). We tested for anticardiolipin antibodies, anti-β2 glycoprotein 1 antibodies, and lupus anticoagulant on 2 occasions ∼6 months apart in 307 patients with a first unprovoked VTE who were part of a prospective cohort study. We then determined if APAs were associated with recurrent thrombosis in the 290 patients who stopped anticoagulant therapy in response to negative D-dimer results. Compared with those without an APA, the hazard ratios for recurrent VTE were 1.8 (95% confidence interval [CI], 0.9-3.7; P = .09) in the 25.9% of patients with an APA on ≥1 occasions, 2.7 (95% CI, 1.1-.7; P = .03) in the 9.0% of patients with the same APA on 2 occasions, and 4.5 (95% CI, 1.5-13.0; P = .006) in the 3.8% of patients with 2 or 3 different APA types on either the same or different occasions. There was no association between having an APA and D-dimer levels. We conclude that having the same type of APA on 2 occasions or having >1 type of APA on the same or different occasions is associated with recurrent thrombosis in patients with a first unprovoked VTE who stop anticoagulant therapy in response to negative D-dimer tests. APA and D-dimer levels seem to be independent predictors of recurrence in patients with an unprovoked VTE. This trial was registered at www.clinicaltrials.gov as #NCT00720915.