Antiphospholipid Patients Admitted in the Intensive Care Unit: What Must The Rheumatologist Know?

PURPOSE OF THE REVIEW: Antiphospholipid syndrome (APS) is a rare systemic autoimmune disorder that can escalate into a 'thrombotic storm' called the catastrophic antiphospholipid syndrome (CAPS), frequently requiring ICU admission for multiple organ failure. This review aims to offer insight and recent evidence on critically-ill APS patients. RECENT FINDINGS: The CAPS classification criteria define this condition as the involvement of at least three organs/systems/tissues within less than a week, caused by small vessel thrombosis, in patients with elevated antiphospholipid antibodies levels. These criteria do not encompass the full spectrum of critically-ill thrombotic APS patients and they need to be cautiously used for the bedside diagnosis of CAPS. Thrombocytopenia is the laboratory hallmark of CAPS, sometimes dropping below 20G/L, but a complete thrombotic microangiopathy pattern is infrequent. Anticoagulation is the pivotal treatment for APS and CAPS, associated with improved outcome. Triple therapy - the combination of anticoagulation, high-dose corticosteroids, and either plasma exchange or intravenous immunoglobulins - remains the standard treatment for CAPS patients. Eculizumab, an anti-C5 monoclonal antibody, may be useful in refractory patients. Despite significant progress, CAPS mortality rate remains high. Its diagnosis and management are complex, requiring a close multidisciplinary cross talk between APS specialists and intensivists.

Testing for the lupus anticoagulant: the good, the bad, and the ugly.

Lupus anticoagulant (LA) represents 1 of the laboratory criteria for classification of patients as having definite antiphospholipid syndrome (APS). The other 2 laboratory criteria are anticardiolipin antibodies and anti-beta2-glycoprotein I antibodies. At least 1 of these antiphospholipid antibody (aPL) tests need to be positive, with evidence of persistence, together with evidence of at least 1 clinical criterion for APS, before a patient can be classified as having definite APS. LA and other aPL assays are also important for diagnosis or exclusion of APS, as well as for risk stratification, with triple-positive patients carrying the greatest risk. Whereas LA is identified through "uncalibrated" clot-based assays, the other aPL assays (anticardiolipin and anti-beta2-glycoprotein I antibodies) represent immunological assays, identified using calibrated solid-phase methods. Because LA is identified using clot-based assays, it is subject to considerable preanalytical and analytical issues that challenge accurate detection or exclusion of LA. In this narrative review, we take a look at the good, the bad, and the ugly of LA testing, primarily focusing on the last 10 years. Although harmonization of LA testing as a result of International Society on Thrombosis and Haemostasis guidance documents and other international activities has led to improvements in LA detection, many challenges remain. In particular, several anticoagulants, especially direct oral anticoagulants and also vitamin K antagonists, given as therapy to treat the pathophysiological consequences of aPL, especially thrombosis, interfere with LA assays and can generate false-positive or false-negative LA findings. Overcoming these diagnostic errors will require a multifaceted approach with clinicians and laboratories working together.

Primary antiphospholipid syndrome in a male presents with acute digital ischemia: Dramatic response to glucocorticoid.

We present a rare case of primary antiphospholipid syndrome in a 38-year-old male who presented with painful digital ischemia. Early initiation of anticoagulation and addition of glucocorticoid led to a significant improvement in the patient.

Prolongated Activated Partial Thromboplastin Time (aPTT) in Pediatric Patients before Surgery-Crying Wolf: Lupus (Anticoagulant) Does Not Always Threaten Children.

A prolonged preoperatory aPTT in children is often the cause of a delay of scheduled surgeries and the repetition of multiple blood tests, with the consequent wasting of resources and significant discomfort for children and parents. The aim of this review is to analyze the situations in which an isolated prolongation of aPTT is found during preoperative evaluation in children, especially when it is due to the presence of antiphospholipid antibodies, providing the readers with the keys to interpret this situation and the possibility to correctly evaluate the hemorrhagic risk of a patient.

Noncriteria antiphospholipid antibodies in antiphospholipid syndrome.

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by thrombotic manifestations and/or obstetric complications in patients with persistently positive antiphospholipid antibodies (aPL). aPL are a heterogeneous group of autoantibodies, but only lupus anticoagulant, anticardiolipin (aCL), and antibeta2-glycoprotein I antibodies (aß2GPI) IgG or IgM are included as laboratory classification criteria. Seronegative APS patients are usually defined as patients with the clinical symptoms of APS but who test negative for aPL. The negativity to classic aPL criteria does not exclude the presence of other aPL. Several noncriteria aPL have been identified. Some noncriteria aPL are well studied, such as IgA aCL and aß2GPI, the antiphosphatidylserine-prothrombin (aPS/PT) antibodies, and the antibodies against the domain I of beta2-glycoprotein I (aDI), both latter groups receiving more attention for their role in thrombotic events and pregnancy complications. Other noncriteria aPL that have been studied are antibodies against annexin V, prothrombin, phosphatidylethanolamine, phosphatidic acid, phosphatidylserine, phosphatidylinositol, vimentin-cardiolipin complex, anti-protein S/protein C. Measurement of some of these noncriteria aPL (aPS/PT, aDI) is useful in the laboratory work-out of APS in specific situations. We have to differentiate between patients who are positive for noncriteria aPL only, and patients who have both criteria and noncriteria aPL to enable us to study their role in the diagnosis or risk stratification of APS. The research on noncriteria aPL is continually developing as the clinical relevance of these antibodies is not yet fully clarified.

Laboratory assessment of antiphospholipid syndrome: Laboratory data.

INTRODUCTION: Thorough assessment of the antiphospholipid syndrome (APS) includes retesting of positive antiphospholipid antibody (aPL) tests after at least 12 weeks, and a full antiphospholipid antibody profile. To what extent this work-up is done in clinical practice is unknown. METHODS: Data on 25 116 in- and out-hospital patients tested for the presence of lupus anticoagulant (LA), the aPL which most strongly correlates with thrombosis, was extracted from the laboratory information system of the only laboratory that performs LA tests in the Capital Region, Denmark. We estimated fraction of repeated tests, tests repeated within the recommended time span, and fraction with a full aPL profile. RESULTS: Out of 25 116 patients, 843 were positive for LA (3.3%), and 3948 results were inconclusive (16%). Only 51% (95% CI of the proportion: 48%-54%) (n = 431) of positive tests were repeated. The proportion of inconclusive LA test results increased from 13% (12%-15%) in 2009 to 20% (19%-22%) in 2020. Out of the positive tests repeated within the first year, only 60/353 (17%; 13%-21%) were repeated within 12-16 weeks; 177/353 (50%; 45%-55%) were re-tested within the first 12 weeks of first positive test result. The proportion of patients with a full antiphospholipid antibody profile increased from 161/1978 (8%) in 2010 to 1041/1978 (43%) in 2020. CONCLUSION: We found several issues with the laboratory workup of APS. This indicates a need for increased awareness of comprehensive laboratory assessment of possible APS as well as a closer collaboration between the laboratory and clinicians.

Cardiac involvement in the catastrophic antiphospholipid syndrome (CAPS): Lessons from the "CAPS registry".

OBJECTIVE: To analyze the demographic, clinical, and laboratory characteristics of catastrophic antiphospholipid syndrome (CAPS) patients with cardiac involvement, and to identify the factors associated with this cardiac involvement. MATERIAL AND METHODS: Based on the analysis of the "CAPS Registry", the demographic, clinical, and serological characteristics of patients with cardiac involvement were analyzed. Cardiac involvement was defined as heart failure, valvular disease, acute myocardial infarction, pericardial effusion, pulmonary arterial hypertension, systolic dysfunction, intracardiac thrombosis, and microvascular disease. Univariate and multivariate analysis was used for multiple comparisons. RESULTS: 749 patients (293 [39 %] women and mean age 38.1 ± 16.2 years) accounting for 778 CAPS events were included, of them 404 (52 %) had cardiac involvement. The main cardiac manifestations were heart failure in 185/377 (55 %), valve disease in 116/377 (31 %), and acute myocardial infarction in 104/378 (28 %). Of 58 patients with autopsy/biopsy, 48 (83 %) had cardiac thrombotic microangiopathy, Stroke (29% vs. 21 %, p = 0.012), transient cerebral vascular accident (2% vs. 1 %, p = 0.005), pulmonary infarction (26% vs. 3 %, p = 0.017), renal infarction (46% vs. 35 %, p = 0.006), acute kidney injury (70% vs. 53 %, p < 0.001), and livedo reticularis (24% vs. 17 %, p = 0.016) were significantly more frequent during CAPS events with versus without heart involvement. Multivariate analysis identified acute kidney injury (OR 1.068, IC 95 % 1.8-4.8, p < 0.001) as the only clinical characteristics that were, independently, associated with cardiac involvement in CAPS events. Cardiac involvement was not related to higher mortality. CONCLUSIONS: Cardiac involvement is frequent in CAPS, with association with kidney involvement, and it is not related to higher mortality. The presence of cardiac microthrombosis was demonstrated in most biopsies/autopsies performed.

Diagnosis and Management of Catastrophic Antiphospholipid Syndrome and the Potential Impact of the 2023 ACR/EULAR Antiphospholipid Syndrome Classification Criteria.

Catastrophic antiphospholipid syndrome (CAPS) is a rare and life-threatening condition characterized by the persistence of antiphospholipid antibodies and occurrence of multiple vascular occlusive events. CAPS currently remains a diagnostic challenge and requires urgent treatment. The diagnosis of CAPS is made difficult by classification criteria used as diagnostic criteria in clinical practice, knowledge derived from retrospective data and case reports, confounding clinical and biological features, and its rapid onset and mortality. The absence of prospective studies of CAPS limits the strength of evidence for guideline treatment protocols. This comprehensive review summarizes the current understanding of the disease, and discusses how the 2023 ACR/EULAR Antiphospholipid Syndrome Classification Criteria impact the definition and therapeutic management of CAPS, which is considered the most severe form of APS. The correct integration of 2023 ACR/EULAR APS classification criteria is poised to facilitate CAPS diagnosis, particularly in critical situations, offering a promising avenue for improved outcomes.

COVID-19 coagulopathy and antiphospholipid syndrome

The presence of thrombotic events in COVID-19 patients has been described since the beginning of the pandemic. This association has been confirmed in most of the reported studies. Autopsy reports have shown that most thromboses are located in the lung, although they have also been observed in other organs such as the skin and kidneys. SARS-CoV2 infection induces a generalized prothrombotic state, which is attributed to a combination of factors such as hypoxia, excess cellular apoptosis, and mainly to overactivation of the immune system. Among immune-mediated prothrombotic situations, antiphospholipid syndrome (APS) stands out. Recurrent thrombotic events are observed in APS in the presence of antiphospholipid antibodies (aPL). There are numerous studies that report high prevalence of aPL in patients with COVID-19 infection. However, the results show discrepancies in the data on the prevalence of aPL, and its role in the pathogenesis of thrombosis in these patients. This could be due to the heterogeneity of the detection procedures for aPL or to transient elevations of non-pathogenic aPL levels in the context of infection. In this review we try to clarify the role of aPL in COVID-19 infection, and attempt to answer the question of whether it is a coagulopathy of its own, or secondary to APS.

La presencia de eventos trombóticos en los pacientes con COVID-19 se describió desde el inicio de la pandemia, asociación que ha sido confirmada en la mayoría de los estudios reportados. Los informes de necropsias han puesto de manifiesto que la mayoría de las trombosis se localiza en el pulmón, aunque también se han observado en otros órganos, como la piel y los riñones. La infección por SARS-CoV-2 induce un estado protrombótico generalizado que se atribuye a una conjunción de factores como la hipoxia, el exceso de apoptosis celular y, sobre todo, una hiperactivación del sistema inmune. Entre las situaciones protrombóticas inmunomediadas destaca el síndrome antifosfolipídico, en el cual se observan eventos trombóticos de repetición en presencia de anticuerpos antifosfolipídicos (AAF). Existen numerosos estudios que reportan una elevada prevalencia de AAF en los pacientes con infección por la COVID-19; sin embargo, los resultados muestran discordancias en los datos de prevalencia de AAF y su rol en la patogenia sobre la trombosis en estos pacientes, lo que que podría deberse a la heterogeneidad de los procedimientos de detección de los AAF o a elevaciones transitorias de los niveles de AAF no patogénicos en el contexto de la infección. En esta revisión se busca aclarar el papel de los AAF en la infección por COVID-19, intentando responder a la pregunta de si se trata de una coagulopatía propia o es secundaria a un síndrome antifosfolipídico.

Antiphospholipid antibodies and the risk of adverse pregnancy outcomes in patients with systemic lupus erythematosus: a systematic review and meta-analysis.

OBJECTIVE: This article aims to evaluate the magnitude of adverse pregnancy outcomes (APOs) risks associated with different antiphospholipid antibody (aPL) profiles in women with systemic lupus erythematosus (SLE). METHODS: Multiple databases were investigated to identify articles that explored the relationship between aPLs and APOs in SLE patients. A random effects model was used for calculating pooled odds ratios (OR). Stata version 15.0 was utilized to conduct the meta-analysis. RESULTS: There were 5234 patients involved in 30 studies. Overall aPL was linked to an increased incidence of any kind of APOs, fetal loss, and preterm birth. Any kind of APOs and preterm delivery were more common in patients with lupus anticoagulant (LA) positive. Anticardiolipin antibody (aCL) was associated with an increased risk of any kind of APOs and fetal loss. The association between aCL-IgM and fetal loss was also significant. Patients with anti-beta2-glycoprotein1 antibody (antiß2GP1) positivity had an increased risk of fetal loss. CONCLUSIONS: Both LA and aCL were risk factors of APOs in patients with SLE. Not only ACL, particularly aCL-IgM, but antiß2GP1 were associated with an increased risk of fetal loss, while LA appeared to indicate the risk of preterm birth.PROSPERO (CRD42023388122).

Hypoprothrombinemia-lupus anticoagulant syndrome secondary to Sjogren's syndrome: A case report. / å¹²ç‡¥ç»¼åˆå¾ç»§å‘ä½Žå‡è¡€é ¶åŽŸè¡€ç—‡-狼疮抗凝物综合征1例.

Hypoprothrombinemia-lupus anticoagulant syndrome (HLAS) is a rare disease in which patients present with varying degrees of bleeding and positive lupus anticoagulant with reduced prothrombin on laboratory tests. This article reports a case of HLAS in a middle-aged woman with recurrent gingival bleeding and epistaxis as the first presentation. After admission, tests revealed prolonged prothrombin time (PT), activated partial thromboplastin time (APTT), and reduced coagulation factor II activity, and positive lupus anticoagulant (LA). Meanwhile, the patient had symptoms of dry mouth and dry eyes for a long time, and the examination of autoantibodies, tear secretion test and salivary gland emission computed tomography (ECT) were consistent with the diagnosis of Sjogren's syndrome. The final diagnosis was HLAS secondary to Sjogren's syndrome. After treatment with methylprednisolone and cyclophosphamide, the coagulation disorder gradually improved, and no recurrent bleeding occurred. HLAS is a rare clinical case, which reminds medical staff to be alert to the possibility of HLAS when encountering patients with unexplained prolonged APTT and PT and positive lupus anticoagulant.

Comparison of different algorithms for lupus anticoagulant detection: a single-center experience.

Background: The laboratory tests for lupus anticoagulant (LA) detection comprise complex and multistep coagulation testing procedures. There is no established gold standard assay or direct comparison of algorithms as recommended by different guidelines. Objectives: This study aimed to evaluate and compare the LA detection performance of different laboratory algorithms suggested by the existing guidelines. Methods: The routine LA test data of 1801 plasma samples, including 188 LA-positive and 1613 LA-negative samples, were re-evaluated by applying the algorithms recommended by existing guidelines and were interpreted using various methods. Diagnostic performance indices for each LA detection algorithm were compared with those of the other algorithms. The efficacies of the different interpretation methods were analyzed to determine a suitable interpretation methodology for each assay. Results: The diagnostic performance for detecting LA varied by the algorithm and method of interpretation used. All laboratory algorithms displayed exceptional diagnostic performance with all diagnostic parameters of >90.0%. Nearly perfect agreement was observed in all algorithms when compared to the Clinical and Laboratory Standards Institute 2014 guideline interpreted by normalized screen-to-confirm ratio (NSCR) and mixing test-specific cutoff (MTC), as a reference assay (Cohen's kappa coefficient, >0.90 [range, 0.94-1.00]). A combination of the index of circulating anticoagulant and NSCR was optimal for interpreting the activated partial thromboplastin time-based test, whereas a combination of the MTC and NSCR was suitable for the diluted Russell's viper venom time-based test. Conclusion: All laboratory algorithms showed equivalent diagnostic performance. Establishing the best method of interpretation for each assay is recommended to improve LA detection performance.

The association of an elevated Th/Ts ratio and lupus anticoagulant with symptomatic osteonecrosis in systemic lupus erythematosus patients.

Objective: This study aimed to assess the risk factors for symptomatic osteonecrosis (ON) in systemic lupus erythematosus (SLE) and identify clinical characteristics and laboratory markers for predicting symptomatic ON occurrence in SLE patients. Methods: Seventy (6.0%) of 1175 SLE patients diagnosed with symptomatic ON were included in this study. An equal number of SLE patients without symptomatic ON, matched in terms of age and gender, were enrolled in the control group. Clinical symptoms, routine laboratory examinations, lymphocyte subsets, and treatments of these patients were retrospectively reviewed and compared between the two groups. Logistic regression analysis was employed to identify risk factors associated with symptomatic ON in SLE. Results: Among the 70 cases in the symptomatic ON group, 62 (88.6%) patients experienced femoral head necrosis, with bilateral involvement observed in 58 patients. Bone pain was reported in 32 cases (51.6%), and 19 cases (30.6%) presented with multiple symptoms. Univariate analysis revealed significant differences between the two groups in various factors, including disease duration (months), cumulative steroid exposure time, history of thrombosis, neurological involvement, the number of affected organs, myalgia/myasthenia, and the use of medications such as glucocorticoids, immunosuppressants, aspirin, and statins (P<0.05). Moreover, lupus anticoagulant (LA) levels were significantly higher in the symptomatic ON group than in the control group (P<0.05). Furthermore, notable distinctions were observed in peripheral blood immune cells, including an elevated white blood cell count (WBC), a decreased percentage of Ts cells (CD3+CD8+), and an elevated Th/Ts ratio. Logistic regression analysis revealed that a history of thrombosis, LA positivity, and an elevated Th/Ts ratio remained positive factors associated with symptomatic ON (P<0.05). Conclusion: Decreased Ts cells and changes in the T lymphocyte subset play an important regulatory role in the development of symptomatic ON. A history of thrombosis and LA are associated with an increased probability of symptomatic ON in SLE and may serve as potential predictors.

The lupus anticoagulant titer is associated with elevated antiphosphatidylserine/prothrombin immunoglobulin-M isotype antibody levels.

BACKGROUND: Clot based assays used for lupus anticoagulant (LAC) detection are typically interpreted in a qualitative fashion and may not reflect LAC potency. In this cross-sectional study, we describe a method for quantifying the LAC titer using serial (dependent) two-fold dilutions in normal pooled plasma. METHODS: Serial dilutions of 51 residual plasma samples from 50 patients were tested using the Russell's viper venom screening time (DRVVT) and activated partial thromboplastin screening time (APTT) methodologies. The measured clotting times and the corresponding dilution factors were then used to derive a four-parameter logistic model. The LAC titer for each patient was interpolated as the sample dilution that corresponds to the upper reference interval limit of the corresponding assay. RESULTS: Calculated APTT and DRVVT LAC titers displayed a strong linear correlation (R2 = 0.84) between each other, but not with the degree of prolongation of the APTT/DRVVT screening time in the neat undiluted samples. Using data driven partitioning, patients could be grouped into low (<10) or high (≥10) DRVVT LAC titer. There were no significant differences in anticardiolipin (aCL) or anti-beta 2 glycoprotein 1 (aB2GPI) antibody levels or prevalence of thromboembolic events between low and high LAC titer groups. In contrast, antiphosphatidylserine/prothrombin (aPS/PT) IgM antibody levels, but not IgG, were significantly higher in the high LAC titer group. CONCLUSIONS: The degree of prolongation of the APTT/DRVVT screening time is not correlated with the LAC titer. Only aPS/PT IgM antibodies levels were strongly correlated with the LAC titers. Additional studies are warranted to determine clinical implications of high LAC titers.

To normalize or not?: Dilute Russell viper venom time testing.

OBJECTIVES: We conducted a comparison between the nonnormalized dilute Russell viper venom time (dRVVT) screen/confirm ratio (SCR) in patient plasma and the normalized SCR obtained using reference pooled plasma. The aim was to assess the impact of normalization on the lupus anticoagulant (LA) status in our patient population. METHODS: In our retrospective analysis, we included a total of 464 patients who underwent dRVVT testing. For those with positive screens, mixing studies were performed, followed by confirmatory testing. Additionally, the dRVVT of reference pooled plasma was measured. A positive conventional (nonnormalized) or normalized SCR was defined as an SCR greater than or equal to 1.2. RESULTS: In total, 5.6% (26) of the 464 samples tested were confirmed positive for LA by both methods, out of which 12 had a clinical history of thrombosis. Although a statistically significant difference between the 2 groups (P = .0096) was found, the magnitude of absolute mean SCR differences (bias) was 0.04 (2.51%). There was 100% concordance of testing results between the 2 groups. CONCLUSIONS: The lupus anticoagulant status by the dRVVT assay was not changed based on normalization. Normalization was of no clinical benefit in our patient population; therefore, there was no need for the extra calculation step. Normalization may be useful for intermethod and interlaboratory studies and not for within-method LA detection.

Risk factors for damage accrual in primary antiphospholipid syndrome: A retrospective single-center cohort study.

BACKGROUND: Despite anticoagulant therapy, a antiphospholipid syndrome (APS) has a higher rate of recurrent events, which can lead to damage accrual and a negative impact on life quality. OBJECTIVES: To evaluate the risk factors and APS subsets associated with damage accrual. PATIENTS/METHODS: We conducted a retrospective single-center study. We reviewed the medical records of 282 APS patients, with a median age of 36 (IQR 30-46) years and a median of 195 (IQR 137-272) months. The primary endpoint was damage accrual during follow-up, defined as organ/tissue impairment present for at least six months or causing permanent loss. The secondary endpoints were early organ damage within six months of disease onset and death. RESULTS: Eighty (28.4%) patients presented damage accrual; 52.5% developed damage within six months of APS onset, and 41.3% had more than one organ involved. Neuropsychiatric involvement, affecting 38.8% of the patients, was the most frequent, followed by peripheral vasculopathy and renal involvement, 35% either. Death happened in 7 (2.5 %) patients; damage accrual was associated with a 6-fold risk of death [OR 6.7 (95% CI 1.3-35.1), p = 0.03]. Microangiopathy and non-criteria manifestations were independent risk factors for damage accrual with 5-fold and 4-fold higher risk, respectively [(OR 4.9 (95% CI 2.1-11.7), p < 0.0001 and (OR 3.8 (95% CI 1.5-10.1), p = 0.007]. The cumulative incidence of damage accrual increased by 5.7-fold and 3.6-fold in patients with microangiopathy and non-criteria manifestations. CONCLUSIONS: APS patients had a higher frequency of damage accrual. Microangiopathy and non-criteria manifestations were independent risk factors for damage accrual.

Coagulation Testing in Real-World Setting: Insights From a Comprehensive Survey.

The objective of this survey was to gain a real-world perspective on coagulation testing by evaluating the availability of various coagulation laboratory tests, assessing specific analytic and postanalytic steps in clinical laboratories in Korea.Participants were surveyed using a 65-question questionnaire specifically focused on their coagulation testing practices related to prothrombin time (PT), activated partial thromboplastin time (aPTT), plasma-mixing studies, lupus anticoagulant (LA) tests, platelet function tests, coagulation factor assays, and the composition of hemostasis and thrombosis test panels. The survey was performed between July and September 2022.The survey achieved a 77.9% (81 of 104) response rate. PT or aPTT tests were performed directly at all participating institutions, followed by D-dimer and fibrinogen tests, platelet function test, and plasma-mixing studies in order of frequency. Variations existed in the performance of mixing test and LA assessment. Patterns of coagulating testing differed depending on the size of the hospital. The survey revealed that most laboratories conducted coagulation tests following the international guidelines such as Clinical Laboratory Standards Institute guidelines and the Korean Laboratory Certification system. However, some coagulation tests, including mixing test and LA tests, are yet to be standardized in Korea.Continuous education on coagulation test methods and internal and external quality control are required to encourage laboratories to enhance the performance of coagulation testing.

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.

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.

Taipan snake venom time has high sensitivity for lupus anticoagulants in non-anticoagulated, triple positive antiphospholipid syndrome patients.

INTRODUCTION: Dilute Russell's viper venom time (dRVVT) and activated partial thromboplastin time (APTT) are the mainstay assays in lupus anticoagulant (LA) detection yet they have limitations, particularly in relation to interferences and specificity. The recently validated Taipan snake venom time (TSVT) screening with ecarin time (ET) confirmatory assays overcome many of those limitations due to the innate specificity engendered from direct prothrombin activation, and insensitivity to the effects of vitamin K antagonists (VKA). The present study aimed to further evidence diagnostic utility of TSVT/ET by performing them in samples from 116 nonanticoagulated patients with established triple-positive antiphospholipid syndrome (APS). METHODS: Samples were identified in three expert centres who performed dRVVT, APTT and solid phase antiphospholipid antibody assays with reagents from a variety of manufacturers. All samples additionally received TSVT/ET analysis using standardised reagents. RESULTS: Ninety seven of 116 (83.6%) were dRVVT- and APTT-positive, 85/97 (87.6%) of which were TSVT/ET-positive, 9/116 (7.8%) were dRVVT-positive only, 6 of which were TSVT/ET-positive, and 10/116 (8.6%) were APTT-positive only, 5 of which were TSVT/ET-positive. 96/116 TSVT/ET-positivity returned a high sensitivity for LA of 82.8%. Low coefficients of determination revealed weak relationships between LA potency and anticardiolipin and anti-ß2-glycoprotein I antibody titres for all three LA assays. CONCLUSIONS: TSVT/ET has high sensitivity for the clinically significant LA found in triple positive APS patients. TSVT/ET can establish multiple LA assay positivity in nonanticoagulated patients negative for one of dRVVT or APTT, and is the only assay pairing insensitive to VKAs, the recommended anticoagulation for APS.