Lupus Anticoagulant Ratio Research Articles

Application Value of Combined Detection of Anti-β2-GPI, ACL, and Lupus Anticoagulant in the Diagnosis of Patients with Antiphospholipid Syndrome.

To investigate the application value of combined detection of anti-beta 2-glycoprotein I antibody (anti-β2-GPI), anti-cardiolipin antibody (ACL), and lupus anticoagulant (LA) in the diagnosis of patients with antiphospholipid syndrome (APS). 30 APS patients in our hospital between Jan. 2020 and Jan. 2021 were chosen as the experimental group, and 30 healthy persons with normal physical examination during the same period were selected as the control group The anti-β2-GPI and ACL indexes of both groups were detected by enzyme-linked immunosorbent assay (ELISA), with the LA levels tested by modified dilute Russell's viper venom time (dRVVT) and LA ratio calculated. The diagnostic efficacy of single detection and combined detection was analyzed by plotting the receiver operating characteristic (ROC) curve. The serum indexes in the experimental group were remarkably higher than those in the control group (P < 0.001). ROC curve analysis suggested that in the diagnosis of APS, the area under the ROC curve by detecting anti-β2-GPI, ACL, LA ratio alone and simultaneously were 0.517, 0.583, 0.683, and 0.817 respectively, and the combined detection of the three had remarkably higher sensitivity and specificity than those of each single detection. The indexes of anti-β2-GPI, ACL, and LA ratio were highly expressed in APS patients, and the combined detection of the three has high diagnostic value and can effectively screen and assist the diagnosis of APS.

The Changes of Peripheral Blood FⅫa-AT, TSP-1, LA Ratio in Patients with Systemic Lupus Erythematosus and the Clinical Value of Combined Diagnosis of Thrombotic Events

To explore the changes of Ⅻ antithrombin (FⅫa-AT), thrombospondin-1 (TSP-1), and lupus anticoagulant (LA) ratio in the peripheral blood factor of patients with systemic lupus erythematosus (SLE) and the clinical value of combined diagnosis of thrombotic events. A total of 133 SLE patients treated in Xingtai People's Hospital were selected and divided into simple SLE group (105 cases) and SLE complicated with thrombosis group (28 cases) according to whether thrombotic events occurred, and 102 cases of healthy people in the same period were selected as control. The clinical data of the 3 groups, the level of peripheral blood FⅫa-AT, TSP-1, and LA ratio were compared, the relationship between each peripheral blood index and SLE disease activity index (SLEDAI) score were analyzed. The influencing factors of thrombotic events in SLE patients were analyzed, and the value of each peripheral blood index in the diagnosis of SLE complicated with thrombotic events were evaluated. The proportion of the patients with age ≥60 year, hypertension, and smoking history in SLE complicated with thrombosis group was higher than those in simple SLE group and control group (P＜0.05). The SLEDAI score, peripheral blood FⅫa-AT, TSP-1, LA ratio levels of the patients in SLE complicated with thrombosis group were significantly higher than those in simple SLE group and control group, and the simple SLE group was significantly higher than the control group (P＜0.05). FⅫa-AT, TSP-1, LA ratio in peripheral blood of SLE patients were positively correlated with SLEDAI score (r=0.663, 0.578 and 0.625). Age, blood pressure, smoking history, peripheral blood FⅫa-AT, TSP-1, LA ratio were the important influencing factors of thrombotic events in SLE patients (P＜0.05). The AUC diagnosed by the FⅫa-AT, TSP-1, and LA ratio in peripheral blood was 0.881, the 95% CI was 0.813-0.931, the sensitivity was 82.14%, and the specificity was 91.43%, which was superior to each index alone (P＜0.05). Peripheral blood FⅫa-AT, TSP-1, LA ratio level changes in SLE patients are significantly related to disease activity, and the combined diagnosis of thrombotic events is more reliable.

C85. Right heart failure due to chronic thromboembolic pulmonary hypertension in systemic lupus erythematosus patient: a case report

Abstract Background Systemic lupus erythematosus (SLE) is a chronic inflammatory disease with varying clinical manifestations and high risk of thrombosis. Chronic Thromboembolic Pulmonary Hypertension (CTEPH) as late complication of acute pulmonary embolic sometimes occured in SLE patients and in advanced condition it can manifest as right heart failure. Case Summary A female, 29 years old with complaints of bilateral ankle oedema and bloated stomach, as well as dyspneu on effort occurred progressively since approximately 4 months. These complaints were also accompanied by hair loss and redness on both cheeks. Physical examination revealed increased jugular venous pressure, systolic murmur in left lower sternal border, ascites, hepatomegaly, and bilateral ankle oedema. Echocardiography revealed dilated right atrium and right ventricle (RV), decreased RV systolic function, severe tricuspid regurgitation, and distended inferior vena cava. Computed tomography (CT) pulmonary angiography showed filling defect in the left pulmonary artery. Lab examination showed an increase in D-dimer, ANA titer &amp;gt;1: 1000, and lupus anticoagulant ratio 1.59. Diuretics therapy, anticoagulant, corticosteroid, and immunosuppressant were given to this patient. Right heart function was improved following the treatment. Discussion The increased risk of thrombosis in this case is related to several factors, including: antiphospholipid antibodies, inflammation and disease activity. CTEPH is formed as a result of poor resolution of the thrombus in the pulmonary arteries, resulting in fibrosis of residual thrombotic material that can impede blood flow. Increased intrapulmonary pressure due to pulmonary vascular obstruction causes RV remodeling and dysfunction.

C85. Right heart failure due to chronic thromboembolic pulmonary hypertension in systemic lupus erythematosus patient: a case report

Abstract Background Systemic lupus erythematosus (SLE) is a chronic inflammatory disease with varying clinical manifestations and high risk of thrombosis. Chronic Thromboembolic Pulmonary Hypertension (CTEPH) as late complication of acute pulmonary embolic sometimes occured in SLE patients and in advanced condition it can manifest as right heart failure. Case Summary A female, 29 years old with complaints of bilateral ankle oedema and bloated stomach, as well as dyspneu on effort occurred progressively since approximately 4 months. These complaints were also accompanied by hair loss and redness on both cheeks. Physical examination revealed increased jugular venous pressure, systolic murmur in left lower sternal border, ascites, hepatomegaly, and bilateral ankle oedema. Echocardiography revealed dilated right atrium and right ventricle (RV), decreased RV systolic function, severe tricuspid regurgitation, and distended inferior vena cava. Computed tomography (CT) pulmonary angiography showed filling defect in the left pulmonary artery. Lab examination showed an increase in D-dimer, ANA titer &amp;gt;1: 1000, and lupus anticoagulant ratio 1.59. Diuretics therapy, anticoagulant, corticosteroid, and immunosuppressant were given to this patient. Right heart function was improved following the treatment. Discussion The increased risk of thrombosis in this case is related to several factors, including: antiphospholipid antibodies, inflammation and disease activity. CTEPH is formed as a result of poor resolution of the thrombus in the pulmonary arteries, resulting in fibrosis of residual thrombotic material that can impede blood flow. Increased intrapulmonary pressure due to pulmonary vascular obstruction causes RV remodeling and dysfunction.

Long-Term Evaluation of Antiphospholipid Antibodies in Patients with COVID-19

Background: The role of antiphospholipid antibodies (aPL) in COVID-19 coagulopathy remains controversial; moreover, follow-up data after >12 weeks are lacking.Methods: In this prospective single-centre study, we determined ‘criteria’ (IgG, IgM) and ‘non-criteria’ (IgA) anti–β2-glycoprotein I (anti-β2-GPI), and anti-cardiolipin (aCL) antibodies, as well as lupus anticoagulant (LAC) in 157 consecutive adult inpatients with COVID-19. Repeat testing was offered after >12 weeks to all patients with initially positive results.Findings: Patients had a median age of 69 years, and 38·9% were admitted to the intensive care unit (ICU). LAC was present in 35·6%, aCL in 12·5%, and anti-β2-GPI in 15·6% of the patients, respectively. The most commonly detected isotype was IgA (17·1%), followed by IgM (5·9%), and IgG (2·6%). Occurrence of LAC and/or aPL was observed in 73 (48·7%) patients and was associated with ICU treatment and higher C-reactive protein (p=0·009, and p=0·019 respectively), but not with thromboembolic events (p=0·130) when compared to the aPL-negative population. Patients with IgA double-positivity showed an increased 30-days mortality (75·0% vs 95·1%; p=0·001). Of the 73 patients with positivity for LAC and/or aPL, 38 (52·1%) patients were available for follow-up after >12 weeks. The median LAC ratio decreased from 1·30 (1·22-1·37) at first timepoint to 1·15 (1·10-1·25) (p=0·001) at follow-up, while aPL positivity remained unchanged.Interpretation: aPL are a transient phenomenon in COVID-19 most likely related to ‘non-criteria’ antibodies and inflammation and are associated with disease severity, but not with macrothrombotic events. Patients with double positivity for IgA aPL have an inferior survival probability.Funding Statement: Laboratory testing was supported in parts by Axonlab and Thermo Fisher Scientific.Declaration of Interests: Dr. Gerber reports non-financial support and funding for accredited continuing medical education program from Axonlab, and from Thermo Fisher Scientific, during the conduct of the study; personal fees and funding for accredited continuing medical education program from Alnylam, grants, personal fees and funding for accredited continuing medical education program from Pfizer, funding for accredited continuing medical education program from Bayer, Bristol Myers Squibb, Daiichi-Sankyo, Takeda, Octapharma, SOBI, Janssen, Novo Nordisk, Mitsubishi Tanabe Pharma, outside the submitted work; Dr. Rossi reports unrestricted research grant, consultancy, travel from Jannsen, Abbvie, and AstraZeneca, outside the submitted work; Dr. Bernasconis institution received fees for his participation to advisory boards, travel grants from Gilead Sciences, ViiV Healthcare, Merck Sharp and Dohme, Pfizer, Abbvie, Sandoz AG, outside the submitted work; All other authors have nothing to disclose.Ethics Approval Statement: Clinical data were extracted from the electronic medical records. The study was approved by the Ethical Committee Ticino, Switzerland (2020-00838 RIF.CE 3621), and the need for a written informed consent was waived due to the non-interventional design of the trial with use of pre-existing biological material and health care data.

Predicting coronary graft occlusion in males with type 2 diabetes: an annual prospective study

Aim. Identification of factors affecting coronary bypass graft patency in patients with type 2 diabetes (T2D) during one year after coronary bypass grafting.Materials and methods. Coronary artery bypass grafting for stable effort angina was ordered in 23 men with T2D. The patients had transthoracic echocardiogram before surgery. All patients were verified for lupus anticoagulant (LA) in blood on the 14th day after surgery. A year later, the patients underwent coronary shuntography to assess bypass patency.Results. LA was detected in 15 of 23 patients (65%). One year after surgery, occlusions of coronary shunts were revealed in 10 of 23 patients. In patients with coronary shunt occlusions, end-diastolic and end-systolic dimensions, end-diastolic and end-systolic volumes, end-systolic and end-diastolic indices (EDD, ESD, EDV, ESV, ESI, EDI, respectively), as well as the LA ratio significantly exceeded those in patients without occlusions (Mann—Whitney p values 0.004, 0.012, 0.012, 0.006, 0.006, 0.004, 0.017, respectively). A method is proposed for predicting coronary shunt occlusions based on assessment of end-diastolic volume of left ventricle and the LA ratio.Conclusion. Echocardiographic values for left ventricle (EDD, ESD, EDV, ESV, ESI, EDI) and the LA ratio are predictors of coronary graft occlusions in patients with type 2 diabetes.

Andexanet Alfa Corrects the Interference of Direct Factor Xa Inhibitors on Lupus Anticoagulant Testing

BackgroundDirect Factor Xa (FXa) inhibitors (e.g. rivaroxaban or apixaban) are widely used oral anticoagulants and are known to interfere with dilute Russell's viper venom time (dRVVT) and aPTT-based lupus anticoagulant (LA) testing, often yielding false-positive LA results. A false positive LA result might incorrectly diagnose a patient with the anti-phospholipid antibody syndrome and lead to a wrong decision for long-term anticoagulation to prevent recurrent thrombosis.Andexanet alfa is a recombinant modified human FXa decoy protein that has been specifically designed as an antidote to neutralise the effect of the direct and indirect FXa inhibitors.AimTo determine whether the addition of andexanet alfa can overcome the interference of rivaroxaban and apixaban on LA testing in plasma samples from both LA positive and LA negative patients.MethodsAfter written informed consent, citrated blood (20mL) was collected from 12 patients on therapeutic doses of rivaroxaban (n=6) or apixaban (n=6) with previously known LA status (3/6 LA positive in each group). Samples were double centrifuged at 3,000 x g for 10 minutes and aliquots were frozen at -40oC until analysed. Normal pooled plasma and rivaroxaban and apixaban calibrated plasma was obtained from a commercial source (Diagnostica Stago) or control plasma from healthy volunteers, prepared as above. IgG was purified by a Protein G column from a known LA positive patient and a control healthy volunteer.Rivaroxaban (Bayer) and apixaban (Bristol-Myers Squibb) tablets were crushed and dissolved in DMSO. Andexanet alfa (Portola Pharmaceuticals, Inc.) was dissolved in distilled water and aliquots were frozen at -40oC until used. Plasma samples were spiked with varying concentrations of FXa inhibitors and andexanet alfa.LA-sensitive aPTT, PT, TCT, dRVVT (Siemens Healthcare Diagnostics) and anti-FXa level (Diagnostica Stago) were performed with and without andexanet alfa on the Sysmex CS5100 analyser.Andexanet alfa (at a final concentration of 250µg/mL) was added to LA positive and LA negative plasma samples to assess the impact on the dRVVT normalised ratio.ResultsAndexanet alfa demonstrated a concentration-dependent increase in LA sensitive aPTT and dRVVT clotting times, with negligible impact on PT or TCT. Andexanet alfa was capable of reversing FXa inhibition in a concentration-dependent manner in plasma samples containing rivaroxaban or apixaban.When rivaroxaban is added to normal plasma it significantly prolongs the dRVVT without phospholipid more than with excess phospholipid leading to a false-positive LA ratio at final concentrations >100ng/mL. This level of rivaroxaban is in the therapeutic range. The addition of andexanet alfa reduced the measurable anti-FXa level and returned the normalised dRVVT ratio to LA negative result (<1.25). In contrast, apixaban and andexanet alfa proportionately prolongs the dRVVT with or without excess phospholipid and even at high concentrations, the normalised LA ratio remains negative (<1.25).Andexanet alfa converted the false positive dRVVT rivaroxaban patient plasmas LA ratio to negative. True LA positive patients remained positive after the addition of andexanet alfa. These results were confirmed by adding LA positive and control purified IgG to known concentrations of rivaroxaban and apixaban (200ng/ml) in normal plasma.ConclusionAndexanet alfa corrects the false positive LA ratio in patients on rivaroxaban without affecting the true diagnosis in LA positive patients. Apixaban and andexanet alfa proportionately prolong the dRVVT with and without phospholipid, so the LA ratio remains negative. For this reason true LA positive patients can be diagnosed whilst on apixaban at therapeutic concentrations without the addition of andexanet alfa. DisclosuresBaker:Biogen Idec: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novo Nordisk: Other: Conference travel support; Astellas and CSL Behring: Research Funding; Bristol-Myers Squibb: Research Funding; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Shire: Membership on an entity's Board of Directors or advisory committees, Other: Conference travel support, Research Funding; Daiichi Sankyo: Research Funding; Portola Pharmaceuticals: Research Funding; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Conference travel support; Biogen Idec: Membership on an entity's Board of Directors or advisory committees; Alexion Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Other: Conference travel support, Research Funding; Roche: Other: Conference travel support. McGregor:Gilead: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Equity Ownership, Other: Conference travel support; Pfizer: Other: Conference travel support; Roche: Honoraria; Abbvie: Equity Ownership; Portola Pharmaceuticals: Equity Ownership.

Dilute Russell's viper venom time reagents in lupus anticoagulant testing: a well-considered choice.

Lupus anticoagulant (LAC) detection represents diagnostic challenges among which the multitude of available reagents and interference by anticoagulant treatment. One of the two advised tests is the dilute Russell's viper venom time (dRVVT). However, it is currently not clear whether all dRVVT reagents may be considered equivalent. The objective of the study was to evaluate the diagnostic performance of two dRVVT reagents, with special attention to the influence of anticoagulant therapy. STA®-Staclot® dRVV Screen/Confirm (Stago, Asnières-sur-Seine, France) and dRVT-LS/dRVTL-LR (Haematex, Hornsby, Australia) were evaluated on 443 patient samples [358 consecutive patients with LAC request including six antiphospholipid syndrome (APS) patients, 18 non-consecutively selected APS patients and 37 vitamin K antagonists (VKA)-treated and 30 direct oral anticoagulants (DOAC)-treated non-APS patients]. Additionally, pooled normal plasma (PNP) was spiked with factor deficient plasma (n=33) and DOAC calibrators (n=21) to evaluate sensitivity for factor deficiencies and false-positivity rates, respectively. A higher number of samples were defined as LAC positive by Stago vs. Haematex [11.5% (41/358) vs. 3.63% (13/358)]. Most discordances were in the VKA and DOAC group. Haematex was less prone to VKA-related factor deficiencies, explaining the absence of false-positive LAC results in VKA-treated non-APS patients compared to 10.8% with Stago. We observed no false-positive LAC ratios with Haematex in DOAC-spiked PNP and a lower number in DOAC-treated non-APS patients. However, increased specificity seemed to be at cost of a reduced sensitivity as Haematex showed less positive APS patient samples (45.8% vs. 87.5%). dRVVT reagents differ in LAC sensitivity and for VKA and DOAC interference.

Testing for lupus anticoagulants – fresh or frozen?

There are no previous studies reporting the effect of using frozen-thawed plasma on lupus anticoagulant ratios in kits with the combined screen and confirm assay. In the following study we chose patients with elevated dilute Russel's viper venom test (dRVVT) normalized ratios and compared the test results of fresh to frozen-thawed plasma. Platelet counts ranged from 2 to 7×10(3)/μL (10(9)/L) after a second centrifugation before freezing. There were 13 out of 14 dRVVT test normalized ratios that decreased after freezing (p<0.001), leading to the misclassification of six of 14 patients with high values that decreased into the reference interval. The major finding of this study is that testing frozen-thawed plasma with platelet counts <10,000/μL (10(9)/L) results in a significant decrease in dRVVT ratios. Although there was a consistent decrease in SCT normalized ratios as well, it did not lead to misclassifications.

Improved Distinction of Factor V Wild-Type and Factor V Leiden Using a Novel Prothrombin-Based Activated Protein C Resistance Assay

A new prothrombin-based activated protein C resistance (APC-R) test is described. In this method, the patient sample is prediluted in a plasma depleted of factor V (FV). A reagent containing APC and a specific activator of FV is added. After an incubation period, clotting is initiated by the addition of the FV-dependent prothrombin activator Noscarin. We analyzed 703 samples from patients undergoing thrombophilia screening. By using a predefined cutoff ratio of 2.5, 100% sensitivity and specificity for the detection of a factor V Leiden (FVL) mutation was found. With a cutoff ratio of 1.2, a complete but narrow distinction of FVL heterozygous (n = 192) and FVL homozygous samples (n = 27) was determined. No interference by the international normalized ratio, activated partial thromboplastin time (aPTT), protein S activity, fibrinogen and factor VIII (FVIII) levels, or lupus anticoagulant ratio was detected. The new prothrombin-based APC-R assay provides improved distinction of FV wild-type and FVL carriers compared with the aPTT-based method. By the use of an FV-dependent prothrombin activator, the assay is not influenced by FVIII concentration or lupus anticoagulants.

Improved Detection of FV Leiden Patients Using a Novel Snake-Venom-Based Activated Protein C Resistance Assay.

A new functional prothrombin-based activated protein C (APC) resistance (APC-R) test (Pefakit® APC-R Factor V Leiden, Pentapharm, Basel, Switzerland) is presented.Methods: The plasma sample is mixed with a reagent containing APC and snake venom specifically activating FV (RVV-V, Daboia russelli) and plasma that has been depleted of FV. During an incubation period of 180 sec the activated FV is inactivated by APC. Subsequently a reagent that contains a FV dependent prothrombin activator (Noscarin, Notechis scutatus) and EDTA is added. The clotting time is recorded. A second determination is performed under identical conditions, with the exception that no APC is added to the first reagent. A ratio between the two measurements is calculated. 703 samples of patients undergoing thrombophilia screening were analysed. Results were correlated to PCR based FVL testing, aPTT, PT, and to levels of Protein C, Protein S, Fibrinogen, FVIII and lupus anticoagulant index.Results: Using a predefined cut-off of a ratio of 2.5 a 100% sensitivity and specificity for the detection of a FVL mutation was found. Using a cut-off ratio of 1.2 a complete but narrow distinction of FVL heterozygous (n=192) and FVL homozygous samples (n=27) was determined. No interference by sample's INR and aPTT, PS, fibrinogen and FVIII levels and lupus anticoagulant ratio was detected.Conclusion: The new snake-venom-based APC-R assay provides an improved distinction of FV wild-type and FVL carriers compared to the data reported for the aPTT based methods. The use of a FV dependent prothrombin activator eliminates effects of FVIII concentration or lupus anticoagulants in the sample.

Anticardiolipin antibodies and lupus anticoagulant in patients treated with different methods of renal replacement therapy in comparison to patients with systemic lupus erythematosus

Antiphospholipid antibodies were found to be associated with certain clinical manifestations such as recurrent venous thrombosis or arterial occlusions in a wide spectrum of immune disorders [6]. We analyzed the plasma concentration of two isotypes (IgG, IgM) of anticardiolipin antibodies (ACA) and lupus anticoagulant (LAC) activity in 84 patients with end-stage renal disease. They were receiving different types of renal replacement therapy and had a high frequency of thrombotic vascular complications. The prevalence of positive tests and the mean ACA concentration obtained in the plasma of renal patients were compared with those in patients with systemic lupus erythematosus (SLE) and in healthy controls. When analyzed as a whole group, renal patients maintained on dialysis (n = 45: hemodialysis, n = 20; peritoneal dialysis) or with a functioning kidney transplant (n = 19) did not differ in mean ACA concentration and LAC activity (n = 84, ACA: IgG 10 +/- 7 U/ml, IgM 2 +/- 1 U/ml, LAC ratio: 1.0 +/- 0.2) from healthy subjects (n = 50, ACA: IgG 10 +/- 3, IgM 2 +/- 1 U/ml, LAC ratio: 1.0 +/- 0.1) but they had a higher incidence of raised IgG-ACA titers (renal replacement 14% vs. normal controls 4%, p less than 0.05). No significant correlation was found between thrombotic events and raised ACA or LAC activity in dialysis patients. In contrast, the proportion of SLE patients (n = 51) with a raised concentration of ACA was significantly higher (IgG: 69%, IgM: 29%) than that among patients with renal replacement therapy (IgG: 14%, IgM: 4%) or normal controls (IgG: 4%, IgM: 2%, p less than 0.002). Moreover, recurrent manifestations of thrombosis in SLE were associated with very high IgG-ACA (n = 11, IgG 117 +/- 91 U/ml) and LAC activity (LAC ratio: 2.4 +/- 0.7) in comparison to SLE patients without thrombotic events (n = 40, ACA: IgG 23 +/- 13). The results of our investigations demonstrate that the pathogenetic role of these phospholipid antibodies in end-stage renal disease is far from established.