Lupus Anticoagulant Research Articles

Lupus Anticoagulant and Anticardiolipin Antibody IgG are Associated with Increased Atherosclerosis at the Suprainguinal Elastic and Infrainguinal Muscular Arteries in the Abdomen and Lower Extremities

PurposeWhether antiphospholipid antibodies (aPLs) cause atherosclerosis in certain arteries with specific compositions and locations remains unknown. We investigated the relationship between aPLs and their association with locations of atherosclerosis in the arteries of the abdomen and lower extremities.MethodsOf 2273 patients, 697 who underwent computed tomography angiography of the abdomen and lower extremities and aPL evaluation were included. Atherosclerosis distribution score (ADS) was employed to quantify atherosclerosis severity. Multiple linear regression analysis was performed using the ADS of the suprainguinal elastic and infrainguinal muscular arteries as dependent variables and all aPLs, conventional risk factors of atherosclerosis, and coagulation-related factors as independent variables.ResultsIn the suprainguinal elastic and infrainguinal muscular arteries, common risk factors for higher ADS were age, smoking, hypertension, higher glycated hemoglobin, male sex, decreased protein S, and increased homocysteine. Lupus anticoagulant (LA) and increased triglyceride level in the suprainguinal elastic arteries and anticardiolipin antibody (aCL) immunoglobulin (Ig)G, longer alcohol consumption duration, and increased fibrinogen level in the infrainguinal muscular arteries were also risk factors for higher ADS.ConclusionLA and aCL IgG were associated with atherosclerosis in the suprainguinal elastic and infrainguinal muscular arteries, respectively. aPLs could predict the location of atherosclerosis.

Lupus nephritis as a specific clinical and immunological phenotype of systemic lupus erythematosus

Lupus nephritis (LN) is the leading cause of death in systemic lupus erythematosus (SLE), so its early detection and treatment is of utmost importance. Features of the onset, clinical signs, certain morphological classes, as well as more aggressive therapy make it possible to assign SLE with LN to a distinct disease phenotype.Objective: to characterize the clinical, immunological and morphological features of the SLE phenotype with a predominant kidney involvement based on a comparative analysis of patients with LN and without LN.Patients and methods. The study included 400 patients with SLE who met the 2012 SLICC criteria and were hospitalized to V.A. Nasonova Research Institute of Rheumatology from 2013 to 2021. The diagnosis of LN was established in 192 (48%) patients, of which in 82 (43%) it was confirmed by pathological study of kidney biopsy specimens (the SLE group with LN). In 208 (52%) patients, no kidney damage was observed, and they constituted the SLE group without LN.All patients underwent a standard examination with an assessment of disease activity according to the SLEDAI-2K index, irreversible changes in organs according to the SLICC damage index, immunological disorders, clinical and biochemical blood tests, urinalysis according to unified methods, glomerular filtration rate, as well as pathological examination of kidney biopsy specimens for confirmation of LN in the presence of an appropriate clinical picture. In patients of both groups, a comparative study of the main clinical, laboratory, immunological manifestations of SLE, the features of the disease onset, its first clinical signs, possible trigger factors, and the drugs used was carried out.Results and discussion. In the LN group, insolation was more likely to trigger the development of SLE than in the group without LN (respectively, in 26% and 13% of cases; p=0.007). In turn, SLE without kidney damage more often than SLE with LN debuted during pregnancy or after childbirth.The first signs of the disease in almost 40% of patients with LN were proteinuria and/or changes in urinary sediment, edema, increased blood pressure, the development of LN in some cases was preceded by polyarthritis or combined lesions of the skin and joints, but no later than 6 months, signs of kidney damage appeared. In the SLE group without LN, polyarthritis (in 33%), combined lesions of the skin and joints (in 26%), and Raynaud's syndrome (in 16%; p <0.0001) were more often observed at the onset. In patients with LN, erythematous lesions of the facial skin ("butterfly", in 42%), serositis (exudative pleuritis — in 44%, pericarditis — in 46%, ascites and hydrothorax — in 5%; p<0.0001), as well as hematological disorders such as anemia (in 63%), leukopenia (in 49%) and thrombocytopenia (in 42%) were present more frequently. With the development of LN, an acute course and high activity of the disease occurred significantly more often. In the study of immunological parameters in the group without LN, lupus anticoagulant (in 6%) and antibodies to SS-A/Ro and SS-B/La (in 18 and 9% of patients, respectively) were detected significantly more often, while in the LN group — hypocomplementemia (in 81%; p<0.0001). Therapy also differed significantly: patients with LN received higher doses of glucocorticoids (p<0.0001), mycophenolate mofetil, and cyclophosphamide.Conclusion. SLE with LN can be considered a distinct disease phenotype with a set of characteristics (clinical and laboratory parameters, response to therapy, prognosis) that distinguish it from other SLE variants.

Thrombophilia and outcomes of venous thromboembolism in older patients

BackgroundLimited data exist on thrombophilic risk factors and clinical outcomes in the elderly with venous thromboembolism (VTE). ObjectivesTo describe the prevalence of laboratory thrombophilic risk factors and their association with VTE recurrence or death in a cohort of elderly people with VTE. MethodsIn 240 patients aged ≥65 years with acute VTE without active cancer or an indication for extended anticoagulation, we performed laboratory thrombophilia testing 1 year after the index VTE. Recurrence or death was assessed during the 2-year follow-up. ResultsA total of 78% of patients had ≥1 laboratory thrombophilic risk factor(s). Elevated levels of von Willebrand factor, homocysteine, coagulant activity of factor VIII (FVIII:C), fibrinogen, FIX:C, and low antithrombin activity were the most prevalent risk factors (43%, 30%, 15%, 14%, 13%, and 11%, respectively). Additionally, 16.2% of patients experienced VTE recurrence and 5.8% of patients died. Patients with a von Willebrand factor of >182%, FVIII:C level >200%, homocysteine level >15μmol/L, or lupus anticoagulant had a significantly higher rate of recurrence than those without these risk factors (15.0 vs. 6.1 [P = .006], 23.5 vs. 8.2 [P = .01], 17.0 vs. 6.8 [P = .006], and 89.5 vs. 9.2 [P = .02] events per 100 patient-years, respectively). Furthermore, patients with a high fibrinogen level or hyperhomocysteinemia with a homocysteine level ≥30 μmol/L had significantly higher mortality than patients with normal levels (18.5 vs. 2.8 [P = .049] and 13.6 vs. 2 [P = .002] deaths per 100 patient-years, respectively). After adjustments for relevant confounders, these associations remained unchanged. ConclusionLaboratory thrombophilic risk factors are common in elderly people with VTE and allow for the identification of a population at the risk of worse clinical outcomes.

Interference in point-of-care international normalized ratio monitoring in patients with lupus anticoagulant is correlated with anti–β2-glycoprotein I antibody titers

BackgroundPatients with antiphospholipid syndrome (APS) receive anticoagulant therapy with vitamin K antagonists (VKAs) to prevent recurrent thrombosis. VKA treatment requires strict monitoring with an international normalized ratio (INR). It is known that lupus anticoagulants (LAs) can lead to elevated INR results with point-of-care-testing (POCT) devices, which could result in inadequate adaptation of anticoagulant therapy. ObjectiveTo determine discrepancies between POCT-INR and laboratory-INR in patients who are LA-positive on VKA therapy. MethodsPaired INR testing was performed with 1 POCT device (CoaguChek XS) and 2 laboratory assays (Owren and Quick method) in 33 patients with LA-positive APS on VKA in a single-center cross-sectional study. Patients were tested for anti–β2-glycoprotein I, anticardiolipin, and antiphosphatidylserine/prothrombin immunoglobulin (Ig) G and IgM antibodies. Agreement between assays was evaluated with Spearman’s correlation, Lin’s correlation coefficient, and Bland–Altman plots. Agreement limits were considered satisfactory if differences were ≤20% as determined by the Clinical and Laboratory Standards Institute. ResultsWe found poor agreement between POCT-INR and laboratory-INR based on Lin’s concordance correlation coefficient (ρc) of 0.42 (95% CI, 0.26-0.55) between POCT-INR and Owren-INR, a ρc of 0.64 (95% CI, 0.47-0.76) between POCT-INR and Quick-INR, and a ρc of 0.77 (95% CI, 0.64-0.85) between Quick-INR and Owren-INR. High anti-β2-glycoprotein I IgG antibody titers correlated with INR disagreement between POCT-INR and laboratory-INR. ConclusionThere is a disagreement between INR values measured with the CoaguChek XS and laboratory-INR in a proportion of patients with LA. Consequently, laboratory-INR monitoring should be preferred over POCT-INR monitoring in patients with LA-positive APS, especially in patients with high anti-β2-glycoprotein IgG antibody titers.

Lupus anticoagulants as a prospective independent predictor in COVID-19 patients.

Lupus anticoagulant (LA) are commonly detected during SARS-CoV-2 infection. However, the relationship between LA and clinical significance is still unclear. A retrospective chart analysis was performed on COVID-19 patients who were tested for LA at our hospital from March 2020 to November 2021. We analyzed the patient's characteristics based on the result of the LA test. In addition, subgroup analysis performed the LA-positive group who had undergone serial LA tests. A total of 219 COVID-19 patients were enrolled in the study, 148 patients (67.6%) were positive for LA test. The LA-positive group received more treatment of high flow nasal cannula (LA-positive 73.0%, LA-negative 57.7%, p=0.024). The LA-positive group showed prolonged aPTT, higher levels of CRP and fibrinogen (all p's < 0.05). Among 148 LA-positive patients, 127 patients (86.5%) were found to be LA-positive within 10 days of SARS-CoV-2 positive, and LA-positive group confirmed a median time to LA loss of 10 days. However, there was a group that was negative for LA in the early stages of infection and became positive about 13 days later. A subgroup analysis showed that these patients had different characteristics due to their longer hospital stays and higher D-dimer levels. In COVID-19 patients, LA is expected to be associated to disease severity. Since the clinical significance of LA is different depending on the onset time of LA positivity, the LA test is suggested to be done at diagnosis of SARS-CoV-2 infection, even if LA is negative, follow-up test should be considered within 10 days.

How to assess parallelism in factor assays: coefficient of variation of results with different dilutions or slope ratio?

Non-parallelism in factor assays can lead to incorrect factor activities. Parallelism can be assessed by calculating the coefficient of variation (CV) of results obtained on 3 dilutions of the same sample. Some authors have proposed that if there is <15% then the average activity is reportable. Some analysers use a slope ratio (SR) to calculate parallelism, with an acceptance range of approximately 0.9-1.1. We evaluated CV and SR in one stage FII-FXII assays on Sysmex CS5100i using Innovin or Actin FS. Frozen normal and pathological plasmas, plasmas containing Direct Oral Anticoagulants, Direct Thrombin Inhibitors or Lupus Anticoagulant were analysed to assess possible non-parallelism. In plasmas with factor levels >25 IU/dl (plus no interfering substances) all CVs were < 15%. One sample (low factor activities 10-15 IU/dl), had CVs > 15% in FII, FVII and FXII assays only. SR outside of 0.9-1.1 were seen in FII and FXII assays at different levels of clotting factor including some within the normal range. Non-parallelism was detected more frequently with SR than CV for those with interfering substances. SR outside of 0.9-1.1 were seen in different levels of clotting factors, including samples which did not contain interfering substances. The target of 15% CV was a better discriminator than a SR for acceptance. When factor levels were reduced to around 10-15 IU/dl, a target 20 %CV was more appropriate than 15%. It might be appropriate for laboratories to assess locally whether their acceptance criteria need to be wider at low levels of clotting factors.

A Clinical Approach of Lupus Nephritis Associated with Catastrophic Antiphospholipid - Antibody Syndrome - Review and Case Report

Abstract Glomerulonephritis is a major cause of morbidity in systemic lupus erythematosus (SLE). In fact, immune complex formation and deposition in the kidney results in intraglomerular inflammation with recruitment of leukocytes and activation and proliferation of resident renal cells. Intense injury may destroy resident renal cells by necrosis or apoptosis resulting in fibrinoid necrosis. When injury is less intense, endocapillary cells respond by proliferating and production of extracellular matrix (proliferative lesions). Renal biopsy, examination of urine sediment and measurement of C3 levels (and to less anti-DNA titers) are essential for the management of lupus nephritis. Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by thrombotic episodes in the arterial or venous circulation, in the presence of antiphospholipid antibodies (aPL), namely lupus anticoagulant (LA), anticardiolipin antibodies, and anti-β2glycoprotein-I antibodies (anti-β2GPI). Catastrophic APS (CAPS) is a very rare (---lt---1%) and extremely severe variant of APS. It is characterized by multiple systems and thrombotic organ involvement that occurs in a very short period (days to weeks). Renal involvement is a common feature in CAPS, the most frequent finding is thrombotic microangiopathy (TMA), but other chronic lesions of APSN can also be found.

The Effect of Polybrene on an aPTT-based Lupus Anticoagulant Test in the Plasma of Patients Receiving Unfractionated Heparin

Objective: Heparins can interfere with lupus anticoagulant (LA) testing, especially when the detection assays do not contain a heparin neutralizer. In this study we evaluated whether hexadimethrine bromide commonly known as polybrene was able to neutralize the effects of unfractionated heparin (UFH) on activated partial thromboplastin time (aPTT)-based LA determination. Material and Methods: The influence of polybrene on the aPTT-based LA testing results of 14 patients receiving UFH therapy was studied. Measurements were performed using Dade Actin FSL (aPTT-LA screen) and Dade Actin FS (aPTT-LA confirm) reagents on a Sysmex CS-1600 analyzer. The aPTT-LA screen/confirm ratios before and after the polybrene treatments were compared. Results: The UFH treatment affected the aPTT-LA screen/confirm ratio in four patterns, 1) no coagulation (NC code), 2) false positive, 3) false low, and 4) unchanged interpretation. After adding polybrene in the patient plasmas, the aPTT-LA screen/confirm ratios returned nearly to baseline without false positive or negative results. Conclusion: The best practice for LA testing should be done outside anticoagulant therapies, but if necessary, the tests can be performed by adding the proper concentration of polybrene.

Evaluating the Relationship Between Antiphospholipid Antibodies and COVID-19 Severity.

Coronavirus 2 (COVID-19) has emerged as a new global pandemic, causing severe acute respiratory syndrome. Furthermore, the existence of antiphospholipid (APL) antibodies (Abs) and ultimately patient death may be linked to the occurrence of thrombotic events in patients with COVID-19. We aimed to investigate if there was a link between the presence of APL Abs and the severity of COVID-19 disease in patients at the Vali-Asr Hospital in Zanjan from June to July 2021. Real-time PCR was used to diagnose COVID-19 in 76 hospitalized patients. A total of 38 patients were hospitalized in the internal medicine ward and another 38 people were admitted to the intensive care unit of the Vali-Asr Educational Hospital in Iran's Zanjan region. Lupus anticoagulant (LAC) detection was done using the dilute Russell viper venom time method, and tests for anticardiolipin (ACL) Abs, IgG and IgM, and anti-beta2 glycoprotein 1 Abs, IgG and IgM, were done on blood and plasma samples of linked patients using the enzyme-linked immunosorbent assay technique. SPSS 24 was used to analyze data. Our findings showed that the presence of LAC was associated with disease severity in COVID-19 patients (p = 0.001). However, there was no significant relationship between APL Abs and mortality in patients affected with COVID-19. The evaluation of APL Abs, particularly LAC, in COVID-19 patients appears to be helpful in predicting the severity of the disease.

New CMC Algorithm for Evaluation of Lupus Anticoagulant

Introduction: Lupus Anticoagulant (LA) is an autoantibody that in vitro inhibit phospholipid-dependent coagulation reactions in the absence of specific coagulation factor inhibition Primary laboratory criteria for LA detection include prolonged clotting time of a phospholipid dependent test, failure of correction on mixing study, shortening of the clotting time in the presence of high phospholipid concentrations & absence of other inhibitors. (1) According to guidelines,for diagnosing LA two tests based on different principles should be used- dRVVT(Dilute Russel's Viper Venom Time) should be the first test considered. Second test should be a sensitive aPTT (Activate Partial Thromboplastin Time).LA is a multistep procedure with screening, mixing and confirmation tests. Devreese et al recently concluded that integration of screening and confirmation in a single procedure and skipping the mixing tests result in a poor diagnostic efficacy for LA (2).LA is an in-vitro inhibitor and elevated Screening test without mixing studies does not prove inhibitor effect & it wastes time & resources to perform confirmatory tests skipping the mixing. Hence, we devised a new algorithm- Christian Medical College (CMC) Algorithm as shown in figure-1 which starts with DRVVT Screen Mix. To identify interferences due to anticoagulants like heparin and fibrin degradation products (FDP) thrombin time (TT) was also included. If Screen Mix is normal APTT Screen Mix was performed. Aim of our new algorithm was to reduce false positives and avoid interferences in LA Materials and methods: Four hundred and ninety-one (491) samples were analysed retrospectively for a period of 5 months from January 2022 to May 2022. The new algorithm was incorporated into STA R Max2 (Diagnostica Stago) analyser and automatic calculation of ratios and interpretation of results were done based on flow charts. LA testing was performed using DRVVT screen and confirm reagents (STA-Staclot DRVV Screen and STA-Staclot DRVV Confirm) and/or APTT reagent (STA-PTT Synthasil). LA test was considered positive when Screen/ Confirm(S/C) ratio was >1.2. We compared this result to the three hundred forty seven(347) samples, over a period of 4 months(September 2021 - December 2021) analyzed in old algorithm where DRVVT screen & APTT were done as the initial steps instead of DRVVT mixing studies as the 1st step. Results: In the new algorithm result were classified into 7 categories. Category 1 had normal DRVVT screen Mix and normal APTT; these represent true negative cases comprising 68.8 % of the cases. Category 2 had normal DRVVT screen Mix, prolonged APTT Screen Mix with normal TT. 1 case in this category had other Antiphosholipid Antibody (APLA) negative & repeat testing for LA was advised. Category 3 had normal DRVVT Screen mix, prolonged APTT Screen Mix with prolonged TT. There was 1 case in this category, who was on heparin, APLA antibody was negative. Repeat testing was advised at a later date. Category 4 had prolonged DRVVT Screen Mix, normal S/C ratio , with normal TT. There were 61 cases (12%) in this category among which 5 cases had normal DRVVT Screen with prolonged Mix Category 5 had Prolonged DRVVT Screen Mix, with normal S/C Ratio, prolonged TT and this category had 13 (2 %) cases. On further evaluation they were found to be on anticoagulants. Category 6 had prolonged S/C Ratio with normal TT, which are the true positive cases, n=67 (13.6%). There were 4 cases where Screen mix was more prolonged than Screen, and Screen fell below the cut off & could have been missed if mixing step was not done Category 7 had prolonged S/C ratio with prolonged TT. There were 10 cases (2%) in this category. On further evaluation 6 patients had history of anticoagulants and 2 had features of DIC. These 8 patients could represent false positive LA and would have been misclassified if TT was not done. Old algorithm had 20 % positive cases & 80 % negative cases. Since the algorithm were incorporated into STA R Max2 hands on time decreased from 240 minutes to 80 minutes. Cost of the reagents were similar by 2 algorithms. Conclusion: The new algorithm gives better clarity in classification of patients into true positive and true negative & detection of interference due to heparin as thrombin time is also done in parallel. Possible false positive cases could be identified at the onset even before repeat confirmatory lupus testing. This study concludes the importance of mixing studies in avoiding false negatives. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

A Case Series of Immune Flare and Lupus Anticoagulant Following COVID-19 Vaccination

Background: Vaccination against COVID-19 has garnered concerns for unusual post-vaccination complications. We present 2 cases of immune flare following COVID-19 vaccination. Case Report: Our first patient was a 53-year-old male who presented with a swollen left leg, hypoxia and palpitations after a trans-Atlantic flight. Chest computed tomography showed bilateral subsegmental pulmonary emboli, with no evidence of right heart strain and Doppler ultrasonography of the lower extremities showed significant clot burden in the left femoral, popliteal, tibial and peroneal veins. Workup revealed thrombocytopenia of 81,000/μL (normal range [NR] 150,000-450,000/μL), elevated D-dimer of 6.25 μg/ml (NR < 0.5 μg/ml), elevated partial thromboplastin time at 94 seconds without heparin. Mixing studies corrected partially to 60.9 seconds (NR 22.5-39.4), indicating the presence of an inhibitor, and lupus anticoagulant was confirmed with dilute Russell viper venom ratio of 3.66 (NR 0.00-1.20) and silica clotting time ratio of 3.95 (NR 0.00-1.22). Anti-beta-2 glycoprotein and anti-cardiolipin antibodies, factor V Leiden mutation, prothrombin G20210A mutation, protein C and protein S were negative. He received 2 doses of the ChAdOx1 nCoV-19 adenoviral vaccine 6 weeks previously. Due to suspicion for vaccine-induced thrombotic thrombocytopenia, enzyme-linked immunoassay for anti-platelet-factor 4 antibody was tested, which was negative. Immediate anticoagulation therapy with low-molecular weight heparin was started and then switched to rivaroxaban. Our second patient was an 18-year-old male who presented with 2 weeks of right-sided lower chest pain. The cardiopulmonary workup was negative, with a computed tomography of the chest showing a borderline enlarged spleen at 13 cm, and hepatic steatosis. He was taking indomethacin for slipped rib pain and was less mobile than usual. One week later, he developed left posterior thigh pain extending down the posterior calf and was found to have totally occluding left leg deep venous thrombosis from femoral vein mid to distal, popliteal, posterior tibial, peroneal, gastrocnemius and soleal veins. Workup was significant for prolonged partial thromboplastin time at 78 seconds, which partially corrected to 62 seconds with mixing studies, elevated C-reactive protein of 5.4, positive antinuclear antibodies (1:1280), normal complement (C3 and C4) and negative RF, SS A/Ro, SS B/La, RNP, smooth muscle, LKM antibodies. He started anticoagulation with low-molecular weight heparin, which was transitioned to apixaban. His family history was significant for lupus in his aunt and grandmother; however, there was no family history of thrombosis. He had received the third mRNA COVID vaccine 2 weeks prior to presentation. Additional workup revealed positive lupus anticoagulant, beta-2 glycoprotein, cardiolipin antibodies, and he was started on warfarin with a target international normalized ratio of 2-3 and repeat testing 3 months later revealed persistent elevation, indicating antiphospholipid syndrome. Although there was low suspicion for vaccine induced thrombotic thrombocytopenia, heparin-induced thrombocytopenia panel was performed and was negative. Discussion: Multiple SARS-CoV-2 vaccines were rapidly developed and approved, but long-term effects are unknown. Recombinant adenoviral vector-based vaccines raised concerns for an unusual post-vaccination coagulopathic syndrome with anti-platelet-factor 4 antibodies seen in 90% of probable and definite cases of vaccine-induced thrombotic thrombocytopenia (Pavord et al). Positive lupus anticoagulant has been noted with severe COVID-19 (Tung et al); however, our first patient had no history of COVID-19. This presentation was attributed at the time to a pro-inflammatory state induced by vaccination that may have caused lupus anticoagulant titers to rise leading to thrombosis as seen in this case. Autoimmune manifestations after COVID-19 vaccination are thought to be due to molecular mimicry, autoantibodies, vaccine adjuvants and a pro-inflammatory cascade among multiple other mechanisms (Chen et al). Similar to other viral infections, COVID-19 and additionally vaccination against it may lead to flare of immune mediated diseases (Talotta et al) as what occurred in our second patient with predisposition to hypercoagulable state given his family history of systemic lupus erythematosus.

Neural Network Diagnoses the Antiphospholipid Syndrome without Interrupting Anticoagulant Therapy

Background The antiphospholipid syndrome (APS) is characterized by the presence of antiphospholipid antibodies (aPL) and is associated with an increased risk of thrombosis and pregnancy morbidity. The Laboratory diagnosis of APS is difficult because most patients already use anticoagulants due to a thrombotic event, resulting in interference with the clotting assays used for lupus anticoagulant (LAC) testing. Nevertheless, the aPL profile defines patient management, making aPL testing warranted during anticoagulant therapy. Sometimes, cessation of anticoagulant treatment is necessary to perform the lupus anticoagulant (LAC) test, which is unfavorable. The thrombin generation (TG) test is a functional and global hemostatic test. Clinical studies have shown that increased TG is associated with thrombosis, also in thrombotic APS patients. We have previously shown that the artificial intelligence method neural networks can be used to diagnose untreated APS patients from a group of healthy, auto-immune disease, and thrombosis controls with high accuracy. At the moment of aPL testing, many patients are already on anticoagulants, hampering the detection of LAC. Therefore, we developed a neural net (NN) for diagnoses APS in a cohort of anticoagulated subjects, based on the TG test. Methods Antiphospholipid antibodies positivity was diagnosed according to the Sapporo-Sydney guidelines. TG was measured using the calibrated automated thrombogram assay (CAT) on platelet poor plasma with PPP reagent (intermediate concentration of tissue factor) in 48 APS patients and 64 control non-APS patients, both treated with vitamin K antagonists (VKAs) TG was explored in more depth by quantifying parameters of prothrombin conversion and thrombin inactivation, using thrombin dynamics (TD) analysis, and assessing the sensitivity of the activated protein C pathway through the addition of thrombomodulin (TM). Five NNs were developed and the most accurate NN was selected for clinical validation based on its sensitivity and specificity. Input parameters for the NN were TG parameters lag time, peak, endogenous thrombin potential, time-to-peak, and velocity index, and TD parameters total prothrombin conversion, maximum prothrombin conversion rate, thrombin-antithrombin complex formation, and thrombin-α2-macroglobulin complex formation, and the inhibition of TG and TD by TM. The top performing NN was clinically validated using the TG and TD data acquired in the validation cohort, consisting of 33 APS patients and 62 controls, both on VKA therapy, 49 auto-immune disease controls, 38 thrombosis controls, 92 patients visiting the hospital for other indications and 37 healthy subjects. All control subjects were negative for aPL. Results TG was slightly increased in APS patients compared to controls. VKA therapy abolished the typical lag time prolongation seen in non-anticoagulated APS patients due to the LAC effect. The rate of prothrombin conversion was significantly increased in anticoagulated APS patients compared to controls, indicating a more prothrombotic phenotype. The selected NN classified APS patients with a sensitivity of 92% and a specificity of 95% in the developmental cohort consisting of APS patients and controls on VKA antagonists (ROCAUC = 0.9805; 0.9542-1.000; p<0.0001). On average, controls and APS patients were assigned an APS likelihood score of 12% and 89%, respectively. The NN was clinically validated in a separate validation cohort of 311 individuals, including 33 anticoagulated APS patients, 62 anticoagulated controls, 38 thrombosis patients, 49 auto-immune disease patients, 92 hospital controls, and 37 healthy controls. The sensitivity of the NN for the detection of APS was 85%. The overall specificity of the NN was 93%, and 100%, 96%, 96%, 92% and 76% respectively in healthy controls, auto-immune disease controls, hospital controls, anticoagulated controls, and thrombosis controls. Conclusions We developed a NN that accurately classifies APS under anticoagulant treatment. Therefore, this NN could be an alternative for diagnosing APS patients already treated with VKAs. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

The Lupus Anticoagulant Titer Is Associated with Elevated Anti-Phosphatidyl-Serine/Prothrombin Antibody Levels

Background Laboratory diagnosis of the antiphospholipid antibody syndrome (APS) requires evidence of persistently positive lupus anticoagulant (LAC) activity in clot-based assays and/or the presence of medium-high titer anticardiolipin (aCL) and/or anti-beta 2 glycoprotein I (aB2GPI) antibodies. Although aCL and aB2GPI methodologies provide quantitative information about the antibody titer, LAC testing is interpreted in a qualitative fashion (presence versus absence). Objectives In this study, we describe a method for measuring the LAC titer and evaluate the relationship between the LAC titer, other antiphospholipid antibodies and clinical outcomes. Methods Residual plasma from 51 LAC-positive samples (50 unique patients) were included in this study. To estimate LAC-titers, samples were tested undiluted and subjected to serial (dependent) twofold dilutions in pooled normal plasma (PrecisionBiologic) up to a final dilution of 1:128, as appropriate. The dilute Russell's viper venom screening time (DRVVT screen, LA Check, PrecisionBiologic) and activated partial thromboplastin screening time (APTT, SynthasIL, Werfen) were measured for each dilution. A four-parameter logistic model of the dilution factor versus the clotting time was used to interpolate the LAC-titer at the upper limit of normal for both assays (APTT of 37s and DRVVT screen ratio of 1.2). Measurements of aCL, aB2GPI and anti-phosphatidylserine/prothrombin antibodies (aPS/PT) were performed using ELISA methodologies (QUANTA Lite, Werfen). Available clinical data were extracted from the electronic medical record. Continuity corrected chi-square test was used as a categorical test of association and quantile regression was used to compare medians for interval/ratio data across subgroups (Stata v17). Results There was a strong positive linear relationship between the APTT and DRVVT titers (Pearson's correlation coefficient, r=0.92, Figure 1A). There was only a moderate relationship between the APTT titer and the APTT screen in the undiluted sample (r=0.50) and almost no relationship between the DRVVT titer and the DRVVT screen ratio or DRVVT screen/confirm ratio in the undiluted sample (r=0.06 and r=0.13, respectively). Data-driven partitioning identified two DRVVT titer groups: low-titer (<10) and high-titer (≥10). Empirical cutpoint estimation (Youden) identified an APTT titer threshold of 5 for predicting the DRVVT titer group. Among patients with available clinical history, 15 of 25 (60%) low-DRVVT-titer and 16 of 20 (80%) high-DRVVT-titer patients had thromboembolic/obstetric events (p=0.26). Autoimmune diagnoses were more prevalent in the low-DRVVT-titer group (19 of 25 patients, 13 with SLE) than the high-DRVVT-titer group (8 of 20 patients, 3 with SLE, p=0.03). Comparing the low and high-DRVVT-titer groups, median aCL IgM (p=0.27), aCL IgG (p=0.99), aB2GPI IgM (p=0.72) and aB2GPI IgG (p=1.00) titers were not different. High-DRVVT-titer samples had a significantly higher median aPS/PT IgM compared to low-DRVVT-titer samples (p <0.01, Figure 1B) but there was no difference observed for IgG aPS/PT (p=0.57, Figure 1B). Conclusions APTT and DRVVT screening times are not strongly correlated with the corresponding APTT or DRVVT LAC-titer and may not indicate LAC potency. High DRVVT LAC-titers were strongly associated with IgM aPS/PT levels, but not with aCL, aB2GPI or IgG aPS/PT levels. Further research is required to evaluate the association between the LAC-titer and recurrent thrombosis in APS. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Thrombotic Manifestations in Patients with Vexas Syndrome

Introduction: VEXAS syndrome, caused by somatic mutations in ubiquitin-like modifier activating enzyme 1 (UBA1) gene, is a late-onset and progressive autoinflammatory disease. Main hematologic manifestations include macrocytic anemia, thrombocytopenia, and dyspoiesis. Concomitant diagnoses of myelodysplastic syndrome (MDS) and plasma cell dyscrasia (PCD) are common. Venous thromboembolism (VTE) and arterial thrombosis (AT) have been reported. We describe the incidence and characteristics of thrombosis in a large cohort of 86 patients with VEXAS syndrome, along with detailed coagulation profiles in a subgroup of patients. We also explore potential predictors of thrombosis, and effect on overall survival (OS). Methods: Two cohorts of patients with confirmed VEXAS were included. Thirty patients were evaluated at the National Institutes of Health (NIH) Clinical Center and 56 patient records reviewed from referring institutions. Logistic regression models were used to determine predictors of thrombosis. Cox proportional hazards models and Kaplan Meier curves were used for survival analysis. Results: The total population consisted of 86 patients. Eighty-five patients (99%) were male with a median age of 64 years (range, 40-84 years) at disease onset. Hematologic manifestations included macrocytic anemia in 63 (73%), MDS in 25 (29%) and PCD in 17 (20%) patients. Thrombosis occurred in 45 patients (52%); 41 (48%) had VTE and 11 (12%) had AT, with a median time to event from disease onset of 18 and 34 months, respectively; five patients (5%) had both VTE and AT. Among VTE, there were 26 (30%) deep venous thrombosis (DVT), 12 (14%) pulmonary embolism (PE), and 7 (8%) superficial thrombophlebitis. Twenty-two (54%) of VTE cases were unprovoked. Recurrent VTE was seen in 15 (17%) of patients, among which 9 (53%) occurred while receiving anticoagulation. Arterial events included myocardial infarction in 7 (8%) patients, stroke in 2 (2%) patients, and peripheral arterial occlusion in 2 (2%) patients. Recurrent AT was seen in 2 (2%) patients. Patients from the NIH cohort underwent extensive coagulation testing. Fourteen patients (46%) had a positive lupus anticoagulant (LA), which was persistently positive 12 weeks apart in 8 of 9 patients re-tested. Of these 8 patients, 6 had a VTE, 1 had a stroke and 1 did not have thrombotic manifestations. Thirteen patients (43%) with thrombotic events were negative for LA. Median levels of fibrinogen, D-dimer, Factor (F) VII, FIX, and especially von Willebrand factor (VWF) and FVIII, were high in 15 tested VEXAS patients, but there was no significant difference between those with and without thrombosis (Table 1). Of 10 patients with high VWF and 17 with high FVIII activity, 6 (60%) and 9 (53%) had a thrombotic event, respectively; these correlated with high levels of CRP and ESR. No patients were found to have abnormal antithrombin III activity, Factor V Leiden, or prothrombin gene mutations. No difference in age, UBA1 gene mutation, median levels of CRP and ESR, presence of MDS or PCD was found between patients with or without thrombosis; MDS, PCD and UBA1 gene mutation were also not predictive of thrombosis. Among inflammatory disease manifestations, cardiac involvement (myocarditis, pericarditis, or pericardial effusion) correlated with the presence of any thrombosis (p = 0.03). When considering VTE alone, cardiac manifestations strongly predicted PE and DVT (p = 0.004 and p = 0.005 respectively), while the presence of chondritis correlated with PE (p = 0.02). Presence of thrombosis did not impact OS (Figure 1). Conclusions: Patients with VEXAS syndrome are at high risk of thrombosis, mainly venous, which can be recurrent despite anticoagulation therapy. The underlying etiology remains unclear, but many VEXAS patients have positive LA, high VWF and FVIII levels, suggesting inflammation, endothelial activation and/or an immune process as pathophysiologic. Cardiac manifestations, including myocarditis, pericarditis, and pericardial effusion, significantly correlated with thrombosis in general, while chondritis correlated with presence of PE. Presence of thrombosis did not impact OS. Given the high incidence of thrombosis, VEXAS patients should be carefully risk assessed for VTE and considered for prophylactic anticoagulation, and indefinite treatment if thrombosis has occurred. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Predictors and Clinical Complications Associated with Antiphospholipid Antibodies in Sickle Cell Disease

Introduction. The antiphospholipid syndrome is characterized by the presence of anti-phospholipid autoantibodies (aPL) leading to a hypercoagulable state as well as an arterial, venous, and microcirculatory vasculopathy. Under several physiological and pathological situations, including the sickling of red blood cells (RBC), negatively charged phospholipids translocate from the inner to the outer surface of cell membranes leading to the potential generation of the antigenic target of aPL. We tested the following two-part hypothesis: 1) repeated exposure of the immune system of patients with sickle cell disease (SCD) to the antigenic target of aPL leads to an increased formation of aPL; and 2) the presence of aPL is associated with pregnancy and SCD-related complications. Methods. We conducted a cross-sectional study in 63 adults with SCD who had aPL testing performed during a hospital admission between August 1999 & June 2017. We compared individual aPL levels with categorical and linear variables using the Kruskal-Wallis test and linear regression analysis, respectively. The anticardiolipin (aCL) IgG and lupus anticoagulant (LA) levels were log-transformed for these analyses. An abnormal aPL was defined as any of the following: IgM or IgG anti-b2GPI >20 IU/mL, IgM or IgG aCL > 20 IU/mL, LA > 10 seconds. Clinical complications were compared by abnormal aPL status using the chi-square test. Results. The median age of the SCD cohort was 32 years (IQR, 21 - 39 years), 49 (78%) were female, 62 (98%) were African American, 5 (8%) had a diagnosis of systemic lupus erythematosus (SLE), 43 (68%) were Hgb SS genotype, 17 (27%) were on hydroxyurea, and 16 (25%) were on chronic anticoagulation therapy. SCD patients with SLE had higher median aCL IgM (6 vs. 1 IU/mL, respectively; P=0.02) and anti-b2GPI IgG (3.5 vs. 0 IU/mL, respectively; P=0.008) levels compared to those without SLE, while lower hemoglobin concentrations were associated with higher aCL IgG levels (β -0.12; P=0.07) and longer LA times (β -0.18; P=0.02). Fifteen of 63 (24%) patients with SCD had an abnormal aPL. Patients with an abnormal aPL had a lower hemoglobin concentration (Figure 1A), a higher white blood cell (WBC; 13.5 vs. 11.8 x109/L, respectively; P=0.06) count, and a lower platelet (268 vs. 340 x109/L, respectively; P=0.05) count at the time of hospitalization compared to those with a normal aPL. A lower hemoglobin concentration (odds ratio [OR], 1.9; P=0.008), a higher WBC count (OR 1.2; P=0.03), and a lower platelet count (10 platelets/µL increment: OR 1.05, P=0.06) were independently associated with the presence of an abnormal aPL by logistic regression analysis, adjusting for age, sex, and prior SLE diagnosis. Consistent with the second part of our hypothesis, several adverse outcomes trended higher in SCD patients with an abnormal aPL. An abnormal aPL was more prevalent among women with ≥ 3 miscarriages, preterm deliveries, or pre-eclampsia as well as during a hospitalization complicated by acute chest syndrome or multiorgan failure (Figure 1B). Conclusions. These data support the hypothesis that patients with SCD have a high predilection to form aPL, and that the presence of an abnormal aPL is associated with pregnancy complications and the severity of acute SCD-related complications during hospitalization. Our study is limited by its small number of patients. Further larger studies are needed to assess the mechanisms of aPL generation as well as to determine the prevalence and associated risk of abnormal aPL status in patients with SCD. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

A Role of Immunothrombosis in Acquired Antibody-Mediated Thrombophilia's: Classical Complement and Neutrophil Activation in APS and HIT

Introduction: Heparin induced thrombocytopenia (HIT) and APS (antiphospholipid syndrome) are acquired thrombophilia's characterized by both arterial and venous thromboembolic events (TE). As a common feature APS and HIT share the presence of pathological antibodies, which play a crucial role in disease pathogenesis. In HIT, antibodies are directed to platelet factor (PF) 4 and heparin, respectively, and in APS, antibodies target anti-phospholipids (anti-cardiolipin antibody, anti-Beta2- glycoprotein I and lupus anticoagulant). There is growing evidence that complement- and neutrophil activation in the form of neutrophil extracellular traps (NETs) play an important role in the pathogenesis of thrombosis, the so-called "immunothrombosis". Insufficient control with subsequent unrestrained complement activation results in thrombosis as seen in patients with paroxysmal nocturnal hemoglobinuria (PNH). Therapeutic inhibition of complement activation abrogates thrombosis in these patients, emphasizing the important role of complement activation in the pathogenesis of thrombosis. It has been demonstrated, that complement activation products efficiently induce neutrophil activation, and therapeutic complement inhibition in sepsis and PNH prevents neutrophil activation. Here, we investigate the role of complement activation and neutrophil activation in patients with APS and HIT, respectively. Methods To assess the association of complement activation and NET Formation, we measured complement activation products (C4bc, C3bc) and marks for neutrophil activation, such as nucleosomes and human neutrophil elastase-α1- antitrypsin complexes (HNE) by ELISA in plasma of 34 primary APS- and 26 HIT- patients and 31 healthy controls. Groups have been compared using the Mann- Whitney-Rank Test. Values are indicated as median and range, p<0.05 is considered statistically significant. Results Patients with APS and HIT showed sign. higher levels of complement activation products as compared to healthy controls. Complement activation mainly of the classical (C4b/c) and alternate pathway (C3b/c) in APS (11 nM and 263 nM) and in HIT (33 nM and 324 nM) were sign. higher (p<0.0001) as compared to the healthy controls (7 nM and 19 nM). C4bc levels were sign. higher in HIT as compared to APS patients (p<0001), but there was no difference in C3b/c levels between these two groups (see figure 1). Patients with HIT had a sig. (p<0.0001) higher nucleosomes (440 U/ml) and HNE (121 ng/ml) as compared to healthy controls (12 U/ml and 26 ng/ml). HNE levels were sign. (p<0.001) higher in APS patients (37 ng/ml) as compared to healthy controls (26 ng/ml), however no difference was observed in nucleosome levels (12 U/ml vs 14 U/ml) (see figure 2). Based on the number of positive antibodies, eleven APS patients have been stratified as high-risk and 24 APS patients as low- to intermediate risk. C4bc levels were sign. increased in the high-risk patients as compared to the low- to intermediate risk group, whereas no difference in C3b/c levels could be observed between the 2 groups. Similarly, HNE complexes sign. increased in the high-risk patients as compared to the low- to intermediate risk group, whereas no difference in nucleosome levels could be observed between the 2 groups. Six HIT patients (22%) had a diagnosed TE event whereas 17 patients (63%) had no diagnosed TE. In four patients (15%) no clinical data were available, and they have been excluded from subgroup analysis. Interestingly, the measured markers for complement - and neutrophil activation in HIT patient with and without thrombosis were not different. Conclusions We demonstrate complement activation in patients with HIT and APS. Based on the simultaneous raise in nucleosomes and HNE, there is evidence of NET formation in HIT, whereas only weak neutrophil activation can be found in APS. In APS classical complement activation and neutrophil activation correlates with APS risk stratification. Our results demonstrate classical complement pathway- and neutrophil activation in HIT and APS patients. These findings may form the base for new therapeutic strategies targeting complement and neutrophil activation. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Choosing Wisely Ten Years on: Inpatient Thrombophilia Testing

Introduction The American Society of Hematology (ASH) Choosing Wisely campaign have created thoughtful conversations between providers and patients in recommending care that is supported by evidence to reduce duplicative testing. However, some have raised concerns regarding the impact on patient care. We provide our institutional experience in exploring the clinical feasibility of the recommendation on reducing unnecessary inpatient thrombophilia testing. Methods This was a retrospective review of patients admitted with a diagnosis of venous thromboembolism (VTE) across the 3 hospitals in Central PA from September 2021 to December 2021. Pregnancy was an exclusion criterion. Thrombophilia workup included tests for factor V Leiden mutation, activated protein C resistance, protein S activity, antithrombin deficiency, prothrombin gene mutation, anti-cardiolipin antibodies, dilute Russell viper venom time, lupus anticoagulant, anti-beta2-glycoprotein antibodies. The cost of testing was extrapolated by institutional hospital cost reports. Descriptive statistics included reporting the categorical variables as number and percent. The categorical variables were compared between groups with the use of Fisher's exact test or the chi-square test. Results During our study period, 310 patients had new VTE. Of those, 47.9% had pulmonary embolism, 33.7% upper or lower extremities deep vein thrombosis (DVT), 1.6% splanchnic DVT, 14.6% multiple DVTs, and 2.2% DVTs in other locations. The median age was 64. Provoked factors were found in 269 patients (86.7%) and 41 patients (13.2%) had unprovoked VTE. Overall, 33 out of 310 patients (10%) underwent thrombophilia workup with a total of 175 tests performed. More thrombophilia testing was ordered in unprovoked group (29.3% vs 7.8%, p=0.0003) compared to provoked. There was no difference between the amount of inpatient hematology consults in both groups (33.83% vs 47.50%, p=0.0920). Of the hematology consult, 19 out of 118 patients (16%) had thrombophilia testing recommended by hematologist. The cost of all tests ordered outside of hematology recommendation was $34,083 (avg $344 per person). Of the group that got tested regardless of provoking factors, there was no difference between hospital length of stay (2-12 days vs 3-12 days, p= 0.0665). Anticoagulation choice was also not affected by thrombophilia testing between the two groups. Discussion Our experience found that many thrombophilia work up were costly and did not impact quality patient care. Despite the relatively low frequency of inpatient workup (10%), eliminating testing could save our health system approximately $136,332 per year ($34,083 per quarter). Therefore, we support ASH's campaign in reducing inpatient thrombophilia testing. We aim to work with our administration to provide education in reducing unnecessary testing as a part of a quality improvement initiative.

Ordering Patterns, Cost, and Utility of Factor V Leiden Testing in an Academic Medical Center

Factor V Leiden (FVL) is one of the most common inherited thrombophilias. It is an autosomal dominant condition, and 99% of individuals with FVL are heterozygous for the variant. Heterozygotes have a mildly increased risk of venous thromboembolism (VTE) compared to non-carriers, with an estimated lifetime risk of 10%. An association between FVL and arterial thromboembolism remains controversial and is likely to be relatively small if present. Although anticoagulation guidelines for VTE published by the American College of Chest Physicians are not affected by the presence or absence of thrombophilia, testing is commonly ordered. FVL in particular is one of the most frequently ordered molecular genetic tests. This testing is costly and may represent an unnecessary healthcare expenditure if it does not affect clinical decision making. This was a retrospective chart review of FVL testing performed at the University of Kansas Medical Center from 7/6/21-7/5/2022. The purpose of the study was to determine FVL testing patterns, cost, impact on clinical decision making, and potential opportunities for quality improvement. FVL screening was obtained in 192 patients during the study period; 21% of testing was obtained inpatient, and 79% outpatient. Hematology ordered testing most frequently overall (46% of the time), followed by cardiology (13%), neurology (12%), and internal medicine (8%). Nineteen (10%) tests were positive, all of which were heterozygous on subsequent gene testing. Additional thrombophilia testing was performed 89% of the time, which was positive in 6 patients (3 with lupus anticoagulant, 3 with heterozygous prothrombin G20210A mutation). Of the 41 tests performed inpatient, 88% were ordered by non-hematology services, and hematology was consulted only 11% of the time prior to testing. Inpatient testing was ordered most frequently by neurology (42%), internal medicine (20%), cardiology and intensive care units (7% each). The most frequent indications for inpatient testing were arterial thrombosis (56%), first venous thrombosis (24%), and recurrent venous thrombosis (10%). Neither anticoagulation type nor duration was change based on results in any of the patients. Regarding outpatient testing, hematology ordered the majority of tests (55%), followed by cardiology (15%), internal medicine, family medicine and surgery (5% each). The most frequent indications were first venous thrombosis (39%), recurrent venous thrombosis (15%), family history without any personal history of thrombosis (11%), and arterial thrombosis (9%). When provoked or unprovoked venous thrombosis was the testing indication, neither duration nor type of anticoagulation was changed in any of the 86 patients. The average charge for FVL testing from hospitals in the Kansas City Area is $119, totaling an estimated $22,848 in charges for the time period reviewed. Given the lack of impact test results had on the duration or type of anticoagulation, the utility of FVL testing appears to be limited in our sample. In particular, FVL testing of inpatients, most often performed for arterial thrombosis by non-hematology services, had no notable impact on patient care. These results suggest that a quality improvement project restricting testing to the outpatient setting and to indications where results would change clinical decision making, would result in significant cost savings. The additional thrombophilia work-up often performed with FVL screening is even more costly, with an average charge of $2500 for protein c, protein s, prothrombin, and anti-thrombin III testing. In addition, given only 3.5% of those tested for additional thrombophilias were found to be positive, investigation into the utility of these tests may also be warranted. This analysis is limited by its retrospective nature and limited follow-up. Future studies based on this data will include quality improvement measures with subsequent re-analysis to determine the effect on test reduction and cost savings.

Assessing the Rate of Compliance with the Revised Sapporo/Sydney Criteria in Diagnosing Antiphospholipid Syndrome: A Multicenter Retrospective Analysis

Background: Antiphospholipid syndrome (APS) is a systemic autoimmune disease defined by thrombotic or obstetrical events in patients with persistent elevation of antiphospholipid antibodies (aPL) (Lim, 2013). The revised Sapporo/Sydney criteria has been adopted by most professional societies as a guidance to APS diagnosis. To be diagnosed with APS, a patient has to meet at least one clinical criteria and one laboratory criteria. Clinical criteria includes either vascular thrombosis or an adverse outcome during pregnancy. The lab criteria consist of the presence of one or more specified aPL, identified on two or more occasions, at least 12 weeks apart (Miyakis et al., 2006). Antibody testing in patients with suspected APS involves immunoassays for IgG and IgM antibodies to cardiolipin (aCL), and beta2-glycoprotein I (anti-β2GPI), as well as a functional assay for the lupus anticoagulant (LA) phenomenon (Miyakis et al., 2006). Testing asymptomatic individuals is not recommended and carries a significant rate of false positivity, given that up to 10% of healthy individuals may have transient aPL elevation (Vila et al., 1994). Furthermore, certain medications, infections, malignancies, autoimmune diseases, and rheumatologic diseases can also induce transient elevation of aPL antibodies without associated thrombotic complications, emphasizing the importance of repeated aPL measurements in the diagnosis (Lim, 2013; Rand & Wolgast, 2012). Weakly positive levels of aCL and anti-β2GPI antibodies should not be considered significant. Most authorities require Ab levels to be at or above the 99th percentile to be considered clinically significant (Rand & Wolgast, 2012). We aim to assess the compliance with revised Sapporo/Sydney criteria in diagnosing APS in our community hospital system. Methods: We conducted a multi-center, retrospective study among adult patients who were diagnosed with APS in a community healthcare system in southeast Michigan. Demographic and clinical characteristics were collected along with history of venous thrombosis, arterial thrombosis, pregnancy complications, aPL testing results and use of anticoagulants. We used SAS for exploratory data analysis and descriptive statistics. Results: A total of 781 patients were diagnosed with APS between August 2016 to December 2021 (table 1). The median age at diagnosis was 51.3 years (interquartile range 18-93 years). 639 (81.8%) patients were females and 142 (18.2%) were males. Majority of patients were white (n=563, 72.1%). 570 (73.0%) patients had history of venous or arterial thrombosis, 309 (49.9%) had pregnancy complications included in the revised Sapporo/Sydney criteria, and 211 (27.0%) had neither history of thrombosis nor pregnancy complications, not meeting the clinical criteria for APS diagnosis. 528 (67.6%) patients did not meet the laboratory criteria for the diagnosis (figure 1). Of these patients, 439 (83.1%) did not have a repeated testing of aPL antibodies.88 (16.7%) had weakly positive levels of aCL and anti-β2GPI antibodies, below the 99th percentile, and 1 (0.2%) had repeated antibodies testing in less than12 weeks. Out of 528 patients who did not meet the laboratory criteria, 321 (60.8%) were started on anticoagulants. Of these 321 patients, 135 (42%) did not have any history of thrombosis or other appropriate indication of anticoagulation, such as atrial fibrillation. Of 321 patients who were treated with anticoagulation, warfarin was the most prescribed accounting in 120 patients (37.4%). The remainder of patients (62%) were treated with apixaban, rivaroxaban or enoxaparin. Conclusion: Our results showed poor compliance with the current guidelines in both selecting the appropriate candidate for testing, and interpreting aPL testing results, leading to an alarmingly high rate of false diagnosis of APS. Obtaining a positive aPL test result in an otherwise disease-free individual can contribute to unnecessary anticoagulation and side effects including bleeding and increased cost burden to patients and families. Therefore, caution must be exercised while ordering aPL tests and adherence to current guidelines should be encouraged in the routine clinical settings. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Resource Utilization and Cost Analysis of a Chromogenic Factor X Assay for Anticoagulation Monitoring and Management

Introduction High risk venous thrombotic states such as heparin-induced thrombocytopenia (HIT) and antiphospholipid antibody syndrome (APLS) contribute to significant patient morbidity and mortality, and financial toxicity. Traditional coagulation assays (prothrombin time [PT], activated partial thromboplastin time [aPTT], and international normalized ratio [INR]) guide anticoagulation but are unreliable in the presence of a lupus anticoagulant and/or disseminated intravascular coagulation (DIC). Further, some agents used for treatment, such as direct thrombin inhibitors (DTI), elevate the PTT, PT, and INR. Collectively, this highlights the challenge of maintaining a therapeutic index with aberrant PTT values. The chromogenic factor X (CFX) assay depends on an enzymatic reaction that generates photometrically (colorimetric) distinct signals that are proportional to factor X levels and therapeutic INR levels. Rationale for the use of CFX assay is to abrogate difficulty in guiding treatment decisions in HIT with DIC, APLS, and with DTI use. It remains unclear how the use of CFX testing and need for hematology consultation impacts clinical and financial resources at an institutional level seeking to incorporate novel coagulation tests. Here we aim to understand how involving a hematologist in decision-making when using this test can improve healthcare utilization and expenditure associated with thrombotic disease and its complications. Methods This study design was reviewed by the Institutional Review Board and met the criteria for exempt review. This is a single institution retrospective cohort analysis. All patients who had CFX assays performed between July 1, 2019 and June 30, 2021 were included. Each encounter was categorized by location (inpatient vs. outpatient), the indication prompting use of the CFX assay, and if hematology was consulted. Costs were aggregated by evaluating individual decentralized de-identified patient accounts. In particular, variable costs were evaluated to capture all costs from services rendered directly related to the anticoagulation management of the patient (i.e. cost of operations). Descriptive analysis was done for aggregated variable costs and expenditures relevant to the CFX-guided anticoagulation treatment episode. A two-sample t-test was used to identify association between numbers of tests ordered when hematology was consulted in patient care. Statistical analysis to identify differences was set at α=0.05 or less. Maximum type I error rate of p<0.05 was used. Results In total, 179 patient charts were analyzed, of which 90 patients met inclusion criteria (Table 1). The majority of patients had the CFX assay performed inpatient; 33 had the test as an outpatient. A breakdown of testing indication is presented in Table 1, with the majority of tests ordered for APLS, HIT, and recurrent thrombosis. As show in Table 2, for inpatients, fewer tests per patient were ordered when hematology is consulted compared (3.4 vs. 5.4 tests/patient, p=0.005 [α = 0.05]). The mean direct variable cost (DVC) was not statistically different, however there was a median $1800 cost savings when hematology was consulted. There is no difference in length of stay (LOS). All outpatient tests were ordered by a hematologist. In total, 40 tests were ordered for 33 patients (1.2 tests/patient) with a mean DVC of $602.75. Conclusion Our study highlights that there was a statistically significant decrease in tests ordered when a hematologist is involved. For institutions adopting novel coagulation testing, expert hematology consultation helps improve fiscal resource utilization and clinical practice. The discordance of mean and median DVC suggest that variation is not normally distributed. This is often seen in healthcare finance where macro-economic or supply-side factors dictate variation in medically ill patients. Further, the wide ranges in DVC and in LOS suggest a possibly more complex patient population for whom hematology was consulted. Therefore, we highlight that consultation with a hematologist should be considered in complex patients, particularly for anticoagulation given the significant implications inadequate treatment can have. Hematologist can help with anticoagulation management, and their involvement appears to correlate with decreased testing and improved overall savings even with the cost incurred of the consultant. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal