Lupus anticoagulant in patients with COVID-19: A review

Introduction: Coronavirus disease 2019 (COVID-19) is characterized by a pro-coagulant state that can lead to fatal thromboembolic events. A high prevalence of lupus anticoagulant has been shown in several studies that may at least partially explain the pro-coagulant profile of COVID-19. However, the relation between COVID-19 and lupus anticoagulant is arguable, and no study has clearly evaluated the concussion of lupus anticoagulant on mortality. Methods: We searched the articles that related to lupus anticoagulant and patients with COVID-19. Two authors independently reviewed the search results to select English language articles discussing lupus anticoagulant in patients with COVID-19. Results: Recent studies found conflicting results about the association between lupus anticoagulant and thromboembolic complications of COVID-19. Studies documented a high prevalence of lupus anticoagulants as well as several other studies. Patients with lupus anticoagulants were older, and their C-reactive protein, high-sensitivity troponin, and activated partial thromboplastin time (aPTT) were significantly higher than patients without lupus anticoagulants. Conclusion: Those started on therapeutic anticoagulation showed more severe and complicated involvements and a higher risk of death. According to our results, lupus anticoagulant is highly prevalent among hospitalized COVID-19 patients. Whether these antibodies promote a hypercoagulable state or they are merely a coincidence, epiphenomenon needs further evaluation.

A Cohort Study of Inferior Vena Cava Thrombosis in Taiwan: An Under-recognized Entity

Background: Inferior vena cava thrombosis (IVCT) is a rare clinical condition. Herein, we report eight cases of IVCT in Taiwanese patients.Methods: Eight Taiwanese patients diagnosed with IVCT between May 2012 and December 2019 were included in this study. The patients’ demographics, presenting characteristics, additional sites of venous thromboembolism, extent of IVCT, prothrombotic risk factors, and IVCT-related adverse events were evaluated.Results: All eight patients with IVCT presented with other coexisting venous thromboembolic manifestations, such as deep venous thrombosis (DVT, 100%) or pulmonary embolism (62.5%). The clinical presentations, including DVT in both lower extremities coexisting with the dilatation of the superficial veins of the abdominal wall (50%), were reported. No congenital anomalies of the inferior vena cava (IVC) were noted. Various thromboembolic risk factors, such as unretrieved IVC filters (25%), pregnancy (37.5%), lupus anticoagulants (37.5%), surgery (25%), antithrombin deficiency (12.5%), hemoglobin H disease (12.5%), and essential thrombocythemia (12.5%), were identified. All patients were administered anticoagulants. One patient (12.5%) developed post-thrombotic syndrome. No mortality was reported in our cohort. Conclusions: This is the first report of IVCT in Taiwanese patients. Typical clinical features of IVC occlusion coexisting with predisposing factors of venous thrombosis, such as lupus anticoagulants, pregnancy, or unretrieved IVC filters, could indicate a diagnosis of IVCT. Moreover, IVCT presenting as a complication resulting from the unretrieved IVC filter was observed, highlighting the potential risks of chronic indwelling filters.

Appropriate Laboratory Testing for Lupus Anticoagulants: An Observational Study at an Academic, Tertiary Care Hospital

Introduction: Lupus anticoagulants (LA) are a heterogeneous group of immunoglobulins that develop spontaneously, with autoimmune disorders or transiently in association with acute infectious or inflammatory conditions. Transient LA are generally presumed to be harmless, while LA that persist over time may be a risk factor for venous and arterial thrombosis. Accordingly, persistence of LA after a first thrombotic episode may signal a recommendation for long term thromboprophylaxis with an anticoagulant, thus, to guide therapy, correct interpretation of LA test results is paramount. LA test interpretation is complicated, however, and clinicians must understand the LA test characteristics, the importance of timing of testing and the implications of positive, negative and equivocal test results to use the information effectively for clinical decision making. We undertook this study to ascertain how clinicians at our institution approach LA testing and to identify knowledge gaps that may amenable to educational interventions aimed at improving patient care in this area. Methods: Our laboratory uses a combination of the dilute Russell viper venom time (dRVVT) and silica clotting time (SCT) for LA screening (Instrumentation Laboratories, Bedford MA, USA). A positive test for either dRVVT or SCT is considered positive for LA. Negative tests for both are required to exclude the presence of LA in a given patient. We provide cutoff values for negative, positive and indeterminate test results and recommend repeat testing after 12 weeks for any indeterminate or positive test to establish persistence in accordance with current guidelines. We recommend NOT testing patients who are currently anticoagulated with a direct oral anticoagulant (DOAC) due to the potential for a false positive test result. We retrospectively analyzed 715 completed LA tests between April 1, 2018 and April 30, 2019 to determine the proportion of positive, negative and indeterminate test results. We then reviewed individual patient records to identify patient and provider characteristics and document additional diagnostic actions taken based on the initial test results. We report our findings descriptively. Results: The average age of patients undergoing laboratory testing for LA was 46.9 years, (median, 47.0 years), with a preponderance of females (73%). The majority of tests were ordered by rheumatology or hematology providers (53%). Anticoagulation with a DOAC was present in 74 (10%). A negative initial test (dRVVT and SCT both negative) was documented in 413 patients (58%), and was repeated in nine individuals (2%) at a second time point. A positive test (dRVVT and/or SCT positive) was documented in 170 (24%), of which 53 (31%) were repeated subsequently and 18 (11%) were themselves repeat tests to follow up on a previous positive test, leaving 99 (58%) initial positive tests that were not repeated. The majority of repeat tests were conducted at a time point <12 weeks after the initial test (n = 37; 70%). Equivocal test results (dRVVT and/or SCT indeterminate) were obtained in 132 patients (18%) and repeated in 25 (19%). Conclusion: We discovered a surprisingly high rate of inappropriate LA test usage at our institution. The results of this investigation will guide our efforts to develop interventions aimed at informing our clinicians about best practices for laboratory testing for LA, and provide opportunities to leverage the features of the electronic health record to improve test ordering procedures. Disclosures No relevant conflicts of interest to declare.

Mixing studies for lupus anticoagulant: mostly yes, sometimes no

Lupus anticoagulants (LAs) represent one manifestation of the clinical condition called antiphospholipid syndrome (APS) and are associated with many adverse clinical outcomes, but primarily with thrombosis and/or pregnancy morbidity. LAs are identified by laboratory testing, principally using clot-based assays based on Russell viper venom time (RVVT) and activated partial thromboplastin time (APTT) test methods. All three of the most recent guidance documents for LA testing recommend using these tests, although they vary in regard to inclusion/exclusion of other test processes. Mixing studies form part of the process of LA identification/exclusion, since in vitro LAs act like coagulation inhibitors. Mixing studies are also supported by all three LA guidance documents, but recommendations vary in regard to relative importance and placement in the LA identification/exclusion algorithm. This Point article takes the position that mixing tests are usually indicated for appropriate identification/exclusion of LAs, but can occasionally be omitted.