Novel, low-volume, point-of-care coagulation test successfully detects anticoagulation resistance in hospitalized patients with COVID-19

Introduction: Severe COVID-19 has been associated with aberrant coagulation factor activities, particularly in patients with a thrombotic event (TE). Management of anticoagulant is critical in the care of hospitalized patients with COVID-19.Hypothesis: Evaluation of a point-of-care (POC), functional, clot-time-based coagulation test to detect the anticoagulant effect of therapeutic unfractionated heparin (UFH) in hospitalized SARS-CoV-2-positive patients who developed a TE. Methods: An IRB-approved analysis of 36 citrated plasma specimens from 26 SARS-CoV-2-positive patients and 10 matched negative controls was performed. A Clotting Time Score (CTS), a measure of factor-specific inhibition (i.e. anticoagulant activity), was derived for each patient. CTS results were compared with traditional coagulation tests. Five UFH COVID-19 samples with low CTS scores (<10) were spiked with uniform dosing of UFH, low molecular weight heparin (LMWH), apixaban, or argatroban and retested to assess anticoagulation response. Results: The CTS detected subtherapeutic UFH anticoagulation levels more frequently in COVID-19 cases compared with controls (76% vs. 17%). Prothrombin Times, activated Partial Thromboplastin Times, anti-Xa levels, and antithrombin activity did not correlate with each other or with the CTS in the COVID-19 samples. CTS correlated with both FV and Factor X activity (R =0.49, Spearman R=-0.68), which form the prothrombinase complex. The CTS was 94% sensitive and 67% specific for the occurrence of TEs in patients on UFH. CTS demonstrated a consistent anticoagulant response only to argatroban (100%) compared with other anticoagulants (60%). Conclusions: The CTS, generated using a novel, low-volume, rapid POC coagulation test is a strong indicator of the therapeutic effect of UFH anticoagulation in COVID-19 patients and may provide a predictive measure of TEs potentially occurring from anticoagulation resistance.

IXPE Mission System and Development Status

IXPE, an international collaboration, will conduct x-ray imaging polarimetry for multiple categories of cosmic x-ray sources such as neutron stars, stellar-mass black holes, supernova remnants and active galactic nuclei. The Observatory uses a single science operational mode capturing the x-ray data from the targets. This paper summarizes the IXPE Mission System: Observatory, Launch Segment and Ground System. The IXPE Observatory consists of spacecraft and payload modules built up in parallel to form the Observatory during system integration and test. The payload includes three x-ray telescopes each consisting of a polarization-sensitive, gas pixel x-ray detector, paired with its corresponding grazing incidence mirror module assembly (MMA), x-ray optics set. A deployable boom provides the correct separation (focal length) between the detector units (DU) and MMAs. These payload elements are supported by the IXPE spacecraft which is derived from the BCP-small spacecraft architecture. IXPE is launched to a circular LEO orbit at an altitude of 600 km and an inclination of -0.2 degrees by a Falcon 9 launch vehicle. The ground system consists of three major elements: the ground stations for data receipt and command upload to the Observatory;the Mission Operations Center (MOC) at University of Colorado Laboratory for Atmospheric and Space Physics (CU/LASP);and Science Operations Center (SOC) at NASA Marshall Space Flight Center (MSFC). This paper summarizes the IXPE mission science objectives, updates the Observatory implementation concept including the payload and spacecraft elements, covers the launch segment, ground system and summarizes the mission status since last year's conference including COVID impacts. © 2021 IEEE.