[Basics for the Use of Andexanet]. / Grundlagen zur Anwendung von Andexanet.

BACKGROUND: For life-threatening or uncontrollable bleeding in association with the thrombin inhibitor dabigatran, the monoclonal antibody fragment idarucizumab is available, and for bleeding in association with the direct factor Xa inhibitors rivaroxaban or apixaban, the modified recombinant FXa protein andexanet is available for reversal. These antidotes represent emergency drugs that are typically used only after performing guideline-compliant multimodal measures. METHODS: An interdisciplinary group of experienced experts in the fields of angiology, hematology, internal medicine, clinical pharmacology, laboratory medicine, transfusion medicine, anesthesiology, intensive care, and hemostaseology developed recommendations relevant to daily clinical practice based on the current scientific evidence. RESULTS: Reversal of oral anticoagulants should be considered for severe bleeding in the following situations: (1) life-threatening bleeding or refractory hemorrhagic shock, (2) intracerebral bleeding, or (3) endoscopically unstoppable gastrointestinal bleeding. After successful hemostasis, anticoagulation (e.g., direct oral anticoagulant, vitamin K antagonist, and heparin) should be resumed promptly, taking into account individual bleeding and thromboembolic risk. DISCUSSION: This article aims to facilitate the management of patients with andexanet by all medical disciplines involved, thereby ensuring optimal care of patients during bleeding episodes.

Interference of DOACs in different DRVVT assays for diagnosis of lupus anticoagulants.

OBJECTIVE: Determination of lupus anticoagulants (LA) is an important, but still challenging test in the diagnosis of antiphospholipid syndrome (APS). This is especially the case in patients using one of the direct oral anticoagulants (DOACs). The aim of our study was to examine the influence of these drugs on DRVVT assays from two companies (in each case: screening test, confirming test and calculated ratio) and on aPTT and lupus-sensitive aPTT. METHODS: We used plasma samples from healthy volunteers spiked with the DOACs dabigatran, rivaroxaban and apixaban (0, 10, 30, 50, 100 ng/mL) for testing. Furthermore, samples from patients receiving a DOAC were investigated. The plasma concentrations of the DOACs were determined using ultra-performance liquid chromatography/electrospray ionization-tandem mass spectrometry (UPLC-MS/MS). RESULTS: Depending on type and concentration, all the DOACs resulted in pathological values in the DRVVT screening assays. In samples spiked with apixaban, no influence on the DRVVT normalized ratio of the two assays was observed, but 7 to 15% of samples from patients receiving apixaban displayed pathological values. In contrast, up to 71% of dabigatran-spiked samples showed normalized ratio values above the cut-off, whereas there was no influence in the patients' samples. In both spiked and patient samples containing rivaroxaban, the DRVVT assays were influenced. CONCLUSION: LA diagnostics should, under DOAC therapy, be limited to situations in which time-critical evaluation is warranted. It is crucial to take into account the finding that even samples containing DOAC concentrations below the limit of detection of the drugs may lead to false-positive DRVVT measurements.

The Sysmex CS-5100 coagulation analyzer offers comparable analytical performance and excellent throughput capabilities.

OBJECTIVES: This study compared the new high-volume blood coagulation analyzer Sysmex CS-5100 System™ (Siemens Healthcare Diagnostics, Erlangen, Germany) to the mid-volume blood coagulation analyzer Sysmex CS-2000i System™ (Siemens) for analytical performance. Additionally, the operational performance of the Sysmex CS-5100 System was compared with the blood coagulation analyzer ACL TOP 700 (Instrumentation Laboratory, Werfen Group, Kirchheim bei Munchen, Germany). MATERIALS AND METHODS: We compared the Sysmex CS-5100 to the Sysmex CS-2000i and the ACL TOP analyzer for routine coagulation, chromogenic and immunological assays. Imprecision studies were performed for the Sysmex CS-5100 and Sysmex CS-2000i systems. A throughput and STAT analysis comparison of the CS-5100 and the ACL TOP was performed. A stress test was performed to characterize the robustness and the error rate of the CS-5100. We also performed correlation analysis between the CS-5100 and the CS-2000i or the ACL TOP in the measurement of patients' samples. RESULTS: The inter-assay precision using the CS systems was impressive (inter-assay CV generally <3.5%) and the correlation between the two Sysmex analyzers was excellent. In the throughput study, the CS-5100 completed the measurement of 100 samples (210 results) in less than 49 min. CONCLUSIONS: Our results demonstrated that the CS-5100 is a robust high-throughput analyzer, well-suited for coagulation laboratories.

Donor-Derived Cell-Free DNA Is a Novel Universal Biomarker for Allograft Rejection in Solid Organ Transplantation.

BACKGROUND: In solid organ transplantation, sensitive real-time biomarkers to assess the graft health are desirable to enable early intervention, for example, to avoid full-blown rejections. During rejection, high amounts of graft-derived cell-free DNA (GcfDNA) are shed into the blood stream. The quantification of this GcfDNA in allotransplantation is considered to fulfill this need, because it can be measured with great precision and at reasonable cost. PATIENTS AND METHODS: Patients from 2 ongoing studies in kidney (KTx) and heart (HTx) transplantation were monitored blinded on a scheduled basis, by means of a published universal droplet digital polymerase chain reaction to quantify the GcfDNA. RESULTS: Immediately after engraftment, GcfDNA reaches high values (>5% of total cfDNA), with a rapid decrease to values of <0.5% within 1 week. Living-related KTx recipients show lower initial values, reflecting the absence of preservation injury. Episodes of rejection in KTx and HTx are accompanied by a significant increase of GcfDNA (>5-fold) above values in patients without complications, occurring earlier than clinical or biochemical hints to rejection. One case of rejection, which became clinically suspect after 1 year and was proven with biopsy, showed a significant 10-fold increase 3 months earlier. CONCLUSIONS: The quantification of GcfDNA has the potential to detect rejection episodes at early stages, when other means of diagnosis are not effective. The method's noninvasiveness enables the monitoring recipients at intervals that are desired to catch rejections at early actionable stages to prevent full-blown rejection. This biomarker will be particularly valuable in regimens to minimize immunosuppression.

Results of the WIRK prospective, non-interventional observational study of recombinant activated factor VII (rFVIIa) in patients with congenital haemophilia with inhibitors and other bleeding disorders.

Recombinant activated factor VII (rFVIIa) has been available for the treatment of acute bleeding and for prevention of bleeding during surgery and invasive procedures in patients with congenital haemophilia with inhibitors (CHwI) and acquired haemophilia since 1996. The study objective was to assess the efficacy and safety of rFVIIa in patients with CHwI, acquired haemophilia, congenital FVII deficiency and Glanzmann's thrombasthenia, in a real-life clinical setting. There were no specific inclusion or exclusion criteria; participation was offered to all German haemophilia centres known to use rFVIIa to treat patients with the above indications. Data on rFVIIa use and efficacy for the treatment of acute bleeding episodes and invasive procedures were recorded. Adverse drug reactions and recurrent bleeding episodes were also monitored. In total, 64 patients (50.0% women) received rFVIIa treatment. Patients experienced 281 evaluable bleeding episodes and underwent 44 invasive procedures. In 252 of 281 (89.7%) bleeding episodes, a stop (66.5%) or a significant reduction (23.1%) in bleeding was observed. No bleeding complications were reported for 42 of 44 (95.5%) invasive procedures covered with rFVIIa. A clear positive association was observed between early initiation of rFVIIa treatment for acute bleeding and efficacy. The total cumulative dose and number of injections were 468.3 ± 545.8 µg kg(-1) and 3.6 ± 4.6 respectively. No drug-related adverse events were reported. rFVIIa use in Germany provided effective haemostatic cover without associated adverse events in the management of acute bleeds and invasive procedures across a range of bleeding disorders.

NO-synthase-/NO-independent regulation of human and murine platelet soluble guanylyl cyclase activity.

OBJECTIVES: Platelets, specialized adhesive cells, play key roles in normal and pathological hemostasis through their ability to rapidly adhere to subendothelial matrix proteins (adhesion) and to other activated platelets (aggregation), functions which are inhibited by nitric oxide (NO). Platelets have been reported to be regulated not only by exogenous endothelium-derived NO, but also by two isoforms of NO synthase, endothelial (eNOS) and inducible (iNOS), endogenously expressed in platelets. however, data concerning expression, regulation and function of eNOS AND iNOS in platelets remain controversial. METHODS AND RESULTS: Using important positive (endothelial cells, stimulated macrophages) and negative (eNOS/iNOS knock-out mouse) controls, as well as human platelets highly purified by a newly developed protocol, we now demonstrate that human and mouse platelets do not contain eNOS/iNOS proteins or mRNA. NOS substrate (L-arginine), NOS inhibitors (L-NAME, L-NMMA), and eNOS/iNOS deficiency did not produce detectable functional effects on human and mouse platelets. von Willebrand factor (VWF)/ristocetin treatment of platelets increased cGMP by NO-independent activation of soluble guanylyl cyclase (sGC) which correlated with Src kinase-dependent phosphorylation of sGC beta(1)-subunit-Tyr(192). CONCLUSIONS: Human and mouse platelets do not express eNOS/iNOS. VWF/ristocetin-mediated activation of the sGC/cGMP signaling pathway may contribute to feedback platelet inhibition.