Measurement of Non-Vitamin K Antagonist Oral Anticoagulants in Patient Plasma Using Heptest-STAT Coagulation Method

Potential of Sulodexide in the Treatment of Diabetic Retinopathy and Retinal Vein Occlusion

Retinal vascular diseases, such as diabetic retinopathy or retinal vein occlusion, are common causes of severe vision loss. Central to the pathophysiology of these conditions are endothelial dysfunction, inflammation, capillary leakage, ischemia, and pathological neoangiogenesis. Capillary damage leads to leakage and the development of macular edema, which is associated with vision loss and requires complex treatment. Sulodexide, a glycosaminoglycan composed of heparan sulfate and dermatan sulfate with high oral bioavailability, exhibits several favorable pharmacologic properties, including antithrombotic, anti-inflammatory, and endothelium-protective effects. Additionally, treatment with sulodexide has been associated with the reduction of oxidative stress and decreased expression of angiogenic growth factors, such as vascular endothelial growth factor. This review aims to provide an overview of the pharmacological properties, mechanisms of action, and therapeutic effects of sulodexide. Furthermore, its potential for clinical application in venous and diabetic diseases, such as venous thromboembolism, chronic venous insufficiency, peripheral artery disease, or diabetic nephropathy, is summarized. We also present experimental and clinical studies evaluating the potential of sulodexide in ocular conditions and discuss its therapeutic implications for the treatment of retinal vascular diseases.

Rivaroxaban dose adjustment using thrombin generation in severe congenital protein C deficiency and warfarin-induced skin necrosis

Rivaroxaban was efficacious and safe in a child with protein C deficiency to prevent the recurrence of skin necrosis or venous thrombosis. The dosage of direct oral anticoagulants in children with thrombophilia is unclear; a thrombin generation assay may be useful to adjust it.

Laboratory determination of old and new targeted anticoagulant agents for prevention of bleeding and thrombotic events in cancer patients

A two-fold prolongation of activated partial thromboplastin time (APTT) is established as therapeutic range for therapy with unfractionated heparin, hirudin and argatroban. The international normalized ratio (INR) of 2 to 3 is required to maintain anticoagulation in the therapeutic range of vitamin K antagonists. The therapeutic range of anti-factor Xa activity during therapy with low-molecular weight heparins and danaparoid are less well and of direct oral anticoagulants (DOAC) poorly defined. The relation of aPTT and INR values to thrombotic and bleeding events are well established despite a large variation of values in affected patients. The relation of coagulation values of the other anticoagulants to clinical events is open. The value of determination in cancer patients is higher because of the increased risk for thrombotic and bleeding events of this patient group. Several activities are currently undertaken to certify methods for in vitro diagnostic testing for DAOCs.

Laboratory Assessment of the Anticoagulant Activity of Direct Oral Anticoagulants: A Systematic Review

BACKGROUND

Direct oral anticoagulants (DOACs) are the treatment of choice for most patients with atrial fibrillation and/or noncancer-associated venous thromboembolic disease. Although routine monitoring of these agents is not required, assessment of anticoagulant effect may be desirable in special situations. The objective of this review was to summarize systematically evidence regarding laboratory assessment of the anticoagulant effects of dabigatran, rivaroxaban, apixaban, and edoxaban.

METHODS

PubMed, Embase, and Web of Science were searched for studies reporting relationships between drug levels and coagulation assay results.

RESULTS

We identified 109 eligible studies: 35 for dabigatran, 50 for rivaroxaban, 11 for apixaban, and 13 for edoxaban. The performance of standard anticoagulation tests varied across DOACs and reagents; most assays, showed insufficient correlation to provide a reliable assessment of DOAC effects. Dilute thrombin time (TT) assays demonstrated linear correlation (r2 = 0.67-0.99) across a range of expected concentrations of dabigatran, as did ecarin-based assays. Calibrated anti-Xa assays demonstrated linear correlation (r2 = 0.78-1.00) across a wide range of concentrations for rivaroxaban, apixaban, and edoxaban.

CONCLUSIONS

An ideal test, offering both accuracy and precision for measurement of any DOAC is not widely available. We recommend a dilute TT or ecarin-based assay for assessment of the anticoagulant effect of dabigatran and anti-Xa assays with drug-specific calibrators for direct Xa inhibitors. In the absence of these tests, TT or APTT is recommended over PT/INR for assessment of dabigatran, and PT/INR is recommended over APTT for detection of factor Xa inhibitors. Time since last dose, the presence or absence of drug interactions, and renal and hepatic function should impact clinical estimates of anticoagulant effect in a patient for whom laboratory test results are not available.