Anticoagulant Therapy

Left Atrial Appendage Closure

In response to a case-based question, has anyone seen data comparing the efficacy and safety of the left atrial appendage closure (LAAC) device Watchman with any DOAC in reducing risk of ischemic stroke in non-valvular atrial fibrillation?

Anticoagulant Therapy

Case Study: A Patient on Xarelto with Elevated D-dimer Results

In 2016, Dr. Louann Lawrence, New Orleans, communicated with a patient who had experienced a DVT and PE in 2014 and was being treated with Xarelto (rivaroxaban). The patient’s physician routinely ordered a D-dimer to assess the risk of a recurrence after discontinuing anticoagulant therapy. Following the physician’s instructions, the patient discontinues Xarelto for 24 […]

Anticoagulant Therapy

D-dimer Reference Range

Paul Smith writes, “I have a family member on Xarelto and his D-dimer reference range was 450 while taking Xarelto. What is the reference range? Hello, Mr. Smith, and thank you for your question. There is some mild confusion about the D-dimer reference intervals (reference ranges) because several distributors use varient methods. These methods result […]

Anticoagulant Therapy

May, 2018 Quick Question: DOACs

Our May, 2018 Quick Question asks, “How do you measure the oral anti-Xa anticoagulants rivaroxaban, apixaban, edoxaban, and betrixaban?” Here are the answers from our 89 respondents. Prothrombin time (PT): 4 (4%) Activated partial thromboplastin time (APTT, PTT): 3 (3%) Chromogenic anti-Xa assay with specific calibrators: 44 (49%) We don’t measure the anti-Xa anticoagulants: 38 […]

Anticoagulant Therapy

AndexXa

On May 4, the FDA approved andexanet alpha (AndexXa, Portola Pharmaceuticsls) as the first and only reversal agent for direct anti-Xa DOACs rivaroxaban (Xarelto), and apixaban (Eliquis) overdose. Tap or click MD Magazine for details. Also see the ANEXXA-A report in Siegal DM, Curnutte JT, Connolly SJ, et al. Andexanet alfa for the reversal of […]

Anticoagulant Therapy

Activated Clotting Time

Please help me (George) learn if the ACT is used for any purpose other than monitoring high dose intravenous heparin during coronary artery bypass graft surgery, percutaneous intervention, ablations, and for monitoring protamine sulfate heparin reversal at the end of the cardiac procedure. Does anyone use the ACT for routine heparin therapy monitoring or for […]

Anticoagulant Therapy

April, 2018 QQ: Dabigatran Assay

Here are the responses to our April, 2018 Quick Question, “How do you measure the oral direct thrombin inhibitor dabigatran?” Standard thrombin time: 7 votes, 8% Activated partial thromboplastin time (APTT, PTT): 5 votes, 5% Chromogenic ecarin clotting time assay: 9 votes, 10% HEMOCLOT thrombin inhibitor assay (plasma-diluted thrombin time): 17 votes, 18% We don’t […]

Anticoagulant Therapy

April Quick Question: Dabigatran Measurement

Our April, 2018 Quick Question is now available. Please select the answer closest to your practice, or send your comment to George at [email protected]. Here is a current article that addresses measurement of all DOACS: Gosselin RC, Adcock DM, Bates SM, et al. International Council for Standardization in Haematology (ICSH) Recommendations for Laboratory Measurement of […]

Anticoagulant Therapy

Xarelto Bleeding Intensity

George communicated with an acquaintance who experienced Coumadin therapy a few years ago and, subsequent to a new DVT, is now on Xarelto. He notes that minor cuts bleed longer and more profusely when on Xarelto compared to Coumadin. Can any of our subscribers confirm this?

Anticoagulant Therapy

Geometric V. Arithmetic Mean

From Dave McGlasson, does anyone have a reference on why a geometric mean is used in the INR calculation? Since we are using 20–30 normal subjects to calculate the mean PT, the range is relatively narrow. The geometric mean indicates the central tendency or typical value of a set of numbers by using the product of […]

Anticoagulant Therapy

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George Fritsma is a medical laboratory scientist, educator, and author. George holds faculty appointments with Rutgers University and Michigan State University, and is a member of the International Society on Thrombosis and Hemostasis, American Association of Clinical Chemists, and American Society for Clinical Laboratory Science.

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