Anticoagulant Therapy

Thrombin Time Technique

From Monali Gupta MD, Toronto General Hospital: Hi George, I compliment you for creating such a wonderful website to understand and learn coagulation. The modules are very educative. I have two questions about the DTI assay described in Module 28, Thrombin Time Assay. Why patients’s plasma is diluted in 1:8 or 1:20 in saline? Why pipetting has […]

Anticoagulant Therapy

DVT with Thrombocytopenia

Here is a case that George heard about on Saturday, May 16. An ultrasound revealed two blood clots in a man’s leg. After two days on Coumadin and Lovenox (LMWH) his platelet count was 4,000/uL so his doctor discontinued the Coumadin. The man had been previously diagnosed with ITP and his doctor wants to arrange […]

Anticoagulant Therapy

NSAIDS Raise Bleeding Risk Post-MI

Heartwire reviews a Februay 24 JAMA report indicating that AMI patients on DAPT who use NSAIDs double their risk of bleeding and secondary cardiovascular events. Read about it in Medscape.

Anticoagulant Therapy

Mixing Studies on Anticoagulation

From Dr. King: We are encountering with increasing frequency requests from hematologists to perform mixing studies on patients that are known to be on some form of anticoagulation. My question is regarding the utility of doing such testing. Another aspect to the question is whether you can do testing for a prolonged PTT when the […]

Anticoagulant Therapy

Rivaroxaban Side-Effects

I spoke with an acquaintance who started on rivaroxaban (Xarelto) a few weeks ago for DVT therapy. He reported transient cognition changes such as slowed speech that resolved when he discontinued the drug. Has any of our subscribers experienced or heard reports of this?

Anticoagulant Therapy

TTR

From Dave McGlasson, George I just read an excellent article by Dr. Jeff Dlott of Quest Diagnostics, Dlott JS, George RA, Huang X, et al. National assessment of warfarin anticoagulation therapy for stroke prevention in atrial fibrillation. Circulation 2014;129: 1407–14 that discusses INR time in therapeutic range (TTR, 2–3) during the first 6 months of […]

Anticoagulant Therapy

Xarelto Bleeding Risks

Since November of 2014, several lawyer-inspired Facebook threads have implicated rivaroxaban (Xarelto) in instance of “uncontrollable bleeding events and blood clots.” The October 9, 2014 issue of the ASH‘s Blood journal presents a meta-analysis that reviewed twelve randomized controlled trials involving 102,607 patients taking TSOACs (target-specific oral anticoagulants, direct oral anticoagulants (DOACs). The authors conclude […]

Anticoagulant Therapy

Anti-Xa AC Reversal: Phase III Results

On January 9, 2014, Portola Pharmaceuticals announced the results of their phase III trial of intravenous Andexanet Alfa, an anti-Xa reversal agent. The trial, ANNEXA-R, tested Andexanet against rivaroxaban, however subsequent trials will generalize it to the additional anti-Xa‘s apixaban and edoxaban. Dave McGlasson comments and a January 9 article appears in The Heart, which […]

Anticoagulant Therapy

FDA Clears Edoxaban

On Thursday, January 8, 2014, the FDA cleared edoxaban (Savaysa, Daiichi-Sankyo) for reducing risk of ischemic stroke in non-valvular atrial fibrillation (AFIB) and for treating DVT and PE in patients who have already been receiving an anticoagulant by injection or by infusion for 5 to 10 days. The anticoagulant joins apixaban and rivaroxaban as the […]

Anticoagulant Therapy

Coumadin and Factor Half-lives

I received a question recently about Coumadin (warfarin) therapy and coagulation factor half-lives. Coumadin reduces the normal carboxylation of the glutamic acid γ-carbon. There are 12–18 glutamic acid units near the amino terminus of the vitamin K-dependent factors II (prothrombin), VII, IX, and X. When vitamin K-catalyzed γ-carboxylation becomes suppressed, these coagulation factors are unable […]

Anticoagulant Therapy

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George Fritsma is a medical laboratory scientist, educator, and author. George is a member of the International Society on Thrombosis and Hemostasis, the International Society for Laboratory Hematology, and the American Society for Clinical Laboratory Science.

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