My friend Dan Southern, Professor Emeritus, Western Carolina University, alerted me to a May 7 Wall Street Journal article describing how protein pump inhibitors such as Nexium, taken for gastro-esophageal reflux disease (GERD), inhibit absorption of clopidogrel (Plavix). Many cardiologists prescribe Nexium to control the heartburn some Plavix patients suffer. Gordon Ens and Kirk Guyer of AspirinWorks helped me find the article, which indicates antacids, Zantac, and Tagamet, all non-protein pump inhibitors may be used. Plavix irreversibly binds the platelet membrane ADP receptor P2Y12 and is prescribed as a 1-2 year follow-up to prevent a secondary vascular event in patients who have had an acute myocardial infarction.

By the way, the Clinical Laboratory Science program at Western Carolina is one of the spate of 2009 USA closings, which include University of South Alabama and Arizona State University, all three large CLS programs. Geo.

We’ve not quite completed our switch to WordPress, and I have several messages and topics pending, so I’ve decided to post to our old shell for now. I’m currently in Denver attending the Wyoming-Colorado Clinical Laboratory Collaborative Conference (CLCC). CLCC has a well-attended annual program sponsored by ASCLS-Colorado, ASCLS-Wyoming, the Clinical Laboratory Managers’ Association, and the Colorado Association for Continuing Medical Laboratory Education (CACMLE), the organization that provides CE credit for our Fritsma Factor lectures.
CACMLE sponsored a delightful program featuring Dr. Kevin Fitzgerald, DVM, who practices in Denver. Dr. Fitzgerald is a comedian and story-teller who appears on Animal Planet.
I provided a seminar entitled “Monitoring Antithrombotic Therapy” that introduced the developing oral anticoagulants Rivaroxaban and Dabigitran. I’ve posted the lecture here as a PowerPoint handout. I hope this is helpful to CLCC participants or to anyone who is interested. Geo.

The US Food and Drug Administration's (FDA) Cardiovascular and Renal Drugs Advisory Committee recommended approval of Rivaroxaban (Xarelto) oral anti-Xa antithrombotic for prophylaxis of deep vein thrombosis (DVT) and pulmonary embolism (PE) in patients undergoing hip replacement or knee replacement surgery. The FDA has until May 28 to vote full approval. See Medical News Today for more information.

I monitor the ASCLS Consumer Forum regularly for hemostasis-related questions from patients and health care providers. The forum receives an average of 50 questions a day, typically five that have to do with coagulation. I'm amazed at how active the forum is, and at the energy and expertise of the ASCLS volunteers who answer questions. One thing that may not get factored into the statistics is the number of follow-up e-mails generated by the initial answer, and the positive relationships that arise between questioners and ASCLS experts.

Nearly all the hemostasis questions have to do with Coumadin dosage and the INR. It comes as no shock that there is so little information provided, and so much misinformation. Here is a case that came my way yesterday via Dr. Louanne Lawrence at the Louisiana State University Medical Center. I've fictionalized (obfuscated) the question to protect the questioner's identity...

Here is a surgery question from Dan Southern, friend and retired professor from Western Carolina University's Clinical Laboratory Science program:

After meeting with my surgeon, I started in motion something that I want your opinion on.He told me that I would be on Coumadin prior and six weeks after hip replacement surgery Based on experience, I don't like Coumadin so I asked if I could wean off my current Plavix and aspirin to Lovenox pre-op and then switch back to Plavix and aspirin post-op. To my surprise, I got my wish. I will inject my abdomen six days pre-op and a few days (to be determined) after discharge with the pre-filled syringes.

Did my surgeon and I make the right decision? Should I have just gone along with Coumadin? What you would do if it were you? The surgeon actually prefers Lovenox but seldom has anyone willing to do the self injections. I can still reverse the decision. Dan

I received a message from Eric Hardy, a 1990s graduate of our University of Alabama at Birmingham CLS program and now a physician assistant practicing in the area. A McNeil Labs representative was advocating for one of the new oral anti-Xa anticoagulants . I have seen no announcement nor ads indicating any of the new oral drugs have been released for the US market. What is their current status? 

The most recent large validation cohort study that supports screening for CYP2C9 and VKORC1 polymorphisms to assist in estimating warfarin dosage is available at The International Warfarin Pharmacogenetics Consortion: Estimation of the warfarin dose with clinical and phamacogenetic data. NEJM 2009; 360: 753-764. Geo.

From C. Jordan:

Does anyone have a weight-based nomogram for continuous IV unfractionated heparin (UFH) infusion when the anti-Xa assay is used for monitoring instead of the PTT?

Partial answer...

Please respond to the quick question posted 2-19-09 on prothrombin time delta checks. Our question system does not provide for an open-ended response, but in addition to choosing the reporting format, we would like to compute the average delta check range. Please report your range as a response to this posting, thank you. Geo.

We've just posted our four latest educational modules, Monitoring Antithrombotic Therapy 1-4. These include reference to the new oral anticoagulants that are under development, Rivaroxiban, Apixiban, and Dabigatran. Our educational modules are up to date and free. They are also available for CE credit through all North American continuing education certification agencies such as ASCP and ASCLS through the Colorado Association for Continuing Medical Laboratory Education (CACMLE). CACMLE charges a modest fee to certify and maintain a record of your continuing education credit. Geo.