Ten Things Every Clinician Should Know About AT9


Written By

Glenn D.O. Pebanco, Pharm.D., BCPS

Reviewed By

Stuart T. Haines, Pharm.D., BCPS, BCACP


Guyatt GH, Akl EA, Crowther M, et al. Executive Summary. Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. CHEST 2012; 141: 7S-47S

The American College of Chest Physicians Antithrombotic Guidelines, 9th edition are now available.  Here's a short summary about what every clinician should know.

2.   The Patient’s Opinion Matters.  Patient values and preferences regarding antithrombotic treatment vary.  Although the AT9 authors believe a reasonable trade-off between stroke and major bleeding events would be in the range of 2 or 3 to 1, they emphasize the need for shared decision making.2  This is the process through which clinicians and patients share information with each other and work toward decisions about antithrombotic treatment that align with the patients’ values, goals, and preferences.

4.   A Break From Testing.  AT9 suggests “see you in 4 weeks” can be delayed up to 12 weeks in patients who are very stable on warfarin therapy.4  But you might want to proceed with caution … perhaps “see you in 12 weeks but I will contact you a couple times before then” would be better.  [See related iForum Rx commentary]

6.   In with New … Out with the Old? The AT9 favors dabigatran over warfarin in patients with AF and a CHADS2 score of at least 1 if they resemble participants in the RE-LY trial.3 In other words, dabigatran is favored in patients without valvular disease (such as mitral stenosis), significant renal impairment (estimated creatinine clearance ≤ 30 mL/min), active liver disease, and who are not pregnant.6  There is no mention of rivaroxaban but one would assume, based on the ROCKET-AF data, the AT9 authors would feel similarly inclined toward rivaroxaban.  Boy, I’d like to be in the room for the discussion 3 years from now when AT10 recommendations are formulated!

8.   To K or not to K?  AT8 previously recommended omitting a dose of warfarin and administering vitamin K in patients who have a elevated INR (5 to 9) and are at increased risk of bleeding.7  The AT9 authors recommend against the routine use of vitamin K in patients taking warfarin with INRs between 4.5 and 10 provided there is no evidence of bleeding.  This is based on findings from a pooled analysis showing no difference in thromboembolic events or bleeding episodes when vitamin K was administered compared to placebo.4

10.  Let’s Go Green! You don’t need a hard copy of the AT9 guidelines (we are in the electronic age after all).  The CHEST editorial staff noted that there are several advantages to the electronic version which include expedited publication, easier navigation, and lower costs for printing and shipping.8  You can get your very own electronic copy of AT9 here.


Case Study: How would you apply AT9 to this patient?

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<p>Is it true that the labelling now tells us not to use at all in CrCl 15-30 ?</p> <p>I had this release from Nov.</p> <p><strong>Ridgefield, CT </strong>- US physicians are being advised to assess renal function prior to prescribing <strong>dabigatran etexilate</strong> (Pradaxa, Boehringer Ingelheim) and to assess renal function in clinical situations that might be associated with declines in kidney function, according to the <a href="http://www.theheart.org/viewDocument.do?document=http%3A%2F%2Fbidocs.boehringer-ingelheim.com%2FBIWebAccess%2FViewServlet.ser%3FdocBase%3Drenetnt%26folderPath%3D%2FPrescribing%2520Information%2FPIs%2FPradaxa%2FPradaxa.pdf" target="_blank">updated drug label</a>.</p> <p>Similar to a <a href="http://www.theheart.org/viewDocument.do?document=http%3A%2F%2Fwww.theheart.org%2Farticle%2F1301029.do" target="_blank">recent European Medicines Agency update</a>, the revised label states that renal function should be assessed prior to starting therapy and tested annually in patients 75 years of age and those with creatinine clearance (CrCl) &lt;50 mL/min. In addition, the label now states that physicians should consider using the 75-mg twice-daily dose in patients with moderate renal impairment who are also taking dronedarone or systemic ketoconazole. Dabigatran should not be prescribed in patients with severe renal impairment (CrCl 15-30 mL/min).</p> <p>&nbsp;</p>

<p>Thank you for this simple and concise format on the changes in anticoagulation recommendations from the Chest guidelines. I like that the first point, and most important, is about the grading. It's important that we realize that we need to pay attention to the grades of the recommendations before utilizing them into our practice.&nbsp;</p>