The SAMe-TT2R2 score[1][2] is a
clinical prediction rule to predict the quality of vitamin K antagonist anticoagulation therapy as measured by time in therapeutic INR range (TTR) (
VKA e.g. warfarin).[3] It has been suggested that it can aid in the medical decision making between VKAs and new oral anticoagulant/non-VKA oral anticoagulant (
NOAC e.g. dabigatran, rivaroxaban, apixaban or edoxaban) in patients with
atrial fibrillation (AF).[4][5] This score can be used with patients with ≥1 additional stroke risk factors using the
CHA2DS2-VASc score, where oral anticoagulation is recommended or should be considered.[6]
This score reflects the need to offer an improved patient care pathway when using oral anticoagulants. While NOACs avoid the need for drug monitoring (e.g. INR monitoring), they have an unstable bioavailability and are not indicated for patients with chronic
kidney failure[7] or in patients with valvular replacement surgery.[8]
In a newly diagnosed non-anticoagulated AF patient, the physician may avoid a ‘trial of warfarin’ (which may expose patients to increased stroke risk during the initial inception phase, with suboptimal anticoagulation control[9]) and make an informed decision between patients likely to do well on a VKA (SAMe-TT2R2 score 0-2) or where a
VKA is perhaps likely to be associated with poor quality anticoagulation control.
Calculate the SAMe-TT2R2 score
Condition/influencing factor
Points
Sex (female)
1
Age (<60 years)
1
Medical history (history of more than two of the following: hypertension, diabetes, CAD, PAD, heart failure, stroke; pulmonary, hepatic, or renal disease)
1
Treatment (interacting medications e.g. amiodarone)
1
Tobacco use (within 2 years)
2
Race (non-Caucasian)
2
Using the above table add together points assigned for different factors to a maximum score of 8.
^Apostolakis S, Sullivan RM, Olshansky B, Lip GY. Factors affecting quality of anticoagulation control among patients with atrial fibrillation on warfarin: the SAMe-TT₂R₂ score" Chest 2013 Nov;144(5):1555-63
^Ruff, Christian T., et al. "Evaluation of the novel factor Xa inhibitor edoxaban compared with warfarin in patients with atrial fibrillation: Design and rationale for the Effective aNticoaGulation with factor xA next GEneration in Atrial Fibrillation–Thrombolysis In Myocardial Infarction study 48 (ENGAGE AF–TIMI 48)." American Heart Journal 160.4 (2010): 635-641
^2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease (Journal of the American College of Cardiology). Published on March 3, 2014
^Azoulay L, Dell'Aniello S, Simon TA, Renoux C, Suissa S. Initiation of warfarin in patients with atrial fibrillation: early effects on ischaemic strokes. Eur Heart J. 2014 Jul 21;35(28):1881-7.
^Clarkesmith DE, Pattison HM, Lip GY, Lane DA. "Educational intervention improves anticoagulation control in atrial fibrillation patients: the TREAT randomised trial. PLoS One. 2013 Sep 9;8(9):e74037.
doi:
10.1371/journal.pone.0074037