SAMe-TT2R2 score

The SAMe-TT2R2 score is to aid decision making between a non-VKA oral anticoagulant (NOAC) and a vitamin K antagonist (VKA).


Excerpt from Evidence based management of atrial fibrillation, Lip, G. H. from 54th St. Andrews Day Festival Symposium: Updates on Acute Medicine

Decisions on rate and rhythm control are determined by patient symptoms. Given that atrial fibrillation (AF) commonly coexists with various comorbidities, attention to cardiovascular risk factors and so-called ‘upstream therapy’ should be part of the holistic approach to AF management.

As part of the management cascade, stroke prevention is the main priority. The major guidelines (European, American, NICE) all now recommend use of a risk factor based approach, with the CHA2DS2-VASc score.

The 2012 ESC and 2014 NICE guidelines recommends a clinical practice shift towards initial focus on identification of ‘truly low-risk’ patients with AF [STEP 1], that is, those patients who with a CHA2DS2-VASc score=0 (male) or 1 (female), who do not need any antithrombotic therapy. Subsequent to this [STEP 2], patients with AF and ≥1 stroke risk factors can be offered effective stroke prevention, which is oral anticoagulation. Oral anticoagulation can be offered as a non-vitamin K antagonist oral anticoagulant (NOAC) or a vitamin K antagonist (eg warfarin) with good quality anticoagulation control as reflected by a time in therapeutic range (TTR) >65–70%.

In a newly diagnosed non-anticoagulated AF patient, decision making between a NOAC and a VKA can be made using the SAMe-TT2R2 score. This is a simple score based on clinical factors that helps discriminate those patients who would do well on a VKA (with a TTR>65%), if SAMe-TT2R2 score 0-2. If the SAMe-TT2R2 is >2, the patient is less likely to achieve a good TTR and alternative strategies (e.g. a NOAC) should be used rather than subject the patient to a 'trial of warfarin' that may expose the patient to stroke and thromboembolism.

Table 1: SAMe-TT2R2 score
Factor Score
Sex (female) 1
Age (<60 years) 1
Me (medical history*) 1
*two of the following: hypertension, DM, CAD/MI, PAD, CHF, previous stroke, pulmonary disease, hepatic or renal disease
Treatment (interacting medications e.g. amiodarone) 1
Tobacco use (within two years) 2
Race (non-Caucasian) 2
Maximum score 8



Male Female


< 60 years > 60 years

Medical history

Hypertension, DM, CAD/MI, PAD, CHF, previous stroke, pulmonary disease, hepatic or renal disease?

>2 of the above conditions
<2 of the above conditions


Interacting medications e.g. amiodarone

True False

Tobacco use

Tobacco use within the past two years

True False



True False

Total score
Score results guide
Evidence based management of atrial fibrillation presentation

Professor G H Lip

  1. Lip GY, Tse HF, Lane DA. Atrial fibrillation. Lancet 2012; 379:648–61. source
  2. Camm AJ, Lip GY, De Caterina R et al. 2012 focused update of the ESC guidelines for the management of atrial fibrillation: an update of the 2010 ESC guidelines for the management of atrial fibrillation. Developed with the special contribution of the European Heart Rhythm Association. Eur Heart J 2012; 33:2719–47. source
  3. National Clinical Guideline Centre (UK). Atrial fibrillation: the management of atrial fibrillation. London: National Institute for Health and Care Excellence (UK); 2014
  4. Apostolakis S, Sullivan RM, Olshansky B et al. Factors affecting quality of anticoagulation control among patients with atrial fibrillation on warfarin: the SAMe-TT2R2 score. Chest 2013; 144:1555–63. source