The SAMe-TT2R2 score 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 eg. warfarin). It has been suggested that it can aid in the medical decision making between VKAs and new oral anticoagulant/non-VKA oral anticoagulant (NOAC eg. dabigatran, rivaroxaban, apixaban or edoxaban) in patients with atrial fibrillation (AF). 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.
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 renal failure or in patients with valvular replacement surgery.
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) 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
Using the above table add together points assigned for different factors to a maximum score of 8.