Clinical guidelines on the management of AF advocate an individual TTR of at least $ 65%157,158 to maximize ef cacy and safety, and this should be the treatment target, although in clinical practice this may be more dif cult to achieve.153-156,159 An analysis of anticoagulation control in the Global Anticoagulation Registry in the Field [GARFIELD-AF] registry (n 9,934), a global observational study, revealed that only 1156 Evidence-Based Medicine [ 1 5 4 # 5 C H E S T N O V E M B E R 2 0 1 8 ] 41.1% had TTR $ 65% and of all the INR values, only 51.4% were in the therapeutic range (INR, 2.0 to 3.0), with one-third being subtherapeutic.155 After adjustment, the risk of stroke/systemic embolism (HR, 95% CI, 1.87-3.06), and major bleeding (HR, 1.54; 95% CI, 1.04-2.26) was greater with TTR < 65%, when compared with TTR $ 65%.155 TTR varies widely by geographical region (TTR $ 65%, An analysis of individual TTR from Swedish registries (n 40,449) revealed an overall mean individual TTR of 68.6% and signi cantly lower annual rates of thromboembolism (2.37% vs 4.41%), all-cause mortality when individual TTR was $ 70% compared with individual TTR < 70%, respectively.154 Recommendation 10. For patients with non-valvular AF, when VKAs are used, we suggest the target should be INR 2.0-3.0, with attention to individual TTR, ideally 70% (Ungraded consensus-based statement). Remark: Action required if TTR sub-optimal (< 65-70%) - implement additional measures (more regular INR tests; review medication adherence; address other factors known to in uence INR control; education/counseling) to improve INR control or consider an NOAC. Remark: When possible, experienced specialized anticoagulation clinics should be utilized for VKA and INR management. 