Geographical variation in VKA popularity is evident, with warfarin commonly used worldwide but acenocoumarol being popular in Spain and phenprocoumon in Germany. In randomized clinical trials, most have used warfarin. Optimal INR Target Range in AF: For stroke prevention in patients with AF receiving a VKA, the optimal INR target range is 2.0 to 3.0,144 aiming for an INR value of 2.5 to maximize the proportion of time spent in the therapeutic INR range. Numerous observational studies of AF patients have demonstrated that the risk of thromboembolism/ischemic stroke is greater when INR is < 2.0,81,83,85,145-147 whereas INR levels > 3.0 are associated with a greater incidence of major bleeding, especially ICH when the INR rises above All the phase 3 NOAC trials employed an INR target of 2.0 to 3.0 among patients receiving ; J-ROCKET employed a lower INR target of 1.6 to 2.6 for the Japanese population.148 In some Asian countries, there is the perception that a lower target INR range (eg, 1.6-2.6) should be used, especially in the elderly. Only 1 small prospective randomized trial allocated 115 secondary prevention AF patients to a conventional-intensity group (INR, 2.2 to 3.5) or a low-intensity group (INR, 1.5 to 2.1).149 Major hemorrhagic complications occurred in 6 patients in the conventional-intensity group (6.6% per year) compared with the low-intensity group (0% per year; P .01). Other Asian registries have suggested that low intensity (INR, 1.5-2.5) was associated with less bleeding, but no information on quality of INR control was reported. There is currently no robust evidence for implementing a target INR range of 1.6 to 2.6, and therefore the conventional, evidence-based INR target of 2.0 to 3.0 should be employed globally. 