Equal effectiveness of very-low-intensity anticoagulation and standard low-intensity anticoagulation: a pilot study

We compared the efficacy of very-low-intensity oral anticoagulation (OA) with that of the recommended standard low-intensity oral anticoagulation, using international normalized ratios (INRs). We enrolled 101 patients into a pilot study--51 patients in the very-low-intensity anticoagulation arm (INR 1.4 to 2.0) and 50 in the standard low-intensity anticoagulation arm (INR 2.0 to 3.0). They were monitored for thrombotic/embolic and hemorrhagic complications for an average follow-up of 1.5 years. Two thrombotic/embolic events occurred in the very-low-intensity group; no thrombotic/embolic events occurred in the standard low-intensity group. No major bleeding occurred in the very-low-intensity group; one major hemorrhagic event occurred in the standard low-intensity group. These findings did not achieve a statistically significant difference in major complications between the two groups. It appears that very-low-intensity OA (INR 1.4 to 2.0) is as effective in preventing thromboses as standard low-intensity OA (INR 2.0 to 3.0).