On 2014 Feb 10, David Keller commented:

In this case of a large patient with high creatinine clearance, dabigatran failed to prevent thromboembolic stroke associated with atrial fibrillation, apparently due to hypo-therapeutic serum levels. This case illustrates that the "open loop" use of the new oral anticoagulants (NOA's) may be ineffective or unsafe in patients who differ markedly from the average for populations tested in the NOA’s clinical trials. Dose-adjusted warfarin can be used safely and effectively in many such "outlier" patients because dosing feedback is obtained by monitoring INR. Clinicians who prescribe NOA's must remain vigilant for patients with clinical characteristics which put them at risk for serum NOA levels which are too high or too low. Dose-adjusted warfarin should be the initial therapeutic consideration for these patients. If the patient cannot take warfarin, it may be prudent to check peak and trough levels of the NOA at appropriate intervals.

On 2014 Feb 10, David Keller commented:

In this case of a large patient with high creatinine clearance, dabigatran failed to prevent thromboembolic stroke associated with atrial fibrillation, apparently due to hypo-therapeutic serum levels. This case illustrates that the "open loop" use of the new oral anticoagulants (NOA's) may be ineffective or unsafe in patients who differ markedly from the average for populations tested in the NOA’s clinical trials. Dose-adjusted warfarin can be used safely and effectively in many such "outlier" patients because dosing feedback is obtained by monitoring INR. Clinicians who prescribe NOA's must remain vigilant for patients with clinical characteristics which put them at risk for serum NOA levels which are too high or too low. Dose-adjusted warfarin should be the initial therapeutic consideration for these patients. If the patient cannot take warfarin, it may be prudent to check peak and trough levels of the NOA at appropriate intervals.