Low-dose international normalized ratio self-management: a promising tool to achieve low complication rates after mechanical heart valve replacement.

BACKGROUND

International normalized ratio (INR) self-management can significantly reduce INR fluctuations, bleeding, and thromboembolic events compared with INR control managed by general practitioners. However, even patients with INR self-management may have an increased risk of bleeding if their INR value is above 3.5. This study evaluated the compliance, clinical complications, and survival of patients after mechanical heart valve replacement with low-dose INR self-management compared with conventional-dose anticoagulation.

METHODS

Group 1 (n = 908) received low-dose anticoagulation with a target INR range of 1.8 to 2.8 for aortic valve replacement and 2.5 to 3.5 for mitral or double valve replacement. Group 2 (n = 910) received conventional-dose anticoagulation with a target INR range of 2.5 to 4.5 for all heart valve prostheses.

RESULTS

In groups 1 and 2, 76% and 75% of INR values, respectively, were in the target range. Results did not differ according to schooling and age. The rate of thromboembolic events per patient year was 0.18% in group 1 and 0.40% in group 2 (p = 0.210). The rate of bleeding complications was 0.74% for group 1 and 1.20% for group 2 (p = 0.502). In most patients with clinically relevant bleeding, these complications occurred although their measured INR values were below 3.5. The survival rate did not differ between the study groups (p = 0.495).

CONCLUSIONS

Low-dose INR self-management is a promising tool to achieve low hemorrhagic complications without increasing the risk of thromboembolic complications. INR self-management is applicable for all patients in whom permanent anticoagulation therapy is indicated. Even INR values below 3.5 can bear the risk of bleeding complications.