OBJECTIVE

To evaluate an effectiveness and safety of a new algorithm for warfarin dose monitoring in patients with atrial fibrillation (AF) and chronic kidney disease (CKD).

MATERIAL AND METHODS

The study included 558 patients with AF and CKD (glomerular filtration rate (GFR) less than 60 ml/min/1.73 m²) referred to the anticoagulant therapy department at the Cardiology Clinic of Sechenov University from Moscow outpatient facilities. Warfarin dosing was failed for 1 year. All patients controlled INR at least 1 time per month (retrospective data). All patients underwent warfarin dose selection based on a new algorithm. The last one includes the principle of slow dose escalation and more frequent INR monitoring considering initial GFR.

RESULTS

Mean age of patients was 71 years, 87% of patients were over 65 years old. CKD stage 3a was diagnosed in 72% of patients, stage 3b — 21%, stage 4 — 7%. CHA2DS2VASc score was >2, HAS-BLED score ranged from 1 to 5 points. Mean follow-up was 18 months. Initially, only 11% of patients maintained therapeutic INR for a target time, after 18 months of follow-up in the anticoagulant therapy department (through a new algorithm for warfarin dosing) — 82%. Thromboembolic events were absent within the follow-up period. There were 3 major and 67 minor bleedings (TIMI scale).

CONCLUSION

The proposed algorithm for warfarin dosing in patients with AF and CKD considers GFR. This approach ensures target INR in most patients. The number of bleeding was significantly lower compared to standard algorithm for warfarin dosing.