The Impact of clinical and genetic factors on stable warfarin dosage / Vacis Tatarunas, Pranas Grybauskas, Audrone Veikutiene, Povilas Jakuska, Rimantas Benetis, Vaiva Lesauskaite

Objectives The main objective of this work was to find the clinically important factors, which determine warfarin dosage for patients after heart valve surgery, who continue anticoagulant therapy for at least of 3 months. Methods Patient’s clinical and anthropometric data was obtained from the case histories. Genotyping was performed using ABI 7900HT Fast Real-Time PCR thermocycler. Results From total cohort (n=195) of the patients, warfarin was underdosed in 52.3% of the patients. Patient’s age and body weight explained 18.1% of warfarin dose variation. Clinical data such as TSH and FT4 level, INR and the use of amiodarone and CCBs`, increased the accuracy of the model by 8.3%. Patient’s genotyping for CYP2C9*1, *2 and *3, VKORC1 (G-1639A) and VKORC1 (G3730A) doubled the accuracy of our model (R2=0.508). Conclusions The highest accuracy of stable warfarin dosage model was observed when a complex of factors such as patient’s antropometric, clinical and genetic data was introduced in the analysis.