SIGNIFICANCE OF WARFARIN PLASMA CONCENTRATION IN ANTICOAGULATION MONITORING

ObjectiveTo study the clinical significance of warfain plasma concentration in oral anticoagulation monitoring following mechanical heart valve replacement.MethodsThirty patients following mechanical heart valve replacement were chosen randomly.They all had rheumatic heart disease.Plasma concentration of warfarin,international normalized ratio (INR),prothrombin time (PT) and oral dosage of warfarin were determined respectively.Changes and correlationships of all the above indexes were compared before and after taking warfarin.At the same time,the clinical complications,such as blooding and thromboembolism were observed.Results① The warfarin plasma concentration increased significantly at the time point of 2 hours after initial dose administration of warfarin (P 0.05 ).It reached peak at 6 hours (P 0.01 ) and tended to remain constant after 72 hours.② After the initial dose of warfarin,there were not significant changes of INR and PT until 36 hours (P 0.05 ).At 36 hours,INR increased greatly and PT prolonged significantly.72 hours later,INR and PT had very significant difference compared with 0 hour (P 0.001 ) and tended to remain constant.③ There were not significant correlationships between warfarin's plasma concentration with INR and PT.The correlation coefficient were 0.274 and 0.276 respectively (P 0.05 ).However,analysis showed a significant relationship between the logarithm of the warfrain concentration with INR and PT after 36 hours.The correlation coefficient were 0.894 and 0.908 (P 0.001 ).ConclusionsThe plasma concentration of warfarin was a sensitive index in monitoring anticoagulation; the combination of warfarin plasma concentration with INR and PT would improwe the precision of anticoagulation and decrease complications.