Control of Oral Anticoagulant Therapy using INR in Patients with Artificial Heart Valves

ABSTRACT

To determine frequency of patients with artificial heart valves who are optimally anticoagulated, over anticoagulated or under anticoagulated based upon INR values. Descriptive, cross sectional study. Pathology Department, Armed Forces Institute of Cardiology, Rawalpindi. Five hundred patients who underwent heart valve replacement at AFIC were selected according to convenience sampling. Prothrombin time along with International Normalized Ratio [INR] was done in every case on automated Coagulation Laboratory [ACL]. Patients were grouped into adequately anticoagulated, under anticoagulated and over anticoagulated according to INR values. Descriptive statistics were used to describe the frequencies and percentages. One way ANOVA followed by post Hoc Sheffe test was applied to compare mean values of INR across the three groups. The p-value less than 0.05 was considered significant. A total of 300 patients [60%] were adequately anticoagulated whereas 175 [35%] and 25 [5%] were under and over anticoagulated respectively. Fifteen patients [60%] of the over anticoagulated group had hemorrhagic complications. INR values of all the three groups were significantly different from each other p-value [<0.005]. Dose of oral anticoagulant [warfarin] should be adjusted according to the results of INR to avoid thromboembolic or hemorrhagic complications