International normalized ratio for the guidance of warfarin treatment in elderly patients after cardiac valve replacement

Thus far, the target value for international normalized ratio (INR) has remained to be determined. The current study aimed to further explore the INR value of the anti-coagulation drug warfarin after cardiac valve replacement. The clinical data of 213 patients who underwent cardiac valve replacement at Linyi Central Hospital (Linyi, China) between January 2010 and May 2013 were retrospectively analyzed. The warfarin dosage, prothrombin time (PT) and INR were compared among patients with hemorrhage or embolism, and those with no complications. A total of 31 cases (14.6%) developed adverse reactions and complications during the medication period, including 21 cases with hemorrhage (9.9%, hemorrhage group) and 10 cases with embolism (4.7%, embolism group), while 182 patients did not (85.4%, normal group). The average dosage of warfarin was 2.0 +/- 0.6, 3.1 +/- 0.7 and 1.7 +/- 0.6 mg/day in the normal, hemorrhage and embolism groups, respectively. The dosage of warfarin, the PT and the INR in the hemorrhage group were all significantly greater than those in the normal group and the embolism group (all P<0.05). INR monitoring is recommended to ensure the safety of the anti-coagulant drug warfarin, but further study is still required to determine a reasonable target INR value.