Clinical study of the appropriate range of warfarin anticoagulant therapy intensity in patients after heart valve replacement

Objective To explore the best range of international normalized ratio for anticoagulation treatment after mitral valve replacement (MVR) and double valve replacement (DVR).Methods We conducted a follow-up study involving 1592 patients who received the warfarin anticoagulant therapy after MVR or DVR in our hospital.Clinical data was collected including the admission information,the dose of warfarin and the INR level,and the occurrence of bleeding and thrombosis were recorded.The patients were divided into 2 (MVR and DVR) groups in terms of the different valve prostheses,and then each group was assigned to four subgroups according to their INR level ( A:INR=1.4-1.7;B:INR=1.7-2.0;C:INR=2.0-2.3;and D:INR=2.3-2.6) to compare the incidence of bleeding and thrombosis among these subgroups.Results The analysis of the incidence of bleeding:In MVR group,the subgroups with different INR levels had significant difference with participants with INR level at D having higher incidence of bleeding than the other 3 groups (Group A:x2=17.991,Group B:x2=13.436,Group C:x2=7.186;P＜0.01 ).We observed significant difference in DVR groups (x2=19.067,P＜0.01 ) with the increased incidence of bleeding of INR level at D compared with the other three groups ( Group A:x2=16.736,Group B:x2=10.486,Group C:x2=7.773;P＜0.01 ).The analysis of the occurrence of thrombosis;The groups of MVR and DVR had no significant differenceson in the incidences of thrombosis in all the levels of INR ( P ＞ 0.05 ).No significant statistical differences were found on the incidence of bleeding and thrombosis at INR level 1.4-2.3 ( P ＞ 0.05 ) Conclusion The present study suggestes that the level of INR at 1.4-2.3 is appropriate after the anticoagulation therapy in the MVR and DVR groups.