A Pilot Study On Low-intensity Anticoagulation Of HVR Patients In Northwest China

Mechanical heart valve replacement is the most commonly used therapy on patients with heart valve lesion. But the mechanical valves can activate coagulation reaction in human body. As a result thrombosis on the mechanical valve can damage the structure of the valve, while thrombo-embolism can block blood supply of important organs, impair their functions or even life threatening. To reduce this potential harm, patients with mechanical valve have to accept life long anticoagulation. But oral anticoagulants impacts the balances between coagulate and and coagulate systems of human body. Insufficient anticoagulation can cause thrombo-embolism and excessive anticoagulation can cause bleeding. Both can be life threatening. In order to resolve this dilemma, serial clinical trails were made to invest a proper anticoagulation standard based on INR.In recent years, following the improvement of modern valve, a trend of low-intensity anticoagulation became more and more prevalent some foreign researchers induce the standard of INR 2.0-3.0, they also got satisfying clinical output. But in our country only some researches based on lab experiment were carried on this field. When we use their standard to guide our patients on anticoagulation, we observe that the bleeding incidents occurred so frequently that some patients could not obey the fix standard. Consider the special aspect ofnorthwest China, we need to invest a new standard of low intensity anticoagulation for patients in northwest China.Three aspects are included in this pilot study. They are: 1. To evaluate the safety of the low dose oral anticoagulation therapy following heart valve replacement (HVR) in northwest china and research the optimal level of the therapy. We exam different patients under different INR levels. We compare their difference of D-dimer and AT-III:C value and record the bleeding or thrombo-embolism incidents. We give chief consideration to clinical events and second consideration to lab results. Then we invest the primary level of low-intensity anticoagulation of patients in northwest china based on INR monitoring 2.Direct the anticoagulation of a group of patients with the level we just invested. Observe the warfarin dose they accepted and their INR fluctuation. We evaluate the important factors interfere with warfarin effects and in which condition the INR is instable that need more frequently monitor.3.Analyse the data of the former two trails .we evaluate the risk factors of bleeding. The results of the study show that: 1. Patients with mechanical valves can accept a low-intensity anticoagulation safely with the target INR level of 1.3-1.7, provided that they have no risk factors of thrombosis. While the patients with risk factors can follow anticoagulation safely with the target INR level of 1.7-2.0. And both presented satisfying clinical results. 2.The hepatic function and location and number of valve play important roles in the dose of the taken warfarin to keep the fixed INR level. We should give more INR tests to the patients with old agedamaged hepatic function and primary stage of the anticoagulation. 3.Intensity of treatment, patient characteristics: old age damaged hepatic function etc and the stage of the treatment show obvious impact on bleeding events.