Objective To explore the role of thrombus precursor protein(TPP) in the monitoring of anticoagulation in the patients with atrial fibrillation (Af) after mechanical heart valve replacement, and suggest the reasonable anticoagulant range. Methods Ninety patients were divided into Af group (n=45), sinus rhythm group (SR group, n=45), and control group (20 patients with non-valvular heart diseases), according to whether Af exist after mitral valve replacement. TPP concentrations and International Normalized Ratio(INR) in the anticoagulant patients were analyzed. Results In patients after mechanical mitral valve replacement, plasma TPP concentrations in both SR group and Af group were lower than that in control group (Plt;0.05,0.01), their INR value were higher than that in control group (Plt;0.01), and Af group had higher plasma TPP concentrations than that in SR group((Plt;)0.05). It was found that there existed contradictions between INR and plasma TPP concentrations in Af group. There were 28 patients with plasma TPP concentrations below 6 μg/ml and without spontaneous bleeding complications in the group with Af, who might be at the optimal anticoagulant status. Their 95% confidence of INR value was 1.90-2.30 and their plasma TPP concentration was 4.29±0.75μg/ml. Conclusion Patients with Af after mechanical heart valve replacement might have higher risk of thromboembolism, INR between 1.90 - 2.30 and plasma TPP concentration between 2.84-6.00 μg/ml might be the optimal anticoagulant therapeutic range.
