Abstract 519: The Early Decrease of Plasma ADAMTS13 Antigen Levels is a Significant Predictor of Future Thrombotic Events in Patients with Acute Myocardial Infarction
Von WilIebrand factor (VWF) is an important cofactor in platelet adhesion and aggregation. Generally, it is known that multimer of VWF is closely associated with strong platelet adherence and aggregation. The early increase of VWF has been reported to be a risk factor for adverse outcome in acute coronary syndrome. Recently, a metalloprotease that cleaves VWF multimers has been identified, namely, ADAMTS13. We previously reported that ADAMTS13 antigen was localized in coronary thrombi obtained from patients with acute myocardial infarction (AMI). The aim of this study was to investigate serial changes in plasma VWF and ADAMTS13 antigen levels and the detailed analysis of the relationship between these plasma levels and prognosis after AMI. We measured serial changes of plasma VWF and ADAMTS13 antigen levels in 92 AMI patients (after admission, one, three, seven, and 14 days after AMI) and 40 control subjects. Plasma VWF antigen levels were significantly higher in AMI patients compared with controls (P < 0.001) on admission, peaked at three days, and gradually decreased afterward. Plasma VWF antigen levels at one day in the AMI patients accompanied with subsequent thrombosis (thrombosis group), including myocardial infarction, unstable angina pectoris, cerebral infarction, subacute thrombosis, and ischemic cardiac death, were significantly increased compared with non-thrombosis group. On the other hand, the plasma ADAMTS13 antigen levels were significantly decreased in AMI patients compared with controls (P < 0.0001) on admission and remained decreased for 14 days. The ADAMTS13 antigen levels in the thrombosis group decreased until three days and gradually increased afterward. Kaplan-Meier analysis and Cox hazards analysis demonstrated that patients with low ΔADAMTS13 levels (Δ = the value at day 3 - value at admission) had significantly higher probabilities of developing thrombosis during one-year follow-up period (P = 0.0104). These findings suggested that monitoring the changes of VWF and ADAMTS13 antigen levels in the early phase of AMI might be valuable for predicting and preventing thrombosis during one-year follow-up in patients with AMI.