Abstract:

Objective: To explore the predictive value of four items of new thrombus markers combined with conventional coagulation tests for thrombosis in antiphospholipid syndrome. Methods: A total of 121 antiphospholipid syndrome (APS) patients who hospitalized at Peking University People's Hospital from March 2022 to January 2023 were selected and divided into thrombus group (50 cases) and nonthrombus group (71 cases) according to whether thrombosis occurred. The differences of laboratory characteristics including antiphospholipid antibodies were compared between the thrombotic and non-thrombotic groups. Chemiluminescent immunoassay was used to detect thrombomodulin (TM), thrombin-antithrombin complex (TAT), Plasmin-α2 plasmin inhibitor complex (PIC), and tissue plasminogen activator inhibitor complex (t-PAIC) in plasma from venous. The independent risk factors of thrombosis in patients with APS were determined using binary Logistic regression. Receiver operating characteristic (ROC) curve analysis was applied to evaluate the efficacy of each index on the prediction of thrombosis. Results: Compared with the patients without thrombosis, the patients with thrombosis were older [49 (32, 64) years vs. 36 (32, 39) years, P < 0.05]. The percentages of male, smoking, hypertension, and global antiphospholipid syndrome score (GAPSS)≥10 in the patients with thrombosis were significantly higher than those in the patients without thrombosis (P < 0.05). The positive rates of anticardiolipin antibody (aCL) and lupus anticoagulant (LA) in the thrombotic group were significantly higher than those in the non-thrombotic group (P < 0.05), and the levels of prothrombin time, activated partial thromboplastin time, fibrinogen, fibrin degradation product in the thrombotic group were significantly higher than those in the non-thrombotic group (P < 0.05).Among the thrombosis group, venous thrombosis accounted for 19 (38.00%), including deep vein thrombosis (16, 84.21%) and pulmonary embolism accounted (5, 26.32%); Arterial thrombosis accounted for 35 (70.00%), including myocardial infarction (6, 17.14%) cerebral infarction (30, 85.71%). The patients in the thrombotic group had significantly greater TM levels than those in the non-thrombotic group (P < 0.05).There were no significant dif-ferences between the two groups in TAT (Z=-1.420, P=0.156), PIC (Z=-0.064, P=0.949), and t-PAIC (Z=-1.487, P=0.137). Univariate and binary Logistic regression analysis of relevant variables showed that advanced age [OR=1.126, P=0.002], elevated TM [OR=1.325, P=0.048], prolonged prothrombin time (PT) [OR=4.127, P=0.008] were independent risk factors for thrombosis in the patients with APS. ROC curve analysis of the above three independent risk factors showed that the combined detection of age, PT and TM had the highest Yoden index (0.727) and sensitivity (83.0%), with a specificity of 89.7%. Conclusion: TAT, PIC, TM, and t-PAIC may reflect thrombus formation from the coagulation system, fibrinolysis system, and endothelial system. The combined of age TM and PT is superior to the application of a single marker, which has diagnostic value for the early identification of APS thrombosis.

Key words: Thrombomodulin, Thrombin-antithrombin complex, Plasmin-α2 plasmin inhibitor complex, Tissue plasminogen activator inhibitor complex, Antiphospholipid syndrome