The Correlations Of Protein C Activity And Soluble Thrombomodulin With CT Pulmonary Artery Obstruction Index In Patients With Acute Pulmonary Embolism

Objective:To investigate the correlations of protein C activity and soluble thrombomodulin concentration with CT pulmonary artery obstruction index in acute pulmonary embolism patients before anticoagulant therapy,and to explore whether PC activity level and sTM concentration can be used to assess the thrombus burden and severity of pulmonary embolism,and to evaluate its significance in clinical diagnosis and treatment.Methods:Forty-six patients with acute pulmonary embolism newly diagnosed by CTPA at departments of respiratory medicine of three different hospitals from December 2016 to November 2017 were selected as group A,32 inpatients with other pulmonary diseases at the same time period were selected as group B and 32 healthy adults as group C.Peripheral venous blood of upper limbs collected within 24 hours before thrombolytic or anticoagulant therapy in the morning in group A.In group B,peripheral venous blood of upper limbs wascollected on the next morning after CTPA confirming no pulmonary embolism.After centrifugation,the upper plasma was collected and stored in a refrigerator at-80°C.The activity of PC was detected by chromogenic substrate method,and the concentration of sTM was detected by enzyme-linked immunosorbent assay(ELISA).Among,the three groups of PC activity,sTM concentration were compare,and the relationship between PC activity and s TM concentration in each group were also studied.In Group A,PESI was scored according to the Severe Index Scale of Pulmonary Embolism.Spearman's rank correlation coefficient was used to analyze the relationship between PESI and PC activity and sTM concentration.In group A,Mastora scores were used to evaluate PAOI before treatment.According to PAOI,29 patients with mild obstruction(PAOI<30%),8patients with moderate obstruction(PAOI 30%-50%),and 9 patients with severe obstruction(PAOI>50%)were grouped in group A.The differences of PC activity and sTM concentration among different PAOI stratifications were compared,and the PC activity,sTM concentration related to PAOI were further explored.Results: The PC activity before treatment in group A was significantly lower than that in group B(35.00 ± 12.31% vs.41.59 ± 6.91%)and in group C(35.00±12.31% vs.71.38±7.67%),and the difference was statistically significant(P<0.05).Before treatment,plasma s TM concentration in group A was higher than that in group C(1450.28 ± 97.82pg/ml vs.1290.14±115.68 pg/ml),while the difference between group A and group B were not significantly different(1450.28 ± 97.82pg/ml vs.1417.99 ± 120.13pg/ml).In group A,the PC activity and the concentration of sTM are different in different blocking groups(P<0.05).And there was a negative correlation between PC activity and sTM concentration(r=-0.391,P=0.007),but no correlation between PC activity and sTM concentration between group B and C(r=0.142 and P=0.438,r =0.026 andP=0.889,respectively),PC activity was negative correlated to PESI score(r=-0.42,P=0.004),PAOI(r=-0.336,P=0.023).There was a positive correlation between sTM concentration and PESI score(r=0.355,P=0.015),PAOI(r=0.316,P=0.033),respectively,in group A.Conclusions: The activity of PC in patients with acute pulmonary embolism is low,while the concentration of sTM is increased.The lower PC activity and the higher concentration of sTM indicate the more serious pulmonary embolism.the level of PC activity and sTM concentration in patients with acute pulmonary embolism can reflect the degree of thrombus burden in vivo.The detection of PC activity and sTM concentration may have implications for the prognosis of APE.