Risk Factors For Postpartum VTE And The Comparison And Optimization Of VTE Risk Assessment Methods

Object:To explore the independent risk factors of Postpartum Venous Thromboembolism(VTE),and compare the predictive value of existing assessment methods and independent risk factors combined in puerperal VTE risk.Methods:This was a case-control study.The VTE group consisted of55 women with postpartum VTE.For each VTE patient,3 women without VTE who admitted at the same month were randomly selected as the control group(n=165).The clinical data of two groups were collected and univariate analysis was carried out through t test and x~2 test.The variable with P<0.1 was selected into multivariate conditional logistic regression analysis to explore the independent risk factors and its influence of postpartum VTE.8 quantitative postpartum VTE risk assessment methods were included through systematically review of databases.There are 4commonly used non-quantitative methods.The risk of postpartum VTE was assessed by 12 methods along or combined with the high-risk factors which were not covered by these methods and the ROC curve was drawn.These methods were comprehensively compared based on AUC,the sensitivity and specificity of high risk(recommended pharmacological prophylaxis).Results:(1)Multivariate logistic regression results showed that the independent risk factors for puerperium VTE were cesarean section(OR5.39,95%CI 1.71～16.97),D-dimer≥0.7mg/L(OR 4.64,95%CI2.06～10.41),catheter indwelling>48hours(OR 4.34,95%CI 1.76～10.70),respiratory or urinary system infections(OR 3.19,95%CI 0.87～11.71),prenatal BMI≥30(OR 2.88,95%CI 1.07～7.72),preterm birth(OR 2.45,95%CI 1.10～5.45),age/5(OR 1.46,95%CI 1.01～2.09).(2)12 puerperium VTE risk assessment methods(AUC)were revised Caprini(0.805),Swedish(0.779),Shanghai(0.774),RCOG(0.746),China consensus(0.742),Maternity Clot Risk(0.737),PHP(0.687),QLD(0.679),SOGC(0.673),revised Padua(0.639),Bretelle(0.622),ACOG(0.588).After combined the high-risk factors D-dimer≥0.7mg/L and catheter indwelling>48hours which were not covered by these methods,the AUC were significantly improved and were 0.854,0.847,0.837,0.826,0.840,0.812,0.799,0.796,0.794,0.786,0.787,0.763,respectively.(3)Except for the Maternity Clot Risk(no recommendations about pharmacological prophylaxis),there was no statistical difference in pairwise comparison of 5 methods of AUC>0.7(P<0.05).Revised Caprini,Swedish,Shanghai were better than 6 methods of AUC<0.7(P<0.05).The sensitivity and specificity of which 5 methods were 69.09%～94.55%and 25.45%～77.58%respectively.Among them,the specificity of the revised Caprini was 25.45%,and was lower than that of4 other methods(P<0.05).There were no significant differences between sensitivities of the Swedish,Shanghai,RCOG and China consensus(P>0.05),while the Swedish specificity was higher than that of Shanghai,RCOG and China consensus(P<0.05).Conclusion:the independent risk factors for VTE during puerperium were cesarean section,D-dimer≥0.7mg/L,catheter indwelling>48hours,respiratory or urinary system infections,prenatal BMI≥30,preterm birth,age/5.The puerperium VTE risk assessment methods combined with D dimer≥0.7 mg/L and catheter indwelling>48 hours can further improve the predictive power.The Swedish is better among 12 methods,is of better clinical application value.