Colour Doppler Flow Imaging Evaluate The Stability Of Deep Venous Thrombosis Of The Lower Limbs And Analysis Of Its Risk Factors

Objectives To summarize the ultrasonographic features and clinical features of unstable lower extremity deep venous thrombosis,to find out the risk factors that affect the stability of thrombus,and to find the critical reference value to determine whether the thrombus is stable or not.Methods A total of 107 patients with deep venous thrombosis of the lower extremities were diagnosed from September 2016 to January 2018 at the Department of ultrasound in the Affiliated Hospital of North China University of Polytechnic University.All patients underwent inferior vena cava filter placement(temporary type).After 10 days,the filter was removed.According to whether the thrombus was collected in the filter,it was divided into two groups: group I(thrombus instability group)52 cases,group II(thrombotic stabilization group)55 cases.The ultrasonic parameters include the location of DVT,the echo of DVT and the flow filling in the DVT tube.Including the clinical parameters collected: age,body mass index,there is no local pain,bilateral lower limb contrast thickening > 3cm,without the formation of collateral circulation and thrombosis period,lower limb swelling degree,no previous history of thrombosis,malignant tumor treatment,biochemical indicators.The database was created by Excel 2013,SPSS 20 was used for statistical analysis,the normal distribution of the data in sx � said that the skewness data to the median(four percentile interval),compared with two groups of measurement data among the single factor variance analysis,t test,rank sum test,count data between two groups the chi square test was used to compare the parameters to determine the critical reference;whether DVT stable values determined by ROC curve analysis;risk factors of unstable DVT were analyzed by Logistic regression analysis;P < 0.05 the difference was statistically significant.Results 1(1)Inferior vena cava filter before and remove the preoperative ultrasonographic features of two groups of comparison,the difference was not statistically significant(P>0.05);(2)The group of patients in the inferior vena cava filter before and remove the ultrasonographic features before operation there is no change compared to DVT site before and after the change was statistically significant(2? =10.458,P=0.001),shows that the ratio of DVT unstable patients occurred change than patients with stable.2 There was statistically significant difference in the history of thrombosis between the two groups(2? =8.518,P=0.004),indicating that the rate of history of thrombus in patients with unstable DVT was higher than that in stable group.3 Group patients with biochemical indexes TG(Z=-2.026,P=0.046),Lp?(2? =-2.868,P=0.004),PT(2? =-3.633,P=0.000)and D-D(2? =-3.222,P=0.001)the difference was statistically significant,suggesting that DVT is not stable in patients with lower triglyceride and lipoprotein alpha stable group and the plasma D-2 dimer was higher than that of stable group,prothrombin time longer than the stable group.4 Factors affecting the stability of deep venous thrombosis of lower extremity: high D-D level [D-D(P=0.004);D-D(1)(OR=4.097,95%CI:1.215~13.811,P=0.023);D-D(2)(OR=9.395,95%CI:2.446~36.087,P=0.001)].[PT(P=0.021);PT(1)(OR=5.402,95%CI:1.569~18.596,P=0.007);PT(2)(OR=2.877,95%CI:1.016~9.644,P=0.045],had a history of thrombosis(OR=6.549,95%CI:1.401~30.606,P=0.017),thrombosis occurred in changes of(OR=3.075,95%CI: 1.015~9.313,P=0.047)is a risk factor of thrombosis instability.5 ROC curves of DVT judgment whether the stability: when the D-D value of 2750mmol/L,the sensitivity of judgment whether the stability of 90.5% thrombus,the specificity was 60%;when the PT value is 13.15 s,the sensitivity of judgment is stable for 83.3% thrombus,the specificity was 71.1%.6 The Logistic regression,two indexes of PT,D-D ROC curve analysis to determine whether thrombosis is stable,the sensitivity was 91.2%,specificity was 72.5%.Conclusions 1(1)The two groups were similar to the preoperative sonogram of the filter,and it was difficult to judge whether DVT was stable.The changes in the location of DVT in the same patient were observed,which could indicate the risk of clinical DVT falling off.(2)Patients who have a history of thrombus history are likely to have unstable DVT.The TG of patients with unstable deep venous thrombosis was lower than that in the stable group,and the Lp alpha and D-D were higher than that in the stable group,and the PT was longer than that in the stable group.2 High D-D level,prolonged PT,past history of thrombus,and changes in the site of the same patient's thrombus are the risk factors for thrombosis instability.3 The quantitative clinical indicators for judging DVT instability were: D-D > 2750?g/L and PT greater than 13.15 s.The sensitivity and specificity of the combined index of D-D and PT to the unstable DVT are higher than that of the single index,and the accuracy is higher.