Clinical Research On Assessing The Risk Of DVT With Venous Stasis Index For Total Knee (hip) Replacement

Background:Venous thromboembolism(VTE)is an important complication in joint replacement,which includes deep vein thrombosis(DVT)and pulmonary embolism(PE).Effective assessment and early detection of DVT and then treated targetedly are able to reduce the risk of pulmonary embolism.It has important significance for patients undergo joint replacement.Ultrasound as a noninvasive,real-time diagnosis method,its accuracy on DVT diagnosis has been recognized.Because of the equipment,detection skill and thinking,we often pay more attention on the detection of femoral vein and popliteal vein,neglect or abandon the detection of distal deep vein,especially the muscle veins in the calf which leading to different DVT incidence among the literature reported.In recent years,it has become the hotspot research to assess the risk of DVT.Using ultrasound to assess the risk of DVT is also gradually increasing.We raised stasis index(SI)according to the three main factors of deep vein thrombosis "vascular endothelial damage,blood hypercoagulable state,blood stasis".In theory,venous stasis index can reflect the risk of ven ous thrombosis,the value is larger,the risk of DVT is higher.Is this the actual situation? How high the venous stasis index(the cut-off value)is more possible to develop DVT? All of the questions need to be verified by clinical research.Objective:1.To improve the diagnosis level of deep vein thrombosis by ultrasound in the lower limbs,especially in the muscular veins,We research the occurrence of DVT,including incidence and locations when using rivaroxaban as a conventional prophylactic after joint replacement to guide the clinical practice in optimizing the diagnosis and treatment of DVT.2.To assess the risk of DVT after joint replacement by the preoperative venous stasis index and the other ultrasound indexes,find the value of the indexes and confirm the cut-off values for DVT prediction.The incidence of deep vein thrombosis and using stasis index of vein to assess the risk of deep vein thrombosis after Total knee or hip replacementandMethods1.Patients:100 patients who underwent total knee or hip replacement(TKRor THR)were enrolled from March 2015 to June,including 45 THR cases(36 cases of unilateral surgery,9 cases of bilateral surgery),55 TKR cases(37 cases of unilateral surgery,18 cases of bilateral surgery),35 males and 65 females,age changing from 18 to 83 years,mean age(61 + 12)years old.Patients were given rivaroxaban(10mg/d)to prevent DVT,and the surgical side limbs were raised,wore elastic stockings and intermittent pneumatic pumps were used in THR patients after sugry.2.Equipment: Philips CX50 portable diasonograph.3 ~ 12 MHz linear array probes was used in routine.Adjust the detection of frequency,focus,depth and gain to optimize image quality.3.Detection methods: common femoral vein diameter(D),blood flow velocity of common femoral vein(Vmax)were measured when patients are breathing quietly.The common femoral artery diameter(DA),common femoral vein diameter(DV)were measured at groin level and the diameter of soleus muscle vein(Dsv)were measured in the calf before surgery.And then calculate stasis index of common femoral vein(SI)(d2/vmax)and DV/DA.DVT was detected by ultrasonography on day1,2,3 and7 after surgery.Compare the differences between DVTgroup and non DVT group,and then confirm the cut-off value to assess the risk of DVT.Results:1.57 patients developed DVT,containing 78 affected limbs.The incidence of DVT was 57%.All of the DVTs were detected in the calves,mainly in the soleus muscle veins.Most patients with DVT occurred on the1 st day after surgery.The incidence of DVT in TKR was higher than that in THR.In all of unilateral operation patients,the incidence of the operated sides was higher than that of the non-operated sides.The diameter of thrombosis in 35 DVT cases(61.4%)was lager than 7 mm.2.The area under the ROC curve(AUC)of SI,D,Vmax and Dsv for assessing the risk of DVT was 0.704,0.702 and 0.693,0.612 respectively,P < 0.05.The AUC of SI is largest and the assessment are the most effective.The cut-off value of SI was 5.15 mm,and the sensitivity,specificity,positive predict value,negative predict value and accuracy rate was 85.90%,48.36%,51.54%,84.29%,63% respectively;The cut-off value of D was 9.85 mm and the value index as above was 91.03%,41.80%,50%,87.93%,61% respectively;The cut-off value of Vmax was 24.95cm/s and the value index as above was 92.31%,30.33%,45.86%,86.05%,54.50% respectively;The cut-off value of DSV was 5.45 mm and the value index as above was 67.95%,63.11%,54.08%,75.49%,65% respectively.3 The SI,D,DV/DA of THR patients for the risk assessment of DVT had statistical significance.The AUC was 0.760,0.805,0.688 respectively;the cut-off value of SI was 6.75,the value index as above was 64.29%,78.95%,36%,92.31%,76.67% respectively.The cut-off value of D was 11.05 mm and the value index as above was 57.14%,78.95%,33.3%,90.91%,75.56% respectively;The cut-off value of DV/DA was 1.275 and the value index as above was 85.71%,55.26%,26.09%,95.45%,60% respectively.Vmax and Dsv had no statistical significant for the risk assessment of DVT after THR.4.Dsv of TKR patients for the risk assessment of DVT had statistical significance.The AUC was 0.668,the cut-off value of Dsv was 6.35 mm.The the value index as above was 56.25%,76.09%,76.6%,55.56%,64.55% respectively;SI,Vmax,D,DV/DA had no statistical significance in TKR patients for the risk assessment of DVTConclusion:The incidence of DVT after joint replacement still reach to 57%,DVT concentrated in the distal lower limbs,especially in the soleus vein.Therefore,ultrasonography should be taken to detect the DVT after the surgery to avoid missing the calves,especially the muscular veins.This study put forward the concept of venous stasis index,verified the effectiveness of SI for the risk assessment of DVT after joint replacement,especially for THR and provided a new effective method for the risk assessment of DVT after joint replacement.Nevertheless,the efficiency of prediction is not high enough,the further research should optimize the measurement method in order to enhance the accuracy of the venous stasis index for DVT assessment.Contrastive study on two measure methods of SI for assessing the risk of DVT after total knee(hip)replacementMethods:1.Patients:52 patients who underwent TKRor THR were enrolled from November 2015 to 2016 March,include 22 THR cases,30 TKR cases,15 males and 37 females,age changing from 22 to 83 years,mean age(57 + 13.9)years old.2.Equipment: Philips CX50 portable diasonograph.3 ~ 12 MHz linear array probe was used in routine.Adjust the detection of frequency,focus,depth and gain to optimize image quality.3.Detection methods: The Common femoral vein diameter(D1),blood flow velocity of common femoral vein(Vmax),mean velocity of common femoral vein(Vm),femoral vein diameter(D2),blood flow velocity of femoral vein(V2),mean velocity of femoral vein(V2m)were measured by bedside ultrasonography and calculated the stasis index of common femoral vein(SI,SIm),the stasis index of femoral vein(SI2 SI2m).DVT was detected by ultrasonography on day1,2,3 and7 after surgery.Compare the differences of the two methods and locations between DVT group and non DVT group.And then confirm the most effective method and location of SI measurement for the risk assessment of DVT.Results:The D1,Vmax,Vm,SI,SIm had statistical significance between the two groups.The D2,V2,V2 m,SI2 was no statistical significant between the two groups.The ROC curves show that SI had the largest AUC and was the most effective for the risk assessment of DVT.Conclusion:Through the comparison of different locations and measure methods of venous stasis index,we found the value of assessment was improved than the first part.SI which be calculated by Vmaxis a little more effective than Vm.Nevertheless,the value of using these indexes to assess the risk of DVT is still not high enough.It may be the reason that blood stasis is an important factor in the formation of DVT,but blood hypercoagulable state and vascular endothelial damage are also the important factors in the formation of DVT which are related to age,gender,concomitant diseases and some other factors.The further research need to increase the sample size and combine with a variety of factors in order to improve the accuracy of SI for the risk assessment of DVT.