Correlation Study Of Thromboelastography And Conventional Coagulation Tests

Hellmut Hartert was the first person to exploit the viscoelastic properties of clotting in blood coagulation with Thromboelastography(TEG)in 1948.Since then,the technology has improved,allowing these analyses to be performed as point-of-care tests with immediately-available results.After the upgrade and improvement,it comes into being rotational thromboelastometry(ROTEM),with the same principle but different parameters.The addition of several activators and inhibitors to the original assay of TEG or ROTEM creates a panel of tests able to quantify the different aspects of blood clotting,just as rapid TEG,heparinaseTEG,extrinsically activated ROTEM(EXTEM),intrinsically activated ROTEM(INTEM),and fibrinogen polymerization ROTEM(FIBTEM)tests.TEG has a number of proposed advantages over conventional coagulation tests: it provides a result much quicker,and provides information on clot formation over time and fibrinolysis,is able to identify what part of the clotting process is disrupted.At present TEG is mainly carried out in some large comprehensive hospitals for detection blood coagulation and guiding blood transfusion in bleeding patients,which has proven superior to conventional coagulation tests in some circumstances.Its application is expected to extend to other areas,such as drug monitoring,the diagnosis and management of congenital bleeding disorders.However,although much progress has been made,the corelation with the conventional coagulation tests(CCTs),the efficacy and safety to guide the clinical diagnosis and treatment are not clear and still need validation.[objective]To explore the correlation and difference between Thromboelastography(TEG)and conventional coagulation tests(CCTs)in detection of blood coagulation in critical patients of emergency department.And to systematically assess the effectiveness and safety of Thromboelastography(TEG)-guided transfusion strategy during severe bleeding,and to provide evidence for its application.[methods]1 From August 2015 to September 2016,critical patients,a total of 193 cases,without abnormal function of platelet and fibrinogen as well as a variety of antiplatelet therapy were included in emergency department of Xijing Hospital.blood samples were taken and analyzed simultaneously for TEG and conventional coagulation tests.The correlation between TEG parameter and conventional coagulation tests was estimated for quantities that were deemed to be measuring similar aspects of the coagulation cascade to study the clinical significance of each parameters.receiver operating characteristic(ROC)curve was used to explore the sensitivity and specificity for R to reflects abnormal PT and APTT.Subgroup analysis was taken to investigate how the ? Angle or MA correspond when platelet or fibrinogen changed independently to study the ability for ??MA to reflect abnormal PLT and FIB.TEG and CCTs results were comprehensively compared to discusses the ability of them to reflects the overall blood coagulation status.Blood product transfusion rate was compared between TEG and conventional coagulation tests guided transfusion in trauma patients.2 Articles about TEG-guided transfusion(including ROTEM)were searched on Pubmed,Embase,The Cochrane Library,CNKI and CBM from establishment of the database to 2017.Randomized controlled trails(RCT)concerning the contrast between TEG-guided transfusion(including ROTEM)and conventional coagulation tests(CCTs)or empirical evidence guided transfusion were collected.Cochrane collaboration's tool for assessing risk of bias was used to assess the quality of included study.The analysis and synthesis of data were conducted by the Review Manager 5.3 statistics software and the forest graph was drawn.For the studies with significantly clinical and methodologic heterogeneity or without original data,descriptive analysis was conducted instead of meta-analyses.and GRADEpro3.6 was used to rate the level of evidence.[results]1 The comparative study of thromboelastography(TEG)and conventional coagulation tests in critical patients of emergency department.1.1 The result of Spearman correlation between TEG parameter and conventional coagulation tests: R correlated weakly with PT(r=0.2,P=0.004)and APTT(r=0.4,P<0.001),MA correlated moderately with PLT(r=0.6,P<0.001)and FIB(r=0.5,P<0.001),FIB correlated weakly with ? Angle(r=0.28,P<0.001)and K(r=-0.30,P<0.001).PLT correlated moderately with ? Angle(r=0.5,P<0.001)and K(r=-0.5,P<0.001).For the TEG parameter,R correlated moderately with K(r=0.5,P<0.001)?? Angle(r=-0.5,P<0.001),K correlated strongly with ? Angle(r=-0.9,P<0.001)?MA(r=-0.8,P<0.001).? Angle correlated strongly with MA(r=0.7,P<0.001).there was no correlation between R and MA(r=-0.17,P=0.019).1.2 According to ROC analysis,to detect PT>15.1s,the sensitivity of TEG with R(>10min)was 32%(95% CI,0.20–0.47)and specificity was 90%(95% CI,0.84–0.94).To detect APTT>41.8s,the sensitivity of TEG with R(>10min)was 39%(95% CI,0.25 –0.54)and specificity was 91%(95% CI,0.85–0.95).To detect APTT<22.7s,the sensitivity of TEG with R(<5min)was 33%(95%CI,0.16-0.55)and specificity was 85%(95%CI,0.78-0.90).1.3 Of the 142 patients with abnormal PLT count or FIB density,the incidence of abnormal ? and MA was 62%,56% respectively in 39 patients with independent abnormal PLT count,the incidence of abnormal ? and MA was 36%,61% respectively in 47 patients with independent abnomal FIB density.1.4 Total of 26 patients with hypertensive intracerebral hemorrhage and 65 patients with trauma included in this study,there were no abnormal changes in conventional coagulation tests in 10 patients with hypertensive intracerebral hemorrhage and 8 trauma patients,but TEG examination showed different levels of fibrinogen or platelet functional abnormalities.1.5 It was predicted that 7 in 65(10%)trauma patients needed plasma infusion in CCTs-guided transfusion but 1 in 65(2%)in TEG-guided transfusion.there was significant statistical difference(X2=4.17,P = 0.03)between two groups.2 The therapeutic effect of thrombelastography in guiding blood transfusion: a systematic review2.1 There was a significant reduction in RBC transfusion rate [RR=0.83,95%CI(0.75,0.92),P=0.00004]?FFP transfusion rate [RR=0.41,95%CI(0.32,0.52),P<0.00001] and reoperation rate[RR=0.56,95%CI(0.33,0.97),P=0.04] in TEG-guided blood transfusion group compared with the traditional coagulation tests or clinical experience group,all of these result with a low quality of evidence in GRADE system.2.2 There was no significant difference in perioperative platelet transfusion rate [RR=0.74,95%CI(0.51,1.06),P=0.10]?blood loss [MD=-66.41,95%CI(-166.12,33.31),P=0.19] and mortality [RR=0.93,95 % CI(0.44,1.95),P=0.84] between TEG-guided transfusion group and CCTs or clinical experience group.the quality of evidence in GRADE system were very low for platelet infusion rate and blood loss,and low for mortality.[conclusions]1 The correlation between TEG parameter and conventional coagulation tests are all not strong.the R value of TEG has a low sensitivity to detect abnormal blood coagulation factor than PT?APTT.? Angle or MA has a low sensitivity to detect independent PLT count or FIB density abnormality,it is more sensitive for TEG to reflect functional abnormality of overal blood coagulation than slight changes on the quantitative of CCTs parameter.TEG can detect some abnormal coagulations which CCTs show normally or can not detect.TEG-guided transfusion may reduce plasma infusion rate in trauma patients.TEG has certain advantages over CCTs but can not completely replace it.CCTs in combination with TEG is more helpful to clinical treatment,not only can we understand the change of the individual component,also can take the whole blood coagulation condition.2 Based on present RCT evidence and compared with the conventional coagulation tests or clinical experience,TEG-guided blood transfusion reduces perioperative RBC infusion rate?FFP infusion rate and reoperation rate,there is no significant difference in safety,but the quality of evidence in GRADE system are low or even very low.further high quality clinical trials remain urgently needed to increase the reliability of the conclusion and to determine their exact benefit and cost effectiveness.this conclusion comes from the patients with cardiac surgery under extracorporeal circulation.whether or not suitable for other population,it needs further research to confirm.