Comparison Of Two Assays In Platelet Aggregometry Of Patients With Coronary Heart Disease: Light Transmittance Aggregometry And Thrombelastography

Background：Dual oral antiplatelet therapy with aspirin and clopidogrel is thetherapy of choice in patients with acute coronary syndromes and in patientsundergoing coronary stent placement to lower the risk of thrombotic events. However,Studies have shown that even if in strict accordance with the dual antiplatelet drugsadministrate which the guidelines recommend, The ischemic events still occurrencein some patients. Responsiveness to aspirin and especially to clopidogrel is notuniform and is subject to considerable interindividual variability.，therefore, we needplatelet function tests to achieve individualized antiplatelet therapy. The plateletaggregation function testing are available for evaluating platelet inhibition inpercutaneous coronary interventiontreated patients in order to help determine theindividual risk for ischemic and bleeding complications. Light transmittanceaggregometry (LTA) was considered as the gold standard for platelet function testing,The blood-citrate tubes were centrifuged to recover platelet rich plasma (PRP) andfurther centrifuged to recover platelet poor plasma (PPP)., aggregation was expressedas the maximum percent change in light transmittance from baseline, with PPP as areference. However, this method also has many shortcomings, One majordisadvantage is that LTA is not very suitable for routine clinical use because it is timeand labour intensive. In addition, it is required large amount of blood and have manyinfluencing factors. Thrombelastography(TEG) is a novel point-of-care plateletfunction testing, relies on the measurement of thrombin-induced clot strength toenable a quantitative analysis of platelet function. At present, there is a little ofresearch about the correlation of TEG and LTA。Objective: We sought to compare and analysis of correlation and agreementbetween TEG and LTA in the detection of platelet function in patients with coronaryheart disease.Method：95patients in the Department of Cardiology of Haidian Hospital wereenrolled between June2012and February2013,72man and23women, with a mean age57.64±9.13years. Excluding patients with liver and kidney dysfunction,malignancies, active bleeding or clotting disorders, multiple organ failure,cerebrovascular disease and other diseases. They were divided into two groupsaccording to the level of blood-lipid, hyperlipidemia group (CHOL>5.18mmol/Land/or TG>1.70mmol/Land/or LDL-C>3.37mmol/L）included55patients,41manand14women, with a mean age55.93±8.95year; normolipidemia group（CHOL≤5.18mmol/LandTG≤1.70mmol/LandLDL-C≤3.37mmol/L）, included39patients,32men and7women, with a mean age59.72±9.27years. According to thediagnosis (acute coronary syndrome (ACS) and Non ACS), Each group is dividedinto two sub-clan,：hyperlipidemia with ACS group, hyperlipidemia with Non ACSgroup;The normolipidemia with ACS group, normolipidemia with Non ACS group.All patients had an aspiration of fasting vein blood, then blood sampling wasfilled into heparin tube (green cap) and3.8%sodium citrate tube (blue cap), Bloodsamples within one hour to the inspection department in our hospital were analyzedby TEG and LTA detection. And the use of ADP as an inducer.Statistical analysis: All the statistical analysis was performed using theStatistical Package for Social Sciences software(SPSS13.0).Continuous variableswere expressed as mean±standard deviation （x±s）.The distribution of constitutionratio of LTA and TEG was analysed by chi-squared test. Single factor linearcorrelation analysis was used for studying LTA and TEG was conducted by Kappaanalysis using MedCalc statistical software(version9.0).Statistically significance wasdefined as P<0.05.Results:(1) platelet aggregation test results: LTA method results of the overallgroup (38.82±17.81)%, the TEG method (33.65±14.77)mm; LTA method forhyperlipidemia group (34.80±18.20)%,the TEG method (33.37±14.87)mm; theLTA method for normolipidemia group (34.20±20.85)%, the TEG method (34.53±14.82)mm; LTA method for hyperlipidemia with ACS group (35.29-19.88)%TEGmethod(34.63-17.02)mm; LTA method result of hyperlipidemia with Non ACSgroupgroup (34.39±17.02)%, the TEG method (32.32±13.02)mm; the the LTAmethod for normolipidemia with ACS group (36.16±10.91)%, the TEG method(35.01±14.73)mm; the the LTA method for normolipidemia with Non ACS groupgroup (31.93±21.15)%, the TEG method (33.97±15.33)mm.（2）The relationship between two assays in different groups:1)The difference of constitution ratio in the percentual regions between LTA andTEG: According to the result of two assays,four percentual regions were got (0-25%、25%-50%、50-75%and75%-100%). Tthe constitution ratio in the percentual regionsbetween LTA and TEG in each group was no significant difference（P＞0.05）.2)The correlation between LTA and TEG:In total subject,we observed thatcorrelation between LTA and TEG was significant but weak(r＝364, P<0.05),Innormolipidemia group, linear correlation analysis indicated that there was nocorrelation between the two assays (P>0.05), so as the normolipidemia with ACSgroup and normolipidemia with Non ACS group;In hyperlipidemia group,linercorrelation analysis indicated significant but is not a highly linear correlation (r=0.66,P<0.05;r<0.7);compared with hyperlipidemia with Non ACS group,hyperlipidemiawith ACS group have better correlation between the assays（r＝0.760vs.r＝0.476,P<0.05）,As a highly linear correlation（r>0.7），We can see from the scatterdiagram;And the hyperlipidemia with Non ACS group were in general, is not highlylinear correlation (r<0.7).3)The agreement between LTA and TEG: Kappa analysis indicated that for LTAand TEG,the agreement existed in total samples、 hyperlipidemia group、hyperlipidemia with ACS group and hyperlipidemia with Non ACS group （k=0.25、0.44、0.50and0.39；separated; P<0.05）, but in total samples and hyperlipidemia withNon ACS group group is very poor (0.21≤K≤0.4). And in normolipidemia group、normolipidemia with ACS group、normolipidemia with Non ACS groupgroup，noagreement existed between two assays（k=0、0.14、－0.157,separated, P>0.05）Conclusion: This study showed that the correlation and agreement between LTAand TEG is.weak Especially in normolipidemia group, there was no correlation andagreement between two assays. but, there was significant correlation and agreementin hyperlipidemia group, especially in hyperlipidemia with ACS group. So the studysuggested that the two assays could not be interchangeable in normolipidemiapatients, but in hyperlipidemia group,especially in hyperlipidemia with ACSgroup,they could be interchangeable in clinic.