| Objective: Platelet aggregation is one of the most important factors in the pathogenesis of atherothrombosis and performing the thrombosis. In the thrombosis disease, assay of platelet aggregation plays an important role in the thrombosis prevention and treatment monitoring. Platelet aggregometry is an important reaction to platelet aggregation. From now on, there are many methods to assay platelet aggregometry. In clinic and some studies, turbidimetric platelet aggregometry (TPA) is the most extensive used method in recent decades, and it used to be considered as gold standard. In this method, preparation of platelet- rich plasma (PRP) and platelet- poor plasma (PPP) requires centrifugation. According to the difference between PRP and PPP, this method uses optics principle to assay platelet aggregation. But this assay has some defects, for example, preparation of PRP needs centrifugation, which may result in change of platelet quantity and activity, and have an influence on result. Otherwise, some substances in blood sample may affect this method, such as hyperlipidemia.Impedance platelet aggregometry (IPA) is a new method to assay platelet aggregation. It uses whole blood by electric principle in process of assaying. IPA can get rid of some defects of IPA, and have some advantages in clinic.But correlation and agreement between TPA and IPA is not known. This study will compare and analysis the relationship between TPA and IPA in different people.Methods: 180 patients in the Second Hospital of Hebei Medical University were enrolled between December 2007 and October 2008, including 150 patients with coronary heart disease or hypertension, 92 men and 58 women, with a mean age 60.54±9.61 years. Exclusion criteria included severe hepatic and kidney dysfunction, malignant tumor, multiple organs failure and cerebrovascular disease. They were divided into two groups according to the level of blood-lipid. hyperlipidemia group included 60 patients (CHOL>5.72mmol/L and/or TG>1.72mmol/L and/or LDL-C>3.64 mmol/L), 35 men and 25 women, with a mean age 60.62±8.85 years; normolipidemic group (CHOL≤5.72mmol/L and TG≤1.72mmol/L and LDL-C≤3.64 mmol/L) included 90 patients, 57 men and 33 women, with a mean age 60.50±10.13 years. 30 paroxysmal supraventricular tachycardia (PSVT) patients planning for radiofrequency catheter ablation were selected for control group, including 16 men and 14 women, with a mean age 45.33±14.19 years. Subjects in this group must reach some criteria, which they did not have, any other diseases except PSVT, or use inhibiting platelet aggregation drugs within 2 weeks, or have an attack of PSVT within 2 weeks. And they must have normal blood-lipid.All of patients had an aspiration of fasting vein blood. Then the study blood sample was filled in two anticoagulative canals. Sodium citrate is the anticoagulant. In hemolysis laboratory and cardiovascular laboratory we assayed the blood samples by TPA and IPA within an hour. Inducers of two assays are ADP 10μmol/L.Statistical analysis: All the statistical analysis was performed using the Statistical Package for Social Sciences software (SPSS 13.0). Continuous variables were expressed as mean±standard deviation ( x±s). The distribution of constitution ratio of TPA and IPA was analysed by chi-squared test. Single factor linear correlation analysis was used for studying correlation between TPA and IPA. The agreement between TPA and IPA was conducted by Kappa analysis using MedCalc statistical software (version 9.0). Statistically significance was defined as P<0.05.Results:⑴The mean of platelet aggregation in the four groups: control group: TPA (52.90±10.36)%, IPA (11.20±3.27)Ω; hyperlipidemia group: TPA(50.13±12.85)%, IPA (7.75±4.40)Ω; normolipidemia group: TPA(51.40±12.98)%, IPA (8.00±3.73)Ω; total subject group: TPA (51.55±12.55)%, IPA (8.02±4.07)Ω.⑵The relationship between two assays in different groups:①The difference of constitution ratio in the percentual regions between TPA and IPA: According to the result of two assays, four percentual regions were got ( 0-25%,25%-50%,50%-75% and 75%-100%). In control group, the difference of constitution ratio in the percentual regions between TPA and IPA, which could be observed in chi-squared test, was not significant (χ2=0.079, P>0.05). But in normolipidemia group(χ2=23.93,P<0.05), hyperlipidemia group(χ2=38.40,P<0.05) and the total samples(χ2=76.54, P<0.05), chi-squared test showed the significant difference of constitution ratio in the percentual regions between TPA and IPA.②The correlation between TPA and IPA: In control group, we observed that significant but not strong correlation for TPA with IPA (r=0.53<0.70, P<0.05). In normolipidemia group, linear correlation analysis indicated significant but weak correlation between two assays (r=0.48<0.70, P<0.05). In hyperlipidemia group, linear correlation analysis indicated significant but very weak correlation between two assays (r=0.39<0.40, P<0.05). In the total subjects, correlation between TPA with IPA was significant but weak (r=0.45<0.70, P<0.05).③The agreement between TPA and IPA: Kappa analysis indicated that for TPA and IPA, the agreement existed but very poor in control group (K=0.26, P<0.05), normolipidemia group (K=0.13, P<0.05) and the total samples (K=0.08, P<0.05). And in hyperlipidemia group, no agreement existed between two assays (K=0.02, P>0.05).Conclusions: Our study showed that there was weak correlation and agreement between TPA and IPA. Especially in hyperlipidemia group, there was very poor correlation and no agreement between two assays. So the study suggested that the two assays could not be interchangeable in clinic.
|
PDF Full Text Request