BACKGROUND/AIMS: Platelet counts and characteristics can influence platelet reactivity during antiplatelet therapy. We compared the effects of both platelet count and indices on platelet reactivity between patients who were treated with either clopodogrel or ticagrelor. METHODS: Patients with coronary artery disease who underwent percutaneous coronary intervention were randomly assigned to either the clopidogrel (n = 63) or ticagrelor (n = 65) groups. Platelet count, platelet indices (including mean platelet volume, platelet distribution width, platelet large cell ratio, and immature platelet fraction), and platelet reactivity were measured before intervention, and 48 hours and 30 days post-intervention. High on-treatment platelet reactivity (HPR) was defined as ≥ 47 unit as assessed by multiple electrode platelet aggregometry. RESULTS: Baseline platelet reactivity was similar between the two groups; however, at 48 hours and 30 days, platelet reactivity was significantly lower in the ticagrelor group than in the clopidogrel group. Platelet count, mean platelet volume, platelet distribution width, platelet large cell ratio, and immature platelet fraction were significantly correlated with platelet reactivity in the clopidogrel group; however, these correlations were attenuated in the ticagrelor group. The use of clopodogrel (hazard ratio [HR] 4.1, 95% confidence interval [CI] 1.4–11.9; p = 0.010) and platelet count (HR 9.7, 95% CI 2.9–32.7; p = 0.001) were independent predictors for 30 day HPR. Platelet count was an independent predictor of HPR in the clopidogrel group but not in the ticagrelor group. CONCLUSIONS: Platelet count and indices are significantly correlated with platelet reactivity. However, antiplatelet treatment with ticagrelor could overcome these associations.
Blood Platelets* ; Coronary Artery Disease ; Electrodes ; Humans ; Mean Platelet Volume ; Percutaneous Coronary Intervention ; Platelet Count* ; Platelet Function Tests ; Purinergic P2Y Receptor Antagonists

OBJECTIVETo investigate the value of evaluating 5 platelet parameters in predicting delayed graft function (DGF) in patients following kidney transplantation.

METHODSWe retrospectively analyzed the pre- and postoperative (within 2 months) data of 330 renal transplant recipients. The cases with DGF and those without were analyzed to assess the association between relationship between DGF following transplantation and the variations of blood platelet parameters including platelet count (PLT), large platelet ratio (P-LCR), mean platelet volume (MPV), platelet volume distribution width (PDW) and platelet hematocrit (PCT).

RESULTSThe DGF and non-DGF cases were comparable for the platelet parameters before the operation. On postoperative day 7 when the diagnosis of DGF was made, PLT (P<0.05) and PCT (P<0.02) were significantly lower while MPV (P<0.01), PDW (P=0.036) and P-LCR (P=0.01) significantly higher in DGF group than in non-DGF group. The AUCs of P-LCR (0.611±0.047), PDW (0.603±0.048) and MPV (0.762±0.037) were significantly higher than the reference area (P<0.05) with cut-off values of 34.80%, 12.95fl and 11.55fl, respectively. MPV showed a high sensitivity, specificity and Youden index for predicting DFG; PDW and P-LCR had a high sensitivity but a low specificity for predicting DFG with a modest diagnostic value. PLT and PCT, with AUCs of were 0.37 and 0.38, respectively, did not have a predictive value for DGF.

CONCLUSIONSSignificant variations in platelet parameters occur in the event of DGF in renal transplant recipients, and monitoring the postoperative changes in MPV, PDW, and P-LCR can help in early diagnosis and treatment of DGF. MPV has a moderate value (0.7-0.9) in predicting DGF, and a MPV>11.55 fl suggests the risk of DGF.

Area Under Curve ; Blood Platelets ; Delayed Graft Function ; Humans ; Kidney ; physiology ; Kidney Function Tests ; Kidney Transplantation ; Mean Platelet Volume ; Platelet Count ; Postoperative Period ; ROC Curve ; Retrospective Studies ; Sensitivity and Specificity

A 6 year 6month-old boy was admitted with complains of severe spontaneou epistaxis and easy brusability. He was one of five siblings, and two of them died of recurred severe epistaxis at their age of six years. There was no history of bleeding tendency to his antecedents and parents, whose marriage was unrelated. Platelet count and partial thromboplastin time were noraml with prolonged bleeding time, but clot retraction was poor. Platelet adhesion(Salzman method) was decreased and platelet aggregation test showed flat curve with no response to epinephrine and ADP. These tests of other were normal. Diagnosis of thrombasthenia was made with the above history and laboratory results.
Adenosine Diphosphate ; Bleeding Time ; Blood Platelets ; Clot Retraction ; Diagnosis ; Epinephrine ; Epistaxis ; Hemorrhage ; Humans ; Male ; Marriage ; Parents ; Partial Thromboplastin Time ; Platelet Aggregation ; Platelet Count ; Siblings ; Thrombasthenia*

A 6 year 6month-old boy was admitted with complains of severe spontaneou epistaxis and easy brusability. He was one of five siblings, and two of them died of recurred severe epistaxis at their age of six years. There was no history of bleeding tendency to his antecedents and parents, whose marriage was unrelated. Platelet count and partial thromboplastin time were noraml with prolonged bleeding time, but clot retraction was poor. Platelet adhesion(Salzman method) was decreased and platelet aggregation test showed flat curve with no response to epinephrine and ADP. These tests of other were normal. Diagnosis of thrombasthenia was made with the above history and laboratory results.
Adenosine Diphosphate ; Bleeding Time ; Blood Platelets ; Clot Retraction ; Diagnosis ; Epinephrine ; Epistaxis ; Hemorrhage ; Humans ; Male ; Marriage ; Parents ; Partial Thromboplastin Time ; Platelet Aggregation ; Platelet Count ; Siblings ; Thrombasthenia*

BACKGROUND: The goal of preoperative screening test is to reduce the perioperative morbidity by patients management in case of abnormal test results. But, in view of the low incidence of perioperative complication in otherwise healthy surgical population and cost of routine preoperative screening tests, further examination of their usefulness is required. METHODS: The charts of 1968 patients performed preoperative screening laboratory tests were reviewed to analyse the results of tests retrospectively. The preoperative screening laboratory tests are hemoglobin, platelet count, bleeding time, prothrombin time, partial thromboplastin time, chest X-ray, electrocardiography (ECG), liver function test (LFT), urinalysis, BUN and creatinine. In cases of abnormal results obtained, further studies (pulmonary function test (PFT), arterial blood gas analysis (ABGA), 2D- echocardiography, holter ECG, coronary angiography and abdominal sonography) were analysed. RESULTS: The incidence of abnormal results of total preoperative screening test is 4.5%. The incidence of abnormal results of ECG, chest X-ray, LFT, hemoglobin, and others are 8.3%, 7.8%, 3.7%, 2% and less than 1% in order. For further study, PFT was done in 58 patients, ABGA in 72 patients, 2D-echocardiography in 96 patients, and Holter ECG in 6 patients. CONCLUSION: This study has shown that routine preoperative laboratory screening tests provided little information. Therefore, further studies would be necessary to evaluate the cost-benefit of preoperative screening test compared with the other methods such as history taking and physical examinations that is needed little cost.
Bleeding Time ; Blood Gas Analysis ; Coronary Angiography ; Creatinine ; Echocardiography ; Electrocardiography ; Humans ; Incidence ; Liver Function Tests ; Mass Screening* ; Partial Thromboplastin Time ; Physical Examination ; Platelet Count ; Prothrombin Time ; Retrospective Studies ; Thorax ; Urinalysis

BACKGROUND: The goal of preoperative screening test is to reduce the perioperative morbidity by patients management in case of abnormal test results. But, in view of the low incidence of perioperative complication in otherwise healthy surgical population and cost of routine preoperative screening tests, further examination of their usefulness is required. METHODS: The charts of 1968 patients performed preoperative screening laboratory tests were reviewed to analyse the results of tests retrospectively. The preoperative screening laboratory tests are hemoglobin, platelet count, bleeding time, prothrombin time, partial thromboplastin time, chest X-ray, electrocardiography (ECG), liver function test (LFT), urinalysis, BUN and creatinine. In cases of abnormal results obtained, further studies (pulmonary function test (PFT), arterial blood gas analysis (ABGA), 2D- echocardiography, holter ECG, coronary angiography and abdominal sonography) were analysed. RESULTS: The incidence of abnormal results of total preoperative screening test is 4.5%. The incidence of abnormal results of ECG, chest X-ray, LFT, hemoglobin, and others are 8.3%, 7.8%, 3.7%, 2% and less than 1% in order. For further study, PFT was done in 58 patients, ABGA in 72 patients, 2D-echocardiography in 96 patients, and Holter ECG in 6 patients. CONCLUSION: This study has shown that routine preoperative laboratory screening tests provided little information. Therefore, further studies would be necessary to evaluate the cost-benefit of preoperative screening test compared with the other methods such as history taking and physical examinations that is needed little cost.
Bleeding Time ; Blood Gas Analysis ; Coronary Angiography ; Creatinine ; Echocardiography ; Electrocardiography ; Humans ; Incidence ; Liver Function Tests ; Mass Screening* ; Partial Thromboplastin Time ; Physical Examination ; Platelet Count ; Prothrombin Time ; Retrospective Studies ; Thorax ; Urinalysis

Glanzmann's thrombasthenia is a rare autosomal recessive hemorrhagic disorder characterized by prolonged bleeding time, ad deficient or absent clot retraction in the presence of normal platelet count. The major underlying abnormality in this disease is grossly defective first-phase aggregation of platelet, which are unresponsive to ADP or other platelet agonists such as epinephrine, collagen, thrombin in any concentration. This disability is caused by a decrease or absence of the platelet membrans glycoprotein IIb-IIIa complex, a member of the integrin family of adhesive receptors involved in cell-cell and cell-matrix fibronectin, and vitronectin On the development of surface labeling technique, a variety of biochemical techniques such as radioimmunoassay, crossed immunoelectrophoresis and SDS-PAGE have been used to study the structure and the function of platelet membrane glycoproteins, and to detect the platelet functional defect. But all of these techniques demand a relatively large amount of homogeneous paletelet population that requires manipulation through isolation and washing procedures before analysis. In order to eliminaste such an intricate procedure, we have applied method for analyzing platelet surface components in whole blood using monoclonal antibody and flow cytometry to recognize the absence of severe reduction of platelet membrane glycoprotien llb-llla complex. Platelet analysis by flow cytometry is a successful alternative rapid diagnostic technique for Glanzmann's thrombasthenia patients as well as well as for carriers of this disease. Fow cytometry technique provides a sensitive tool for investigating platelet functional defects caused by altered expression or deficiency of platelet surface proteins.
Adenosine Diphosphate ; Adhesives ; Bleeding Time ; Blood Platelets* ; Clot Retraction ; Collagen ; Electrophoresis, Polyacrylamide Gel ; Epinephrine ; Fibronectins ; Flow Cytometry* ; Glycoproteins ; Hemorrhagic Disorders ; Humans ; Immunoelectrophoresis, Two-Dimensional ; Membrane Glycoproteins* ; Membrane Proteins ; Membranes* ; Platelet Count ; Platelet Membrane Glycoproteins ; Radioimmunoassay ; Thrombasthenia* ; Thrombin ; Vitronectin

OBJECTIVE: To evaluate the performance of a microfluidic platelet function test platform (MPFTP) previously established by our research group. METHODS: The effects of flow shear rate and storage time on platelet function test were analyzed taking the MPFTP as the object. The intra-assay variability of the MPFTP was evaluated. The function of platelet in peripheral venous blood from 24 healthy volunteers was assessed using the MPFTP and light transmission turbidity, either in the presence of 20 μmol/L acetylsalicylic acid (AS, an inhibitor of cyclooxygenase 1) or 50 μmol/L 5-phospho-2-methylthioadenosine (2-MeSAMP, a P2Y₁₂ receptor inhibitor). The diagnostic performance of both methods in assaying platelet function inhibition by AS and 2-MeSAMP was analyzed by using receiver operating characteristic (ROC) curve. RESULTS: Under the flow shear rate of 1 500 s^-1, our MPFTP could dynamically monitor platelet adhesion and aggregation, as well as quantify platelet function. Platelet aggregation increased with the increase of flow shear rate, while sample storage at room temperature for up to 5 h did not affect results of platelet function test. The intra-assay variability coefficient of variation of the MPFTP was <15%. The area under the curve of ROC showed that this platform had good diagnostic performance in the identification of platelet function inhibition by AS and 2-MeSAMP. CONCLUSION This MPFTP shows good analytical performance for the assay of platelet function and can be developed into a new clinical platelet function test device in the future.
Humans ; Platelet Function Tests

BACKGROUND: Clopidogrel inhibits platelet P2Y12 adenosine diphosphate (ADP) receptors and has been widely used in patients with ischemic stroke. However, a considerable number of patients suffer from cerebrovascular events despite the use of clopidogrel. The rapid platelet function assay (RPFA) has been used for monitoring the antiplatelet effects on the P2Y12 ADP receptor. This study was performed to measure the platelet response to clopidogrel using RPFA in patients with ischemic stroke, and to identify the clinical factor related with clopidogrel resistance. METHODS: A total of 86 patients taking clopidogrel (75 mg/day) were enrolled. Demographic data, vascular risk factors, the presence of obesity and metabolic syndrome, drug history, hemoglobin, platelet counts, and stroke subtypes were recorded. RPFA presented the results as P2Y12 Reaction Units (PRU), base PRU (BASE), and Inhibition (%). Inhibition was calculated as (1-PRU/BASE)x100. The patients showing ineffective aggregation- inhibition (percentage of Inhibition < 20) on RPFA were defined as non-responders to clopidogrel. RESULTS: The response of platelet aggregation-inhibition to clopidogrel showed a variable distribution with mean and standard deviation of 32.2+/-22.3%. Twenty four (27.9%) patients showed the inhibition below 20%. There was no difference between responders and non-responders regarding the clinical factors above. We found no influence of co-medication with the statins on platelet response to clopidogrel. CONCLUSIONS: There is a patient variability in response to clopidogrel and a considerable portion of stroke patients have clopidogrel resistance on the platelet function test. The clinical usefulness of routine platelet function test requires further validation.
Adenosine Diphosphate ; Blood Platelets ; Hemoglobins ; Humans ; Obesity ; Platelet Aggregation ; Platelet Count ; Platelet Function Tests ; Receptors, Purinergic P2 ; Risk Factors ; Stroke ; Ticlopidine

To explore the influence of raising oxygen (dissolved oxygen) content on function of platelet concentrate, the platelet concentrate was prepared by a CS-3000 plus blood cell separator. Experiments were divided into 2 groups: test group and control group. After raising oxygen content in platelet plasma under sterile operation, the platelet samples of two groups were preserved in oscillator with horizontal oscillation at 22 +/- 2 degrees C. The platelet count, platelet aggregation rate, lactic acid content and CD62p expression level of platelet were detected on 0, 1, 2, 3, 4, 5 days of platelet preservation. The results showed that the platelet count and platelet aggregation rate decreased with prolongation of preserved time, while the lactic acid content and CD62p expression level of platelet increased gradually. Compared with control group, there were significant differences in aggregation rate of platelet preserved for 2-3 days, and in CD62p expression level of platelet preserved for 1-3 days, while significant difference was found in lactic acid content of platelet preserved for 1-3 days. It is concluded that raising content of oxygen in platelet plasma can provide more oxygen to compensate oxygen supply deficiency for platelet metabolism and improve the efficiency of platelet oxygenic metabolism and the quality of platelet during preservation.
Blood Platelets ; drug effects ; physiology ; Blood Preservation ; methods ; Humans ; Lactic Acid ; metabolism ; Oxygen ; pharmacology ; Platelet Aggregation ; drug effects ; Platelet Count ; Platelet Function Tests