Effects of low osmolar contrast (iomeprol) on haemorheology and platelet activation in patients with coronary artery disease

Background Non-ionic low osmolar contrast agents are widely used during coronary angiography. As these agents cause activation of thrombotic pathways in vitro, this may have potentially significant clinical impact. However, limited evidence exists as to their in vivo effects from selective coronary cannulation. Methods We initially performed an in vitro experiment to assess the effect of serial contrast (Iomeprol 300, Bracco) dilution on platelet indices [mean platelet count (MPC), platelet volume (MPV), platelet granularity (MPG)]. The in vivo effect of contrast injection on platelet activation markers [soluble P-selectin (sPsel), soluble CD40 ligand (sCD40L)], MPC, MPV, MPG, haemoglobin and haematocrit was subsequently determined in 35 patients (mean age 58 ± 11; 22 males) undergoing cardiac catheterisaton. Results No significant in vitro effect of contrast on MPC or MPV was seen but there was a significant increase in MPG (p = 0.40, 0.10 and 0.01, respectively). In the in vivo study, there was a reduction in mean haemoglobin and haematocrit levels, suggesting an average increase in plasma volume of 6.5 ± 5.8%. The in vivo effect of Iomeprol was associated with an unadjusted reduction in sPsel concentrations (p = 0.04) and MPV (p < 0.05), with denser platelets (p < 0.05). There was no difference in MPC or sCD40L concentration (both p = NS). After adjustment for the haemodilution effect, no significant reduction in P-sel levels was seen with contrast (p = 0.27), although the adjusted post-contrast change in MPG (p = 0.01), MPC (p = 0.01) and sCD40L (p < 0.05) levels were significant. Conclusion Low osmolar contrast led to a minimal effect on soluble and physical indices of platelets within the coronary artery, primarily due to plasma volume expansion.     

Soluble CD40L, platelet surface CD40L and total platelet CD40L in congestive heart failure: relationship to platelet volume, mass and granularity

Background. Many complications associated with congestive heart failure (CHF) have a thrombosis-related aetiology, which may involve platelets. The immune modulator pair CD40-CD40L has been proposed to be an important link between inflammation and thrombosis and may be important in the pathophysiology of CHF. Objective. To study soluble CD40L (sCD40L), platelet surface CD40L (%GCD40L) and total platelet CD40L (pCD40L) levels in CHF patients, their relationships to other platelet indices (platelet volume, mass and component) and to assess their prognostic value. Methods. We measured sCD40L (by ELISA); pCD40L (by a platelet lysate assay); platelet surface CD40L (%GCD40L) expression by flow cytometry; mean platelet volume (MPV), mean platelet mass (MPM) and mean platelet component (MPC); in 108 patients with stable CHF. Levels were compared with 37 ‘healthy controls’ and 63 ‘disease controls’. After a median follow-up period of 490 days, clinical endpoints were determined. Results. pCD40L was significantly higher in CHF than disease controls, but not sCD40L or %GCD40L levels. CHF patients and disease controls had higher MPV (one-way anova , P < 0.0001), whilst MPC was significantly lower in CHF patients (P < 0.0001), compared to healthy controls. All indices related to CD40L (i.e. sCD40L, pCD40L and %GCD40L) were neither related to disease severity or left ventricular ejection function, nor to clinical endpoints at follow-ups. Conclusion. Patients with stable CHF patients did not exhibit enhanced levels of CD40L and the latter did not predict clinical events at follow-up. The lack of difference in CD40L levels between CHF and disease controls suggests that CD40L may not have a major role in CHF per se, but in the comorbidities associated with CHF.     

急性ST段抬高型心肌梗死PCI术后血小板CD40L及血小板指标临床相关性分析

【摘要】：目的：研究急性ST段抬高型心肌梗死PCI术后血小板CD40L及血小板指标之间相关性。方法：在我院接收的急性ST段抬高型心肌梗死患者中,选择2014年5月至2015年5月实施PCI术的患者58例作为研究对象,此组患者为观察组,选择同期健康体检人员53名作为对照组,对所有研究对象的血小板CD40L、血小板体积分布宽度(PDW)、血小板计数(PLT)、血小板压积(PCT)、血小板平均体积(MPV)、肌钙蛋白I(Tn-1)等指标进行测定,患者测定时间为手术前、后,对照组人员测定时间为参加研究时,比较两组研究对象各个指标水平,研究血小板CD40L及血小板指标的相关性。结果：观察组患者术前测得血小板CD40L(MFI)、Tn-1与对照组有显著差异,有统计学意义(P<0.05);观察组患者术前测得PCT、PLT、PDW、MPV与对照组差异较小,无具统计学意义(P>0.05);观察组患者术后测得血小板CD40L(MFI)、Tn-1、MPV、PDW均与对照组有显著差异,有统计学意义(P<0.05);观察组患者术后测得PCT、PLT与对照组差异较小,无统计学意义(P>0.05);观察组患者术后测得血小板CD40L(MFI)、Tn-1、MPV、PDW均与术前有较大差异,有统计学意义(P<0.05);观察组患者术后测得PCT、PLT与对照组差异较小,无统计学意义(P>0.05);STEMI患者行PCI术后,MPV、PDW与血小板CD40L呈正相关关系,P<0.05;Tn-1、PCT、PLT与血小板CD40L之间没有相关性,P>0.05。结论：血小板形态发生变化是急性ST段抬高型心肌梗死患者进行PCI术后血小板活化的特征,而血小板CD40L的表达受到血小板指标的影响,会产生炎症、凝血等情况,应予以重视。     

Effect of clopidogrel pretreatment on inflammatory marker expression in patients undergoing percutaneous coronary intervention

Platelets play an important role in the inflammatory response. In a nonrandomized comparison, we examined the effect of clopidogrel pretreatment on platelet inflammatory marker expression in patients undergoing percutaneous coronary intervention (PCI). Platelet expression of the inflammatory markers CD40 ligand (L) and CD62 P-selectin (P) and serum levels of interleukin-6 and CD40L were compared in patients pretreated (>24 hours before PCI) or not pretreated with clopidogrel. Blood samples were obtained before and after the procedure, and from 18 to 24 hours later. Marker expression in resting and adenosine diphosphate (ADP) (50 micromol/L) and thrombin receptor activating peptide (TRAP) (10 micromol/L) activated samples was quantified by flow cytometry. Serum CD40L and interleukin (IL)-6 levels were determined by enzyme-linked immunosorbent assay. Seventy-nine patients were recruited into the study. Forty-two percent were pretreated with clopidogrel for a median of 5 days (range 1 to 1,325). Clopidogrel pretreatment was associated with lower ADP-activated platelet CD40L expression in baseline and postprocedural samples. Similarly, platelet CD62P expression at all time points in ADP-activated and in baseline and postprocedural TRAP-activated samples was lower in patients pretreated with clopidogrel. These differences remained after multivariate adjustment between the groups. Serum CD40L levels increased from 2.13 +/- 2.37 ng/ml at baseline to 4.77 +/- 3.86 ng/ml at 18 to 24 hours after the procedure (p <0.0001). Similarly, serum IL-6 levels increased at 18 to 24 hours after the procedure (14.8 +/- 42.0 pg/ml before vs 25.5 +/- 36.0 pg/ml at 18 to 24 hours after the procedure, p <0.0001). Clopidogrel pretreatment did not affect serum IL-6 or CD40L levels. Thus, clopidogrel pretreatment reduces platelet inflammatory marker expression in patients undergoing PCI.     

Soluble CD40 ligand and interleukin-6 in the coronary circulation after acute myocardial infarction

BACKGROUND: Inflammation, operated by blood, vascular and immune cells interaction, is implicated in plaque disruption and CD40 ligand (CD40L) was identified on activated T cells and platelets. We sought to investigate the roles of local inflammation in acute myocardial infarction (AMI). METHODS: Coronary sinus (CS) and arterial (A) levels of interleukin (IL)-6 and soluble CD40L (sCD40L) and matrix metalloproteinase (MMP)-9 activity in serial blood samples obtained until 48 h after percutaneous coronary intervention (PCI) were determined. In tissue specimens obtained by aspirating thrombectomy and directional coronary atherectomy, CD40L was immunohistochemically stained. RESULTS: Trans-cardiac gradient (CS-A) of IL-6, indicating cardiac release into the coronary circulation, significantly increased at 24 h after PCI in patients with AMI (group MI, n=17) in contrast with angina pectoris (n=10). Soluble CD40L levels in CS showed earlier peak, yielding trans-cardiac gradient, at 9 h in both groups. The maximum (max) release of IL-6 in MI, but not sCD40L, positively correlated with end-diastolic volume index (R=0.84) and negatively with ejection fraction (R=-0.66) by contrast ventriculography at 6-month follow up. Immunohistological study revealed the expression of CD40L in intra-coronary occlusive and mural thrombi. Aspirating thrombectomy significantly reduced the increase in both sCD40L levels and MMP-9 activity, but not max IL-6 release in MI. CONCLUSIONS: In contrast with myocardial injury represented by IL-6 release, acute rise in sCD40L levels with the MMP-9 activation in the coronary circulation may possibly reflect local inflammation with platelet activation and be a novel marker of plaque damage by PCI.     

Indexes of hypercoagulability measured in peripheral blood reflect levels in intracardiac blood in patients with atrial fibrillation secondary to mitral stenosis

Systemic thromboembolism is a major complication in patients with mitral stenosis, especially in those who have atrial fibrillation (AF). It has been suggested that there may be increased regional left atrial coagulation activity in such patients, despite normal systemic coagulation activity on peripheral blood sampling. Our aim was to investigate whether there were significant differences between intracardiac versus peripheral indexes of hypercoagulability in 25 patients (5 men; mean age 60 years) with mitral stenosis who were undergoing percutaneous balloon mitral valvuloplasty and who were all in chronic AF. Two days after halting warfarin therapy, intracardiac (right and left atria) and peripheral (venous and arterial) blood samples from patients were obtained and compared with levels in matched healthy controls in sinus rhythm. Thrombogenicity was assessed by levels of fibrin D-dimer, fibrinogen, indexes of platelet activation (soluble P-selectin and beta thromboglobulin [betaTG]) and indexes of endothelial dysfunction (soluble thrombomodulin [sTM] and von Willebrand factor [vWF]). There were no statistically significant differences in the various markers between the femoral vein and artery, left and right atria, and between the femoral vein and both atria (all p = NS). Plasma fibrinogen, vWf (both p <0.005), and D-dimer (p = 0.011) were significantly higher and levels of sP-selectin and sTM were lower (both p <0.005) in patients when compared with controls. There was no significant difference in plasma betaTG levels. Our results suggest that there is no significant variation in indexes of thrombogenesis, platelet activation, and endothelial dysfunction between left atrium, right atrium, and the peripheral artery or vein. Peripheral samples therefore do reflect atrial coagulation, platelet, and endothelial activities.     

Serum myeloperoxidase levels and platelet activation parameters as diagnostic and prognostic markers in the course of coronary disease

Early prediction of coronary artery disease complications is vital for the prevention and effective treatment of patients with coronary cardiac disease. It has been reported that inflammatory markers play a key role in the progression of cardiovascular diseases. Platelet count and platelet morphological parameters were analyzed on a fully-automated hematological analyzer ADVIA 2120 (Siemens). Serum myeloperoxidase (MPO) level was determined with an enzyme immunoassay (BioCheck). The measuring range of this assay is between 0 and 40 ng/ml. We demonstrate that serum MPO concentration and platelet activation increase systematically with the advancement of coronary artery disease. Moreover, MPO level is significantly higher in patients with unstable coronary artery disease and myocardial infarction compared with healthy subjects and patients with stable angina. The diagnostic sensitivity of these parameters was higher than of TnI (cardiac troponin I), CK-MB (creatine kinase-heart type), CRP (C-reactive protein), and fibrinogen and DD (D-dimers). MPO, L-PLT (large platelet), MPV (mean platelet volume), and MPC (mean platelet component concentration) may serve as attractive diagnostic and prognostic markers in the assessment of the risk for unstable atheroma in the course of coronary artery disease.     

2型糖尿病合并冠心病患者血小板表面CD62P和CD40L的表达水平

目的 探讨2型糖尿病合并冠心病患者血小板表面CD62P和CD40L的表达水平及其和血清高敏C反应蛋白的关系.方法 选择单纯冠心病患者34例、单纯2型糖尿病患者33例、2型糖尿病合并冠心病患者30例及对照者30例,采用流式细胞术分别检测血小板表面CD62P和CD40L的表达水平,并与血清高敏C反应蛋白作相关分析.结果 2型糖尿病合并冠心病组血小板CD62P、CD40L和高敏C反应蛋白水平较对照组、单纯冠心病组及单纯2型糖尿病组显著升高(P<0.01),血小板CD62P和CD40L与血清高敏C反应蛋白水平呈正相关(r分别为0.343和0.495,P均<0.05).结论 2型糖尿病合并冠心病患者的血小板表面CD62P和CD40L表达水平明显升高,并与血清高敏C反应蛋白明显正相关.血小板表面CD62P和CD40L的表达水平可能是预示糖尿病患者合并冠状动脉粥样硬化的重要指标.     

Platelet surface CD62P and CD63, mean platelet volume, and soluble/platelet P-selectin as indexes of platelet function in atrial fibrillation: a comparison of "healthy control subjects" and "disease control subjects" in sinus rhythm.

OBJECTIVES: The aim of this work was to comprehensively study the role of platelets in atrial fibrillation (AF), in relation to the underlying cardiovascular diseases and type of AF, and to analyze the effect of antithrombotic treatment on different aspects of platelet activation. BACKGROUND: Platelet activation is present in nonvalvular AF, but there is debate whether this is due to AF itself and/or to underlying cardiovascular diseases. METHODS: A total of 121 AF patients were compared with 65 "healthy control subjects" and 78 "disease control subjects" in sinus rhythm. Platelet activation was assessed using 4 different aspects of platelet pathophysiology: 1) platelet surface expression of CD62P (P-selectin) and CD63 (a lysosomal glycoprotein) (by flow cytometry); 2) mean platelet volume (MPV) (by flow cytometry); 3) plasma levels of soluble P-selectin (sP-selectin, enzyme-linked immunoadsorbent assay); and 4) total amount of P-selectin per platelet (pP-selectin) ("platelet lysis" assay). RESULTS: Both AF patients and "disease control subjects" had higher levels of CD62P (p < 0.001), CD63 (p < 0.001), and sP-selectin (p < 0.001) compared with "healthy control subjects," with no difference between AF patients and "disease control subjects." Patients with permanent AF had higher levels of sP-selectin (p = 0.014) and MPV (p = 0.025) compared with those with paroxysmal AF. The presence of AF independently affected the levels of CD62P expression, while "high-risk" AF patients (CHADS score > or =2) had higher levels of CD62P compared with those with "low risk." Introducing warfarin resulted in a reduction of pP-selectin (p = 0.013). CONCLUSIONS: There is a degree of excess of platelet activation in AF compared with "healthy control subjects," but no significant difference between AF patients and "disease control subjects" in sinus rhythm. Platelet activation may differ according to the subtype of AF, but this is not in excess of the underlying comorbidities that lead to AF. Platelet activation in AF may be due to underlying cardiovascular diseases, rather than due to AF per se.     

Platelet indexes in relation to target organ damage in high-risk hypertensive patients: a substudy of the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT)

OBJECTIVES: We sought to investigate the relationship between target organ damage (TOD) in hypertension and a prothrombotic/hypercoagulable state, using a new technique of "platelet lysis" to quantify the amount of P-selectin per platelet (pP-sel), and to correlate it with other platelet markers (e.g., mass, volume and granularity, soluble P-selectin [sP-sel], and beta-thromboglobulin [beta-TG]). BACKGROUND: The increased risk of TOD in hypertension may be related to a prothrombotic/hypercoagulable state, with abnormalities in platelets, such as increased expression of P-selectin. METHODS: We studied 199 patients (mean age 68 years, 75% men) with hypertension. Of these, 125 had TOD (e.g., stroke, previous myocardial infarction, angina, left ventricular hypertrophy). Values obtained were compared with those from 59 healthy normotensive control subjects (mean age 68 years, 58% men). RESULTS: Hypertensive patients had a higher mean platelet volume, mass, pP-sel, sP-sel, and beta-TG and lower platelet granularity (all p < 0.01), but a similar platelet count, as compared with controls. Within the hypertensive group, those with evidence of TOD had significantly larger platelets with greater mass but had lower granularity, sP-sel, and pP-sel levels than those without TOD, possibly reflecting increased aspirin use. On multivariate analysis, aspirin use was a determinant of pP-sel (p = 0.03) and sP-sel (p = 0.01), but the use of other drugs or other co-morbidity (e.g., diabetes, smoking) did not influence either P-selectin value. CONCLUSIONS: Patients with hypertension have evidence of changes in platelet physiology, as reflected by a higher level of pP-sel. Patients with TOD also had larger platelets, with greater mass, and the use of aspirin lowered pP-sel and sP-sel levels. These changes may have implications for the pathophysiology of cardiovascular and cerebrovascular disease in hypertension.     

Plasma mediated neutrophil stimulation during coronary angioplasty: autocrine effect of platelet activating factor.

BACKGROUND--Polymorphonuclear neutrophils are involved in the development of myocardial injury during ischaemia and reperfusion. Coronary angioplasty has been shown to result in neutrophil activation. This may be a result of contact with ligands expressed by endothelial cells or response to soluble stimuli released from ischaemic tissue into the plasma or both. OBJECTIVE--To investigate plasma mediated neutrophil activation during angioplasty. METHODS AND RESULTS--Plasma samples were collected from the coronary sinus, femoral artery, and femoral vein of 14 patients undergoing angioplasty, before and after the first balloon inflation and at the end of the procedure. Plasma samples were incubated with washed neutrophils isolated from healthy donors. Expression of the adhesion molecules CD18 integrin and L-selectin (Leu-8) was measured by flow cytometry, and superoxide anion production was measured by chemiluminescence. Plasma samples from the coronary sinus and femoral artery but not from the peripheral vein induced increased expression of neutrophil CD18 after balloon deflation. Modification of the expression of L-selectin was not noted. Production of superoxide anion by neutrophils was stimulated by plasma samples from the coronary sinus, but not by those from the femoral artery or vein. This plasma mediated neutrophil stimulation was prevented when the neutrophils were pretreated with platelet activating factor receptor antagonists BN52021 or BN50739. The platelet activating factor concentration detected in the coronary sinus was not higher than in control plasma. CONCLUSION--Brief ischaemia during coronary angioplasty leads to the release of soluble stimuli capable of inducing neutrophil integrin expression and free oxygen radical production. Platelet activating factor may act as an autocrine neutrophil stimulus under these conditions.     

Percutaneous transluminal mitral valvuloplasty reduces circulating soluble CD40 ligand in rheumatic mitral stenosis

BACKGROUND: Recent data suggest that the pathogenesis of vascular inflammation and thrombosis involves CD40 ligand (CD40L), which is mostly derived from platelets. Previous studies have demonstrated that platelet activation occurs in peripheral blood of patients with rheumatic mitral stenosis (MS). However, in patients with MS, the plasma level of soluble CD40L has never been investigated. METHODS AND RESULTS: Seventeen patients with symptomatic MS undergoing percutaneous transluminal mitral valvuloplasty were studied (group 1, 11 patients in permanent atrial fibrillation and 6 patients in sinus rhythm). Solid-phase, sandwich enzyme-linked immunosorbent assay determined the plasma levels of soluble CD40L in the femoral vein and artery, and right and left atria before valvuloplasty, and those in the peripheral venous blood obtained 10 min after valvuloplasty, and at the 4-week follow-up after valvuloplasty. The Doppler pressure half-time method was used to calculate the mitral valve area. Additionally, plasma concentrations of soluble CD40L in the peripheral venous blood obtained from 17 control patients were measured (including nine healthy volunteers in sinus rhythm [group 2] and eight patients in permanent lone atrial fibrillation [group 3]). Plasma levels of soluble CD40L were significantly elevated in group 1 patients (437.6 +/- 370.2 pg/mL) [mean +/- SD] compared with group 2 (203.8 +/- 218.0 pg/mL) and group 3 patients (173.5 +/- 105.0 pg/mL) [p < 0.05]. The area of mitral valve increased significantly after valvuloplasty (1.10 +/- 0.20 cm(2) vs 1.47 +/- 0.29 cm(2), p < 0.0001). The mean left atrial pressure fell significantly and immediately after valvuloplasty (22.8 +/- 4.9 mm Hg vs 17.6 +/- 5.5 mm Hg, p = 0.0004). The peripheral venous plasma levels of soluble CD40L obtained before valvuloplasty significantly fell after valvuloplasty (before, 437.6 +/- 370.2 pg/mL; vs 10 min after, 215.4 +/- 113.9 pg/mL; vs 4 weeks after, 217.5 +/- 111.9 pg/mL; p < 0.02). CONCLUSIONS: Patients with moderate-to-severe MS had higher venous plasma levels of soluble CD40L than healthy volunteers or patients with lone atrial fibrillation. Additionally, the elevated venous plasma levels of soluble CD40L fell significantly following valvuloplasty.     

氯吡格雷对冠心病患者PCI前后CD40配体的影响

目的：探讨冠心病患者血小板膜CD40配体（CD40L）和血清可溶性CD40配体（sCD40L）在冠脉内介入治疗（PCI）前后的变化及其临床意义。方法：选择30例经冠状动脉造影确诊为冠心病的患者,接受规范的抗心绞痛治疗,术前给予氯吡格雷75mg／d,行PCI术前及术后6h,采用流式细胞仪测定患者活化血小板CD40L的表达率,采用酶联免疫吸附法测定血清sCD40L的含量。结果：30例冠心病患者PCI术前血小板CD40L的表达率水平为（3．73±2．15）％,术后6h为（2．46±0．90）％,较术前显著降低（P〈0.01）。PCI术前血清sCD40L的含量为（11．72±4．25）ng／ml,术后6h为（9．98±3．32）ng／ml,较术前显著降低（P〈0.01）。结论：氯吡格雷降可低冠心病患者PCI术后早期血清和血小板膜CD40L的含量和表达,预防血栓栓塞事件发生。     

NLR、MPV及hs-CRP与冠心病的临床类型及冠脉狭窄程度的关联

目的:监测中性粒细胞/淋巴细胞(NLR)、平均血小板体积（MPV）及超敏C反应蛋白（hs-CRP）3项指标在冠心病类型及冠脉狭窄程度中的临床价值。方法: 选取我院心内科行冠脉造影明确为冠心病的220例患者,其中不稳定型心绞痛(UAP)64例,急性心肌梗死(AMI)76例,对照组为稳定型心绞痛（SAP）患者80例。分别监测两组患者的白细胞计数（WBC）,中性粒细胞计数（NC）,淋巴细胞计数（LC）,hs-CRP,血小板计数（PLC）,MPV,计算NLR,分析冠心病类型及冠脉狭窄程度与3项指标的关联性。并进行多因素Logistic回归分析。结果: WBC、NLR、MPV、hs-CRP在3组的差异有统计学意义（P<0.05）,不同程度的冠脉狭窄中三者亦有统计学差异,冠脉狭窄愈严重,NLR、hs-CRP及MPV愈大（P<0.05或P<0.01）。多因素回归分析提示hs-CRP是UAP及AMI的危险因素,NLR和MPV是AMI的独立危险因素。结论: NLR、MPV、hs-CRP与冠心病临床类型及冠脉狭窄程度有关联。     

Soluble CD40 ligand, platelet surface CD40 ligand, and total platelet CD40 ligand in atrial fibrillation: relationship to soluble P-selectin, stroke risk factors, and risk factor intervention

BACKGROUND: Abnormal levels of soluble CD40 ligand (sCD40L) have been reported in patients with hypertension, coronary artery disease, diabetes mellitus, heart failure, and stroke, all of which are conditions that are associated with nonvalvular atrial fibrillation (AF). We hypothesized the following: (1) CD40 ligand (CD40L)-related indexes (ie, platelet surface expressed CD40L, the soluble fragment of CD40L [sCD40L], and the total amount of CD40L per platelet [pCD40L]) are elevated in patients with AF compared to control subjects; (2) these indexes correlate with soluble P-selectin (sP-selectin), which is an established platelet marker; and (3) these indexes differentiate "high-risk" from "low-risk" subjects. METHODS: We performed a case-control study of 121 AF patients, 71 "disease control subjects," and 56 "healthy control subjects." Peripheral venous levels of platelet surface-expressed CD40L were analyzed by flow cytometry, while levels of sCD40L, pCD40L, and sP-selectin were measured by enzyme-linked immunosorbent assay. RESULTS: AF patients had significantly higher sCD40L levels compared to healthy control subjects (p = 0.042), with no difference in platelet surface CD40L and pCD40L levels. A positive correlation was noted between levels of sCD40L and pCD40L, and not with sP-selectin. CD40L-related indexes failed to distinguish between high-risk and low-risk AF patients. AF patients receiving optimal antithrombotic therapy had significantly lower pCD40L levels (p < 0.001) compared to control subjects. Optimized AF management also resulted in significant reductions in the levels of sCD40L (p = 0.023) and pCD40L (p < 0.001). CONCLUSION: CD40L-related indexes are not useful in the risk stratification of AF patients, and abnormal sCD40L levels can be reduced by intense multifactorial risk management. While there is a significant, albeit modest, excess of platelet activation in AF patients (as measured by sCD40L levels) compared to healthy control subjects, this is not in excess of that seen in patients with underlying cardiovascular diseases.     

Relationship between plasma inflammatory markers and platelet aggregation in patients with clopidogrel resistance after angioplasty

We evaluated the relationship between plasma inflammation markers and clopidogrel resistance in patients after stent implantation. The plasma levels of C-reactive protein (CRP), P-selectin, platelet soluble CD40 ligand (sCD40L), interleukin 6 (IL-6) and platelet aggregation were measured in 352 patients undergoing percutaneous coronary intervention (PCI) at baseline and after 6 months. The plasma levels of CRP, P-selectin, sCD40L, IL-6 was higher in 65 (18.5%) patients with clopidogrel resistance than in those with normal responsiveness at 6 months after PCI. There was a significant positive correlation between soluble CD40L levels and platelet aggregation (r = .28, P < .05). Diabetes (DM) and sCD40L level were independent predictors for unresponsiveness after stent implantation according to stepwise multivariate analyses. The hazard ratio (HR) for sCD40L level was 3.02 (95% CI = 1.28 to 3.25; P = .036) and for DM 2.53 (95% CI = 1.28 to 6.55, P = .03). We conclude that sCD40L and DM may influence clopidogrel resistance.     

Automated assessment of the neutrophil and platelet activation status in patients with essential thrombocythemia

Neutrophil and platelet activation are consistently found in essential thrombocythemia (ET), but the techniques employed to demonstrate such abnormalities are complex. To ascertain whether the ADVIA 120 analyzer can be employed to assess neutrophil and platelet activation status in ET, 55 such patients and the same number of matched healthy individuals were studied and the results correlated with neutrophil CD11b and platelet P-selectin expressions measured by flow cytometry. Compared with controls, ET patients had significantly higher values of neutrophil myeloperoxidase index (MPXI), mean platelet volume (MPV), platelet distribution width (PDW), and platelet component distribution width, and significantly lower values of neutrophil lobularity index and mean platelet component (MPC). Patients with the JAK2 mutation had significantly lower values of MPC and higher values of MPV and PDW than those with wild-type allele. A positive correlation was observed between MPXI and neutrophil CD11b expression and a negative correlation between MPC and platelet P-selectin expression. The intensity of the agreement between the variables obtained by the two methods was moderate. These results support the possible value of MPC as surrogate parameter of platelet activation in ET.     

Usefulness of mean platelet volume as a biomarker for long-term outcomes after percutaneous coronary intervention

Larger size platelets have enhanced reactivity. The mean platelet volume (MPV) is a marker of platelet activation and is usually measured as part of blood testing. The aim of the present study was to investigate the utility of the MPV as a biomarker in prognosticating the long-term outcomes after percutaneous coronary intervention (PCI). The baseline MPV values from consecutive patients undergoing PCI were screened. Of the 1,432 patients, the composite primary end point of mortality or myocardial infarction at 1 year occurred in 80 (5.6%). The patients in the highest tertile (MPV >9.1 fL) had an increased frequency of the primary end point compared to those in the mid (8.1 to 9.1 fL) and lowest (<8.1 fL) tertiles (9.0%, 4.5%, and 3.5%, respectively; p <0.01). Logistic regression analysis demonstrated diabetes (odds ratio 2.44, 95% confidence interval 1.48 to 4.00) and highest tertile of MPV (odds ratio 2.42, 95% confidence interval 1.47 to 3.99) as the best predictors of adverse outcomes. In patients with acute coronary syndrome, the preprocedural MPV and troponin levels demonstrated a comparable predictive relation to the primary end point (receiver operator characteristics curve analysis, area under the curve 0.64, p = 0.01; and 0.63, p = 0.01, respectively). In conclusion, an elevated MPV was a strong independent predictor of long-term outcomes after PCI. The preprocedural MPV had prognostic value similar to that of troponin in patients with acute coronary syndrome. These findings could be of importance in the clinical evaluation of patients before PCI and the design of future studies assessing antiplatelet therapies.     

Comparison of platelet activation in platelet concentrates measured by flow cytometry or ADVIA 2120

Background and Objectives The ADVIA 2120 Haematology Analyser is capable of measuring parameters that can be used as markers of platelet activation, mean platelet component (MPC), platelet component distribution width (PCDW) and mean platelet mass (MPM). This study investigated the degree of correlation of these measures of platelet granularity with CD62P measurement of platelet activation by flow cytometry in platelet concentrates. Materials and Methods Pooled platelets in plasma/citrate phosphate dextrose (CPD) anticoagulant or apheresis platelets in plasma/acid citrate dextrose formula A (ACD‐A) anticoagulant were evaluated. Pooled platelets were tested during 13 day storage, and apheresis platelets within 24 h of venepuncture. These were assessed for platelet activation using CD62P and the ADVIA, with or without extra EDTA anticoagulant. Results In pooled platelets, PCDW correlated strongly with CD62P, both with and without the addition of extra EDTA anticoagulant. There was a good correlation between MPC and CD62P with additional EDTA, but a weaker correlation without extra EDTA. There was no correlation between CD62P and MPM. In apheresis platelets the correlation between PCDW and CD62P was poor, whereas MPC correlated strongly with CD62P if EDTA anticoagulant was added. Conclusion The usefulness of ADVIA platelet granularity measures to predict the degree of platelet activation depends upon the anticoagulant present in the platelet concentrate, and whether extra EDTA is added to the sample. Although ADVIA MPC and PCDW measurement could not replace CD62P or other gold standard methods of assessing platelet activation, these ADVIA 2120 parameters may provide a quick check of platelet concentrate quality.     

Phase I study of eptifibatide in patients with sickle cell anaemia

The α IIb β 3 antagonist eptifibatide is an effective treatment for patients with acute coronary syndromes (ACS). Platelet reactivity and CD40 ligand (CD40L) may play a role in the pathophysiology of sickle cell anaemia (SCA) similar to that in ACS, suggesting that inhibition of platelet aggregation and CD40L release by eptifibatide may benefit patients with SCA. Following eptifibatide infusion, safety and pharmacodynamic data were obtained from four SCA patients in their non-crisis, steady states. Eptifibatide was well tolerated, with no adverse changes in the haematological, biochemical or coagulation parameters studied. Eptifibatide did not increase plasma levels of platelet factor 4 or beta-thromboglobulin, P-selectin exposure or platelet:leucocyte aggregate formation. Moreover, decreases in platelet aggregation and soluble CD40L (sCD40L) levels achieved in SCA patients were comparable to those observed in the treatment of ACS. Finally, indicators of inflammation, macrophage inflammatory protein-1 α , tumour necrosis factor- α and myoglobin were reduced following eptifibatide infusion, while vasodilation correlatives, matrix metalloproteinases (MMP-2 and MMP-9) and leptin were increased. Based on these phase I results, eptifibatide may benefit SCA patients by inhibiting platelet aggregation, decreasing sCD40L levels and favourably altering plasma levels of inflammatory mediators.