Indicator Of Platelet Activation Research Articles

Soluble CD40 ligand, interleukin (IL)-6, and hemostatic parameters in metabolic syndrome patients with and without overt ischemic heart disease

Soluble CD40 ligand (sCD40L, also known as CD154) is a marker for platelet activation which could increase coagulation and inflammation. In this case-control study, we aimed to assess the levels of plasma sCD40L, IL-6, and some hemostatic parameters in patients with metabolic syndrome (MetS) whether or not associated with overt ischemic heart disease (IHD). We measured plasma sCD40L (an index of platelet activation), interleukin (IL)-6 (a proinflammatory cytokine), and some hemostatic parameters (tissue factor [TF], thrombin–antithrombin [TAT] and D-dimer) in 47 patients with metabolic syndrome (21 with and 26 without overt IHD) versus 25 comparable healthy control subjects. Significantly higher levels of sCD40L, IL-6, and thrombotic markers (TF, D-dimer and TAT) were found in patients with metabolic syndrome compared to healthy controls. The levels of IL-6 and sCD40 were highest in patients with overt IHD. Strong positive correlations existed between sCD40L and IL-6 ( r = 0.67, p = 0.003), TF ( r = 0.59, p = 0.008), and platelets count ( r = 0.64, p = 0.005). Higher levels of sCD40L, IL-6, and thrombotic markers exist in MetS patients, particularly those with IHD. The strong positive correlations between sCD40L and IL-6, TF, and platelets count support a link between the CD40–CD40L system and the underlying inflammatory and hypercoagulable state in MetS patients.

Increased Platelet Activation in Young Patients with Prehypertension

Mean platelet volume (MPV) and sP-selectin levels are considered as indicators of platelet activation. In this study, we assessed platelet activation in prehypertensive patients by comparing MPV and sP-selectin levels of these patients with healthy conrols. The study population consisted of 25 newly diagnosed prehypertensive individuals (18 men, mean age = 34 ± 6 y) and 25 healthy control subjects (16 men, mean age = 33 ± 6 y) eligible for the current study. Blood pressure (BP) , lipid profile, plasma glucose, HOMA-IR values, sP-selectin levels, platelet counts, and MPV were measured in both groups. Other than systolic blood pressure (SBP) and diastolic blood pressure (DBP), baseline demographic characteristics of both groups were similar. No significant difference was found between the platelet counts of the two groups. Despite comparable platelet counts, platelet activation parameters were found significantly higher in the prehypertensives. Prehypertensives had larger a MPV value compared to that of the control group (8.24 ± 0.46 fl vs. 7.70 ± 0.64 fl; P = 0.001) and plasma sP-selectin levels were also significantly higher in the prehypertensive patients (163.60 ± 41.21 ng/ml vs. 132.80 ± 36.46; P = 0.007). Spearman correlation analysis revealed moderate positive correlation between SBP and platelet activation parameters (for SBP and MPV, r = 0.60, p = 0.001; for SBP and sP-selectin r = 0.51, p = 0.009). Prehypertension causes platelet activation as evidenced by increased MPV and plasma sP-selectin levels. Increased platelet activation might be related to increased vascular thrombotic risk in those patients.

Impact of Mild hypertriglyceridemia on fibrinolysis, Lp(a), and platelet activation indexes in mildly hypercholesterolemic patients

The relationship between high triglyceride values and alterations of the fibrinolytic system in cardiovascular heart disease (CHD) patients is well known. The aim of the study was to evaluate the effect of moderate hypertriglyceridemia on fibrinolysis, lipoprotein(a) [(Lp(a)], and platelet activation indexes in asymptomatic patients. To this end, 46 nondiabetic, dyslipidemic patients (age 51±8 years), with no associated pathologies and 23 normolipidemic, homogeneus patients (in terms of age, sex, and smoke habits) were studied. The dyslipidemic patients were split up into two groups: 23 type IIb hyperlipoproteinemia patients (Group I), and 23 type IIa hyperlipoproteinemia patients (Group 2). The control group had total cholesterol values of <5.18 mmol/L and triglyceride concentrations of <2.25 mmol/L. The result showed a significant difference (p<0.05) in the baseline plasminogen tissue activator inhibitor (PAI-1 b) values for the Group 1 patients as compared with the Group 2 and the controls, in the baseline tissue plasminogen activator (t-PA b) values for the Group 1 patients as compared with the Group 2 patients and in the lipoprotein (a) (Lp(a)) (p<0.01) values for the Group 2 as compared with the controls. On the other hand, no statistically significant difference was observed in β-thromboglobulin (β-TG), platelet factor 4 (PF4). This study shows that mild hypertriglyceridemia in asymptomatic hypercholesterolemic patients is associated with a different regulation of the fibrinolytic mechanism. In patients with moderate hypercholesterolemia, higher blood concentrations of Lp(a) were found than in the controls.

Increased mean platelet volume is associated with arterial stiffness

The brachial-ankle pulse wave velocity (baPWV) is a useful index of arterial stiffness. Mean platelet volume (MPV), an indicator of platelet activation, is associated with hypertension, stroke, and coronary artery disease, all of which may be caused by arteriosclerosis. However, little research has been conducted to investigate the relationship between MPV and arterial stiffness. In this cross-sectional study, we investigated the relationship between platelet count, MPV, and baPWV in 2645 apparently healthy Chinese participants (1676 men, 969 women) in a general health examination. Different metabolic parameters were compared across MPV quintiles (Q1: ≤8.1 fl, Q2: 8.2–8.5 fl, Q3: 8.6–9.6 fl, Q4: 9.7–10.7 fl, and Q5: ≥10.8 fl). Age-adjusted mean values of baPWV gradually increased with MPV quintiles (Q1 = 1124, Q2 = 1134, Q3 = 1199, Q4 = 1207, and Q5 = 1270 cm/s). Univariate analysis showed that age, sex, smoking status, body mass index (BMI), systolic blood pressure (SBP), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), fasting plasma glucose (FPG), total platelet count, and MPV were significantly associated with baPWV. In addition, age, sex, BMI, MPV, SBP, and FPG were significant factors in the multivariate model with baPWV. Notably, MPV was found to be a significant determinant for baPWV (β = 0.198; P < 0.001). The findings show that elevated MPV is positively correlated to arterial stiffness.

Platelet Indices in Patients With Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a chronic progressive disease characterized by persistent elevation of pulmonary artery pressure. Vasoconstriction, remodeling, and thrombosis cause increased pulmonary vascular resistance and pressure. Previous studies have demonstrated that platelet activation occurs in patients with PAH. Our aim was to assess the mean platelet volume (MPV), an indicator of platelet activation in patients with PAH. The study group consisted of 22 patients with PAH. An age-, gender-, and body mass index-matched control group was composed of 25 healthy volunteers. All patients underwent physical examination, echocardiography, and diagnostic cardiac catheterization. We measured serum MPV values and platelet counts in patients with PAH and control participant. MPV was significantly higher among the patients with PAH when compared with control group (8.68 ± 0.87 vs 8.02 ± 0.68 fl, respectively; P = .006). We have shown that MPV was elevated in patients with PAH.

Platelet indices in patients with acute pulmonary embolism

Previous studies have demonstrated that platelet activation occurs in patients with acute pulmonary embolism (PE). The aim of this study was to assess the mean platelet volume (MPV), an indicator of platelet activation in patients with acute PE. The study group consisted of 107 patients with acute PE. Seventy subjects matched for age, gender, body mass index (BMI) and frequency of concomitant diseases served as control group. All patients and control subjects underwent physical examination and echocardiography. We measured MPV values and platelet counts on admission. MPV was significantly higher among patients with acute PE when compared with control group (9.6 ± 1.0 vs. 8.1 ± 0.8 fL respectively; < 0.001). Platelet count was significantly lower among acute PE patients when compared with control group (227.1 ± 77.0 vs. 268.7 ± 58.4 × 109/L, respectively; < 0.001). MPV was correlated with right ventricular (RV) diameter (p < 0.001, r = 0.33) in correlation analysis. In linear regression analysis, MPV was independently correlated with RV dimension (β = 0.29, p = 0.001). We have shown that MPV, an indicator of platelet activation, was increased in patients with acute PE and it was correlated with RV diameter. Platelet count was decreased in patients with acute PE.

Peripheral hemorheological and vascular correlates of coronary blood flow

The slow coronary flow phenomenon (SCF), a condition described by the presence of inappropriate delay in the progression of intracoronary contrast during angiography in the absence of stenoses, has been shown in some patients presenting with chest pain. While several conditions leading to "secondary" slow flow are known, there are no definitive conclusions regarding the exact pathogenesis of "primary" SCF. The present paper outlines the mechanisms that may lead to SCF, emphasizing the role of hemorheological and vascular factors in the pathogenesis of this phenomenon. Small vessel dysfunction has been proposed in the pathogenesis of SCF since the first description of this syndrome in 1972. Abnormalities in coronary microvascular function result from increased microvascular resistances and impaired endothelial release of vasoactive substances, especially in production and bioavailability of endothelium derived NO. Inflammatory conditions (increased levels of C-reactive protein, interleukin-6 and adhesion molecules) and metabolic abnormalities such as impaired glycemic control, hyperuricemia and elevated serum gamma-glutamyltransferase were also found to contribute to microvascular dysfunction in patients with SCF. New studies have also indicated that increased blood viscosity and one of its major determinants, erythrocyte aggregation, is associated with the SCF. Rheological variables play a role in the control of shear stress and contribute to blood flow velocity changes. Although platelets do not have a significant influence on blood viscosity, it has been demonstrated that they are involved in the development of SCF. Increased mean platelet volume (MPV), an indicator of platelet activation and platelet aggregability is also significantly higher in patients with SCF compared with patients with normal coronary flow.

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.

Platelet distribution width and the extent of coronary artery disease: Results from a large prospective study

It has been postulated that large platelets may be an indicator of platelet activation, and thus be related to the extent of coronary artery disease (CAD). Platelet distribution width (PDW) directly measures the variability in platelet size. However, no data has been so far reported on this index and CAD. Thus, the aim of the current study was to investigate whether PDW is associated with the extent of CAD. We measured PDW in 1882 consecutive patients undergoing coronary angiography. Significant CAD was defined as stenosis >50% in at least one coronary vessel. We additionally measured Carotid Intima-Media Thickness (IMT) in 359 patients. Patients with higher PDW were older (p = 0.012), with higher weight (p < 0.0001) and waist (p < 0.0001), larger prevalence of diabetes (p = 0.014), dilated cardiomyopathy or valvular heart disease (p < 0.0001) and less often family history of CAD (p = 0.021), more often on statins (p = 0.005), and diuretics (p = 0.016). PDW was significantly associated with baseline glycaemia (p = 0.002) and Red Blood Cell count (p < 0.0001), but inversely related to platelet count (p < 0.0001). PDW was not associated with the prevalence of coronary artery disease (OR [95% CI] = 0.91 [0.81–1.04], p = 0.16; adjusted OR [95% CI] = 0.96 [0.82–1.12], p = 0.56). No relationship was observed between IMT and PDW as tertiles or as continuous variable (Mean IMT: r = 0.04; p = 0.46; Maximal IMT: r = 0.036, p = 0.49). This study showed that PDW is not related to the extent of CAD and carotid IMT. Thus, PDW can not be considered as a risk factor for CAD.

Mean platelet volume is increased in patients with severe obstructive sleep apnea

Increased platelet activation and aggregation which are closely related to cardiovascular complications have been reported in patients with obstructive sleep apnea (OSA). The aim of this study was to assess the mean platelet volume (MPV), an indicator of platelet activation in patients with OSA. The 95 subjects referred for evaluation of OSA underwent overnight polysomnography. Blood samples were taken for MPV determination. According to the apnea-hypopnea index (AHI), subjects were divided into three groups; group 1: control subjects without OSA (AHI < 5, n = 24), group 2: patients with mild to moderate OSA (AHI: 5–30, n = 42), and group 3: severe OSA (AHI > 30, n = 29). Body mass index (BMI) of patients with severe OSA was significantly higher than control subjects (31.5 ± 4.0 vs. 28.2 ± 5.0; p = 0.02). The MPV was significantly higher in patients with severe OSA than in the control group (8.9 ± 1.0 vs. 8.2 ± 0.7 fl; p = 0.01). Correlation analysis within 71 patients with OSA indicated that MPV was correlated with AHI (p < 0.001, r = 0.44) and DI (p = 0.001, r = 0.37). In multivariate regression analysis, when MPV was taken as independent with other study variables which are potential confounders such as age, gender and BMI, MPV was independently correlated with both AHI (β = 0.44, p < 0.001) and DI (β = 0.38, p < 0.001). We have shown that MPV was significantly higher in patients with severe OSA when compared with control subjects and MPV was correlated with AHI and DI.

Increased Mean Platelet Volume in Patients With Aortic Stenosis

Systemic thromboembolism is a serious complication in patients with aortic stenosis (AS). Previous studies have demonstrated that platelet activation occurs in patients with AS. The aim of this study was to assess the mean platelet volume (MPV), an indicator of platelet activation in patients with AS. The study group consisted of 43 patients with AS. An age-, gender-, and body mass index-matched control group consisted of 35 healthy volunteers. All patients and control participants underwent echocardiographic examination. We measured the serum MPV values in patients and control participants. Mean platelet volume was significantly higher among patients with AS when compared with the control group (8.7 ± 1.0 vs 7.9 ± 0.9 fL, respectively; P = .001). We have shown that MPV was significantly elevated in patients with AS compared to control participant.

Coronary heart disease is associated with mean platelet volume in type 2 diabetic patients

Background: Mean platelet volume (MPV) is an indicator of platelet activation which is a central process in the pathophysiology of coronary heart disease (CHD). The aim of the study was twofold; first to determine whether MPV values is increased in patients with DM, and secondly to evaluate the relation between diabetic complications and MPV. Methods: The study population included 258 patients divided into two groups. Group A composed of 158 type 2 diabetic patients with coexistent coronary artery disease (stenotic lesions of 50%) (78 women, 80 men; mean age 53.9_10.8; mean diabetes duration 13.1_6.0). One hundred subjects (48 women, 52 men; mean age 53.9_11) without type 2 diabetes with normal coronary angiographies were taken as the control group (group B). To evaluate the extension of CHD, Gensini scoring system was used. Results: The MPV was significantly different in the patient group compared to the controls (9.79 ± 1.5 fl vs 8.3 ± 0.9 fl, P<0.001). The existence of CHD was associated with MPV with odds ratio (95% CI) of 2.31 (1.55–4.42, p50.001). Conclusion: We have found that diabetic patients with coronary heart disease have significantly higher MPV values compared to control subjects without diabetes and with angiographically normal coronary arteries.

Effect of hemolysis on canine kaolin‐activated thromboelastography values and ADVIA 2120 platelet activation indices

The impact of hemolysis on thromboelastography (TEG) and platelet activation indices has not been evaluated. The aim of this study was to investigate the influence of hemolysis induced mechanically (HM) and hemolysis induced by freezing (HF) on TEG, platelet counts (PLT), and platelet activation indicators. Blood from 17 dogs was divided into the following samples: controls, HM, and HF. HM was induced by 20 repetitions of expulsion of blood through a 23 g needle. Freezing was at -80 degrees C, followed by warming to 37 degrees and dilution with equal parts room temperature blood at 22 degrees C. TEG variables that were examined included reaction time (R), coagulation time (K), angle (alpha), maximum amplitude (MA), and clot rigidity (G). Platelet indices were measured with the ADVIA 2120 hematology analyzer. Hematocrit (HCT) (mean+/-SD) for controls, HM, and HF were 0.41+/-0.02, 0.39+/-0.03, and 0.25+/-0.02 L/L, respectively, consistent with decreases in HCT of 4.8% (HM) and 39.0% (HF). HM resulted in decreased R (2.5+/-0.9 minutes compared with 5.2+/-1.9 minutes for controls; P<0.001), and HF resulted in increased K (15.2+/-8.6 minutes compared with 5.3+/-4.0 minutes in controls; P<0.01) and decreased alpha (20+/-11 degrees compared with 46+/-17 degrees in controls; P<0.001). MA was decreased more in HF samples (26+/-2 mm) than in HM (38+/-8 mm) or control samples (49+/-9 mm; P<0.0001). The same applied to G values. PLT decreased after HM but not after HF. Hemolysis of both types resulted in decreased mean platelet component (MPC) concentration: control, 19.3+/-2.0, HM 15.5+/-3.4, and HF 14.3+/-0.7 g/dL (P<0.0001). In hemolyzed samples decreased MPC and R suggested activated primary and secondary hemostasis, respectively, but decreased MA and G indicated reduced clot firmness, possibly due to hyporeactive platelets. TEG and platelet activation indices should be interpreted cautiously after hemolysis.

Increased Levels of Platelet Microparticles in HIV-Infected Patients With Good Response to Highly Active Antiretroviral Therapy

Increased Levels of Platelet Microparticles in HIV-Infected Patients With Good Response to Highly Active Antiretroviral Therapy

Mean platelet volume is associated with insulin resistance in non-obese, non-diabetic patients with coronary artery disease

Mean platelet volume (MPV), an indicator of platelet activation, has been shown to be elevated in patients with coronary artery disease (CAD) in some studies. Insulin resistance contributes to increased platelet activation and it is one of the risk factors for CAD. The aim of this study was to assess the relationship between insulin resistance and MPV in non-obese, non-diabetic patients with CAD. Seventy-seven non-obese, non-diabetic CAD patients were divided into two groups, insulin resistant and insulin sensitive according to the homeostasis model assessment insulin resistance index (HOMA-IR). The insulin-resistant group was composed of 45 patients (30 males/15 females; mean age 59.8±11.1 years). The insulin-sensitive group was composed of 32 patients (17 males/15 females; mean age 58.9±12.2 years). Insulin and HOMA-IR values were significantly higher in insulin-resistant CAD patients than in insulin-sensitive CAD patients. The MPV values were significantly higher in insulin-resistant CAD patients than in insulin-sensitive CAD patients (8.6±1.0 fl vs. 8.0±0.7 fl; respectively, p=0.01). The MPV was poorly correlated with HOMA-IR (r=0.30, p=0.054) and insulin (r=0.22, p=0.053). We have shown that MPV was significantly elevated in insulin-resistant non-obese, non-diabetic CAD patients when compared to insulin-sensitive non-obese, non-diabetic CAD patients.

Evaluation of Platelet Parameters in Patients With Pulmonary Hydatid Cyst

Background:Echinococcosis is a near-cosmopolitan zoonosis caused by adult or larval stages of tapeworms (cestodes) into the genus Echinococcus (family Taeniidae). It was demonstrated that platelets were capable of killing parasites independent from leukocytes. Purpose: The aim of our study was to examine mean platelet volume (MPV), platelet mass (PM) and platelet count (PC), which are practical indicators of platelet activity in preoperative and postoperative periods of the patients with hydatid cyst.Methods:In this retrospective study we evaluated 72 patients admitted to clinic of chest surgery with a diagnosis of pulmonary hydatid cyst in our hospital between January, 2006, and October, 2008. The MPV, PC, and PM were evaluated by complete blood count. PM was calculated by multiplying MPV and PLT.Results:Preoperative MPV values of the patients was found to be significantly higher than postoperative MPV values (mean: 8.07±0.83, 7.78±0.87, p= 0.002). Preoperative PM values (median: 2456.75, range: 1013.70–5046.60) was found to be higher when compared to postoperative PM values (median: 2280.80, range: 134.20–4042.60) (p= 0.039). PC values were not significantly different between two periods (Preoperative-postoperative PC mean values: 320.48±98.42, 307.29±96.45, p= 0.286).Conclusion:In this study, we demonstrated that there were no statistical difference in PC for both periods but, MPV and PM were found statistical higher than postoperative period in preoperative period. PM and PM can be used as markers of disease activity in patients who undergo surgical resection of hydatid cyst.

Parathyroid Hormone, Platelet Free Cytosolic Calcium and Platelet Indices among Asian Indian and Qatari Subjects

Asian Indians (AI) are more prone to coronary artery disease (CAD) than other ethnic groups. These variations in events are not fully explained only by differences in conventional cardiovascular risk factors. Thus, other factors must be account for such pattern. Disturbed some of the platelet activation indices including mean platelet volume (MPV) &amp; platelet distribution width (PDW) as well as increased platelet free cytosolic calcium (Cai) play critical roles in platelet activation and thrombus formation. Parathyroid hormone (PTH) may increase risk for ischemic arrhythmias and its effects on MPV, PDW and Cai is of growing interest. There are limited data concerning these parameters in AI. Therefore we aimed to study the PTH and platelet Cai levels as well as MPV and PDW in healthy AI versus Qatari (Qt) subjects. Twelve healthy, nonsmoking AI were age matched with 11 healthy nonsmoking Qt subjects. PTH levels, as measured by ELISA, demonstrated a significant higher levels in AI (32.7±10.3 vs 23.5±9.95, P&lt;0.05). Platelet Cai, as measured by X ray microanalysis, exhibited a non‐significant increase among AI subjects compared with Qt ones (0.117±0.0854 vs 0.097±0.034, P=0.366). MPV and PDW were elevated among AI versus Qt subjects (MPV, 7.865±0.57 vs 7.7±0.294, P=0.284)) &amp; (PDW, 15.929±0.369 vs 15.4±0.698, P&lt;0.05). These differences may clarify the reported discrepancy in CAD rates between the two ethnic groups.

Platelet-Large Cell Ratio and the extent of coronary artery disease: results from a large prospective study

Even though platelet volume has been supposed to be indicator of platelet activation, contrasting results have been reported on its relationship with the extent of coronary artery disease (CAD). No data have been so far reported on Platelet-Large Cell Ratio (P-LCR). Thus, the aim of the current study was to investigate whether P-LCR is associated with CAD. We measured P-LCR in 1882 consecutive patients undergoing coronary angiography. Significant CAD was defined as stenosis >50% in at least 1 coronary vessel. We additionally measured Carotid Intima-Media Thickness (IMT) in 359 patients. The relationship between P-LCR and platelet aggregation was evaluated by PFA-100 and Multiplate. Patients with higher P-LCR were older (P=0.038), with larger prevalence of diabetes (P<0.0001), dilated cardiomyopathy or valvular heart disease (P=0.004) and less often family history of CAD (P=0.045), more often on statins (P=0.002), and diuretics (P=0.016). P-LCR was significantly associated with baseline glycaemia (P=0.001) and RBC count (P<0.001), but inversely related to platelet count (P<0.0001). P-LCR was not associated with the prevalence of CAD (adjusted P=0.3) or its severity. In addition, P-LCR was not related to Carotid IMT or platelet aggregation in patients with or without aspirin therapy. This study showed that P-LCR is not related to platelet aggregation, aspirin resistance, the extent of CAD and carotid IMT. Thus, P-LCR can not be considered as a marker of platelet reactivity or a risk factor for CAD.

Mean platelet volume in patients with prehypertension and hypertension

Patients with hypertension have evidence of platelet activation. Mean platelet volume (MPV), an indicator of platelet activation has been shown to be elevated in patients with hypertension. Prehypertension is also associated with an increase in cardiovascular morbidity and mortality. The aim of this study was to assess the MPV in patients with prehypertension and hypertension. This study included newly diagnosed and untreated 87 prehypertensive patients, 30 hypertensive patients and 35 normotensive control subjects matched for age, gender, and body mass index. All patients and controls gave informed consent. The MPV values of patients with prehypertension and hypertension were significantly higher than those of the control group (8.4 +/- 0.8 and 8.8 +/- 0.7 versus 7.9 +/- 0.5 fl; p < 0.05 and p < 0.001 respectively). It was also higher in hypertensives than in prehypertensives (8.8 +/- 0.7 versus 8.4 +/- 0.8 fl; p < 0.05). However, we found that the presence of the hypertension (beta = 0.28, P = 0.003) was only significant predictors of higher MPV in a multivariable model that adjusted for other variables. We have shown that, MPV, an indicator of platelet activation was significantly higher in patients with prehypertension and hypertension when compared with control subjects. We have also showed that MPV was also higher in patients with hypertension than in patients with prehypertension. However, presence of the hypertension was only significant predictor of higher MPV.

Plasma viscosity and mean platelet volume in patients undergoing coronary angiography

Markers of platelet activation and haemorrheological indices have been demonstrated to play a role in the pathophysiology of atherosclerosis and cardiovascular events. In this study, we aimed at investigate the association between plasma viscosity and platelet indices in patients undergoing coronary angiography. Three hundred and eighty four consecutive patients scheduled to undergo coronary angiography were included in the study. Prior to coronary angiography, blood samples were withdrawn to determine routine biochemical markers, blood cell analyses and viscosity measurements. According to the results of coronary angiography, patients were classified either in a subgroup with coronary artery disease (CAD; 1 or more stenoses >50%) or normal coronary arteries (NCA; no stenoses or <50%). There was a statistically significant correlation between plasma viscosity and mean platelet volume levels in all patients undergoing coronary angiography (r=0.199, p<0.001). Additionally, when correlation analysis was performed within each group, plasma viscosity significantly correlated with MPV both in patients with CAD (r=0.18, p=0.004) and in patients with NCAs (r=0.272, p=0.002). Linear regression analysis revealed that plasma viscosity was positively associated with MPV while platelet number was inversely but significantly associated with MPV. We have shown for the first time that MPV correlates with plasma viscosity in patients undergoing coronary angiography, suggesting a relation with plasma proteins and activation of circulating platelets or peripheral consumption of platelets. To evaluate this relation further controlled studies also in patients with acute coronary syndromes are warranted.