Hemorheological Parameters Research Articles

Red cell distribution width and the risk of cerebral vein thrombosis: A case–control study

BackgroundRed cell distribution width (RDW) is a marker of cardiovascular diseases and venous thromboembolism, but its role in cerebral vein thrombosis (CVT) is unknown. AimsTo investigate whether high values of RDW are associated with an increased risk of CVT. MethodsA case–control study of CVT patients (≥18years-old) referred to our center contrasted with healthy individuals. Odds ratios (ORs) were calculated for RDW values >90th percentile by multivariable logistic regression and adjusted for demographic characteristics, hemorheological parameters, renal function, fibrinogen and CRP. Quartiles based on the distribution of RDW values were used in an additional model to assess a dose–response relationship. The risk of CVT associated with the combined presence of high RDW and either thrombophilia abnormalities or oral contraceptive use was also estimated. Results143 cases (median age 36years, 18–79) and 352 controls (42years, 18–80) were investigated. RDW values >90th percentile (>14.6%) were associated with an increased risk of CVT (OR 2.44, 95% CI 1.39–4.28). The association remained after further adjustment for hemorheological parameters (OR 3.73, 95% CI 1.72–8.09), inflammatory markers (OR 3.77, 95% CI 1.72–8.25) and renal function (OR 3.62, 95% CI 1.53–8.55). The risk appeared restricted to these extreme levels (>14.6%), as there was no graded association between values of RDW and CVT risk over quartiles. There was a synergistic effect on the risk of CVT for the combination of high RDW and thrombophilia abnormalities (OR 33.20, 95% CI 6.95–158.55) or oral contraceptive use (OR 37.99, 95% CI 8.78–164.45). ConclusionsValues of RDW >90th percentile are associated with CVT.

Comparatively evaluating effect contribution of promoting blood circulation of herb pairs containing Angelicae Sinensis Radix on Xin-Sheng-Hua granule by withdrawal analysis

Xin-Sheng-Hua granule (XSHG) is a popular remedy commonly used in clinic for the treatment of lochiostasis after delivery. To comparatively investigate the roles of herb pairs containing Angelicae Sinensis Radix (Danggui) upon the formula by evaluating the blood coagulation and hemorheology function in acute blood stasis rats, acute blood stasis rat model was established by ice water bath and subcutaneous injection of adrenaline. And the blood stasis mice were administrated intragastrically with different samples of the formula minus herb pairs containing Danggui and the whole formula (XSHG, SHD, DY, DC, DT, DH, DJ and DZ). The whole blood viscosity (WBV), plasma viscosity (PV), erythrocyte sedimentation rate (ESR) and haematocrit (HCT) were applied to evaluate the effects of the formula minus herb pairs containing Danggui on hemorheology of blood stasis rats. The thrombin time (TT), activated partial thromboplastin time (APTT), prothrombin time (PT), and plasma fibrinogen (FIB) were used to observe the effects of the formula minus herb pairs containing Danggui on blood coagulation function of blood stasis rats. Additionally, the maximum aggregation induced by adenosine diphosphate (ADP) was tested to observe the effect of different samples on platelet aggregation index of blood stasis rats.Afterwards, multi-attribute comprehensive index methods and principal component analysis were both applied to comprehensively assess the total effects of the formula minus herb pairs containing Danggui on promoting blood circulation and dissipating blood stasis. Compared with normal group, the hemorheological parameters and coagulation indexes of model group had statistical differences (P<0.01). Compared with model group, different samples (XSHG, SHD, DY, DC, DT, DH, DJ and DZ) could improve the blood hemorheology indexes, coagulation parameters and platelet aggregation in acute blood stasis rats. According to multi-attribute comprehensive index methods and the principal component analysis, the effects of promoting blood circulation by removing blood stasis became poor when excluding herb pairs containing Danggui from the formula, the sample DY and DC had the weakest effect of activating blood circulation and dissipating blood stasis, and the effect of sample DY was slightly poorer than DC. The orders of contribution of herb pairs containing Danggui on the formula were Danggui-Yimucao>Danggui-Chuanxiong>Danggui-Honghua>Danggui-Zhigancao>Danggui-Taoren>Danggui-Jiangtan. In conclusion, various herb pairs containing Danggui played different roles on the effects of improving the abnormality of hemorheology and coagulation function. And the herb pairs Danggui-Yimucao were particularly important for the formula, which was consistent with the characteristics of XSHG and the traditional effect of Yimucao. Moreover, it could lay foundation to further reveal the compatibility mechanism of XSHG.

Influence of stent implantation on erythrocyte aggregation in human native coronary arteries and saphenous vein grafts.

Stent implantation into atherosclerotic coronary vessels induces the release of particulate debris and soluble vasoactive substances, which impair downstream microvascular function. Microvascular perfusion, however, is also determined by hemorheological parameters. We therefore analyzed now changes in erythrocyte (RBC) aggregation in coronary arterial blood during stent implantation. Symptomatic male patients with stable angina pectoris and stenosis in their native right coronary artery (RCA) or saphenous vein graft on right coronary artery (SVG-RCA) were enrolled. Coronary arterial blood was taken before and coronary aspirate during stent implantation with a distal occlusion/aspiration device. RBC aggregation was determined using the erythrocyte adhesiveness/aggregation test. The ratio of clot-free area to whole area of a spread blood drop was quantified (rCFA). To evaluate the impact of soluble factors within aspirate plasma on RBC aggregation, separated RBCs of healthy volunteers were exposed to patients' coronary arterial blood and aspirate samples. rCFA was comparably increased in coronary aspirate of RCAs and SVG-RCAs after stent implantation (RCA: 25.7±2.1% vs 32.2±2.1%; SVG-RCA: 28.9±1.9% vs 33.3±2.0%, P<.01). The rCFA of healthy volunteers was increased after adding coronary aspirate plasma. Stent implantation into atherosclerotic coronary arteries induces an increase in RBC aggregation, potentially contributing to impaired microvascular perfusion.

Inflammatory and oxidative stress phenotypes in transgenic sickle cell mice

The Townes mouse model of homozygous sickle cell disease (SS) has emerged as the major experimental model for studying pathophysiological mechanisms of human sickle cell disease (SCD). We therefore investigated hematological and hemorheological parameters as well as organ-specific inflammatory and oxidative stress molecular profiles in these animals in steady state conditions. Evidences of SCD-related intravascular hemolysis, impaired red blood cell (RBC) deformability, leukocytosis and altered plasma nitric oxide byproducts (NOx) level were found in the SS mice. The SS mice have damaged, enlarged and dysfunctional spleen as attested by high AOPP levels, low SOD and GPx activities and low pro-inflammatory cytokines mRNA expression. SS mice exhibited cardiomegaly, high cardiac mRNA levels of proinflammatory markers and low cardiac GPx activity. While lungs did not display any noticeable defects, liver and kidney were particularly sensitive to oxidative stress and inflammation as suggested by high AOPP levels in both organs, elevated renal NF-κB and TNF-α, and increased hepatic VCAM-1 and IL-1β. Our data indicate a tissue-specific phenotype regarding oxidative stress and inflammation in SS mice that may help to optimize the development of novel potential drug treatments.

The association of gynaecological malignancies with hemorheological parameters during the surgical interventions

Aim: According to previous literature there is an association between cancer and thrombosis. The aim of our study was to investigate the changes of rheological parameters in women with gynaecological cancer pre and post surgery and to address any possible relation between them and the increased risk of thrombosis.

Effects of cigarette smoking on hemorheologic parameters, plasma osmolality and lung function.

Cigarette smoking deteriorates human health via vascular disorders, cancer and especially respiratory diseases. The aim of this study is to investigate effects of cigarette smoking on hemorheologic parameters, plasma osmolality and lung function in individuals without diagnosis of chronic obstructive pulmonary disease (COPD). Patients diagnosed without COPD utilizing respiratory function test were enrolled in the study with three groups, ex-smokers (n = 21), current-smokers (n = 35) and never-smokers (n = 43). Hemorheologic parameters and plasma osmolality were measured in hemorheology laboratory. SPSS 17.0 was used for statistical analysis. Blood and plasma viscosity, fibrinogen and hematocrit levels, mean corpuscular volume and mean corpuscular hemoglobin concentration were significantly elevated in ex-smokers and current-smokers compared to never-smokers. The standardized red blood cell deformability and oxygen delivery index and lung function were statistically lower in current-smokers than never-smokers. Pulmonary blood flow rate was statistically lower in current-smokers and ex-smokers than never-smokers. Plasma osmolality was statistically significantly higher in ex-smokers and current-smokers than never-smokers. Our findings clearly show that cigarette smoking has severe effects on hemorheologic parameters, plasma osmolality and lung function even in individuals without COPD. Blood and plasma viscosity with plasma osmolality might be useful markers to detect early hemorheologic-hemodynamic alterations in cigarette smokers.

Identification of erythrocyte biomarkers in amyotrophic lateral sclerosis.

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease of the motor system. It has been hypothesised that red blood cells (RBCs) may be involved in the disease process by the release of damaging molecules. The aim of this ex vivo study is to compare RBCs biochemical and hemorheological parameters between ALS patients and healthy donors to identify novel biomarkers of the ALS disease. We included 82 ALS patients and 40 gender age-matched healthy donors. We performed quantification of erythrocyte aggregation and deformability, nitric oxide (NO) efflux from RBCs, acetylcholinesterase (AChE) enzyme activity and intraerythrocytic concentration of nitrite, nitrate and S-nitrosogluthatione (GSNO). Erythrocyte deformability and AChE activity were increased in patients with ALS in comparison to healthy donors. NO efflux from RBCs and concentration of intraerythrocytic nitrite were lower in ALS patients. In patients, we found that for higher NO range of values the respiratory function is worse and that for higher AChE range of values the RBCs nitrite content increase. The results of the present study indicate that NO efflux from RBCs and RBCs AChE should be further explored as potential biomarkers for ALS.

Controlled reperfusion reduces hemorheological alterations in a porcine infrarenal aortic-clamping ischemia-reperfusion model.

Restoration of blood flow after prolonged acute ischemia causes further injury to tissues. The role of increased oxidative stress is emphasized in the pathogenesis, and impairment of hemorheological factors may also hinder proper microcirculation. Controlled reperfusion at lowered pressure with diluted blood may help to decrease reperfusion injury. Four-hour infrarenal aortic clamping was performed in 16 Yorkshire pigs. In 8 animals blood flow was restored subsequently (full reperfusion, FR), in the other 8 animals clamping was followed by an initial 30 minutes of controlled reperfusion (CR) at 60 mmHg pressure with a 1 : 1 ratio mixture of blood and reperfusion solution. Blood samples were taken before the intervention, at the end of ischemia, 15 minutes, 60 minutes, 1 day and 1 week after the start of reperfusion. Hemorheological parameters were measured. Hematocrit, plasma and whole blood viscosity decreased significantly during CR, these attenuated at 1 day. At 1 week whole blood and plasma viscosities were elevated in the FR group. Erythrocyte deformability did not change significantly at any measurements. Erythrocyte aggregation decreased during CR but not in FR, and was found elevated in both groups at 1 week. Our results suggest slightly improved hemorheological properties in case of controlled reperfusion compared to full reperfusion, which may help to reduce tissue damage.

Association of whole blood viscosity with non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is an independent risk factor for increased cardiovascular disease. Altered hemorheological parameters have also been shown to play a crucial role in atherogenesis. Moreover, increased viscosity is observed in insulin resistance, metabolic syndrome, hypertension, diabetes, ischemic heart disease, and stroke. A recent study confirmed that whole blood viscosity (WBV) is a predictor of cardiovascular events. This study aimed to investigate the association of WBV with NAFLD. In this cross-sectional study, we investigated the relationship between WBV and NAFLD in 1329 subjects (962 men and 367 women) in a general health examination. WBV at low shear stress was elevated in patients with NAFLD. In addition, the prevalence of metabolic syndrome and NAFLD increased as WBV quartiles increased both in men and in women. Multiple regression analysis further identified WBV as an independent and significant determinant for NAFLD. The findings showed that WBV at low shear stress is increased in NAFLD. Moreover, WBV at low shear stress is independently associated with NAFLD even after adjusting other cardiovascular risk factors.

Erythrocyte deformability — A partner of the inflammatory response

We aim to establish an in vivo animal model of acute inflammation using PAF (platelet activating factor) as inflammatory agent and to study the erythrocyte deformability changes induced by the inflammatory response. Counting the number of rolling and adherent neutrophils to endothelium after 2, 4 and 6h of intrascrotal injection of PAF we showed the induction of an inflammatory state. Blood samples are collected in order to measure the erythrocyte deformability and to quantify NO efflux from the red blood cells (RBCs). The results show an increased number of rolling and adherent neutrophils after 2h and 4h of inflammation as well as decreased values of erythrocyte deformability in the same time-points. This result is in line with the need of a low blood viscosity to the recruitment process that will improve leukocyte migration towards the endothelial wall. NO efflux from RBCs is also affected by the inflammatory response at the first hours of inflammation. This animal model demonstrates in vivo the association between an acute inflammatory response and the rheological properties of the blood, namely the RBCs deformability. For those reasons we consider this as an adequate model to study acute inflammatory responses as well as hemorheological parameters.

Hemorheological effects of secoisolariciresinol in ovariectomized rats.

Postmenopausal women often develop hemorheological disorders which may affect the systemic blood circulation and present a cardiovascular risk factor. We evaluated effects of secoisolariciresinol (SECO), a phytoestrogen, on hemorheological parameters and lipid peroxidation in a model of the age-related and/or surgical menopause induced by ovariectomy in rats. Arterial blood was sampled from sham-operated female rats, ovariectomized rats (OVX), and OVX treated with SECO (OVXSECO) (20 mg/kg/day intragastrically for two weeks). Plasma estrogen concentration and the following hemorheological parameters were measured: RBC aggregation (half-time of aggregation, T1/2; amplitude of aggregation, AMP; aggregation index, AI), RBC deformability (elongation index, EI), whole blood viscosity at the shear rate of 3-300s-1, plasma viscosity, hematocrit, plasma fibrinogen. Lipid peroxidation was evaluated by measuring conjugated dienes (CD) and thiobarbituric acid reactive substances (TBARS) in plasma. Ovariectomy in rats caused a 60% decrease in plasma estrogen level and triggered the development of macro- and microhemorheological abnormalities. Blood viscosity increased by 12-31%, RBC elongation index reduced by 16-28%, and T1/2 and AI increased by 35% and 29% respectively. The increase in blood viscosity correlated predominantly with reduced RBC deformability. Plasma CD and TBARS were elevated by 47% and 104% respectively. SECO therapy for OVX rats reduced blood viscosity by 9-18% and T1/2 by 32%, and increased EI by 4-17%. SECO therapy disrupted the correlation between blood viscosity and RBC deformability. Lipid peroxidation was significantly inhibited, as shown by the reduction in CD and TBARS plasma concentrations by 89% and 70% respectively. SECO did not affect plasma viscosity, estrogen or fibrinogen levels. SECO treatment for OVX rats improves blood macro- and microrheological parameters, possibly through antioxidant protection of RBC.

Effects of early intervention with Huoxueqingjie decoction on hemorheological parameters and D-dimer, thromboxane A2, and prostaglandin I2 levels in patients with severe acute pancreatitis

Effects of early intervention with Huoxueqingjie decoction on hemorheological parameters and D-dimer, thromboxane A2, and prostaglandin I2 levels in patients with severe acute pancreatitis

Changes in coagulation functions and hemorheological parameters may predict hematoma formation after total knee arthroplasty.

BackgroundHematoma formation around the knee is commonly seen after total knee arthroplasty (TKA) and may cause patient discomfort and worry regarding the success of the surgery. This study aimed to evaluate the coagulation functions and hemorheological parameters in patients undergoing TKA and investigate their associations with hematoma formation.MethodsThis study prospectively included 146 patients treated for knee osteoarthritis by unilateral TKA between August 2013 and August 2014. Apixaban was administered twice during the 12–24-h period after surgery. Blood coagulation functions were evaluated according to activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time, and fibrinogen preoperatively and on postoperative days 1, 3, 7, and 14. Hemorheological parameters were also measured. Patients were divided into a hematoma group and a non-hematoma group for comparison.ResultsOn postoperative day 1, the hematoma group showed significantly prolonged APTT and PT and significantly decreased hematocrit relative to baseline values (P < 0.05). The whole blood high shear rate, whole blood low shear rate, plasma viscosity, and hematocrit did not differ significantly between the two groups at baseline or from postoperative days 1–14 in (P > 0.05).ConclusionsProlonged APTT and PT on the first day after TKA as well as decreased hematocrit may indicate an increased risk of hematoma formation. Postoperative use of apixaban may promote the formation of ecchymoses but is not a major contributing factor.

The atherosclerotic risk profile is affected differently by fish flesh with a similar EPA and DHA content but different n-6/n-3 ratio.

The aim of this study was to evaluate the effect of consuming gilthead sea bream fillets, with different n-6/ n-3 ratios, on atherosclerotic biomarkers. Twenty healthy subjects were included in a randomised single-blinded cross-over trial. Participants were randomized into 2 groups, both of which received approximately 630 g per week of gilthead sea bream fed with either 100% fishmeal (FM) or partial replacement with plant proteins (PP) over two consecutive 10 week periods, respectively. Group A consumed firstly the FM fillets followed by the PP fillets, whereas the reverse order was adopted for group B. Group A reported a significant decrease of 29.3% (Δ = -26 mg/dL) in total cholesterol after the first phase of the intervention, before returning to baseline levels after the dietary intervention with fish fed with PP. Similarly, in group A, both LDL-cholesterol and triglycerides decreased significantly by 21.6% (Δ = -19 mg/dL) and 11.7% (Δ = -10.7 mg/dL), respectively, before increasing again after the intervention. Improvements in the inflammatory cytokines, interleukin-6 and -8 were also noted. Moreover, whole blood viscosity appeared significantly improved in group A, as seen by a significant increase of 7.59% (Δ = +4.59 mPA) for erythrocyte filtration rate. In conclusion, similar EPA+DHA content with different n- 6/n-3 ratio fish flesh intake was shown to have varied affects on lipid, inflammatory and haemorheological parameters in a group of healthy subjects.

Impaired Hemorheological Parameters and Increased Carotid Intima-Media Thickness in Children with Subclinical Hypothyroidism

Background: Subclinical hypothyroidism (SH) is defined as elevated serum thyroid-stimulating hormone (TSH) concentration associated with normal serum-free thyroxine levels. Effects of hypothyroidism on hemorheology had widely attracted the attention of researchers during the last decade. Objective: The purpose of this study is to determine alterations in hemorheological parameters and carotid intima-media thickness (CIMT) in children with SH. Methods: Fifty-three SH children and 31 healthy controls were enrolled. Erythrocyte deformability and aggregation were determined by an ektacytometer and plasma viscosity (PV) by a cone-plate rotational viscometer. CIMT was evaluated sonographically. Results: Erythrocyte deformability of the SH group measured at 0.53 and 1.69-30 Pa was lower than that of the control group. The erythrocyte aggregation index, aggregation half time and PV were not different between the groups. However, the aggregation amplitude and mean corpuscular hemoglobin concentration were significantly higher in SH compared to the control group. There was a negative correlation between TSH and deformability values measured at 5.33-30.0 Pa. CIMT in patients with SH was significantly higher than in the control group (p = 0.001; SH = 0.48 ± 0.04 mm, control group = 0.43 ± 0.03 mm). Conclusion: Impaired hemorheology and increased CIMT are well-known risk factors for developing cardiovascular pathologies. The results of the current study suggest the treatment of children with SH in order to avoid early circulatory problems.

Alterations of hemorheological parameters and tubulin content in erythrocytes from diabetic subjects

Treatment of human erythrocytes with high glucose concentrations altered the content and distributions of three tubulin isotypes, with consequent reduction of erythrocyte deformability and osmotic resistance. In erythrocytes from diabetic subjects (D erythrocytes), (i) tubulin in the membrane-associated fraction (Mem-Tub) was increased and tubulin in the sedimentable fraction (Sed-Tub) was decreased, (ii) deformability was lower than in erythrocytes from normal subjects (N erythrocytes), and (iii) detyrosinated/acetylated tubulin content was higher in the Mem-Tub fraction and tyrosinated/acetylated tubulin content was higher in the Sed-Tub fraction, in comparison with N erythrocytes. Similar properties were observed for human N erythrocytes treated with high glucose concentrations, and for erythrocytes from rats with streptozotocin-induced diabetes. In N erythrocytes, high-glucose treatment caused translocation of tubulin from the Sed-Tub to Mem-Tub fraction, thereby reducing deformability and inducing acetylation/tyrosination in the Sed-Tub fraction. The increased tubulin acetylation in these cells resulted from inhibition of deacetylase enzymes. Increased tubulin acetylation and translocation of this acetylated tubulin to the Mem-Tub fraction were both correlated with reduced osmotic resistance. Our findings suggest that (i) high glucose concentrations promote tubulin acetylation and translocation of this tubulin to the membrane, and (ii) this tubulin is involved in regulation of erythrocyte deformability and osmotic fragility.

Acute and long-term effects of hyperbaric oxygen therapy on hemorheological parameters in patients with various disorders.

Inhalation of 100% oxygen in a hyperbaric chamber has been accepted as a useful treatment for patients with various pathologies who suffer from hypoxia. The oxidative effects of hyperbaric oxygen (HBO) on RBCs have been investigated in animals but there is not enough data on hemorheological parameters in patients following HBO treatment (HBOT).In this study, we investigated the effect of HBO on hemorheological and haematological parameters during treatment. Red blood cell (RBC) deformability and aggregation, blood and plasma viscosity and superoxide dismutase activity were investigated in patients who underwent HBOT. Hematological parameters were determined by an electronic hematology analyzer. A Laser-assisted Optical Rotational Cell Analyzer (LORCA) was used to measure RBC deformability. RBC aggregation was measured for cells in autologous plasma and for cells resuspended in PBS containing Dextran70 (3% ) by using a Myrenne Aggregometer. A Wells-Brookfield cone/plate rotational viscometer was used for viscosity measurements. According to our results, a significant decrement of the hematocrit and the RBC count was observed after the 20th session of HBOT compared to the baseline, but none of the hemorheological parameters changed significantly. Our results showed that HBOT did not cause any significant changes in hemorheological parameters, thereby not representing any problems for the patients.

Association between blood viscosity and common carotid artery elasticity.

Elastic properties of the vessel wall are associated with atherosclerosis and major cardiovascular events. Several physiological and pathological conditions can affect arterial elasticity, but few studies have considered the role of hemorheological parameters. The present study aimed to investigate the relationship between hemorheological parameters and vascular stiffness in the carotid artery district. One hundred and two individuals were enrolled. Blood and plasma viscosity were measured by a cone-plate viscometer (Wells-Brookfield DV-III, Stoughton, U.S.A.). Echo-Doppler evaluation of carotid arteries was performed in order to calculate elastic indexes (strain, β-stiffness index and distensibility). The association between hemorheological parameters and carotid elasticity indexes was assessed by simple and multiple regression analyses. In simple correlation analysis, only blood viscosity was directly associated with β-stiffness index (r = 0.20, p = 0.05) and inversely with strain (r =-0.26, p = 0.01) and distensibility (r =-0.34, p = 0.001). After adjusting for cardiovascular risk factors, blood viscosity, but not plasma viscosity or hematocrit, was independently associated carotid arterial measures, together with age, obesity, hypertension, and dyslipidemia. The results of the present study demonstrate a strong association between blood viscosity and common carotid elasticity indexes.

Acute carbon monoxide poisoning alters hemorheological parameters in human

Acute carbon monoxide (CO) poisoning seriously hinders oxygen delivery to tissues. This harmful effect of CO may be aggravated by accompanying changes in the viscosity of blood. We had previously reported increased plasma viscosity in people chronically exposed to CO. This study was planned to test our hypothesis that acute CO poisoning increases blood viscosity. For this purpose four main parameters contributing to blood viscosity - hematocrit, erythrocyte deformability, erythrocyte aggregation and plasma viscosity - were determined in patients with acute CO poisoning and compared with healthy controls. Plasma viscosity and erythrocyte aggregation tendency were lower in the CO group (p < 0.05). Erythrocyte deformability was also lower in CO group (p < 0.05). Our results indicate that acute CO poisoning has diverse effects on hemorheological parameters such as attenuating hematocrit value, plasma viscosity, erythrocyte aggregation tendency and erythrocyte deformability.

Unsolved Favorable Effect of Statin on Blood Viscosity.

Refer to the page 147-153 In an interesting study, Jung et al.1) found an effective reduction of whole blood viscosity in statin naive acute coronary syndrome (ACS) patients with early statin administration. In statin naive ACS patients they found an apparent decrease in whole blood viscosities at both of the two shear rates. The hypothesis that a lipid-lowering reagent, statin, contributes to blood viscosity decrease is very attractive and gave rise to immediate therapeutic possibilities. Jung et al.1) claimed that this was the first report on the potential effect of statin on blood viscosity reduction. Using a capillary scanning method,2) they compared diastolic blood viscosity (at a shear rate of 1 s-1) and systolic blood viscosity (at a shear rate of 300 s-1). Generally, blood viscosity at low shear rates is strongly affected by red blood cell (RBC) aggregation, whereas blood viscosity at high shear rates is influenced by RBC deformability and plasma viscosity. It is commonly accepted that whole blood viscosity is an overall indicator reflecting RBC aggregation, RBC deformability and plasma viscosity. If there is any change among three components, the whole blood viscosity would be altered. Thus, one can expect that there would be apparent alteration of above hemorheological parameters. Unfortunately, plasma viscosity was not measured in the present study, without plasma viscosity information, it is difficult to determine whether the reduction of blood viscosity was caused by a plasmatic factor or cellular factor. With careful reviewing the measured clinical data listed in Table 21) both aggregation index (AI) and half time (t1/2) showed no difference in Group II. AI represents the quantity of RBC aggregation, whereas half time does aggregation kinetics. In general, the high value of AI accompanies the small value of half time. Also, fibrinogen, which is the strongest factor in RBC aggregation, was not significantly changed between baseline and one month for Group II. For deformability, there was also no significant difference of EImax. However, half shear stress (SS1/2) was increased in Group II (from 2.08±0.14 to 2.25±0.28). The increase of half shear stress indicates a decrease of RBC deformability.2) This means that RBC deformability was decreased with statin administration. However, systolic blood viscosity was decreased with statin administration. Therefore, an explanation of the mismatch between viscosity change and RBC deformabilty change is unclear, and there was no hemorheological data to explain the reduction of blood viscosities at the two shear rates. In Table 21) white blood cell (WBC) count shows a significant correlation in Group II. In fact, there have been reports on a correlation between WBC count and whole blood viscosity.3),4),5) Steinberg and Charm3) examined blood viscosity with varying concentrations of WBCs. Furthermore, a WBC count was correlated with hypertension.6) Therefore, it is required to examine the role of statin on a WBC count in future study. In the study of Jung et al.,1) platelet count was provided but the degree of activation and deactivation were not known. Upon activation by agonists or shear stress in flow, platelets were released in excess of 300 active molecules from intracellular granules.7) These factors caused an increase in either the RBC aggregation8) or whole blood viscosity. Therefore, it is also required to investigate the correlation between blood viscosity and platelet-released molecules. Even though the results of Jung et al.1) could not easily be delineated with the provided clinical and hemorheological data, its potential is high and further investigation is strongly recommended.