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PubMed1985

[Evaluation of blood viscosity and erythrocyte filterability in chronic ischemic heart disease].

In 40 patients suffering from chronic ischemic heart disease (16 with history of myocardial infarction, 10 with unstable angina and 14 with stable angina) and in an equal number of sex-and age-matched control subjects, we have determined plasma and blood viscosity according to RAND et al. using a Wells-Brookfield Micro-Viscometer, shear rate 230 sec-1, and red cell filterability according to REID et al. Significant differences were found in patients suffering from ischemic heart disease, in comparison with the control group, for blood viscosity (p less than 0.01), plasma viscosity (p less than 0.001) and red cell filterability (p less than 0.001). The changes of hemorheological parameters in ischemic heart disease, especially in patients suffering from unstable angina and in those with history of myocardial infarction, point to the opportunity of a pharmacological treatment aiming at improving the district microcirculation.

Adult↗
PubMed1993

The effect of pentoxifylline on retinal capillary blood flow velocity and whole blood viscosity.

Ten normal, healthy, nonsmoking volunteers participated in a double-masked, placebo-controlled one-day trial of 2,000 mg of oral pentoxifylline to determine the short-term effects of orally administered pentoxifylline on retinal circulation and rheologic properties of whole blood. Retinal capillary blood velocity and leukocyte density, whole blood viscosity, and whole blood filterability were measured before and after therapy by the blue-field entoptic phenomenon computer simulation, rotational viscometry, and micropore filtration techniques, respectively. Treatment with pentoxifylline for one day resulted in a significant improvement in retinal capillary blood flow velocity (P = .02) and in viscosity (P < .01), but not filterability, of whole blood. These results suggest that pentoxifylline may be useful in the treatment of early diabetic retinopathy.

Administration, Oral↗
PubMed2004

Microviscometry reveals reduced blood viscosity and altered shear rate and shear stress profiles in microvessels after hemodilution.

We show that many salient hemodynamic flow properties, which have been difficult or impossible to assess in microvessels in vivo, can be estimated by using microviscometry and fluorescent microparticle image velocimetry in microvessels >20 microm in diameter. Radial distributions in blood viscosity, shear stress, and shear rate are obtained and used to predict axial pressure gradient, apparent viscosity, and endothelial-cell surface-layer thickness in vivo. Based solely on microparticle image velocimetry data, which are readily obtainable during the course of most intravital microscopy protocols from systemically injected particle tracers, we show that the microviscometric method consistently predicted a reduction in local and apparent blood viscosity after isovolemic hemodilution. Among its clinical applications, hemodilution is a procedure that is used to treat various pathologies that require reduction in peripheral vascular-flow resistance. Our results are directly relevant in this context because they suggest that the fractional decrease in systemic hematocrit is approximately 25-35% greater than the accompanying fractional decrease in microvascular-flow resistance in vivo. In terms of its fundamental usefulness, the microviscometric method provides a comprehensive quantitative analysis of microvascular hemodynamics that has applications in broad areas of medicine and physiology and is particularly relevant to quantitative studies of angiogenesis, tumor growth, leukocyte adhesion, vascular-flow resistance, tissue perfusion, and endothelial-cell mechanotransduction.

Blood Flow Velocity↗
PubMedDate not supplied

Effects of prolonged oxygen therapy on pulmonary hypertension and blood viscosity in patients with advanced cor pulmonale.

In 16 patients with chronic bronchitis and advanced cor pulmonale admitted to hospital due to heart failure, a controlled 6-weeks oxygen therapy, 17 h a day, was performed. The trial was started when patients were out of the exacerbation of the disease in a respiratory and circulatory steady state. Pulmonary hemodynamics, blood viscosity, packed cell volume and basic lung function data before and after oxygen therapy were compared. A significant fall of mean pulmonary arterial pressure from 42 to 30 mm Hg without a change in the cardiac output was found. Blood viscosity and packed cell volume-significantly decreased. Arterial oxygen tension did not significantly change. It seems that 17-hours per day oxygen therapy is sufficient to induce regression of anatomic changes in pulmonary arteries, a main cause of pulmonary hypertension in hypoxic cor pulmonale.

Adult↗
PubMed1987

Effect of linoleic and oleic acids on blood pressure, blood viscosity, and erythrocyte cation transport.

It has been proposed that dietary linoleic acid lowers blood pressure (BP) by being converted to arachidonic acid and prostanoids of the two-ene series. We tested the effects of linoleic acid on plasma arachidonic acid, blood pressure, blood viscosity, and RBC cation transport. Oleic acid, the major dietary monounsaturated fat and which is not a prostanoid precursor, was used as a control. Seventeen adults consumed 23 g/d of linoleic acid or oleic acid provided by genetic variants of safflower seed, each for 4 weeks in a double-blind crossover design. Linoleic and oleic acids were enriched significantly in the plasma cholesteryl esters, phospholipids and triglycerides during the respective periods of supplementation but there was no increase in arachidonate. Mean BP was 116.1/76.8 during ingestion of oleic and 113.6/74.6 during ingestion of linoleic acid (p = 0.09 systolic, p = 0.12 diastolic). The power of the study was over 75% for detecting a significant (p less than 0.05) effect of 4 mm Hg in systolic BP or diastolic BP. Whole blood and plasma viscosity, and RBC Li/Na countertransport, Na/K cotransport, and Na pump systems (Vmax) were unchanged during the protocol. Therefore, variations in dietary linoleic or oleic acids are unlikely to have major effects on BP or on several membrane-dependent erythrocyte functions related to hypertension.

Adult↗
PubMed1992

Sulodexide oral administration influences blood viscosity and fibrinolysis.

The aim of this study was to verify the effects of oral administration of a new enteric-coated formulation of sulodexide on blood viscosity and fibrinolysis. Six outpatients suffering from peripheral artery occlusive disease were administered orally two enteric-coated tablets containing 50 mg of sulodexide, twice daily for seven days. On the first and seventh administration days, the following parameters were evaluated: plasminogen activator inhibitor (PAI-1) activity, PAI-1 antigen, tissue plasminogen activator (t-PA) and whole blood, serum and plasma viscosity, before (0 time) and 2, 4 and 8 hours after ingestion of the drug. Following the first administration (50 mg), a slight reduction of PAI was registered; after 7 days' administration, a clear-cut lowering of functional and antigenic PAI was observed, together with an increase of t-PA. As to the drug's influence on blood viscosity, after 7 days the most evident reduction was that registered for plasma viscosity. No side effects were observed throughout the treatment period.

Aged↗
PubMed1997

[Effect of jiangtangkang on blood glucose, sensitivity of insulin and blood viscosity in non-insulin dependent diabetes mellitus].

OBJECTIVE: To study the hypoglycemic effect of Jiangtangkang (JTK), a Chrysanthemum product and its influence on sensitivity of insulin in non-insulin dependant diabetes mellitus (NIDDM). METHODS: Newly discovered (71 cases) and poorly controlled (117 cases) NIDDM were divided to JTK, 8 g each time, 3 times per day, and the control (Glibenclazide in newly discovered, no treatment in poorly controlled) group respectively. RESULTS: After 2 months of treatment, the fasting blood glucose (FBG), postprandial blood glucose (PBG), glucosylated hemoglobin (GHb) improved remarkably and insulin of plasma remained unchanged in JTK group, their blood viscosity and triglyceride decreased after 6-month reatment, the FBG, PBG lowered in the control group while their viscosity and lipids were unaffected. Insulin tolerance test on newly discovered NIDDMs showed an increased sensitivity to insulin, their serum chromium elevated, and the urinary albumin in poorly controlled persons lowered significantly. CONCLUSIONS: JTK might improve the sensitivity to insulin and decrease the blood viscosity in NIDDM.

Adult↗
PubMed1999

[Rheologic modifications induced by heparin therapy. Capillary blood viscosity, erythrocyte deformability, aggregation index].

BACKGROUND: The most important problem with which doctors have to deal every day in their practice, is occlusive vascular disease, at the basis of which there is commonly a process of thrombosis. For this reason, it is very important to define early the subjects at thrombosis risk and an appropriate therapeutic strategy. METHODS: We considered 13 inpatients at thrombosis risk, c/o sezione di Clinica Medica I, dipartimento di Medicina Interna e Terapia Medica, Università di Pavia, IRCCS Policlinico S. Matteo, and 12 healthy volunteers, between March and June 1998, evaluating age, sex, weight, diseases and ongoing therapy, hemocytological, hemocoagulational and hemorheological tests before and after heparinic therapy. RESULTS: General blood viscosity, measured by the rotational and double-filtration method, presented no significant changes; on the contrary, capillary blood viscosity and erythrocyte deformability, measured by our new double-filtration method, showed respectively an increase and a decrease. CONCLUSIONS: Calcium heparin is the most frequently used antithrombotic drug in thrombotic diseases and their prevention, but its action on the hemorheological profile is not clear. This study showed that it increases erythrocyte aggregation rate and decreases erythrocyte deformability, having a negative effect on the microcirculation.

Anticoagulants↗
PubMed1980

The effect of improvement in diabetic control on plasma and whole blood viscosity.

Rheological studies were made on the blood of 12 diabetic patients after a period of poor diabetic control (HbA1 12.6 +/- 0.7% (mean +/- SD); mean home capillary blood glucose level 11.7 +/- 1.2 mmol/l), and after at least three months of improved control (HbA1 9.1 +/- 0.4%, p < 0.01; mean home capillary blood glucose level 9.2 +/- 0.6 mmol/l). There were significant decreases in plasma fibrinogen levels (4.1 +/- 0.6 to 3.7 +/- 0.6 g/l, p < 0.01), plasma viscosity (1.31 +/- 0.1 to 1.25 +/- 0.04, p < 0.001), and whole blood viscosity at low (22.8 +/- 2.7 to 20.2 +/- 2.9, p < 0.01) and high shear rates (3.4 +/- 0.2 to 3.1 +/- 0.2, p < 0.01). Ten diabetics with clinically evident complications were matched with diabetics of similar age, sex, duration and current control of diabetes. There were no significant differences in plasma or whole blood viscosities between the two groups. Hyperviscosity in diabetes seems strongly related to hyperglycaemia and to be influenced by the quality of diabetic control.

Adolescent↗
PubMed1976

Abnormal blood viscosity in Raynaud's phenomenon.

The exact cause of Raynaud's phenomenon is still unknown. Since the principal feature of this condition is the precipitation of the attacks by cold, blood viscosity was measured in ten patients and in ten normal controls at 27 degrees C and 37 degrees C. The viscosity of the patients' blood was significantly higher (p less than 0.05) at 27 degrees C than that of the controls when measured at a low shear-rate (0.77 s-1). This, as well as the higher yield stress of the patients' blood, suggests that Raynaud's phenomenon may be caused by an abnormal local increase in the viscosity and yield stress of the blood in response to a fall in temperature.

Adolescent↗
PubMed2002

Lower plasma noradrenaline and blood viscosity on carvedilol vs atenolol in men with recent myocardial infarction.

The Carvedilol Acute Myocardial Infarction Study (CAMIS) investigates cardiac remodeling in patients (n = 250) randomized to carvedilol vs atenolol and treated for 12 months after acute myocardial infarction. In a sub-study, we compared sympathetic, hemorrheological and vascular effects in small but particularly well-matched groups of participants who had been on reasonably equipotent but unchanged doses of carvedilol (n = 10) or atenolol (n = 10) for at least 4 weeks. Blood pressures (p < 0.05), plasma adrenaline (p = 0.034), plasma vasopressin (p = 0.022) and whole blood viscosity at shear rate 0.5 cp (p = 0.050), 1.1 cp (p = 0.023), 5.8 cp (p = 0.049) and 201 cp (p = 0.060) taken in the laboratory at baseline before 2 h of using the hyperinsulinemic, isoglycemic glucose clamp were lower on carvedilol. Plasma noradrenaline was lower on carvedilol at baseline and throughout the clamp (p < 0.0005). Forearm vascular resistance as measured by plethysmography during the clamp tended to be lower on carvedilol (p = 0.074). No significant difference was found between the groups in glucose disposal rate measured by clamp, maximal forearm blood flow and minimal forearm vascular resistance after 10 min of ischemia, or in ambulatory blood pressure and heart rate taken a few days later. Thus, potential benefits of carvedilol vs atenolol were seen in these post-infarction patients in a laboratory setting. These findings suggest that the inhibitory effects on the sympathetic nervous system and related blood viscosity are stronger with carvedilol than with atenolol.

Adrenergic alpha-Antagonists↗
PubMed1980

Effect of hematocrit on the blood viscosity of patients with chronic respiratory failure and secondary polycythemia.

The blood of patients with chronic global respiratory failure and polycythemia exhibits higher viscosity than that of normal subjects. Plasma changes have been excluded as causal factors. The viscosity of whole blood, plasma and blood after correction of hematocrit (Ht; 45%) with autologous plasma, has been determined. The results indicate that in such patients the increase in Ht is not the most important factor affecting the rheological properties (increased viscosity) of blood. A high Ht value may be only pat of the mechanism that increases the blood viscosity of patients with chronic obstructive pulmonary disease. There is evidence that other factors are responsible for increased blood viscosity in chronic respiratory failure.

Blood Viscosity↗
PubMed1991

Effect of sulodexide on blood viscosity in patients with peripheral vascular disease.

Thirty patients with Stage II peripheral vascular disease were treated with sulodexide, a new, medium molecular weight glycosaminoglycan, and placebo using a double-blind, crossover study design. After a 1-month wash-out period, patients were treated for 1 month with one or other trial medication and then crossed over to the alternative preparation for a further month. Measurements were made at baseline and at the end of each treatment period of serum, plasma and whole blood viscosities (at various shear rates), fibrinogen levels and red cell filterability. Tolerance parameters were also assessed at the same times. The results showed that there were statistically significant reductions in plasma and whole blood viscosity and in fibrinogen levels after sulodexide, but not after placebo. Neither treatment had any marked effect on red blood cell filterability. Local and systemic tolerance of the treatment was excellent, and some patients reported an improvement in symptoms whilst they were taking sulodexide; this, however, could not be quantified in this study. It is suggested that the viscosity and fibrinogen reducing effect of sulodexide make it a useful form of treatment in patients with atheromatous vascular diseases of the lower limbs.

Adult↗
PubMed2000

Pharmacological concentrations of arginine influence human whole blood viscosity independent of nitric oxide synthase activity in vitro.

l-Arginine, the natural precursor of NO, is infused in patients to restore endothelial function. Concentrations up to 7.5 mM l-arginine have been measured after parenteral administration. We investigated whether such high concentrations of amino acids influence blood viscosity in vitro. Incubation of whole blood from healthy volunteers with l-arginine, d-arginine, which has no effect on stereospecific NO synthases (NOS), the NOS substrate L-AME, the NOS inhibitor L-NNA, the amino acids l-lysine and l-glutamic acid, and finally NaCl dose-dependently decreased (up to 30% at 10(-2) M) low shear viscosity, which is primarily determined by erythrocyte aggregation. In contrast, the lipophilic NOS inhibitor L-NAME had no effect on low shear viscosity. All molecules failed to influence high shear viscosity, which is primarily determined by red cell deformability, and the erythrocyte shape remained unaltered. We conclude that high concentrations amino acids may decrease blood viscosity at low shear rate independent of NOS activity. This effect may contribute to the improved blood flow after intravascular administration of l-arginine.

Adult↗
PubMed1993

[Effects of oxyfedrine on high blood viscosity and myocardial necrosis induced by epinephrine and ice water stress in rats].

Acute high blood viscosity (HBV) and myocardial necrosis was established by epinephrine (Epi) and ice water stress in rats. Effects of iv oxyfedrine (Oxy) on HBV, plasma viscosity (PV), hematocrit, erythrocyte electrophoretic time (EET), and fibrinogenic viscosity (FV) were studied in model. Results showed that Oxy 1 mg.kg-1 iv markedly decreased the arterial and venous blood HBV at shear rates of 700 s-1 and 70 s-1, respectively (P < 0.01). There were significant differences in the alleviation of HBV among 3 groups (Oxy 0.01, 0.1, and 1 mg.kg-1 iv). The above doses markedly decreased the HBV, PV, and FV, and shortened the EET. Effects of iv Oxy on the myocardial necrosis rat model were scrutinized under the light and electron microscopes. Oxy iv 1 mg.kg-1.d-1 x 1, 3, and 5 d prevented or mitigated the occurrence and development of myocardial necrosis. The structure of heart mitochondria and myofibrils were clearly discernible. This action may be related to the alleviation of HBV by Oxy.

Animals↗
PubMed1987

Blood viscosity in primary open-angle glaucoma.

To determine whether hemorrheologic factors play a part in optic nerve cupping and visual field loss in glaucoma, blood viscosity was measured at three shear rates in 27 patients with primary open-angle glaucoma and 18 healthy control subjects matched for sex, mean arterial blood pressure and smoking habits. The study was conducted between 1984 and 1986. The mean viscosity was significantly higher in the glaucoma group than in the control group at all three shear rates. The possible relevance of raised blood viscosity as a causal factor in optic nerve cupping in patients with glaucoma is discussed.

Aged↗