Relation of blood viscosity to demographic and physiologic variables and to cardiovascular risk factors in apparently normal adults.

Abstract

Although increased blood viscosity occurs in several cardiovascular diseases, little is known of factors influencing blood rheology in normal adults. Accordingly, we examined the relations of whole blood viscosity (WBV) to its rheologic determinants (hematocrit level, plasma viscosity, protein concentration, and red cell aggregability and rigidity), to demographic and laboratory variables, and to cardiovascular risk factors in 128 normotensive employed adults. Hematocrit levels accounted for 67-84% of variability of WBV at shear rates from 208 to 0.1 sec`with lesser contributions from plasma viscosity, red cell aggregability, and rigidity (multiple r=0.95-0.97); WBV was predicted accurately from standard measurements of hematocrit and total plasma protein levels (multiple r=0.78-0.92 in "learning" and "test" analysis). Male sex, obesity, dietary Na+ intake, and increasing age had additive effects on WBV (multiple r.0.59, p<0.00001); the last three of these factors and black race independently predicted plasma viscosity (multiple r=0.36, p<0.001). Among regulators of plasma volume, plasma renin activity and urinary Na+ excretion bore independent positive relations to WBV. Diastolic and mean blood pressures were independent predictors of WBV and hematocrit levels (all p <0.05). Conventional risk factors (e.g., triglycerides, obesity, and cholesterol levels) were positively related to WBV or plasma viscosity. Thus, in apparently normal adults, 1) WBV or plasma viscosity are increased by male sex, obesity, high sodium intake, aging, and black race, 2) WBV is positively related to plasma renin activity, 3) WBV or plasma viscosity are related to diastolic and mean blood pressures, triglycerides and cholesterol concentrations, and 4) WBV can be predicted from simple measurements of hematocrit and total plasma protein levels. (Circulation 1990;81:107-117) Changes in whole blood viscosity (WBV) have been reported in several human cardiovascular diseases,'-22 indicating that blood viscosity may be a major cardiovascular risk factor. A positive relation between blood pressure and blood viscosity or All editorial decisions for this article, including selection of reviewers and the final decision, were made by a guest editor. This procedure applies to all manuscripts with authors from the

The role of rheological and haemostatic factors in hypertension

“…One study indicated that, compared to a control with diastolic BP (DBP) than with systolic BP (SBP). [27][28][29][30]32 This is consistent with the contribution group of 24 subjects, 45 patients with mild hypertension had similar haematocrit, red blood cell mass of the haematocrit, and hence blood viscosity, to peripheral vascular resistance, which is a determiand plasma volume levels. In contrast, 43 other subjects with moderate to severe hypertension had a nant of DBP.…”

“…Table 2 shows that significant correlations number of subjects. In contrast, one recent paper by Vayá et al 18 noted no difference in haematocrit level between BP and haematocrit have been reported in a range of population studies, [26][27][28][29][30][31][32][33] although this does when comparing a group of 21 hypertensives with a group of controls, which agreed with some earlier not seem to be true among hypertensive patients, 34 possibly due to the effects of treatment and/or renal reports. 11, 20 An increased haematocrit among hypertensives could be due to either an increase in red impairment.…”

The anti‐oestrogen tamoxifen produces haemodilution in normal postmenopausal women

“…This effect is likely to be, in part, attributable to favourable effects on serum lipids and haemostatic factors [3,5,13]. Haematocrit, which is an independent risk factor for vascular disease [14][15][16][17] perhaps by influencing blood viscosity [18] and erythrocyte-mediated platelet adhesion [19], has not been assessed in previous studies of the response of cardiovascular risk factors to tamoxifen. Our data demonstrate that tamoxifen prevents the age-related increase in haematocrit which occurs in postmenopausal women [17], and which was observed in the placebotreated women in the current study.…”

Increased Blood Viscosity in Ischemic Stroke Patients with Small Artery Occlusion Measured by an Electromagnetic Spinning Sphere Viscometer

“…[8][9][10] Furthermore, relationships have been reported between blood viscosity and some cardiovascular risk factors, such as hypertension, dyslipidemia, smoking, and obesity. [11][12][13][14] An increase in blood viscosity has been identified in the acute phase of ischemic stroke, similar to other thrombotic diseases. [15][16][17][18][19] However, actual 4 measurements of blood viscosity have not been performed because of the stereotypical belief that blood viscosity increases equally in all ischemic stroke subtypes, which is within expectations and with less clinical value.…”