| 1. |
- Gustavsson, Carl Gunnar, et al.
(författare)
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Blood viscosity in relation to blood haemoglobin concentration in healthy subjects and in patients with different cardiovascular diseases
- 1994
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Ingår i: Clinical Hemorheology. - New York, USA : Pergamon Press. - 0271-5198. ; 14:5, s. 677-683
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Blood viscosity was measured at different shear rates using a rotational viscometer, and the correlation between blood viscosity and blood haemoglobin concentration was studied. In 10 healthy controls correlation coefficients were: 0,966 at shear rate 40,0 s-1, 0,931 at 19,6 s-l, 0,817 at 2,3 s-1 and 0,816 at 0,8 s-l , p<0,01 to p < 0,001. The regression lines for these relationships were then applied to the patient groups to calculate what blood viscosity should be predicted solely from the individual haemoglobin concentration, "predicted blood viscosity". In 34 patients with cardiovascular diseases (20 patients with coronary artery disease (CAD), 8 patients with idiopathic dilated cardiomyopathy and 6 patients with primary pulmonary hypertension) the correlation between blood viscosity and haemoglobin concentration was less good, for the total patient material 0,748 to 0,613, p < 0,001 at all shear rates, and for the CAD patients 0,664 to 0,428, p < 0,05 at 3 out of 4 shear rates. Apparently the poorer correlation in the patients was due to a larger influence from factors unrelated to haemoglobin concentration/haematocrit, as the quotients between individually measured and predicted blood viscosity correlated with measured blood viscosity when the haematocrit factor had been eliminated by in vitro standardisation of sample haematocrits to 45%. Key words: Blood viscosity; Haemorheology; Haemoglobin concentration; Microcirculation.
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| 2. |
- Gustavsson, Carl Gunnar, et al.
(författare)
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Changed blood rheology in patients with idiopathic dilated cardiomyopathy
- 1994
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Ingår i: Angiology. - New York, USA : Westminster Publications, Inc.. - 0003-3197 .- 1940-1574. ; 45:2, s. 107-111
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Rheologic properties of blood were studied in 8 patients with dilated cardiomyopathy (DCM) and in 10 healthy subjects. Whole-blood viscosity was measured at four different shear rates, by means of a computer-controlled rotational viscometer. The patients had significantly higher blood viscosity at all shear rates, both at their natural hematocrits and after an in vitro adjustment of sample hematocrits to 45%. Erythrocyte filterability (5 μm pore size) was significantly lower, fibrinogen concentration significantly higher, and HDLcholesterol concentration significantly lower in the patient group. No significant differences were found regarding hematocrit, mean corpuscular volume, haemoglobin concentration, leukocyte count and filterability (8 μm pore size), plasma viscosity, and total cholesterol concentration. The measured hemorheologic abnormalities may contribute to the previously reported reduction of coronary blood flow reserve in DCM patients and to myocardial microcirculatory disturbances, which have been suggested as a cause for DCM.
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| 3. |
- Persson, Sylvi, et al.
(författare)
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Increased blood viscosity and decreased red cell filterability in patients with dilated cardiomyopathy
- 1991
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Ingår i: 7th European Conference on Clinical Haemorheology, Southampton, United Kingdom, July 16-19, 1991..
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Konferensbidrag (refereegranskat)abstract
- Abstract Rheological properties o f blood were studied in eight patients with dilated cardiomyopathy (DCM) and ten healthy controls . Whole blood viscosity was measured at 4 different shear rates, using a computer controlled rotational viscometer. Patients had significantly higher blood viscosity at all shear rates, both at the patients natural hematocrits and after in vitro adjustment of sample hematocrits to 45%. Erythrocyte filterability measured by St George's Filtrometer and expressed as red cell transit time (RCTT) were significantly lower in patients. Hematocrits were higher but not statistically significant. No differences were found regarding plasma viscosity, leucocyte count and leucocyte filterability. The blood rheology changes found in this study may contribute to myocardial perfusion disturbances, which have been suggested a s a cause for DCM. The coronary blood flow reserve is reduced in patients with DCM as well as in patients with angina pectoris, both with and without coronary artery stenosis (Syndrome X). In all three patients cathegories we have found increased blood viscosity but DCM differs by by normal plasma viscosity.
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| 4. |
- Persson, Sylvi, et al.
(författare)
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Studies on blood rheology in patients with primary pulmonary hypertension
- 1990
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Ingår i: 32nd Annual Meeting of the International College of Angiology, Toronto, Canada, June 24-29, 1990.
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Konferensbidrag (refereegranskat)abstract
- Abstract Background: Disturbances of blood rheology may create unfavorable changes of blood flow. The present study was performed to reveal possible hemorheologic abnormalities in primary pulmonary hypertension. Methods: Six patients with primary pulmonary hypertension (PPH) and 10 healthy controls of comparable age and smoking habits were studied. Blood viscosity was studied with a computer-controlled rotational viscometer, at natural hematocrit and at standardized hematocrit (45%). A capillary U-tube was used for plasma viscosity studies. Blood cell filterability was measured by theSt. George's Filtrometer (according to Dormandy et a1). Nucleopore filters of 5 (erythrocytes) and 8 (leukocytes) micrometers were used. Results: Whole blood viscosity in PPH patients was higher than in controls at four different shear rates (p<0.025-0.005). This was partly due to a higher concentration of red cells in the patients. After standardization to 45% however, the difference was still there at the highest shear rate used (40 s-1). It was also found that the passage time for erythrocytes through the filter was increased in the patient group, indicating decreased erythrocyte deformability. There were no significant differences between the groups in plasma viscosity, plasma fibrinogen, concentration of leukocytes, or leukocyte deformability. Conclusions: Patients with PPH show increased whole blood viscosity values. This is partly explained by an increased hematocrit. It is also found, however, that the deformability of erythrocytes in these patients is decreased. These changes may influence blood flow in an unfavorable way. Therapeutic measures against hemorheologic disturbances may be a possible complement to the commonly used vasodilatory treatment.
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| 5. |
- Persson, Sylvi Ulrika, et al.
(författare)
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Studies on blood rheology in patients with primary pulmonary hypertension
- 1991
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Ingår i: Angiology. - New York, USA : Westminster Publications, Inc.. - 0003-3197 .- 1940-1574. ; 42:10, s. 836-842
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Tidskriftsartikel (refereegranskat)abstract
- Abstract The rheologic properties of blood were studied in 6 patients with primary pulmonary hypertension (PPH) and compared with those of a control group of 10 healthy subjects. Blood viscosity was studied with a rotational viscometer and blood cell deformability with a filtrometer giving values for clogging particles (CP) and red cell transit time (RCTT). Blood viscosity at varying shear rates was found to be increased both at natural (p<0.025-0.005) and standardized hematocrit, 45% (p<0.05 at 40 s-1) in patients with PPH. Red cell deformability was reduced as indicated by a significant increase of RCTT (p<0.01). Increased values for hematocrit (p<0.001), hemoglobin concentration (p< 0.001), and erythrocyte count (p<0.005) were found and decreased values for mean corpuscular hemoglobin concentration (MCHC) (p< 0.025) and HDL cholesterol (p<0.005). Plasma viscosity, white cell deformability, white cell count, mean corpuscular volume (MCV), and plasma fibrinogen concentration did not significantly differ from the values found in the control group. It is concluded that patients with PPH have impaired blood rheology. The hemorheologic abnormalities in these patients may be of hemodynamic significance.
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