| 1. |
- Baskurt, Oguz, et al.
(author)
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New guidelines for hemorheological laboratory techniques
- 2009
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In: Clinical hemorheology and microcirculation. - 1386-0291 .- 1875-8622. ; 42:2, s. 75-97
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Journal article (peer-reviewed)abstract
- This document, supported by both the International Society for Clinical Hemorheology and the European Society for Clinical Hemorheology and Microcirculation, proposes new guidelines for hemorheological methods used in experimental and clinical studies. It is based on a similar document entitled: "Guidelines for measurement of blood viscosity and erythrocyte deformability" published in 1986 by the Expert Panel on Blood Rheology of the International Committee for Standardization in Hematology. Recent methods techniques and instruments, as well as new approaches to interpretation of results, are added to these new guidelines; wide spread adoption should improve comparability between hemorheological laboratories and increase the reliability of rheological tests.
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| 2. |
- Fredly, Siv, et al.
(author)
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Skin microcirculation in healthy term newborn infants - assessment of morphology, perfusion and oxygenation
- 2015
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In: Clinical hemorheology and microcirculation. - : IOS Press. - 1386-0291 .- 1875-8622. ; 59:4, s. 309-322
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Journal article (peer-reviewed)abstract
- Despite microcirculations fundamental role, assessments of its function are limited. We explored the applicability of Computer Assisted Video Microscope (CAVM), Laser Doppler Perfusion Measurements (LDPM) and Diffuse Reflectance Spectroscopy (DRS) to study skin microvascular morphology, perfusion and oxygen saturation in twenty-five healthy newborns day 1-3 of life. Results: Day 1-3 (mean (SD)): Microvascular density (CAVM; number of microvessels crossing a grid of lines/mm line, c/mm): Chest: 11.3 (1.5), 11.0 (1.7), 10.7 (1.6). Hand: 13.2 (2.0), 13.2 (1.9), 12.4 (1.6). Capillary density was significantly higher in the hand than in the chest each day (p less than 0.001). Perfusion (LDPM; arbitrary units): Chest: 109.1 (26.0), 101.4 (24.6), 100.8 (25.3). Hand: 58.9 (17.5), 54.3 (15.8), 46.9 (14.8). Perfusion was significantly higher in the chest than in the hand each day (p less than 0.01). Microvascular oxygen saturation (DRS; %): Chest: 88.1 (5.2), 87.8 (10.0), 86.7 (9.0). Hand: 79.9 (15.2), 82.7 (11.8), 82.2 (12.1) (p less than 0.05). Capillary flow velocities (CAVM) were similar in the chest and hand: 60-70% capillaries had "continuous high flow" and 30-40% "continuous low flow". Multimodal skin microvascular assessments with CAVM, LDPM and DRS are feasible with reproducible data in newborns. The hand has lower perfusion, higher capillary density and higher oxygen extraction than the chest.
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| 3. |
- Hadimeri, Ursula, et al.
(author)
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A single treatment, using Far Infrared light improves blood flow conditions in arteriovenous fistula
- 2017
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In: Clinical hemorheology and microcirculation. - : IOS Press. - 1386-0291 .- 1875-8622. ; 66:3, s. 211-217
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Journal article (peer-reviewed)abstract
- BACKGROUND: A native arteriovenous fistula (AVF) is recommended for angio access in patients on chronic hemodialysis (HD). Fistula patency has been improved by exposure to Far Infrared light (FIR).OBJECTIVE: To investigate whether a single FIR treatment could alter blood velocity, AVF diameter or inflammatory markers. METHODS: Thirty patients with a native AVF in the forearm were included. Each patient was his/her own control. Ultrasound (US) examinations were performed before and after a single FIR treatment.RESULTS: A single FIR treatment resulted in a significant increase in blood velocity over the AV fistula from a mean of 2.1 +/- 1.0 m/s to 2.3 +/- 1.0 m/s (p = 0.02). The diameter of the arterialized vein became wider; 0,72 cm +/- 0.02 to 0,80 cm +/- 0.02, (p = 0.006). The increase in fistula blood velocity correlated positively with base line serum-urate p = 0.004) and the increase in venous diameter with the base line plasma orosomucoid concentration (p = 0.005).CONCLUSIONS: This study shows that a single FIR treatment significantly increased AVF blood velocity and vein diameter. Thus, one FIR treatment can help maturation of AVF in the early postoperative course.
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| 4. |
- Hahn, Robert G., et al.
(author)
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Biomarkers of endothelial injury in plasma are dependent on kidney function
- 2019
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In: Clinical hemorheology and microcirculation. - : IOS PRESS. - 1386-0291 .- 1875-8622. ; 72:2, s. 161-168
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Journal article (peer-reviewed)abstract
- BACKGROUND: Injury (shedding) of the endothelial glycocalyx layer, which alters local blood flow and microvascular permeability, is assessed by measuring components of this layer in circulating blood. The influence of renal function on their concentrations is unknown. METHODS: Plasma and urine concentrations of three shedding products (syndecan-1, hyaluronic acid, and heparan sulfate) and creatinine were measured over 5 hours in 15 healthy volunteers and 15 postoperative patients; this guaranteed a spread of kidney functions. Renal clearances were calculated. RESULTS: Low renal clearances of syndecan-1 (mean 3.5 mL/min) and hyaluronic acid (0.8 mL/min) correlated inversely with the 6-fold variability in the plasma concentrations of these substances (r = -0 . 45 and-0.49). Low creatinine clearance correlated inversely (r = -0.60) and plasma creatinine directly (r = 0.52) with the two-fold variability in heparan sulfate, which was the only shedding substance that also correlated with C-reactive protein (r= 0.51) and, therefore, showed higher concentrations after surgery. CONCLUSIONS: The present explorative study suggests that a 6-fold variability in the plasma concentrations of three commonly measured endothelial shedding products can be understood by the kidneys ability to excrete them. This finding has implications when interpreting results of studies where shedding is assessed.
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| 5. |
- Lind, Lars, et al.
(author)
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Shear stress in the common carotid artery is related to both intima-media thickness and echogenecity : the prospective investigation of the vasculature in Uppsala seniors study
- 2009
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In: Clinical hemorheology and microcirculation. - 1386-0291 .- 1875-8622. ; 43:4, s. 299-308
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Journal article (peer-reviewed)abstract
- It has previously been shown that the degree of shear stress (SS) in the carotid artery is related to both plaque occurrence and intima-media thickness (IMT). Since the echogenecity also is an important feature of plaques, we investigated if a reduced shear stress also is related to the echolucency of plaque and the intima-media complex. In the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS) study, a population-based study of 1016 subjects aged 70, left common carotid artery diameter, IMT, the grey scale median (GSM) of the intima-media complex (IM-GSM) and the blood flow velocity were measured by ultrasound. Occurrence of plaque was noted, and the echogenecity of the plaques was visually estimated by the Gray-Weale classification. Shear stress was inversely related to both IMT and IM-GSM (p=0.0084 and p=0.003, respectively), independently of gender and coronary risk, estimated by the Framingham risk score. Shear stress was lower in subjects with carotid plaque (44% of the sample) than in those without (p=0.0013), and was inversely related to the echogenecity in the subjects with plaque (p=0.0092), independently of gender and coronary risk. A low shear stress in the common carotid artery was associated with both a thick IMT and an echolucent intima-media complex. A similar picture was seen when overt plaques were evaluated, suggesting that shear stress is of importance for both the extent and composition of atherosclerosis.
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| 6. |
- Sallisalmi, Marko, et al.
(author)
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Plasma hyaluronan and hemorheology in patients with septic shock : a clinical and experimental study
- 2014
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In: Clinical hemorheology and microcirculation. - 1386-0291 .- 1875-8622. ; 56:2, s. 133-144
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Journal article (peer-reviewed)abstract
- BACKGROUNDTotal plasma hyaluronan concentration is increased in septic shock. High-molecular-weight hyaluronan has a high intrinsic viscosity. Excessive release of high-molecular-weight hyaluronan in sepsis may induce hyperviscosity.METHODSPlasma viscosity and the molecular size of plasma hyaluronan were determined in 20 patients with septic shock and in 20 healthy controls. Ex vivo, the effects of 0.4% and 0.047% high-molecular-weight hyaluronan 1560 kDa, 0.9% saline, and 6% hydroxy-ethyl-starch 130 kDa were compared to plasma and whole blood viscosity and red blood cell aggregation at a systemic hematocrit of 0.4, and at a microcirculatory hematocrit of 0.2.RESULTSPlasma viscosity and total plasma protein content were low in septic shock patients on days one and four of treatment. Hyaluronan concentration was 10-fold higher in sepsis on day 1. Molecular weight of hyaluronan was relatively low, mostly 50-500 kDa, and did not change significantly in sepsis. Ex vivo, 0.4% high-molecular-weight hyaluronan 1560 kDa increased blood viscosity but did not promote red blood cell aggregation. Dilutions of 6% hydroxyl-ethyl-starch 130 kDa and 0.047% high-molecular-weight hyaluronan 1560 kDa had comparable effects on blood viscosity and red blood cell aggregation.CONCLUSIONSPlasma viscosity of the septic patients remained low for four days despite markedly elevated concentration of relatively small-molecular-weight hyaluronan.
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| 7. |
- Sandhagen, Bo, et al.
(author)
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Whole blood viscosity and erythrocyte deformability are related to endothelium-dependent vasodilation and coronary risk in the elderly : The Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study
- 2012
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In: Clinical hemorheology and microcirculation. - 1386-0291 .- 1875-8622. ; 50:4, s. 301-311
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Journal article (peer-reviewed)abstract
- It has previously been shown that a high hemoglobin value, a major determinant of whole blood viscosity (WBV), predicts cardiovascular events. One putative mechanism might be an impaired endothelial function. Erythrocyte deformability is another rheologic feature of the erythrocyte being of importance for the flow properties of the blood, especially in the capillaries. The present study evaluates the relationships between blood viscosity, erythrocyte deformability assessed as erythrocyte fluidity (EF), coronary risk and endothelial vasodilatory function. In the population-based PIVUS study (1016 subjects aged 70); endothelium-dependent vasodilation (EDV) was evaluated by the invasive forearm technique with acetylcholine given in the brachial artery and the brachial artery ultrasound technique with measurement of flow-mediated dilatation (FMD). WBV, plasma viscosity (PV) and EF were measured in a random sample of 573 subjects. WBV and PV were positively and EF negatively related to Framingham risk score. EDV was inversely related to both whole blood and plasma viscosity. FMD was not related to any rheologic variable. In multiple regression analyses WBV and EF were significantly related to EDV independently of gender, hypertension, smoking, hypercholesterolemia, obesity and diabetes. Acetylcholine-induced vasodilation in the forearm, but not FMD, was negatively related to whole blood viscosity and positively related to EF independently of traditional risk factors in elderly subjects, indicating a pathophysiological link between impaired hemorheology and coronary risk.
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| 8. |
- Wester, Torjus, et al.
(author)
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Skin microvascular morphology and hemodynamics during treatment with veno-arterial extra-corporeal membrane oxygenation
- 2014
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In: Clinical hemorheology and microcirculation. - : IOS Press. - 1386-0291 .- 1875-8622. ; 56:2, s. 119-131
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Journal article (peer-reviewed)abstract
- Objectives: To explore the potentials of microcirculatory assessments for predicting outcome of patients treated with extra corporeal membrane oxygenation for cardiogenic shock. Methods: Eight patients with acute cardiogenic shock treated with ECMO and eight healthy controls were examined with skin vital microscopy and laser Doppler perfusion measurements. Results: Three patients died on ECMO (group 1). Five patients were successfully weaned off ECMO (group 2). Four patients were discharged from hospital and one died after successful weaning from bleeding complications. Patients surviving ECMO (group 2) had microcirculatory findings comparable with healthy controls. Patients in group 1 showed major skin microvascular pathology: pericapillary bleedings (n = 1), pericapillary dark haloes (n = 2) and capillary micro thrombi (n = 1). As compared with survivors they had lower functional capillary density (FCD) (n = 3), higher heterogeneity of functional capillary density (n = 3) and significantly reduced capillary mean flow-categorical velocity (n = 2). Laser Doppler measurements in group 1 had non-significant lower laser Doppler flux values as compared with survivors and controls. Conclusion: Skin microvascular pathology as detected with video microscopy (pericapillary bleedings or haloes, micro-thrombi/capillaries with “no flow”, low FCD with high spatial distribution heterogeneity or low mean flow-categorial velocity seems to be associated with poor prognosis.
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| 9. |
- Wärme, Anna, et al.
(author)
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High doses of erythropoietin stimulating agents may be a risk factor for AV-fistula stenosis
- 2019
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In: Clinical Hemorheology and Microcirculation. - : IOS Press. - 1386-0291 .- 1875-8622. ; 71:1, s. 53-57
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Journal article (peer-reviewed)abstract
- BACKGROUND: A native AV-fistula (AVF) for access in hemodialysis (HD) is preferable. Stenosis, a major hurdle, is associated with older age and diabetes mellitus. PURPOSE: This case-control study aimed to clarify if any medical and/or laboratory factors, that can be altered, could be associated to AVF stenosis. METHODS: 33 patients with a patent AVF without need of intervention during a two year period (Controls) were matched by diagnosis and age with 33 patients (Cases), that had at least one radiological invasive examination/intervention due to suspected AVF malfunction (case-control mode 2:1). RESULTS: Cases had higher weekly doses of Erythropoietin-Stimulating Agent (ESA) than Controls both before intervention (mean 8312 +/- 7119 U/w versus 4348 +/- 3790, p = 0.005) and after the intervention (7656 +/- 6795, versus 4477 +/- 3895, p = 0.018). Before intervention serum phosphate was higher in Cases while there was no significant difference in blood hemoglobin, weekly standard Kt/V, parathyroid hormone, calcium, albumin, C-reactive protein, smoking habits, BMI or other medication. CONCLUSION: Higher doses of ESA were administered in patients with AVF stenosis. Since ESA may cause local hypertrophic effects on the vascular endothelium, we should prescribe lower doses of ESA in patients at risk. Further studies should clarify such connection.
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| 10. |
- Wärme, Anna, et al.
(author)
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High doses of erythropoietin stimulating agents may be a risk factor for AV-fistula stenosis
- 2019
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In: Clinical hemorheology and microcirculation. - : IOS Press. - 1386-0291 .- 1875-8622. ; 71:1, s. 53-57
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Journal article (peer-reviewed)abstract
- BACKGROUND: A native AV-fistula (AVF) for access in hemodialysis (HD) is preferable. Stenosis, a major hurdle, is associated with older age and diabetes mellitus. PURPOSE: This case-control study aimed to clarify if any medical and/or laboratory factors, that can be altered, could be associated to AVF stenosis.METHODS: 33 patients with a patent AVF without need of intervention during a two year period (Controls) were matched by diagnosis and age with 33 patients (Cases), that had at least one radiological invasive examination/intervention due to suspected AVF malfunction (case-control mode 2:1).RESULTS: Cases had higher weekly doses of Erythropoietin-Stimulating Agent (ESA) than Controls both before intervention (mean 8312 +/- 7119 U/w versus 4348 +/- 3790, p = 0.005) and after the intervention (7656 +/- 6795, versus 4477 +/- 3895, p = 0.018). Before intervention serum phosphate was higher in Cases while there was no significant difference in blood hemoglobin, weekly standard Kt/V, parathyroid hormone, calcium, albumin, C-reactive protein, smoking habits, BMI or other medication.CONCLUSION: Higher doses of ESA were administered in patients with AVF stenosis. Since ESA may cause local hypertrophic effects on the vascular endothelium, we should prescribe lower doses of ESA in patients at risk. Further studies should clarify such connection.
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