Clinical Hemorheology and Microcirculation - Volume 6, issue 1
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Clinical Hemorheology and Microcirculation, a peer-reviewed international scientific journal, serves as an aid to understanding the flow properties of blood and the relationship to normal and abnormal physiology. The rapidly expanding science of hemorheology concerns blood, its components and the blood vessels with which blood interacts. It includes perihemorheology, i.e., the rheology of fluid and structures in the perivascular and interstitial spaces as well as the lymphatic system. The clinical aspects include pathogenesis, symptomatology and diagnostic methods, and the fields of prophylaxis and therapy in all branches of medicine and surgery, pharmacology and drug research.
The endeavour of the Editors-in-Chief and publishers of
Clinical Hemorheology and Microcirculation is to bring together contributions from those working in various fields related to blood flow all over the world. The editors of
Clinical Hemorheology and Microcirculation are from those countries in Europe, Asia, Australia and America where appreciable work in clinical hemorheology and microcirculation is being carried out. Each editor takes responsibility to decide on the acceptance of a manuscript. He is required to have the manuscript appraised by two referees and may be one of them himself. The executive editorial office, to which the manuscripts have been submitted, is responsible for rapid handling of the reviewing process.
Clinical Hemorheology and Microcirculation accepts original papers, brief communications, mini-reports and letters to the Editors-in-Chief. Review articles, providing general views and new insights into related subjects, are regularly invited by the Editors-in-Chief. Proceedings of international and national conferences on clinical hemorheology (in original form or as abstracts) complete the range of editorial features.
The following professionals and institutions will benefit most from subscribing to
Clinical Hemorheology and Microcirculation: medical practitioners in all fields including hematology, cardiology, geriatrics, angiology, surgery, obstetrics and gynecology, ophthalmology, otology, and neurology. Pharmacologists, clinical laboratories, blood transfusion centres, manufacturing firms producing diagnostic instruments, and the pharmaceutical industry will also benefit.
Important new topics will increasingly claim more pages of
Clinical Hemorheology and Microcirculation: the role of hemorheological and microcirculatory disturbances for epidemiology and prognosis, in particular regarding cardiovascular disorders, as well as its significance in the field of geriatrics. Authors and readers are invited to contact the editors for specific information or to make suggestions.
Abstract: Haemorheological parameters of 74 patients suffering from acute brain ischaemia were investigated not later than three hours after the acute event. In the acute phase whole blood viscosity and its constituants as well as platelet aggregability were found most severely disturbed and the statistical difference to controls was highly significant. Correlations between haemorheological changes and the duration of clinical symptomatology have been established and haemorheological parameters were found continuously changing throughout 4 weeks in part provoked by haemorheologic treatment.
Keywords: Stroke, haemorheology, platelet aggregation, hyper-fibrinogenaemia, red cell filterability
Abstract: The Italian Acute Stroke Study Hemodilution (I.A.S.S.-H.) recruits 1,200 patients with recent (12 hrs) acute stroke admitted to university-hospital departments of neurology in Italy. The patients, randomized centrally by telephone, are allocated as follows: 50% to the treated group (hemodilution treatment) and 50% to the control group (standard treatment). Randomization is stratified by centers and severity of neurological deficit on admission. Hemodilution treatment is performed by venesection and infusion of dextran 40; standard treatment will be provided by each Center within a common general regimen. At the end of six months the Clinical Coordination Center collects the follow-up data…on mortality and disability by telephone. Hemodilution treatment will be considered of benefit if it reduces significantly mortality and disability risk, compared with the control group.
Abstract: In addition to the important role which blood platelets play in the pathogenesis of stroke recent studies have implicated the red blood cell (RBC) in the events which lead to brain infarction. The hypothesis that patients with specific types of stroke have hemorheological abnormalities which originate from decreased RBC deformability will be examined. The specific types of cerebral infarction are classified into cardioembolic stroke, thromboembolic stroke and lacunar infarction. Normal subjects and persons at high risk for stroke are also under study. Preliminary results on blood from normal individuals, high risk cases and stroke patients show that apparent whole blood…viscosities, especially at low rates of shear, are elevated for both the high risk and acute stroke group, with the acute stroke group being significantly higher than the high risk group. Within the stroke group those patients with a Starr-Edwards heart valve and cardioembolic stroke have appreciably higher apparent viscosities than individuals with other types of stroke.
Abstract: The involvement of haemorheologic variables in disturbed blood flow conditions of the brain can be globally verified as an increase of blood viscosity whereby hyperfibrinogenaemia, hyperaggregability of platelets and of erytrocytes and impaired erythrocyte flexibility as well as relative polycythaemia are the major contributing factors. Haemorheological disturbances are amenable to therapeutic intervention and various concepts have been established with the aim to lower blood viscosity (haemodilution), suppressing platelet hyperreactivity (ASA, pentoxifylline) and improving erythrocyte flexibility (pentoxifylline).
Keywords: Haemorheology, cerebrovascular disease, blood viscosity, medical treatment, haemodilution, Pentoxifylline
Abstract: A hemorheological analysis which measured blood filterability was carried out on 3 groups of patients with cerebrovascular accidents (CVA). In two groups: severe CVA (52 patients, ischemic and hemorrhagic of whom 50% died), and mild CVA (10 patients, no deaths) alterations in blood filterability were observed in two phases,during the course of deterioration and subsequent improvement. Changes were most marked in patients with complications or in whom the outcome was fatal. In a third group of patients with severe CVA (10 subjects), hemodilution was able to maintain hematocrit at a low level, although it only temporarily corrected blood filterability. Hemorheolical…parameters appear to have clincal significance. However, the relationship between the lesions and therapeutic goals (hemodilution and drugs acting at the cellular level) will need to be based on a more rational understanding of the mechanisms underlying these hemorheological disturbances.
Abstract: Blood rheology measurements (blood viscosity, plasma viscosity, and erythrocyte deformability) were made at 15°C and 37°C in 16 patients with Raynaud’s phenomenon (11 secondary) compared with 16 healthy matched controls. At both temperatures the patients showed a significant reduction in filterability of washed erythrocytes through pores of 3 µm and 5 µm diameter and an increase in plasma viscosity. The rheological abnormality was greater at 15°C than 37°C in both patients and controls. A cold provocation test (immersion of the hand for 5 min in water at 4°C) had no effect on the deformability of erythrocytes taken from the cubital…fossa. The temperature dependency of erythrocyte and plasma rheology, although not specific for Raynaud’s phenomenon, will contribute to impaired microvascular perfusion in cold extremities.
Keywords: Rheology, Erythrocyte deformability, Raynaud’ s disease
Abstract: In a controlled, randomised, double-blind study, 71 patients with acute occlusion of retinal vessels (26 arterial, 45 venous) were treated with a basic therapy (BT: pentoxifylline + prednisolone) whereby in accordance with the randomisation, in normotensive patients additional therapy consisted of hypervolaemic haemodilution (HHD) with dextran 40, and in hypertensive patients with or without signs of cardiac insufficiency of isovolaemic haemodilution (IHD) with human albumin. The following parameters were determined before and during therapy: blood chemistry (PCV, erythrocyte count, erythrocyte volume, platelet count, plasma fibrinogen), haemorheoogy (apparent viscosity of whole blood at the shear rates 0.03 s−1 , 1,24 s−1…and 49.4 s−1 , plasma viscosity, erythrocyte flexibility), platelet function test (ADP-induced platelet aggregation, spontaneous aggregation of platelets by the method of BREDDIN (PAT III), coagulation test (PT, PTT, TCT, RCT), visual function (visual acuity, field of view, analogue scale). None of the therapeutical methods used was able to modulate all the haemorheological parameters exclusively in the sense of improving the flow properties of the blood. Erythrocyte flexibility increased significantly with BT, whereas no significant change was detected with the combination of BT and IHD, and in contrast, there was a significant decrease with the combination of BT and HHD for the period of treatment by dextran infusion. The apparent viscosity of whole blood at the low shear rate remained virtually unchanged with BT, while it decreased with the combination of BT and HHD, but showed the most pronounced decrease with the combination of BT and IHD. Comparison of the haemorheological efficacy of these methods of therapy showed that the most favourable conditions for an improvement of function in impairment of blood supply to the retina were provided by the combination of BT and IHD. Clinical assessment of function showed that no marked differences in the results in arterial impairment of blood supply to the retina could be detected. For impairment of venous retinal blood flow, an increase in visual acuity and more favourable fields of view were initially found with all types of therapy. After 6 months, however, the functional results were better in patients treated with BT+IHD. Furthermore, secondary glaucoma occurred less often with this treatment.
Keywords: Vascular Retinopathies, Haemorheology, Pentoxifylline, Iso- and Hypervolaemic Haemodilution
Abstract: Fifteen young, healthy males were put on Furosemide for 24 hours. Blood rheology was quantified (blood- and plasma-viscosity, hematocrit, red cell aggregation and filterability, colloid oncotic pressure of plasma, blood volume change) together with electrolytes, serum electrophoresis, blood pressure, pulse rate and body weight. Results show that there are hemorheological changes explainable by hemoconcentration. Blood- and plasma-viscosity, colloid oncotic pressure rise. Blood volume is reduced, and the other hemorheological variables are unaltered. Hemoconcentration could present a potential risk for cardiovascular patients, which has received little attention so far.
Abstract: The mechanical characteristics of the structural components of polymorphonuclear granulocytes (PMN) and lymphocytes were tested by aspirating tongues from these cells into micropipettes with internal diameter (Dp) > ∼ 2um. PMN tongues deformed in a continuous manner, while lymphocyte deformation was slower and approached a limiting steady level. The greater rigidity of the lymphocytes appeared to arise from their large, solid nucleus, while the PMN cytoplasm acted as a viscous fluid at these large scale deformations. Overall WEC deformability was also tested by measuring the time required for complete cell entry (te) into…pipettes with Dp = 4 to 6um. The relative ease of entry of PMN and lymphocytes depended on the pipette diameter; lymphocytes entered more slowly than PMN for Dp = 4um, but more quickly than PMN for Dp = 5.9um. The predicted threshold pressure at which entry could just be induced was greater for lymphocytes than for PMN at Dp < 5um, but similar for the two cell types for Dp > ∼ 5um. Apparently the greater stiffness of lymphocytes makes it relatively difficult for them to enter the smaller pipettes, but for the larger pipettes their smaller volume allows them to enter more rapidly than the PMN. Thus, the relative contributions of PMN and lymphocytes to blood flow resistance are likely to depend strongly on the vessel size. It was also noted that active PMN with pseudopodia took much longer to enter pipettes than smooth, passive PMN, therefore indicating that rheological tests on white blood cells must consider the possibility of cell activation.
Keywords: White Blood Cell Rheology, Flow Resistance
Abstract: Haemorheologic studies, were performed in 68 patients (pts) with Polycythaemia Vera (PV) under treatment by venesection alone or by cytostatic drugs with or without venesection. PV pts had higher haematocrit (PVC) and elevated whole blood viscosity (WBV) even after reconstitution of blood to 0.45 PCV, in comparison with a control group. MCV and MCH were parallely reduced. In the pts with marked hypochromic microcytosis prolonged erythrocyte filtration times (EFT) were recorded; however this finding seemed better attributable to the larger filtered RBC number than to impaired erythrocyte deformability. The supposed influence of hypochromic microcytosis, due to repeated venesections, on blood…viscosity parameters in treated PV pts could not be confirmed. PV pts with “vascular risk” factors had higher values of WBV, plasma viscosity, and fibrinogen. It is concluded that: 1) hypochromic microcytosis is not per se associated with abnormal haemorheological behavior and 2) plasmatic factors greatly contribute to hyperviscosity in treated PV pts.