Clinical Hemorheology and Microcirculation - Volume 5, 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: To keep plasmapheresis membranes unclogged, shear flow of blood over them is necessary, but the role of shear has not been established. A simple convection mechanism, applicable only to finite-sized particles, is described and shown to correlate available plasmapheresis data better than the “lift” and “concentration polarization” models previously proposed.
Abstract: Three membranes of comparable pore size that are relevant to clinical membrane plasmapheresis were studied to ascertain what determines their hydraulic resistance (transmembrane pressure/flux). Plasma was filtered through membranes both naked and covered with a layer of erythrocytes of known thickness. While the naked membranes showed a different resistance that rose with time during plasma filtration, resistances observed clinically were seen only when a cell layer was present. Studies at two levels of plasma flux indicated that intramembrane resistance depends upon time of exposure, not the amount of plasma filtered. Cell layers reduce the amount of protein deposited in the…membrane.
Keywords: plasmapheresis, membrane, protein adsorption, cell layers, hydraulic resistance
Abstract: The microporous membranes and ultrafilters used in cascade filtration membrane plasmapheresis were, in most, developed and qualified using blood of approximately normal composition. It is not a priori evident that these devices will perform satisfactorily when challenged with the high levels of protein concentration associated with hyperviscosity syndrome or paraproteinemia. We describe here the techniques for in-vivo assessment of the efficacy of the primary and secondary membrane plasma filters and illustrate their use via a technical case report of a patient with IgM paraproteinemia.
Abstract: The effect of patient pathology on plasma production performance during plasma exchange was studied operating a continuous flow centrifugal separator (IBM 2997) in a standardized way. The disease categories were TTP, Neuro-Muscular Disorders, Hyper-Viscosity Syndrome and others (which included Hemolytic Amemia and Goodpastures Syndrome). Plasma production performance was considered from two points of view: Plasma production efficiency and residual platelet count in the separated plasma. Analysis of 254 procedures showed plasma separation efficiency is high – greater than 80% – and not strongly affected by patient pathology. Platelet clearance from separated plasma is dependent on patient pathology and was found…to range from 60% to 90%.
Abstract: The authors recently proposed (1) the concept “Erythrocyte Transport Function” (E.T.F.) This is expressed by the ratio: haematocrit over whole blood viscosity (φ/η); it has been used as a new criterion of blood-changes arising during a programme of plasmapheresis. In addition, the parameters “A” (whole blood viscosity at 1% haematocrit and one sec−1 rate of shear) and “β” (a shear-sensitivity index) recently proposed (2) have been used. Data are presented on how far these new measurements supplement plasma viscosity in reflecting blood-changes during plasmapheresis. It is suggested that φ/η which closely follows changes in plasma viscosity, has numerical as…well as rheological implications in monitoring plasmapheresis.
Keywords: Erythrocyte Transport Function, whole blood viscosity, plasmapheresis, plasma viscosity
Abstract: Massive plasma exchange (more than 3 litres) can be achieved during various hyperviscosity syndromes using cell separators. The authors report on a rheological survey undertaken on 30 patients with Kahler’s disease, 7 cases of Waldenström’s disease, 2 cases of CLL with monoclonal gammapathy, 3 cases of non Ibdgkinian malignant lymphoma and 2 cases of isolated cryoglobulinemia. The rheological parameters studied covered plasma and blood viscosity, red blood cell aggregability (nephelometry and study with a rheoscope). The results revealed a systematic decrease in plasma and blood viscosity following exchange procedures, with a slow recovery after the exchange. A…decrease in aggregability is observed when exchange procedures are carried out using diluted albumin (4%). In conclusion, systematic assessment of the rheological parameters can be considered as a good test for following up plasma exchange procedures during diseases accompanied by a hyperviscosity syndrome.
Keywords: Blood and plasma viscosity, Red Blood cell aggregation, Plasma exchange
Abstract: A “relative viscosity-haematocrit-rate of shear” relationship is used in the study of blood ultrafiltration in a parallel-plate plasmapheresis device. Some preliminary in vitro experimental work with platelet-poor ox-blood is presented.
Abstract: Cascade filtration (CF) is a double membrane filtering procedure, where the plasma, separated in the first step from blood, is simultanously pumped on a second membrane with lower cut-off, thus retaining the larger plasma molecules like IgM. The lower molecular plasma fractions containing the albumin, are reinfused to the patient. By this way the IgM level was reduced to 44% after each CF, while IgG was lowered only to 73% and albumin to 80% of its initial value. The plasma viscosity accordingly dropped from 1.77 to 1.27 m Pa·s. This special kind of plasmapheresis was done without any plasma protein…substitution.
Abstract: Fourteen patients with severe Raynaud’s phenomenon, 7 with primary Raynaud’s phenomenon and 7 with secondary Raynaud’s phenomenon based on progressive systemic sclerosis, were treated with plasma filtration. Haemorheological parameters were determined before and after treatment. Eight patients (6 patients with secondary Raynaud’s phenomenon) responded very well. The frequency of Raynaud’s phenomenon and cold induced attacks were strongly reduced The skin which was tough and tense before filtration became supple and pliable, so that patients could use their extremities more easily. Also their facial expression became livelier. Fingertip ulcerations showed increased healing tendency. Elevated red blood cell aggregation and plasma…viscosity were markedly reduced after plasma filtration.
Abstract: RAYNAUD-attacks, i.e. cold induced episodes of hypoperfusion of the upper extremities are characterized by a “tricolore-phenomenon”. They are thought to occur as a consequence of vasospastic diseases (M. RAYNAUD). However, abnormal high viscosity may cause a very similar secondary phenomenon in hematological diseases, especially due to an overproportional increase in blood viscosity at low shear in hypothermia. Previously, anticonstrictive interventions (e.g. sympathectomy, vasodilator drugs) were applied, more recently plasmapheresis was recommended, albeit with variable success. Such therapy would be logical in case of a humoral cause of RAYNAUD-attacks. Simple hemorheological tests (rheoaggregometry of red cell aggregation, plasma viscosity, hematocrit determination)…appears to differentiate clearly between primary M. RAYNAUD and secondary RAYNAUD-phenomena in disorders such as systemic sclerosis, rheumatoid arthritis. In the latter, there is a strongly increased tendency to red cell aggregation, demonstrable in accelerated rate of aggregate formation and in a highly abnormal shear resistance of the aggregates in flow.
Keywords: M. RAYNAUD, Systemic sclerosis, RAYNAUD-phenomenon, red cell aggregation, photometric aggregometry, Myrenne-aggregometer, plasma viscometry
Abstract: Six claudicants without rest pain or diabetes were included in this study. 2000ml plasma were replaced by 1500ml Haemaccel and 500ml isotonic NaCl solution at weekly intervals. The following tests were carried out before, immediately after, and on the 1st, 2nd and 5th days following the first treatment: whole blood viscosity at 95, 2.5 and 0.7s shear rates, plasma viscosity, red cell filtration, fibrinogen, ESR, full blood count, calf blood flow measured at rest and at reactive hyperaemia, brachial and ankle systolic pressures, and exercise step test. There was a significant decrease of plasma viscosity, fibrinogen and whole blood viscosity…at each shear rate after treatment, returning to the baseline values between 5 and 7 days. There was no improvement in the functional tests despite the changes observed in viscosity. No adverse side-effects resulting from the use of Haemaccel were observed.