Clinical Hemorheology and Microcirculation - Volume 12, issue 3
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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.
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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: Contrast media (CM) widely used in medicine are hyperosmotic, have a higher plasma viscosity, density and different ionic strength than ordinary blood plasma. Therefore, a bolus administration of such CM for X-ray diagnostics should alter the physico-chemical properties of blood and among these its rheological behaviour. To address this question, blood samples were incubated with ionic and non-ionic X-ray CM (75 mg I/ml). In order to quantify the complex rheological behavior we studied the whole blood apparent viscosity (0.05s−1 –100s−1 ), sedimentation/packing ability of RBC and RBC aggregation by light back scattering in addition to microscopic examination of samples. The…shape qual i ty index was lowest for ionic monomeric CM meglumineamidotrizoate and the non-ionic CM metrizamid. These CM also alter in a drastic manner the rheological behaviour of blood. Whereas most non-ionic monomeric CM (iopamidol, iohexol, iopromide, ioversol and iotriside) have shown an intermediate influence, the ionic dimeric ioxaglate and the non-ionic dimeric iotrolan deteriorate the morphology as well as the rheology of RBC in a less pronounced way.
Keywords: Ionic and non-ionic contrast media, Blood rheology, Red cell morphology, Red cell aggregation, Microhematocrit, Packing behaviour
Abstract: Ioxaglate is an ionic low osmolar contrast medium (CM) widely used in radiological procedures, particularly for its effects on blood coagulation. In cases of cardiovascular and renal disease, where the microcirculatory system is of great importance, the hemorheologic properties of contrast media are emphasized. In vitro studies (SEFAM erythrometer) to compare nonionic low osmolality CM and ioxaglate 50 % and 75 % vol/vol) have shown that ioxaglate decreases less the deformability of red blood cells. Further, morphological alterations (i.e. the formation of echinocytes and stomatocytes) occur more frequently with nonionic CM, whatever their osmolality, suggesting their chemotoxic effect. Preclinical…experiments indicate that the hemorheologic properties of these media could be valuable clinically, limiting in particular CM nephrotoxicity in patients at risk (diabetes, pre-existing renal insufficiency etc.). The difficulties encountered in providing a clinical demonstration of these local effects explain why the possible consequences of these properties in cardiac and vascular disease have to date remained theoretical.
Keywords: Contrast media, Ioxaglate, Red cell filtrability, Red cell morphology, Clinical relevance
Abstract: Contrast media can be expected to have effects on the rheology of blood because of their elevated densities, osmolarities and viscosities compared with plasma. These properties also vary markedly between the different types of media currently available and so their haemorheological effects can be expected to vary. In this in vitro study the ionic media Urografin, Cardioconray and Hexabrix have been compared with the non-ionics Optiray and Omnipaque. All of the media caused progressive reduction in low (0.277s−1 ) shear rate blood viscosity as their concentrations increased, reflecting the marked reduction in rouleaux formation that was induced. Simultaneously, the…high (128.5 s−1 ) shear rate viscosity increased. This is, at least in part, a reflection of the high viscosities of the media and the cellular crenation and rigidity induced by osmotic shrinkage. Of the media tested Urografin and Cardioconray had the greatest effects and Hexabrix the least.
Abstract: The in vitro hemorheological effects of three new, so called low osmolar, radio-contrast media (CM) were compared. Two of the CM were non-ionic compounds, Iohexol and Iopamidol, the third one was the ionic dimer Ioxaglate. Their osmolalities varied from 574 to 679 mosmol/kg. with viscosities from 4.8 to 7.5 mPa.s. Red blood cell (RBC) aggregation (syllectometry and calCulation of the aggregation factor, AF), RBC deformability (ektacytometry and calculation of the Taylor factor, Tk), plasma viscosity as well as low and high shear viscosity of various blood-CM mixtures were measured. Changes in these parameters, induced by various grades of dilution and/or…hyperosmolality were related to changes in morphological parameters, found in an earlier, comparable study. It was shown that, in contrast to both non-ionic CM and despite its own hyperosmolality, Ioxaglate had no effect on RBC morphology and caused less deterioration of RBC deformability and aggregation than hyperosmolar saline. So far no explanation has been found for this phenomenon. Transformation from normal RBC biconcave morphology to echinocytes due to a hyperosmolar environment was invariably associated with a decrease in elongation index (more rigid cells), disturbance of rouleau formation and an abnormal sylleetogram. The values of AF and Tk were not always consistent with the other parameters reflecting RBC aggregation and deformability.
Abstract: When nonionic contrast media come into contact with blood, large red cell aggregates are formed. These aggregates, visible to the naked eye, have caused confusion among radiologists and prompted fear of embolism. Studies on the stability of the aggregates are reviewed. Large, irregular aggregates induced by nonionic contrast media are more stable than rouleaux and even more stable than irregular aggregates induced by glucose. However, they disperse under slight mechanical stress and in an ionic environment. Shear forces during injection and contact with an ionic flush solution and plasma prevent embolic complications during angiography.
Abstract: The increased aggregation of red blood cells seen in vitro with contrast media probably is of very little, if any, clinical importance. Of more importance is, however, the rheological changes which might be induced during a bolus injection due to rigidification of red blood cells which might change the possibility of red blood cells to pass through capillaries in the micro circulation.
Abstract: We have investigated the efficacy of laboratory tests for monitoring the acute-phase response in 54 patients who underwent elective abdominal surgery. Post-operative changes in slow responding acute-phase proteins such as fibrinogen were monitored by erythrocyte sedimentation rate and plasma viscosity in all patients and by erythrocyte aggregation and disaggregation in 22 patients. These tests were of limited efficacy as they were also influenced by the post-operative fall in haematocrit and/or albumin. Of faster responding acute-phase proteins, the blood concentrations of interleukin-1, interleukin-6 and tumour necrosis factor had largely returned to normal pre-operative values within 24 hours of surgery. C-reactive protein…showed a more appropriate time course, but its extreme sensitivity to the surgical procedure (1400% rise in blood concentration on day 3) would limit its value for the detection of post-operative complications. Existing tests for monitoring the acute-phase response are not recommended for the routine detection of post-operative complications.
Abstract: A viscometric study including measurements in static and dynamic flow conditions has been carried out on fractionated sickle blood separated into light and dense fractions studied in both oxygenated and deoxygenated states. The results, compared to those obtained from control blood at the same hematocrit, show : - for the oxygenated light cell fraction a decreased red blood cell (RBC) disaggregation due to plasma viscosity increase, for the oxygenated dense fraction a modified RBC aggregation due to both membrane cell alterations and plasma viscosity increase, - for both light and dense fractions in deoxygenated state, a loss of RBC aggregation…which abolishes dynamic rheological properties (thixotropy and viscoelasticity) in relationship with the presence of polymerized hemoglobin.
Abstract: About twenty PIH cases and twenty normal pregnant women in their third trimester were subjected to haemorheological investigations. The whole blood viscosity (wbv) and plasma viscosity (pv) were significantly higher in the PIH group than in the normal group. Filterability index (I), haematocrit and plasma fibrinogen were not significantly elevated. Diastolic pressure in PIH was not significantly correlated with any of these viscosity parameters. However whole blood viscosity was significantly correlated and filterability was highly significantly correlated with foetal distress. This implies the role of pathohaemorheology in malperfusion in the foeto-placental circulation and subsequent perinatal morbidity associated with pregnancy induced…hypertension (PIH).
Abstract: Rheological parameters (hematocrit, plasma viscosity and red blood cell aggregation index), glycosylated hemoglobin (HbA1c) and retinal arteriovenous passagetime (AVP) were measured in 93 patients with type I diabetes. The stage of diabetic retinopathy was graded by means of ophthalmoscopy and video fluorescein angiography. The mean values of hematocrit (men 46 ± 4%, women 43 ± 3 %), RBC aggregation index (13,8 ± 3,8, normals: 14,6 ± 3,2) were equal to normals. Plasma viscosity (1,33 ± 0,09 mPas, normals:1,24 ± 0,05 mPas) was increased. The groups with increasing stage of diabetic retinopathy showed no difference in hematocrit, RBC aggregation and HbA1c…and an increase of plasma viscosity. In patients with bad glycemic control plasma viscosity was increased and RBC aggregation index was similar as compared with patients with good glycemic control. If retinal arteriovenous passagetime was worse plasma viscosity and RBC aggregation were more increased. This indicates, that alterated plasma viscosity and RBC aggregation may be one of the reasons for disturbed microcirculation and fundus changes ill diabetic retinopathy.
Keywords: Blood rheology, hematocrit, plasma viscosity, red blood cell aggregation, diabetic retinopathy, glycemic control