Clinical Hemorheology and Microcirculation - Volume 39, issue 1-4

Authors: Késmárky, Gábor | Kenyeres, Péter | Rábai, Miklós | Tóth, Kálmán

Article Type: Research Article

Abstract: Evaluation of plasma viscosity has been underutilized in the clinical practice. Plasma viscosity is determined by water-content and macromolecular components. Plasma is a highly concentrated protein solution, therefore weak protein–protein interactions can play a role that is not characterized by electrophoresis. The effect of a protein on plasma viscosity depends on its molecular weight and structure. The less spheroid shape, the higher molecular weight, the higher aggregating capacity, and the higher temperature or pH sensitivity a protein has, the higher plasma viscosity results. Plasma is a Newtonian fluid, its viscosity does not depend on flow characteristics, therefore it is simple …to measure, especially in capillary viscosimeters. Its normal value is 1.10–1.30 mPa s at 37°C and independent of age and gender. The measurement has high stability and accuracy, thus little alterations may be pathologically important. Inflammations, tissue injuries resulting in plasma protein changes can increase its value with high sensitivity, though low specificity. It can increase in parallel with erythrocyte sedimentation rate (ESR), but it is not influenced by hematocrit (anemia, polycytemia), or time to analysis. Based on these favorable features, in 1942 plasma viscosity was recommended to substitute ESR. In hyperviscosity syndromes plasma viscosity is better in follow-up than ESR. In rheumatoid arthritis, its sensitivity and specificity are better than that of ESR or C-reactive protein. Plasma fibrinogen concentration and plasma viscosity are elevated in unstable angina pectoris and stroke and their higher values are associated with higher rate of major adverse clinical events. Elevation of plasma viscosity correlates to the progression of coronary and peripheral artery diseases. In conclusion, plasma viscosity should be measured routinely in medical practice. Show more

Keywords: Plasma viscosity, erythrocyte sedimentation rate, C-reactive protein, hyperviscosity syndromes, ischemic heart disease, acute phase response

DOI: 10.3233/CH-2008-1088

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 243-246, 2008

Authors: Kirchhof, Kristin | Groth, Thomas

Article Type: Research Article

Abstract: The layer-by-layer technique was used to build-up polyelectrolyte multilayers (PEMs) composed of heparin, an anionic glycosaminoglycan (GAG) and chitosan, a cationic biodegradable polysaccharide on model biomaterial surfaces. The surface coatings shall control adhesion of cells and thus their subsequent proliferation and differentiation. PEMs were characterized physicochemically by static contact angle and quartz crystal microbalance (QCM) measurements. Variations in procedure parameters such as the pH value of the solutions were crucial to the formation process and surface properties in terms of wettability and mass increase. Cell–surface interactions were studied with human fibroblast on PEMs. It was found that the pH value …of solutions had a strong impact on cell adhesion making surfaces extremely cytophobic or moderately cytophilic. Adsorption of fibronectin to the terminal heparin layer could be used to increase cell adhesion in a concentration-dependent manner. Show more

DOI: 10.3233/CH-2008-1089

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 247-251, 2008

Authors: Lamby, P. | Prantl, L. | Gais, S. | Walter, M. | Bachthaler, M. | Nerlich, M. | Feuerbach, S. | Jung, E.M.

Article Type: Research Article

Abstract: Background: A free-flap graft refers to the free transfer of tissue to cover tissue defects caused by trauma or malperfusion in plastic surgery. The basic principle, which makes a free flap working is an adequate blood flow. We applied new techniques which are able to detect the blood flow of the anastomosis and of dermal and subdermal tissue layers in a reliable way. Methods: To this end we applied innovative Ultrasound-techniques (contrast enhanced high resolution Ultrasound (US), color coded Doppler sonography (CCDS), Cross Beam™, Power Doppler, Tissue Harmonic Imaging™ (THI), Speckle Reduction Imaging™ (SRI)), as well as the Indocyanine …Green (ICG) fluorescence angiography to evaluate the vascular integrity of 15 parascapular flaps implanted to the fore foot over a period of four years. The age of the subjects ranged from 16 to 60 years. The US machine (GE Logiq 9) was equipped with a Logiq 9L transducer (6–9 MHz) and the modalities of CHI (Contrast Harmonic Imaging) and True Agent Detection (dual view of B-Mode and contrast mode). Results: The borders of the investigated flaps could be best detected using Cross Beam™ Technology with SRI™ and THI™. Power Doppler was able to detect anastomotic vessels even if they were twisted or elongated. Reduced perfusion curves were seen in cases with low anastomotic flow in CCDS. The CHI™ allowed dynamic flow detection of the microcirculation of the tissue graft over a depth of up to 3 cm including quantitative perfusion curves of tissue microcirculation by using TIC™ analysis. There is a strong correlation between the perfusion indices measured by ICG fluorescence angiography and CHI™. Furthermore the ICG showed a remarkable enhancement of fluorescence in the flap borders, which need to be explored in future investigations. Conclusion: These new applications provide useful and effective methods for improved postoperative monitoring of free flaps in plastic surgery and can lead to substantial reduction in the overall risk of flap failure. Show more

Keywords: Free parascapular flap, fluorescence angiography, ultrasound, contrast enhanced microcirculation

DOI: 10.3233/CH-2008-1094

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 253-263, 2008

Authors: Matschke, K. | Jung, F.

Article Type: Research Article

DOI: 10.3233/CH-2008-1093

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 265-279, 2008

Authors: Mrowietz, C. | Hiebl, B. | Franke, R.P. | Park, J.-W. | Jung, F.

Article Type: Research Article

Abstract: Various radiographic contrast media (RCM) significantly influence the morphology of erythrocytes, especially the formation of echinocytes [Scand. J. Clin. Lab. Invest. 35 (1975), 1–43; Microvasc. Res. 60 (2000), 193–200; Herz 23 (2003), 35–41]. Microscopic studies, however, have shown that these changes of erythrocyte morphology are possibly reversible [Acta Radiol. 37 (1996), 214–217]. The aim of this study was to proof if the RCM-induced echinocyte formation can be reversed by a resuspension in autologous plasma. In this study four RCMs were tested (Iodixanol, Iohexol, Iomeprol and Iopromide). These RCM induced echinocyte formation (after suspension of erythrocytes in plasma/RCM mixtures …for 10 min at 37°C), which was reversible after resuspension in autologous RCM-free plasma (resuspension time 5 min at 37°C). Especially for Iomeprol and Iopromide – the RCMs which induced the strongest echinocyte formation – an echinocyte reduction from 94.2% to 44.5% and for Iopromide from 80.6% to 50.4% occurred. The echinocyte formation was influenced by the type of RCM as well as by the RCM concentration. The same was true for the reversibility of echinocyte formation due to resuspension in autologous plasma (type of RCM: p≤0.0001; concentration of RCM: p=0.0847). Iodixanol was associated with the least numbers echinocytes formed (after suspension in the plasma/RCM-mixture as well as after the resuspension in autologous plasma). A 100% reversibility back to discocytes was observed in none of the RCMs after resuspension in autologous RCM-free plasma. In conclusion, a significant reversibility of RCM-induced echinocyte formation in autologous plasma could be observed. Show more

DOI: 10.3233/CH-2008-1097

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 281-286, 2008

Authors: Leithäuser, B. | Gerk, U. | Mrowietz, C. | Jung, F. | Park, J.-W.

Article Type: Research Article

Abstract: Xantinole nicotinic acid (NA) dose dependently lowers plasma levels of atherogenic lipoproteins and increases blood flow through vasodilation. The aim of this study was to evaluate the effect of NA on cutaneous microcirculation in patients with coronary artery disease and hyperlipidemia. In this open pilot study, five men and three women (74.2±9.1 yrs; 81.4±7.9 kg; 171.6±7.0 cm) with angiographically proven coronary artery disease and hyperlipidemia were included. Nailfold capillary microscopy was used for measurements of erythrocyte velocities at rest and after three minutes of ischemia, before and one hour after intake of 1000 mg of NA. The blood pressure …(120±12/73±8 mmHg vs. 113±10/72±5 mmHg; p=0.19/0.83) and the heart rate (72±8/min vs. 70±7/min; p=0.38) remained unchanged. The mean capillary red blood cell velocity at rest (vRBC ; 0.27±0.23 mm/s vs. 0.32±0.18 mm/s; p=0.089) and the time to maximal post ischemia erythrocyte velocity (tpeak ; 21.0±7.9 s vs. 24.3±15.5 s; p=0.49) did not change. The maximal post ischemic erythrocyte velocity (vmaxRBC ; 0.93±0.33 mm/s vs. 1.19±0.19 mm/s; p=0.0096) raised slightly but significantly, the duration of post-ischemia hyperemia (DpH; 101±16 s vs. 127±15 s; p=0.0005) increased markedly. One patient reported about flush in the whole body. The administration of 1000 mg of NA resulted in a significant improvement of the cutaneous microcirculation in patients with coronary artery disease and hyperlipidemia. Show more

Keywords: Nicotinic acid, coronary artery disease, microcirculation, naifold capillary microscopy, reactive hyperemia

DOI: 10.3233/CH-2008-1091

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 287-292, 2008

Authors: Leithäuser, B. | Zielske, D. | Seyfert, U.T. | Jung, F.

Article Type: Research Article

Abstract: Purpose: The use of clopidogrel is standard in interventional cardiology. Haemorrhage occurs in some patients, which implies a need for a non-transfusional therapy. Desmopressin showed its efficacy as an antidote of acetylsalicylic acid. In this trial the effects of desmopressin on platelet glycoproteins and the platelet's ability to aggregate under the influence of clopidogrel are studied. Methods: The trial was conducted as an open, prospective, single-centre, randomised pilot study with n=17 healthy volunteers in a parallel-group design. 1 h after an oral loading dose of 375 mg clopidogrel the effects of a single-dose of 300 μg of Octostim® …nasal spray (n=9) on platelet aggregation, activity of platelets on the density of membrane-bound receptors are measured. Results: Ristocetin cofactor and platelet reactivity rose significantly after the administration of Octostim® nasal spray with 31.9% and 5.3%, respectively (p=0.0329; p=0.0414). The ADP-induced platelet aggregation increased after the administration of Octostim® nasal spray by approximately 20% (p=0.0564). The fraction of CD62- and CD63-positive platelets did not change after clopidogrel nor after desmopressin (p=0.4203; p=0.6774). The density of GPIIb/IIIa receptors per platelet did not change after desmopressin (p=0.9652). The density of GPIb/IX receptors per platelet rose after desmopressin without reaching the level of significance (p=0.0802). In the desmopressin group alone the receptor density rose by 5.5% (p=0.0783). Conclusion: The administration of desmopressin improved the primary haemostasis when given in addition to a clopidogrel therapy. Patients undergoing a heart catheter procedure with clopidogrel might benefit from the use of desmopressin when having a bleeding episode. Show more

Keywords: Desmopressin, clopidogrel, primary haemostasis, flow cytometry, platelet aggregation

DOI: 10.3233/CH-2008-1092

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 293-302, 2008

Authors: Nash, Gerard B. | Watts, Tim | Thornton, Colin | Barigou, Mostafa

Article Type: Research Article

Abstract: Leukocytes and platelets must adhere to the wall of blood vessels to carry out their protective functions. Rheological factors influencing these processes are the delivery of the cells to the wall, referred to as margination, and the local shear rates and stresses at the wall. Margination requires leukocytes and platelets to be excluded from the central flow of the much more numerous red blood cells. This exclusion may be influenced by red cell aggregation. Red cell aggregation also influences development of plug flow in small vessels, which in turn modifies the wall shear rate and stress from those expected in …ideal Poiseuille flow. Promotion of aggregation by added agents such as high molecular weight dextrans or by reduction in shear rate, increases margination of leukocytes and efficiency of attachment to the vessel wall. Interestingly, however, fewer studies exist for platelets, and these suggest that margination is actually promoted by increasing shear rate. Direct studies of the effects of red cell aggregation on platelets are required, but it appears that aggregation has different effects on delivery of platelets compared to leukocytes. These differences may represent adaptations for efficient adhesion of leukocytes and platelets in different regions of the circulation. Show more

Keywords: Red cell aggregation, leukocyte adhesion, platelet adhesion, margination

DOI: 10.3233/CH-2008-1109

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 303-310, 2008

Authors: Özbek, C. | Mailänder, C. | Schilling, U. | Bach, R.

Article Type: Research Article

DOI: 10.3233/CH-2008-1095

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 311-321, 2008

Authors: Park, J.-W. | Leithäuser, B. | Jung, F.

Article Type: Research Article

Abstract: Introduction: The introduction of phosphodiesterase-5 inhibitors as sildenafil, tadalafil, or vardenafil, has tremendously improved the treatment of erectile dysfunction. Patients with the common comorbidity of cardiovascular disease and erectile dysfunction, however, are at risk for critical hypotension in case of self-treatment of cardiac angina with nitrates after the intake of a phosphodiesterase-5 inhibitor. Methods: We evaluated the safety of 5 mg sublingual nitrendipine after pre-treatment of 8 healthy male volunteers (42.1±9.6 yrs) with 20 mg tadalafil. Randomly four different protocols were compared using six hours blood pressure recordings: (1) baseline, (2) 20 mg tadalafil, (3) 5 mg nitrendipine, and …(4) 20 mg tadalafil+5 mg nitrendipine. Results: The blood pressure was not significantly affected by tadalafil. Nitrendipine lowered the systolic blood pressure significantly by −1.91 mmHg (p=0.0079). The co-medication of 20 mg tadalafil+5 mg nitrendipine lowered the blood pressure significantly by −2.86 mmHg (p<0.0001). There was no statistically significant difference between tadalafil and nitrendipine (p=0.598). Relevant hypotension (systolic blood pressure of <85 mmHg) was observed in none of the study individuals during the four protocols. Conclusions: Sublingual nitrendipine seems to be safe for self-treatment of an anginal attack in patients with stable coronary artery disease, who have taken a phosphodiesterase-5 inhibitor. However, our findings on hemodynamic changes in apparently healthy volunteers have to be confirmed in patients with coronary artery disease. Show more

Keywords: Phosphodiesterase-5 inhibitors, cardiovascular disease, erectile dysfunction, nitrendipine

DOI: 10.3233/CH-2008-1096

Citation: Clinical Hemorheology and Microcirculation, vol. 39, no. 1-4, pp. 323-328, 2008