Clinical Hemorheology and Microcirculation - Volume 38, issue 2

Authors: Travagli, Valter | Zanardi, Iacopo | Boschi, Letizia | Gabbrielli, Alessandro | Mastronuzzi, Vita A.M. | Cappelli, Roberto | Forconi, Sandro

Article Type: Research Article

Abstract: The absence of a simple and clinically practical method to determine whole blood viscosity can partly justify why the medical community has been slow in realizing the significance of whole blood viscosity. For this reason, the availability of a technique able to evaluate blood viscosity in a rapid and direct manner is welcome. To evaluate the feasibility in hemorheological laboratory of a new torsional oscillation viscometer, it was compared with a conventional cone–plate system. The viscosity comparison has been related to hematocrit value both on whole blood and suspended blood in a saline solution. The results showed a good repeatability …and reproducibility of the new equipment, with a best-fitting data of the hematocrit 0–100% range characterized by coefficient of determinations, r2 >0.95. Furthermore, a comparison of whole blood viscosity as measured by the two instruments was done on blood samples collected from hospitalized patients. Reasonable agreement for the viscosity values was found between the two methods with linear determination coefficients between the two measurement methods comprised between r2 =0.7329 and 0.9263, depending on shear stress phase and the corresponding shear rate. Show more

Keywords: Blood viscosity, hematocrit, torsional-oscillation viscometer, rheometer

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 2, pp. 65-74, 2008

Authors: Blankfield, Robert P.

Article Type: Research Article

Abstract: There is evidence that changes in intravascular volume influence long-term cardiovascular events, and that this effect is independent of blood pressure. Using the Poiseuille–Hagen equation for laminar flow through a cylinder, assuming that blood pressure remains unchanged despite any change in intra-arterial volume, and assuming that blood in the large arteries has a constant viscosity, then it can be shown that the rate of arterial blood flow changes according to the equation Q2 =Q1 [1+(ΔV/VTI )]2 , where Q1 represents the original rate of flow, Q2 represents the new rate of flow, ΔV represents the change in intra-arterial …volume, and VTI represents the total intra-arterial volume. Furthermore, if one is willing to extrapolate from a single artery to the entire circulatory system, such that Q1 represents the initial cardiac output, Q2 represents the new cardiac output, ΔV represents the change in intravascular volume, and VTI represents the total intravascular volume, then it can be demonstrated that even small changes in intravascular volume have hemodynamic consequences. Specifically, an intra-arterial volume change of 2.7 cc will alter cardiac output by approximately 1% in the average human, with hemodynamic consequences comparable to a 1 mm change in the mean arterial pressure. The calculations in this paper suffer from a number of weaknesses, and there are justifiable reasons to consider the assumptions and extrapolations employed in this paper to be invalid or overly simplistic. Despite these limitations, the primary rationale for believing the assumptions and extrapolations to have merit is that the conclusions that result are consistent with, and help explain, a considerable amount of current research literature. Based upon these calculations, even small changes in intravascular volume would be expected to change the pressure on endothelial cells at arterial branch points and bifurcations, thereby influencing the development of atherosclerosis. Show more

Keywords: Intravascular volume, arterial blood flow, atherosclerosis

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 2, pp. 75-81, 2008

Authors: Plá, Laura Verónica | Stoltz, Jean François | Valverde, Juana R. | Riquelme, Bibiana D.

Article Type: Research Article

Abstract: The aim of this study was to analyze the strength of red blood cells agglutination, induced by autoantibodies in patients with Cold-Agglutinin Hemolytic Disease (CAHD), and the hemorheological profile (deformability and osmotic fragility) by the utilization of rheo-optical techniques. The strength of the antigen–antibody reaction was approached by the work required to dissociate mechanically red blood cells agglutinates. It is focused on the evaluation of the qualitative adhesiveness of cell approached by the dissociation kinetics carried out in a Couette flow (erythroaggregameter). The analysis was performed by recording the increase of the reflectivity signal as the agglutinates are dissociated by …shear into smaller ones. A total of eight patients aged <54 years with recent diagnostic of CAHD detected by positive Direct Anti-globulin Test (DAT) and very low RBC counts at 20°C, were studied. Two parametric values were interesting: the dimensionless energy parameter and the characteristic dissociation time, which showed good correlation with hematological parameters. In conclusion, the dissociation method provides a powerful tool for estimating the qualitative adhesiveness of red blood cells agglutinated by autoantibodies in patients suffering of cold-agglutinin hemolytic disease and it would be very interesting to evaluate the severity of the disease. Show more

Keywords: Adhesive energy, red blood cells agglutination, erythroaggregameter, autoimmune hemolytic anemia, hemorheo- logical parameters, adhesion strength

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 2, pp. 83-91, 2008

Authors: Presti, Rosalia Lo | Carollo, Caterina | Montana, Maria | Canino, Baldassare | Catania, Anna | Caimi, Gregorio

Article Type: Research Article

Abstract: In a group of young subjects with acute myocardial infarction (AMI) (97 men and 8 women; mean age 39.6±5.5 years) we examined the thiobarbituric acid – reactive substances and the total antioxidant status at the initial stage and after 12 months. The same parameters were examined in a group of 55 control subjects. Our results show that, while in control subjects there was a negative correlation (p<0.001) between these two parameters, no correlation was found in juvenile myocardial infarction at the initial stage as well as after 12 months.

Keywords: Juvenile myocardial infarction, lipid peroxidation, antioxidant status

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 2, pp. 93-96, 2008

Authors: Zorger, N. | Jung, E.M. | Hamer, O.W. | Paetzel, C. | Schreyer, A. | Seitz, J. | Stehr, A. | Steinbauer, M. | Feuerbach, S. | Herold, T.

Article Type: Research Article

Abstract: Objective: Feasibility of intraarterial MR angiography of the renal arteries and comparison of the accuracy of intraarterial MR angiography with selective intraarterial digital subtraction angiography (DSA) for detection of stenoses. Materials and methods: Ten consecutive patients (mean, 68 years) with suspected renal artery stenosis underwent a digital subtraction angiography and an intraarterial gadolinium-enhanced MR angiography, performed on a 1.5-T system. For intraarterial MR angiography 60 ml diluted contrast agent (10 ml gadodiamide in 50 ml 0.9% saline solution) was injected through a conventional angiography catheter placed in the suprarenal abdominal aorta using a flow rate of 3.5 ml/s. A three-dimensional …(3D) gradient-echo sequence was performed. Differences in the quantitative measurement of stenoses of lesions between DSA and intraarterial MR angiography were evaluated by three observers. Overall impression of the intraarterial MR angiography was documented on a four-point scale (1 = excellent to 4 = poor). Interobserver variability was calculated. Results: Intraarterial MR angiography of the renal arteries was feasible in all patients (100%) with a mean overall impression of all images of 1.8 (SD: 0.71). One of 9 accessory renal arteries was not visualized with intraarterial MR angiography. The overall sensitivity/specificity for detection of significant stenoses (≥50% stenosis) were 83%/87%. Interobserver variability of intraarterial MR angiography ranged between fair and substantial (0.359–0.622). Conclusion: Intraarterial MR angiography of the renal arteries in humans is feasible and has an acceptable sensitivity in detecting stenoses using injections of diluted contrast agent at concentrations as low as 17%. Show more

Keywords: Magnetic resonance, vascular studies, gadolinium, angiography, contrast media, arteries, renal arteries, stenosis, obstruction

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 2, pp. 97-104, 2008

Authors: Prantl, L. | Schmitt, St. | Geis, S. | Tsui, T.Y. | Lamby, P. | Nerlich, M. | Kubale, R. | Zorger, N. | Herold, T. | Feuerbach, S. | Jung, E.M.

Article Type: Research Article

Abstract: Purpose: Contrast harmonic ultrasound (CHI) with a linear transducer is a new diagnostic approach that allows dynamic and quantitative flow detection of tissue perfusion in microsurgery. The aim of the study was the evaluation of perfusion of the dermal and subdermal layers of microvascular tissue transplants with CHI in comparison to ICG-fluorescence angiography. Material and method: In a prospective clinical study Indocyanine-Green Fluorescence Video Angiography and Contrast Enhanced High Resolution Ultrasound (5–10 MHz; linear transducer; Logiq 9; GE) were used for evaluation of the microcirculation in 10 transplanted free parascapular flaps. Two regions were analysed, the centre of the flap …and the region of the anastomosis. The perfusion patterns of both methods were compared. Results: The perfusion indexes measured by ICG-fluorescence angiography correlated very precisely in all patients with the quantitative perfusion curves of contrast-enhanced US with CHI. Two flaps with slow filling and low dye intensity showed low contrast enhancement in CHI with modified perfusion curves with slow increase. In two cases a reduced perfusion and filling were found. There were no statistical differences between the two diagnostic methods (p>0.01). Conclusion: CHI improves US detections of dermal and subdermal microcirculation in comparison to ICG fluorescence angiography. CHI is a new diagnostic method for postoperative monitoring of free flaps. Show more

Keywords: Parascapular flaps, contrast harmonic ultrasound, fluorescence angiography, microcirculation

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 2, pp. 105-118, 2008

Authors: Yvonne-Tee, Get Bee | Rasool, Aida Hanum Ghulam | Halim, Ahmad Sukari | Wong, Abdul Rahim | Rahman, Abdul Rashid Abdul

Article Type: Research Article

Abstract: Introduction: Recent development had allowed non-invasive assessment of microvascular function in vivo; however, the method has not been fully optimized and standardized. In this study, we aimed to characterize the “effective” occlusion duration needed to elicit sufficient postocclusive hyperemia (PORH) responses in forearm skin using laser Doppler fluximetry (LDF), in subjects with differing age, gender and menstrual phases. Materials and methods: A total of 120 healthy subjects were studied (20 subjects each in the age ranges of 21–30, 31–40, 41–50 for both genders). Male subjects were randomized to receive 1, 2 or 3 min occlusion on three study days. Females …attended six study days: the first three days (with different occlusion times) were performed during low estrogenic phase of menstrual cycle and subsequent three visits were done during high estrogenic phase. Skin perfusion was measured before, during and after occlusion using LDF. The magnitude and temporal courses of PORH were expressed as PORHmax (absolute maximal increase in hyperemia perfusion) and Tp (time-to-peak), respectively. Results: For PORHmax analysis, the occlusion duration should be applied based on one's age, gender and menstrual phase. The PORH responses were more consistent during high estrogenic phase with 2 min found as the “effective” occlusion duration in all female groups. For Tp analysis, 3 min occlusion produced the significant change in all age ranges for both genders irrespective of menstrual phase. Conclusion: This study revealed that for assessment of microvascular function using PORH+LDF model, the occlusion duration for PORHmax is influenced by age, gender and menstrual phase. Measurement based on Tp is however independent of these factors. Show more

Keywords: Laser Doppler methods, microvascular, optimization, postocclusive hyperemia, skin

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 2, pp. 119-133, 2008

Authors: Olatunji, Lawrence A. | Soladoye, Ayodele O. | Oyeyipo, Peter I.

Article Type: Research Article

Abstract: Oral contraceptive (OC) steroids use has been associated with variable effects on blood lipid and rheological properties, and abnormal plasma lipid and hemorheological profiles has been shown to be in almost all conditions associated with accelerated atherosclerotic cardiovascular disorders. This study aimed at investigating the effect of increased calcium intake on plasma levels of lipids, malondialdehyde (lipid peroxidation index), free radical defense system and hemorheological variables in OC-treated female Sprague–Dawley rats. OC-treated and OC+Calcium-treated groups received a combination of ethinyl estradiol and norgestrel for 10 weeks by oral gavage. OC+Calcium-treated rats fed on 2.5% calcium diet while other groups fed …on 0.9% calcium diet in addition to drinking water ad libitum. Results showed that LDL-cholesterol, total cholesterol/HDL-cholesterol ratio, LDL-cholesterol/HDL-cholesterol ratio, plasma viscosity, hematocrit and plasma fibrinogen were significantly higher while plasma HDL-cholesterol, 17β-estradiol, testosterone and calcium levels were significantly lower in OC-treated rats when compared with the control rats. The altered plasma lipid and calcium levels were prevented by increased calcium intake, whereas the OC-induced changes in hematocrit, plasma viscosity, fibrinogen, 17β-estradiol and testosterone were not affected by increased dietary calcium. Plasma lipid peroxidation index, ascorbic acid and albumin levels were comparable in all the groups. The present study demonstrated that OC-induced altered blood lipid and rheological properties were not associated with increased lipid peroxidation. The results also suggest that calcium enriched diet may improve lipid profile but not hemorheological parameters, by a mechanism that is independent of circulating 17β-estradiol and testosterone in OC-treated rats. Show more

Keywords: Calcium supplementation, hemorheology, lipoproteins, oral contraceptive, oxidative stress

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 2, pp. 135-142, 2008