H. Kiesewetter

Video fluorescein angiography: method and clinical application.

Video fluorescein angiography, combined with a picture analyzing system, is a clinically applicable, objective method of evaluating the retinal blood-flow parameters. Optical density measurements were performed on videorecordings of fluorescence angiograms by means of a picture-analyzing system in order to determine the circulation parameters of the retina. These included: the arm-retina time (ART), the arteriovenous passage time (AVP), and the mean arterial dye-bolus velocity (MDV). Normal values for these parameters were derived from measurements in 75 healthy volunteers. The mean arm-retina time (ART) was 11.2 ± 3.3 s, the mean arteriovenous passage time (AVP) 1.45 ± 0.4 s and the mean arterial dye-bolus velocity (MDV) 6.39 ± 1.7 mm/s. No significant correlation could be shown between pulse or blood pressure and one of the retinal circulation parameters. A group of ten healthy volunteers was examined twice in order to obtain the intraindividual variation for the measuring parameters. The coefficient of variation for the ART was 18%, 10% for the AVP, and 26% for the MDV.

Effects of garlic coated tablets in peripheral arterial occlusive disease

SummaryFor the first time, a weak clinical efficacy of a 12-week therapy with garlic powder (daily dose, 800 mg) is demonstrated in patients with peripheral arterial occlusive disease stage II. The increase in walking distance in the verum group by 46 m (from 161.0 ± 65.1 to 207.1 ± 85.0 m) was significantly higher (P<0.05) than in the placebo group (by 31 m, from 172.0 ± 60.9 to 203.1 ± 72.8). Both groups received physical therapy twice a week. The diastolic blood pressure, spontaneous thrombocyte aggregation, plasma viscosity, and cholesterol concentration also decreased significantly. Body weight was maintained. It is quite interesting that the garlic-specific increase in walking distance did not appear to occur until the 5th week of treatment, connected with a simultaneous decrease in spontaneous thrombocyte aggregation. Therefore, garlic may be an appropriate agent especially for the long-term treatment of an incipient intermittent claudication.

[Determination of reference ranges of rheologic parameters: study of 653 randomly selected probands of the Aachen district].

To determine reference ranges for rheologic parameters (hematocrit, plasma viscosity, erythrocyte aggregation, erythrocyte rigidity) a randomized study involving 653 subjects was carried out. Conditions of sampling, transportation and storing of blood specimens were established prior to the survey. Only 283 subjects met the criteria for enrollment in the study; the others were rejected because of inconspicuous history, normal findings in physical and Doppler-sonographic examination and absence of the risk factors hypertension, diabetes mellitus, overweight, rheumatic diseases, and smoking. The reference range for hematocrit was determined by an impedance-measuring device to equal 39-52% for males and 34-50% for females. The reference range for plasma viscosity, measured by a capillary-tube-plasma viscometer, was found to vary from 1.14 mPas to 1.34 mPas. The reference values for the standardized erythrocyte aggregation index was determined with the mini erythrocyte aggregometer to range from 8 to 21. Erythrocytes measured with the selecting-erythrocyte rigidometer showed a rigidity reference range between 0.83 and 1.19. Analysis of the results revealed that the parameters were independent of age (except in young children) and sex (with the exception of hematocrit).SummaryTo determine reference ranges for rheologic parameters (hematocrit, plasma viscosity, erythrocyte aggregation, erythrocyte rigidity) a randomized study involving 653 subjects was carried out. Conditions of sampling, transportation and storing of blood specimens were established prior to the survey. Only 283 subjects met the criteria for enrollment in the study; the others were rejected because of inconspicuous history, normal findings in physical and Doppler-sonographic examination and absence of the risk factors hypertension, diabetes mellitus, overweight, rheumatic diseases, and smoking.The reference range for hematocrit was determined by an impedance-measuring device to equal 39–52% for males and 34–50% for females. The reference range for plasma viscosity, measured by a capillary-tube-plasma viscometer, was found to vary from 1.14 mPas to 1.34 mPas. The reference values for the standardized erythrocyte aggregation index was determined with the mini erythrocyte aggregometer to range from 8 to 21. Erythrocytes measured with the selecting-erythrocyte rigidometer showed a rigidity reference range between 0.83 and 1.19. Analysis of the results revealed that the parameters were independent of age (except in young children) and sex (with the exception of hematocrit).

Quantification of characteristic blood-flow parameters in the vessels of the retina with a picture analysis system for video-fluorescence angiograms: initial findings

Fluorescence angiograms of the retina were performed on 12 healthy, adult subjects between the ages of 20 and 52 years with a 30° fundus camera (C. Zeiss), a low-light TV camera and a video recorder. Characteristic blood-flow parameters for the retina were obtained from the video recording using the picture-analysis system (Mikrovideomat 3, C. Zeiss). These included: the arm-retina time (ART), the arteriovenous passage time (AVP) and the arterial contrast-medium velocity (ACMV). Normal values for these parameters were derived for the four retinal quadrants and then discussed. In addition, the filling characteristics of venules were measured and discussed.

Primary and secondary microcirculatory disorders in essential hypertension

SummaryIn this prospective cross-sectional study blood fluidity and peripheral microcirculation were measured in patients suffering from essential hypertension with and without macroangiopathy. The cutaneous microcirculation was evaluated by intravital microscopy and the intramuscular by pO2 needle electrode. Disorders in the microcirculation without macroangiopathy in the system of the feeding arteries are defined as primary microangiopathy. Disturbed microcirculation with macroangiopathy in the feeding arteries in one area but no detectable microcirculatory disorder in another region is defined as a secondary microcirculatory disorder. Of the 57 patients in this study 27 had a primary microcirculatory disorder. It was remarkable that all 27 hypertension patients had a microcirculatory disorder in the area of the skin. Intramuscular microcirculatory disorder on its own without affection of the skin was not detected in any case. An exclusively secondary microcirculatory disorder occurred in 16 patients. This study shows that 93% of the patients with long-term essential arterial hypertension have microcirculatory disorders. It is most interesting that about one-half of these hypertension patients had a primary microcirculatory disorder, i.e., no indication of a hemodynamically active stenosis was found in the large vessels.

Haemorheology in patients with branch retinal vein occlusion with and without risk factors

Abstract• Purpose: The study was carried out to ascertain the role of blood viscosity in patients with branch retinal vein occlusion (BR-VO) with and without risk factors. • Methods: In 292 patients with acute BRVO (mean age 65 ± 10 years) and 292 controls matched for gender, age, and cardiovascular risk factors, haematocrit, plasma viscosity, erythrocyte aggregation and erythrocyte rigidity were measured. A subgroup analysis in patients with and without risk factors was performed. • Results: Haematocrit and plasma viscosity values were significantly higher in BRVO patients than in controls, but erythrocyte rigidity and erythrocyte aggregaton did not differ. Subgroup analysis revealed no differences in haematocrit and plasma viscosity values between patients with and those without cardioavascular risk factors. • Conclusions: This study shows increased plasma viscosity and haematocrit values in patients with BRVO which are not associated with the presence of other cardiovascular risk factors. Thus, changes in blood fluidity appear to be important factors in the pathogenesis of BRVO.

Prädiktorfunktion hämorheologischer Parameter im Hinblick auf die Inzidenz manifester Durchblutungsstörungen: Konzept der Aachen-Studie

SummaryThe prevention of cardiovascular disease has up till now generally been limited to control of the classical risk factors.The primary problem of the risk factor model is, that although a statistically verified relationship exists between risk factors and vascular disease, an individual prognosis is presently impossible. Surveys that show a relation between risk factors and impaired blood fluidity support the conception that a change in blood fluidity could be considered an early detection screening of vascular diseases.Prospective studies have shown that the hematocrit is related to circulatory disturbances. The main aim of the present study was to determine the clinical relevance of rheological parameters (hematocrit, plasma viscosity, erythrocyte rigidity, thrombocyte aggregation, erythrocyte aggregation), and the importance of altered blood fluidity as a predictor of manifest cerebral, cardiac or peripheral vascular disturbance.The prevention of cardiovascular disease has up till now generally been limited to control of the classical risk factors. The primary problem of the risk factor model is, that although a statistically verified relationship exists between risk factors and vascular disease, an individual prognosis is presently impossible. Surveys that show a relation between risk factors and impaired blood fluidity support the conception that a change in blood fluidity could be considered an early detection screening of vascular diseases. Prospective studies have shown that the hematocrit is related to circulatory disturbances. The main aim of the present study was to determine the clinical relevance of rheological parameters (hematocrit, plasma viscosity, erythrocyte rigidity, thrombocyte aggregation, erythrocyte aggregation), and the importance of altered blood fluidity as a predictor of manifest cerebral, cardiac or peripheral vascular disturbance.

RETINAL BLOOD FLOW IN DIABETIC CHILDREN AND ADOLESCENTS

A total of 209 diabetic children and adolescents aged 6–17 years (mean, 12.6 ± 2.3 years) were examined by ophthalmoscopy, video fluorescein angiography and hemoglobin (HbA1c) tests. Microaneurysms were found in 26% of the children (ophthalmoscopy, 11%; angiography, 23%). The prevalence of retinopathy was 16% in patients aged 6–10 years, 27% in those aged 11–13 years and 36% in those aged 14–17 years. Only five diabetics aged 11–17 years showed lesions other than microaneurysms (hard exudates, intraretinal hemorrhages or retinal capillar leakage). Retinal blood flow was quantified using video fluorescein angiography. The arm-retina time (ART) and the arteriovenous passage time (AVP) as parameters of the retinal microcirculation were obtained using an image analysing system. The mean value for ART was 9.7±2.5 s and that for AVP was 1.43±0.52 s. AVP was significantly shorter in diabetic children and adolescents with good glycemic control (HbAlc, <7%; AVP, 1.35±0.44 s) than in those with bad glycemic control (HbA1c, ≥ 9 % ; AVP, 1.65 ±0.51 s).

Hämodilution bei Patienten mit peripherer arterieller Verschlußkrankheit im Stadium IIb: Prospektiver randomisierter Doppelblind-Vergleich von mittelmolekularer Hydroxyäthylstärke und kleinmolekularer Dextranlösung

Isovolemic hemodilution is a simple method of treating patients with peripheral arterial occlusion disease and hematocrit values of 43% or more. Dextran, a plasma substitute, has been used for that purpose since the early 1950s. However, the use of dextran in some diseases, e.g., hemorrhagic diathesis, kidney insufficiency, and microangiopathy is not without risk. Anaphylactic reaction, too, has occurred in some cases. Since the end of the 1970s hydroxyethyl starch, a plasma substitute, is available for the therapy of microcirculatory disorders and hemorrhagic diathesis. The side effects of hydroxyethyl starch are less serious and anaphylactic reactions are less frequent and moderate in extent. The clinical efficacy of both substances was compared in this survey. It could be stated that middle molecular hydroxyethyl starch is even clinically superior to low molecular dextran because the distance that the patients could walk increased significantly.SummaryIsovolemic hemodilution is a simple method of treating patients with peripheral arterial occlusion disease and hematocrit values of 43% or more. Dextrane, a plasma substitute, has been used for that purpose since the early 1950s. However, the use of dextran in some diseases, e.g., hemorrhagic diathesis, kidney insufficiency, and microangiopathy is not without risk. Anaphylactic reaction, too, has occurred in some cases. Since the end of the 1970s hydroxyethyl starch, a plasma substitute, is available for the therapy of microcirculatory disorders and hemorrhagic diathesis. The side effects of hydroxyethyl starch are less serious and anaphylactic reactions are less frequent and moderate in extent. The clinical efficacy of both substances was compared in this survey. It could be stated that middle molecular hydroxyethyl starch is even clinically superior to low molecular dextran because the distance that the patients could walk increased significantly.

Do different ischemic brain lesions have different hemorheological profiles

SummaryThe following hemorheological parameters were determined in 68 patients with ischemic brain lesions and in 28 controls: yield shear stress, erythrocyte aggregation, erythrocyte rigidity, plasma viscosity, and hematocrit. The patients were classified into various groups on the basis of etiological criteria. The results revealed differences between certain hemorheological variables (erythrocyte aggregation, plasma viscosity) in some of the stroke groups. Plasma viscosity was significantly higher in patients with Binswangers disease and significantly lower in the control group compared with values measured in patients with macroangiopathy and microangiopathy. Erythrocyte aggregation was significantly lower in the controls than in the other groups. Discriminant analysis revealed that plasma viscosity, erythrocyte aggregation and hematocrit were the most useful variables for classification.