Clinical Hemorheology and Microcirculation - Volume 49, issue 1-4

Authors: Clevert, D.A. | Helck, A. | D'Anastasi, M. | Gürtler, V. | Sommer, W.H. | Meimarakis, G. | Weidenhagen, R. | Reiser, M.

Article Type: Research Article

Abstract: Purpose: To evaluate whether the image fusion with contrast enhanced ultrasound (CEUS) and CT affects the diagnosis of endoleaks in unclear cases. Methods and materials: 35 patients with follow-up examinations after enodvascular aneurysm repair (EVAR) were included in this retrospective study. Mean patient age was 73 years (range 54–83 y). B-scan, colour doppler and CEUS (1.2 ml SonoVue® , Bracco Imaging Germany) were performed in all patients by an experienced examiner using two different high-end ultrasound system (Siemens ACUSON S2000™, Siemens Healthcare, Erlangen, Germany or Logic E9, GE Healthcare, Milwaukee,WI, USA) with a multifrequency curved array transducer. The examiner was …initially blinded to the CT results. Additional image fusion with CT-angiography (CTA) was then performed. The ultrasound examinations were later read by two blinded unbiased investigators with more than five years of clinical ultrasound in consensus. Results: All patients were examined using all diagnostic ultrasound tools of the study. The results show that image fusion is easy and convenient to perform. Conventional ultrasound examination with B-scan and colour Doppler examination detected one Type I and one Type II endoleak, contrast enhanced ultrasound detected one Type I and three Type II endoleaks after EVAR whereas CTA depicted one Type I and two Type II endoleaks. Ultrasound image fusion with CT-angiography confirmed one Type I and three Type II endoleaks. Conclusion: In comparison to conventional ultrasound and CTA the use of CEUS improved the visualization and classification of endoleaks. CEUS shows even small blood flow which can be depicted due to the real time imaging of endoleaks. In unclear cases additional ultrasound image fusion with CEUS and CT angiography improves the visualisation of small endoleaks and this may cause a change in the follow-up interval. CEUS is a good alternative to CT in the detection and follow-up of endoleaks, especially in patients with contraindications to CT contrast agents due to allergies or renal failure, enabling reduced additional costs and exposure to radiation. Show more

Keywords: Aortic aneurysm, EVAR, ultrasonography, CEUS, image fusion

DOI: 10.3233/CH-2011-1460

Citation: Clinical Hemorheology and Microcirculation, vol. 49, no. 1-4, pp. 91-104, 2011

Authors: D'Anastasi, M. | Schneevoigt, B.S. | Trottmann, M. | Crispin, A. | Stief, C. | Reiser, M.F. | Clevert, D.A.

Article Type: Research Article

Abstract: Purpose: Acoustic radiation force impulse imaging (ARFI) is a newly developed technique for the sonographic quantification of tissue elasticity. It has been used in the assessment of various abdominal organs. The testes are extraabdominal organs with limited overlying tissue, making them ideally suited to ARFI assessment. To our knowledge no published data exist on ARFI elastography of the testes. Method: 23 male volunteers (mean age 45.13 ± 17.3, range 23–75) with no known testicular pathology underwent normal B-mode sonography with ARFI elastometry of both testes using a Siemens Acuson S2000™ (Siemens Healthcare, Germany) system. 15 measurements were performed on each …testis; 5 each in the upper pole, middle portion and lower pole. Results were statistically evaluated. Results: 95% of the SWV values were found to lie within the reference interval ranging from 0.62 to 1.01 m/s. There was a significant association between measured SWV and age (P = 0.0056) and testicular volume (P = 0.0003). Conclusion: ARFI elastometry proved to be feasible in the assessment of testicular stiffness. Older age and lower testicular volumes were associated with increased parenchymal stiffness. Further studies with more subjects may be required to define the normal range of values for each age group. Show more

Keywords: Testis, ARFI imaging, ultrasonography

DOI: 10.3233/CH-2011-1461

Citation: Clinical Hemorheology and Microcirculation, vol. 49, no. 1-4, pp. 105-114, 2011

Authors: Müller, S. | Gosau, M. | Strobel, D. | Gehmert, S. | Moralis, A. | Reichert, T.E. | Prantl, L. | Jung, E.M.

Article Type: Research Article

Abstract: Purpose: Postsurgical evaluation of bone microcirculation in osseous and osseocutaneus free flaps by contrast enhanced ultrasound (CEUS) with time intensity curve (TIC) analysis and [18 F]-positron emission tomography/computed tomography (Fluoride-PET/CT). Patients and Methods: 10 patients with osseous or osseocutaneus microvascular flaps were evaluated with CEUS. Ultrasound was carried out by an experienced examiner with a high resolution linear probe (6–9 MHz, LOGIQ E9, GE) after intravenous bolus injection of 2.4 ml SonoVue® (BRACCO, Germany). Time intensity curves (TIC) in selected regions of interest (ROI) were analyzed and compared with the evaluation of [18 F]-positron emission tomography/computed tomography and the …clinical course for at least 2 month. Results: 9/10 patients showed evidence for soft tissue and osseous microcirculation of the transplants in CEUS correlating with the clinical course. The soft tissue parts of the transplant showed a mean value of 84% (range 51–98%) and the bone parts a mean value of 39% (range 11–75%) for the Area under the curve (AuC) compared with the AuC for the anastomotic vessel region. Mean values for time to peak (TTP) were 27,1 sec (range 8.7–52.0 sec) for the anastomotic vessels, 29.3 sec (range 7.9–62.0 sec) for the soft tissue of and 32.0 sec (range 7.4–69.0 sec) for the transplant bone. In 1/10 patients flap failure occurred, after denudation the bone was left as an avascular transplant. AuC showed a mean value of 0.5 % for the bone region compared with the vessel region. Fluoride-PET/CT assessed bone vitality in 7 patients as “good” in 1 patient as “uncertain” and in 1 patient as “poor”. CEUS assessment was corresponding with Fluoride-PET/CT in 4 patients, clinical assessment in 6 patients. Conclusion: Fluoride-PET/CT is a valuable tool to make an indirect statement about the perfusion of the transplanted bone and was used as control in this study. CEUS is a new and promising method for the evaluation of microcirculation of buried free microvascular bone grafts and the osseous part of osseocutaneous flaps and may be used for a steady monitoring in the first postoperative days. Show more

Keywords: Osseous flaps, osseocutaneous flaps, buried flaps, contrast-enhanced ultrasound, fluoride-PET, tissue microcirculation

DOI: 10.3233/CH-2011-1462

Citation: Clinical Hemorheology and Microcirculation, vol. 49, no. 1-4, pp. 115-128, 2011

Authors: Schreyer, Andreas G. | Landfried, K. | Jung, E.M. | da Silva, N. Platz Batista | Poschenrieder, F. | Dornia, C. | Wiggermann, P. | Dendl, L.M. | Holler, E. | Stroszczynski, C. | Friedrich, C.

Article Type: Research Article

Abstract: GvHD is a serious complication in patients after allo-SCT, presenting with unspecific symptoms such as abdominal pain or cramps and diarrhea. Early diagnosis of GvHD, after differentiation from other causes leading to the same symptoms, such as viral or bacterial enteritis, is highly important because the time needed for diagnosing GvHD is directly correlated to a worsening of the outcome. We examined 23 patients presenting with the abdominal symptoms mentioned above, of whom 20 had received an allo-SCT in their history and were thus potential candidates for enteric GvHD. The other three patients were included because they also presented with …abdominal symptoms similar to those of GvHD, which could be ruled out due to their history. We wanted to evaluate CEUS in these patients as an additional subgroup to gain more data on the value of CEUS in early detection of enteral GvHD and in the differentiation of GvHD against other causes of abdominal discomfort. All patients underwent CEUS with particular attention to penetration of the intravenously applied microbubbles in the bowel lumen. In the patients having allo-SCT in their history we strove to achieve histological confirmation of GvHD of the GI-tract. The resulting examinations were documented digitally. Out of 17 patients with confirmed GvHD of the GI tract, 14 showed penetration of the intravenously applied microbubbles into the bowel lumen, leading to a sensitivity and specificity of 82% and 100% for transmural bubble penetration for GvHD of the GI-Tract, since the patients without GvHD of the GI tract showed no transmural bubble penetration. In patients with viral or bacterial infections of the GI tract, no transmural penetration of the microbubbles into the bowel lumen was observed. For microbubble penetration as a criterion for GvHD of the GI-Tract, this leads to a negative predictive value (NPV) of 67%, and a positive predicative value (PPV) of 100%. Show more

DOI: 10.3233/CH-2011-1463

Citation: Clinical Hemorheology and Microcirculation, vol. 49, no. 1-4, pp. 129-136, 2011

Authors: Greis, Christian

Article Type: Research Article

Abstract: Ultrasound contrast agents consist of tiny gas-filled microbubbles the size of red blood cells. Due to their size distribution, they are purely intravascular tracers which do not extravasate into the interstitial fluid, and thus they are perfect agents for imaging blood distribution and flow. Using ultrasound scanners with contrast-specific software, the specific microbubble-derived echo signals can be separated from tissue signals in realtime, allowing selective imaging of the contrast agent. The signal intensity obtained lies in a linear relationship to the amount of microbubbles in the target organ, which allows easy and reliable assessment of relative blood volume. Imaging of …the contrast wash-in and wash-out after bolus injection, or more precisely using the flash-replenishment technique, allows assessment of regional blood flow velocity. Commercially available quantification software packages can calculate time-related intensity values from the contrast wash-in and wash-out phase for each image pixel from stored video clips. After fitting of a mathematical model curve according to the respective kinetic model (bolus or flash-replenishment kinetics), time/intensity curves (TIC) can be calculated from single pixels or user-defined regions of interest (ROI). Characteristic parameters of these TICs (e.g. peak intensity, area under the curve, wash-in rate, etc.) can be displayed as color-coded parametric maps on top of the anatomical image, to identify cold and hot spots with abnormal perfusion. Show more

Keywords: Ultrasound, microbubbles, blood flow, perfusion, microcirculation, vascularization, quantification, bolus kinetics, flash-replenishment kinetics, VueBox$\trademark$

DOI: 10.3233/CH-2011-1464

Citation: Clinical Hemorheology and Microcirculation, vol. 49, no. 1-4, pp. 137-149, 2011

Authors: Connes, Philippe | Machado, Roberto | Hue, Olivier | Reid, Harvey

Article Type: Research Article

Abstract: Sickle cell anemia (SCA or SS homozygous sickle cell disease) is an inherited blood disorder caused by single nucleotide substitution in the β-globin gene that renders their hemoglobin (HbS) much less soluble than normal hemoglobin (HbA) when deoxygenated. The polymerization of HbS upon deoxygenation is the basic pathophysiologic event leading to RBC sickling, hemolysis, vasoocclusion and ultimately to chronic organ damage. The metabolic changes imposed by exercise may initiate sickling and vaso-occlusive episodes. Further, in patients with SCA, exercise limitation may be related to anemia or chronic complications such as pulmonary vascular disease, congestive heart failure and chronic parenchymal lung …disease. Few studies have investigated the cardiorespiratory responses of patients with SCA during either symptom-limited maximal exercise test on cyclo-ergometer or during a six minute walk test. Therefore, patients are advised to start exercise slowly and progressively, to maintain adequate hydration during and after exercise, to avoid cold exposure or sudden change in temperature, and to avoid sports associated with mechanical trauma. There are, however, lack of evidence to allow practitioners to prescribe an exercise program for patients with SCA, and individuals are usually encouraged to exercise on a symptom-limited basis. Finally, this review will also highlight the basic principles that are often used for exercise practice and could be used for exercise prescription and rehabilitation in patients with sickle cell anemia. Show more

Keywords: Sickle cell disease, exercise rehabilitation, exercise testing, clinical complications, physical fitness

DOI: 10.3233/CH-2011-1465

Citation: Clinical Hemorheology and Microcirculation, vol. 49, no. 1-4, pp. 151-163, 2011

Authors: Ahmadizad, Sajad | Moradi, Akram | Nikookheslat, Saeed | Ebrahimi, Hadi | Rahbaran, Adel | Connes, Philippe

Article Type: Research Article

Abstract: The purpose of this investigation was to examine the effects of age on the acute responses of hemorheological variables and biochemical parameters to a single bout of sub-maximal endurance exercise. Fifteen young (20–30 years), 15 middle-aged (40–50 years) and 12 old (60–70 years) male subjects participated in the study. All subjects performed one single bout of endurance exercise encompassed 30-min cycling at 70–75% of maximal heart rate which was followed by 30-min recovery. Three blood samples were taken before, immediately after exercise and after 30-min recovery. Resting levels of hematocrit, red blood cells count, plasma albumin and fibrinogen concentrations, plasma …viscosity and whole blood viscosity were significantly different among the three groups (P < 0.01). Thirty minutes of cycling resulted in significant increases (P < 0.05) in all parameters; while these changes were temporary and returned to pre-exercise level at the end of recovery. Responses of all parameters to exercise and recovery were not significantly different among the three groups (P > 0.05). Fibrinogen changes during exercise and recovery were corrected for exercise- and recovery-induced changes in plasma volume. Data analysis showed effects of exercise and recovery only for raw data (P > 0.05). In addition, raw and corrected fibrinogen data in response to exercise and recovery were not age-related. Our results demonstrate that age does not affect the hemorheological responses to an acute endurance exercise in healthy men. Show more

Keywords: Blood viscosity, plasma viscosity, fibrinogen, age, exercise

DOI: 10.3233/CH-2011-1466

Citation: Clinical Hemorheology and Microcirculation, vol. 49, no. 1-4, pp. 165-174, 2011

Authors: Baskurt, Oguz K. | Ulker, Pinar | Meiselman, Herbert J.

Article Type: Research Article

Abstract: Nitric oxide (NO) is accepted to be an important factor affecting the degree of vascular tone in various portions of the circulation. Until recently, research in this area has focused on endothelial cells as a NO source, and there is general agreement that: 1) the level of wall shear stress is the primary determinant of endothelial nitric oxide synthase (eNOS) expression; 2) exercise training induces changes of endothelial cell NO synthesizing activity; 3) phosphorylation patterns of eNOS are altered following exercise episodes. However, there is now a growing body of evidence for the existence of similar nitric oxide synthesizing mechanisms …in human red blood cells (RBC). Erythrocyte NOS activity has been demonstrated to be induced by applied shear stress and mechanical deformation of RBC, and there are closely linked increases of intracellular nitric oxide levels and of release of NO into the suspending phase. In brief, the RBC is an enzymatic source of NO that is dependent on flow dynamics and from which NO is released in very close proximity to vessel walls. Although reports regarding the influence of exercise on RBC nitric oxide synthesizing mechanisms are not yet concordant, it seems logical to suggest that this source of NO may play a role in the regulation of local blood flow dynamics during exercise. Show more

Keywords: Nitric oxide, exercise, shear stress, eNOS, phosphorylation

DOI: 10.3233/CH-2011-1467

Citation: Clinical Hemorheology and Microcirculation, vol. 49, no. 1-4, pp. 175-181, 2011

Authors: Brun, Jean-Frédéric | Varlet-Marie, Emmanuelle | Romain, Ahmed-Jérôme | de Mauverger, Eric Raynaud

Article Type: Research Article

Abstract: It is well known that body composition influences blood rheology (higher blood viscosity and RBC aggregation in obese individuals). On the other hand, blood rheology is related to exercise performance (the fitter the athlete the more fluid the blood). The ‘paradox of hematocrit’ is that most of the time trained athletes have a lower hematocrit while doping aims at increasing it, a situation which seems to challenge physiology and can be explained by the fact that systemic hematocrit may have poor physiological relevance at the microcirculatory level in exercising muscles. However, recent studies dealing with the marked differences among hemorheologic …profiles observed in selected sports lead to the concept that the relationships between hemorheology and performance on one hand and body composition and hemorheology on the other hand are more complex and somewhat different according to the variety of exercise and the physiological and/or pathophysiological background. Increased fat mass, but also fat free mass independently of fat mass, are both correlated to impairments of blood fluidity, consistent with the emerging concept that beside increases in fat mass, increases in fat free mass may also be related to metabolic and circulatory disturbances. Show more

Keywords: Insulin resistance, exercise, training, metabolic syndrome, far mass, fat-free mass, body fluids, hematocrit, blood viscosity, plasma viscosity, hemorheology, erythrocyte aggregation, erythrocyte deformability

DOI: 10.3233/CH-2011-1468

Citation: Clinical Hemorheology and Microcirculation, vol. 49, no. 1-4, pp. 183-197, 2011

Authors: Romain, Ahmed-Jérôme | Brun, Jean-Frédéric | Varlet-Marie, Emmanuelle | Raynaud de Mauverger, Eric

Article Type: Research Article

Abstract: Regular exercise has been reported to improve blood rheology, but all the studies investigating this issue included a reduced number of subjects, and thus it was logic to perform a meta-analysis of them in order to better characterize this physiological effect. Research was handed on Medline from 1950 to 2010. Studies were selected if they were in English and if they had one or several of these following outcomes: lactate, blood viscosity, RBC rigidity, hematocrit (%), RBC aggregation, fibrinogen and plasma viscosity. They were also kept if they included exercise in their protocol. Results were computed with the fixed effect …model and the weighting method was the inverse variance. 11 studies with 175 people were found and included in this meta-analysis. None of these studies had the whole mentioned outcomes. The meta-analysis shows significant effects on on RBC aggregation (−0.59 CI 95% [−0.72; −0.46]), whole blood viscosity (−0.30 [−0.31; −0.28] p < 0.001) and hematocrit (−0.296%; CI 95% [−0.57; −0.01]). Aggregation, hematocrit and viscosity data showed significant heterogeneity, aggregation I2 = 94.95%, hematocrit I2 = 96.46%, viscosity I2 = 99.25%. RBC aggregation (0.53 CI 95% [0.40; 0.66]). Three studies could be included for an intervention versus control analysis which shows significant effects on hematocrit (−1.06% CI 95% [−1.43; −0.68]) but bot on aggregation, with again a significant heterogeneity (hematocrit I2 = 96.46%). These results confirm that regular exercise decreases hematocrit and RBC aggregation, but the heterogeneity which is evidenced should be pointed out. This heterogeneity will require a new computation taking into account a “random effect” by using a pooling method. In addition, this heterogeneity leads to conclude that more studies are needed to further analyze these effects which are described by a low number of articles, which could explain some of the non-significant results. Show more

Keywords: Training, blood viscosity, RBC rigidity, hematocrit (%), RBC aggregation, fibrinogen, plasma viscosity, meta-analysis

DOI: 10.3233/CH-2011-1469

Citation: Clinical Hemorheology and Microcirculation, vol. 49, no. 1-4, pp. 199-205, 2011