Clinical Hemorheology and Microcirculation - Volume 45, issue 2-4

Authors: Liuni, Andrew | Luca, Mary Clare | Gori, Tommaso | Parker, John D.

Article Type: Research Article

Abstract: Animal studies have consistently demonstrated the ability of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors to limit the damage induced by ischemia-reperfusion (IR) in the cardiac, cerebral and mesenteric circulation through a mechanism dependent on the upregulation of cyclooxygenase-2 (COX-2). Our group performed studies aimed at investigating the mechanism of HMG-CoA reductase inhibitor-mediated endothelial protection from IR injury, in particular the role of COX-2, in a human in vivo model of IR-induced endothelial dysfunction. We demonstrated that HMG-CoA reductase inhibition protects against IR-induced endothelial damage, an effect that was lost upon COX-2 inhibition. These observations may suggest a mechanistic explanation for …the cardioprotection observed in clinical settings such as percutaneous coronary interventions and coronary artery bypass surgery and may also propose a mechanistic hypothesis for the reported cardiotoxic effects of cyclooxygenase-2 inhibitors observed in clinical studies. These studies are summarized and discussed in the present paper. Show more

Keywords: Endothelium, ischemia, reperfusion, ischemic preconditioning, statins

DOI: 10.3233/CH-2010-1294

Citation: Clinical Hemorheology and Microcirculation, vol. 45, no. 2-4, pp. 161-167, 2010

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

Article Type: Research Article

Abstract: Previous reports have demonstrated that red blood cells (RBC) have an active nitric oxide (NO) synthesizing mechanism which has properties similar to endothelial nitric oxide synthase (eNOS). This red cell NOS activity contributes to the NO export from RBC. The present study explored the influence of shear stress applied to RBC on NO concentrations of cell suspensions. RBC were exposed to shear stress by filtration through 5µm diameter pores under 10cm H2 O pressure, generating a wall shear stress of ∼110Pa. NO concentration in the RBC suspensions were measured using electrochemical NO probes before and after filtration through the micropores. …NO concentration was found to be significantly increased after a single passage of RBC suspensions through the micropores. The increment in NO concentration depended on the presence of calcium, being 21.8±4.4 nM with 1 mM calcium and 13.7±2.7 nM without added calcium. Including the calcium chelator EDTA completely abolished this increase. The increment of NO was also affected by the level of oxygenation, being more pronounced under hypoxic conditions. These results confirm that RBC NO generating mechanisms can be stimulated by exposing red cells to shear stress and that calcium plays a role in this stimulation. Show more

Keywords: Nitric oxide, shear stress, erythrocyte, calcium, oxygenation

DOI: 10.3233/CH-2010-1293

Citation: Clinical Hemorheology and Microcirculation, vol. 45, no. 2-4, pp. 169-175, 2010

Authors: Ahmadizad, Sajad | Bassami, Minoo

Article Type: Research Article

Abstract: The purpose of this study was to investigate the effects of time of day on responses of the main determinants of blood rheology to acute endurance exercise. Ten healthy male subjects (age, 26.9 ± 5.5 yr) performed two bouts of running at 65% of VO2peak for 45min on a motorised treadmill in the morning (08:00h) and evening (20:00h), which were followed by 30 min recovery. The two exercise trials were performed in two separate days with 7 days intervening. Haemorheological variables were measured before, immediately after exercise and after recovery. Haematocrit, haemoglobin and RBC count were increased significantly (p …< 0.01) after 45min running in both morning and evening trials and normalised following recovery, irrespective of time of day. Plasma viscosity increased significantly (F2,18 = 12.4, p < 0.01) following sub-maximal exercise in both trials and returned to pre-exercise level at the end of recovery. Baseline values (p < 0.05) but not responses of plasma viscosity to exercise were significantly affected by time of day. Neither a significant main effect of exercise nor a significant (p > 0.05) time-of-day effect was found for plasma proteins. It was concluded that sub-maximal running at 08:00 or 20:00 h does not induce different responses in the main determinant of blood rheology. Show more

Keywords: Endurance exercise, time of day, plasma viscosity, fibrinogen, haematocrit

DOI: 10.3233/CH-2010-1295

Citation: Clinical Hemorheology and Microcirculation, vol. 45, no. 2-4, pp. 177-184, 2010

Authors: Jabs, Alexander | Fasola, Federica | Muxel, Selina | Münzel, Thomas | Gori, Tommaso

Article Type: Research Article

Abstract: Pathophysiological studies have clearly demonstrated that the relationship between endothelial [dys]function and tissue ischemia is bidirectional: while it is well accepted that endothelial dysfunction has a key role in the progression and destabilization of coronary atherosclerosis, it is also well known that the endothelium is particularly sensitive to ischemia and reperfusion injury, and that this damage critically determines the extent of tissue damage, e.g. myocardial infarct size. Therefore, protecting the endothelium from ischemia could potentially have important clinical implications. In this scenario, reactive oxygen species [ROS] play a particularly important role: these elusive mediators are involved in determining the endothelial …toxic effect of risk factors and are involved in reperfusion injury; however, most importantly, ROS are also key mediators of endothelial preconditioning, a protective process that is characterized by a reduced sensitivity to ischemia and reperfusion injury. We report considerations regarding these phenomena and their potential pharmacologic manipulation as discussed in a lecture at the recent Conference of the European Society of Clinical Hemorheology and Microcirculation held in Pontresina, Switzerland. Show more

Keywords: Oxygen free radicals, ischemia, reperfusion, endothelium, endothelial dysfunction, nitric oxide, ischemic preconditioning

DOI: 10.3233/CH-2010-1297

Citation: Clinical Hemorheology and Microcirculation, vol. 45, no. 2-4, pp. 185-191, 2010

Authors: Zengel, P. | Siedek, V. | Berghaus, A. | Clevert, D.A.

Article Type: Research Article

Abstract: Purpose: Obstructive diseases of the salivary glands are often based on Sialolithiasis; however, conventional radiological imaging or ultrasound does not provide a diagnosis in 5–10% of all cases. It was the aim of our study to examine the effectiveness and viability of an intraductal applied contrast-enhanced ultrasound (IA-CEUS) to improve the visualization of obstructive diseases of the salivary glands in comparison to conventional ultrasound and clinical symptoms. Materials and methods: The study included fifteen patients with swelling of indeterminate cause and/or pain of one or more salivary glands. A high-end ultrasound machine (Siemens, ACUSON, S 2000, Germany) with a multi-frequency …linear 9MHz transducer was used to carry out contrast-enhanced ultrasound with SonoVue® . Results: All patients were examined using all diagnostic ultrasound tools of the study. The results show that the procedure is easy and convenient to perform, as well as efficient, but more significantly, that the intraductal contrast agent improved the diagnostic assessment capabilities of ultrasound for patients with obstructive salivary gland diseases, thereby helping to identify the best treatment. Conclusion: In comparison to conventional ultrasound, the use of an intraductal applied contract-enhanced ultrasound not only improved the visualization of the glandular duct system as a whole, but was less time-consuming as well as more reproducible. Thus, IA-CEUS with an intraductal applied contrast agent (IA-CEUS) is a promising tool that provides additional helpful information and an improvement for cases involving patients with unclear symptoms. Show more

Keywords: Intraductal, ultrasound, salivary gland, obstruction, classification

DOI: 10.3233/CH-2010-1298

Citation: Clinical Hemorheology and Microcirculation, vol. 45, no. 2-4, pp. 193-205, 2010

Authors: Girlich, C. | Schacherer, D. | Lamby, P. | Scherer, M.N. | Schreyer, A.G. | Jung, E.M.

Article Type: Research Article

Abstract: The aim was to describe the perfusion pattern of the inflamed bowel wall and the surrounding tissue in inflammatory bowel disease and diverticulitis of the sigmoid colon applying a high resolution matrix transducer and the new hybrid technique. We performed contrast enhanced ultrasound (CEUS) using an updated version of the 1–5MHz (C1-5-D convex probe) and the 6–9MHz probe (9L-D linear probe) as well as a matrix 6–15MHz transducer (ML 6–15-D Matrix Array Linear Probe) and updated post-processing procedures to examine microvascularization of inflamed bowel wall in Crohn’s disease (11 patients), ulcerative colitis (1 patient) and diverticulitis of the sigmoid colon …(2 patients). Assessment of mural microvascularization was successful as well as identification of fistulas (2 patients) and covered perforation (1 patient). Moreover analysis of time intensity curves revealed increase of signal intensity up to 20dB. Summarizing, application of high resolution linear probes and use of updated post-processing methods substantially improve detection of inflammation-caused increased microcirculation of the bowel wall and the surrounding tissue as well as identification of complications as fistulas or covered perforations. Show more

DOI: 10.3233/CH-2010-1299

Citation: Clinical Hemorheology and Microcirculation, vol. 45, no. 2-4, pp. 207-215, 2010

Authors: Thalhammer, Christoph | Ferriani, Viviana | Husmann, Marc | Rufibach, Kaspar | Meier, Thomas | Amann-Vesti, Beatrice R.

Article Type: Research Article

Abstract: Purpose: Factors predicting renal function and recurrent stenosis following percutaneous renal revascularization are poorly identified. The predictive value of hemodynamic duplex ultrasound (DUS) parameters was evaluated. Methods: In a prospective observational study patients undergoing stenting of renal artery stenosis (RAS) were included. Renal resistance index (RI) and peak systolic velocity (PSV) were measured at baseline, one day, and six months after intervention. Results: At 6-months follow-up 16 (16.8%) restenosis of 105 treated renal arteries were detected. Baseline RI was 0.69 ± 0.12 and increased significantly to 0.72 ± 0.09 after 6 months (p < 0.0001), however, RI did not predict …restenosis. PSV at baseline and age were independent predictors for increased RI at 6 months (p = 0.0078 and p = 0.0019). Diabetics had a significant higher RI before revascularization (0.74 ± 0.08) than non-diabetics (0.68 ± 0.12, p = 0.04). PSV after stenting was higher in patients with restenosis (1.4 ± 0.4 m/sec vs. 1.0 ± 0.3 m/sec, p = 0.002) and was an independent predictor for restenosis. Conclusions: Increased PSV within the stent one day after the procedure is predictive for restenosis. Patients with high grade RAS and older patients have a worse outcome. DUS is recommended to detect patients at risk for restenosis after percutaneous renal revascularization. Show more

Keywords: Renal artery stenosis, duplex ultrasound, percutaneous renal revascularization, intrarenal resistance index

DOI: 10.3233/CH-2010-1300

Citation: Clinical Hemorheology and Microcirculation, vol. 45, no. 2-4, pp. 217-224, 2010

Authors: Stock, K. | Hann von Weyhern, C. | Slotta-Huspenina, J. | Burian, M. | Clevert, D.A. | Meining, A. | Prinz, C. | Pachmann, C. | Holzapfel, K. | Schmid, R.M. | Lersch, C.

Article Type: Research Article

Abstract: Objectives: The evaluation of subepithelial tumors of the stomach is normally the domain of gastroscopy and endoscopic ultrasound. We investigated these rare tumors using transabdominal B-mode ultrasound and performed perfusion analysis of these tumors with contrast enhanced ultrasound. Methods: Patients with gastrointestinal stromal tumors (GIST, n = 3), leiomyoma (n = 1) and schwannoma (n = 1) were routinely examined using conventional B-mode-ultrasound, colour Doppler ultrasound and contrast-enhanced ultrasound (contrast media: Sonovue® ; ultrasound device: Siemens Acuson Sequoia™ 512). Gastroscopy, endosonography with puncture of the subepithelial tumor and computed tomography were also performed in all patients. After surgery, the …resected stomach tumors were correlated with the preoperative imaging findings. Results: All calculated tumor sizes using any imaging modalities showed a good correlation with the macroscopic tumor sizes ex-vivo. Histologically increased tumor size of the GISTs was correlated with large, central avascular areas. The GISTs and the leiomyoma presented with mixed echogenicity in B-mode-ultrasound. Colour Doppler ultrasound was able to detect some vessels in the periphery of the tumor only. Using contrast-enhanced ultrasound the GISTs and the leiomyoma presented hypervascular. The contrast pattern of these lesions was from the periphery to the centre or diffuse or a progressive centrifugal fill in during the arterial phase. We also registered slowly progressive washout starting at the end of the arterial phase and increasing into the late phase. The contrast media behaviour in the schwannoma was different from that describt above within the GISTs: it was noted to have a diffuse intralesional pattern at the start of the arterial phase followed by an early, rapidly progressing washout-phenomenon. Conclusion: In our pilot study B-mode transabdominal ultrasound was able to visualise gastric subepithelial tumors larger than three centimetre. Contrast-enhanced ultrasound is a proven method in clinical practice for the perfusion analysis of gastric subepithelial tumors. It can also be used for the planning of ultrasound-guided biopsies to avoid punctures of necrotic tumor parts. Show more

Keywords: Ultrasonography, contrast-enhanced ultrasound, microperfusion, perfusion pattern, stomach, gastrointestinal stromal tumor, schwannoma, leiomyoma

DOI: 10.3233/CH-2010-1302

Citation: Clinical Hemorheology and Microcirculation, vol. 45, no. 2-4, pp. 225-232, 2010

Authors: Velcheva, Irena | Antonova, Nadia | Damianov, Petar | Dimitrov, Nikolay

Article Type: Research Article

Abstract: The aim of the study was to investigate the changes of the common carotid local hemodynamic factors like wall shear stress and tensile forces in 16 patients with chronic unilateral cerebral infarctions (CUCI), 58 patients with risk factors (RF) for cerebrovascular disease (CVD) and 25 healthy control subjects. The blood flow velocities (BFV), the internal diameters (D) and the vessel wall intima-media thickness (IMT) in the common carotid arteries (CCA) were recorded with color duplex sonography. Systolic (SBP) and diastolic (DBP) blood pressure were measured and mean blood pressure (MBP) was calculated by the formula of Wiggers. Whole blood viscosity …(WBV) at the shear rate of 94.5 s−1 was measured on the day of the Doppler ultrasound examination with a rotational viscometer Contraves Low Shear 30. Wall shear stress (WSS), the circumferential wall tension (T) and the tensile stress τ were calculated. The main RF in the patients’ groups were hypertension and hyperlipidemia. The SBP, WBV and IMT were significantly increased in the patients with UCI and RF for CVD in comparison to controls. Lower systolic WSS and τ and higher T were established in the patients with UCI. The IMT correlated with WSS and τ. The study confirms the complex influence of the changes in WBV and blood pressure for the development of carotid atherosclerosis. Show more

Keywords: Cerebral infarctions, color duplex sonography, common carotid artery, wall shear stress, whole blood viscosity

DOI: 10.3233/CH-2010-1306

Citation: Clinical Hemorheology and Microcirculation, vol. 45, no. 2-4, pp. 233-238, 2010

Authors: Velcheva, Irena | Titianova, Ekaterina | Antonova, Nadia

Article Type: Research Article

Abstract: The study aimed to follow the influence of some hemorheological parameters and mean blood pressure (MBP) on the carotid blood flow asymmetry in 20 patients with chronic unilateral cerebral infarctions (UCI) as compared to 30 patients with transient ischemic attacks (TIAs), 17 patients with risk factors (RF) for cerebrovascular disease (CVD) and 11 healthy controls. Hemorheological variables: hematocrit (HT), plasma (PV) and whole blood viscosity (WBV), serum lipids and echocardiographic parameters were investigated. Blood pressure (systolic, diastolic and mean) was registered and color duplex sonography of the carotid arteries was performed. The lumen diameter, the intima media thickness (IMT) and …the blood flow velocity (systolic, mean and diastolic) in the carotid arteries were examined and the velocity asymmetry ratio (AR) was calculated. Significant increase of HT in UCI, of mean blood pressure (MBP) in the patients with RF and TIAs and of IMT and velocity parameters in all patients was established. The correlation analysis revealed parallel influence of HT, MBP, cardiac function, IMT, lumen diameter and some of the modifiable RF on the carotid AR in patients with chronic UCI affecting mainly the collateral circulation. The complex investigation of these factors would enable us to individualize the therapeutic approach in the patients with cerebral ischemic events. Show more

Keywords: Asymmetry ratio, carotid blood flow velocity, hematocrit, mean blood pressure, color duplex sonography, echocardiography, unilateral cerebral infarctions

DOI: 10.3233/CH-2010-1301

Citation: Clinical Hemorheology and Microcirculation, vol. 45, no. 2-4, pp. 239-244, 2010