Decrease of arterial wall shear stress (WSS) is associated with higher probability of atherosclerotic plaque development in many disease conditions. End-stage renal diseases (ESRD) patients suffer from vascular disease frequently, but its nature differs from general population. This study was aimed at proving an association between common carotid wall shear stress and the presence of carotid bifurcation plaques in a group of ESRD patients. ESRD subjects, planned for the creation of a dialysis access and therapy were included. Wall shear rate (WSR) was used as a surrogate of WSS and was analyzed in the common carotid arteries by duplex ultrasonography. Intima media thickness (IMT) was measured at the same site. The presence/absence of carotid bifurcation plaques was recorded. The endothelial function was estimated by the levels of von Willebrand factor (vWf). 35 ESRD patients were included (19 females, 17 diabetics). Atherosclerotic plaque was present in 53 % of bifurcations. Wall shear rate was lower in arteries with plaques (349±148 vs. 506±206 s-1, p=0.005) and was directly related to the height of IMT and inversely to the activity of vWf (r= –0.65, p=0.016). Lower wall shear rate in the common carotid arteries is linked to the endothelial dysfunction and to the presence of atherosclerotic plaques in carotid bifurcations in ESRD subjects. Faster arterial dilatation may facilitate this process in ESRD subjects., J. Malík ... [et al.]., and Obsahuje seznam literatury
Previous studies revealed altered levels of the circulating insulin-like growth factor-I (IGF-I) and of its binding protein-3 (IGFBP-3) in subjects with coronary atherosclerosis, metabolic syndrome and premature atherosclerosis. Hyperlipidemia is a powerful risk factor of atherosclerosis. We expected IGF-I and IGFBP-3 alterations in subjects with moderate/severe hyperlipidemia but without any clinical manifestation of atherosclerosis. Total IGF-I and IGFBP-3 were assessed in 56 patients with mixed hyperlipidemia (MHL; cholesterol>6.0 mmol/l, triglycerides>2.0 mmol/l), in 33 patients with isolated hypercholesterolemia (IHC; cholesterol>6.0 mmol/l, triglycerides<2.0 mmol/l), and in 29 healthy controls (cholesterol<6.0 mmol/l, triglycerides<2.0 mmol/l). The molar ratio of IGF-I/IGFBP-3 was used as a measure of free IGF-I. IHC subjects differed from controls by lower total IGF-I (164±60 vs. 209±73 ng/ml, p=0.01) and IGF-I/IGFBP-3 ratio (0.14±0.05 vs. 0.17±0.04, p=0.04). Compared to controls, MHL subjects had lower total IGF-I (153±54 ng/ml, p=0.0002) and IGFBP-3 (2.8±0.6 mg/ml, p<0.0001), but higher IGF-I/IGFBP-3 ratio (0.25±0.06, p<0.0001). Differences remained significant after the adjustment for clinical and biochemical covariates, except for triglycerides. Patients with both IHC and MHL have lower total IGF-I compared to controls. The mechanism is presumably different in IHC and MHL. Because of prominent reduction of IGFBP-3 in patients with MHL, they have reduced total IGF-I despite the actual elevation IGF-I/IGFBP-3 ratio as a surrogate of free IGF-I., J. Malík, T. Štulc, D. Wichterle, V. Melenovský, E. Chytilová, Z. Lacinová, J. Marek, R. Češka., and Obsahuje bibliografii a bibliografické odkazy
Arterial sites with low wall shear stress (WSS) are more prone to the development of atherosclerotic plaques, as was observed in carotid arteries in subjects with atherosclerosis risk factors. Type 2 diabetes mellitus (DM), hypertension, hyperlipidemia and other components of the metabolic syndrome, are associated with high risk for symptomatic cerebrovascular disease. It was shown by others that untreated type 2 DM is associated with lower WSS in common carotid arteries. However, the cardiovascular risk of type 2 DM could be modified by therapy. The aim of our study was to test the hypothesis that treated type 2 DM subjects with metabolic syndrome still have lower WSS in common carotid arteries than healthy controls. We enrolled 26 compensated DM subjects with metabolic syndrome, treated by metformin, statins and ACEI for more than 6 months, and 22 aged-comparable healthy controls. Wall shear rate (WSR) was used as a measure of WSS. A linear 3-11 MHz probe was used to measure blood velocity and internal diameter in the common carotid arteries. We compared observed values of WSR adjusted for age by ANCOVA. Wall shear rate was significantly lower in DM group than in control subjects: peak (systolic) values of wall shear rate were 410±130 s-1 vs. 487±111 s-1 (p<0.005). DM subjects had significantly lower WSR, because of both thinner lumen and slower blood flow velocities. Lower WSR was accompanied by higher IMT (0.73±0.12 mm vs. 0.64±0.11 mm, p<0.001). Treated subjects with compensated type 2 DM with metabolic syndrome still have atherogenic hemodynamic profile. These findings might help to understand faster progression of atherosclerosis in diabetic subjects with metabolic syndrome despite up-to-date medication., E. Chytilová ...[et al.]., and Obsahuje seznam literatury
More than 50 % of end-stage renal disease (ESRD) patients treated by chronic hemodialysis die from cardiovascular diseases, including congestive heart failure (CHF). The incidence of CHF is rising in both general and ESRD population. However, the mechanisms, which lead to the development of CHF in dialyzed patients, differ considerably. First, there are several factors leading to increase of the left ventricular afterload: volume overload between dialyses, hypertension, increased arterial stiffness, anemia, vascular access flow (arteriovenous fistula) and sympathetic activation. Second, hypertension, left ventricular hypertrophy, anemia and frequently present coronary artery disease worsen myocardial oxygenation. The combination of these factors explains the high incidence of CHF in dialyzed patients and their roles are reviewed in this article., J. Malík ... [et al.]., and Obsahuje seznam literatury
Early recognition of collapsing hemodynamics in pulmonary embolism is necessary to avoid cardiac arrest using aggressive medical therapy or mechanical cardiac support. The aim of the study was to identify the maximal acute hemodynamic compensatory steady state. Overall, 40 dynamic obstructions of pulmonary artery were performe d and hemodynamic data were collected. Occlusion of only left or right pulmonary artery did not lead to the hemodynamic collapse. When gradually obstructing the bifurcation, the right ventri cle end-diastolic area expanded proportionally to pulmonary artery mean pressure from 11.6 (10.1, 14.1) to 17.8 (16.1, 18.8) cm 2 (p<0.0001) and pulmonary artery mean pressure increased from 22 (20, 24) to 44 (41, 47) mmHg (p<0.0001) at the poin t of maximal hemodynamic compensatory steady state. Sim ilarly, mean arte rial pressure decreased from 96 (87, 101) to 60 (53, 78) mmHg (p<0.0001), central venous pressure increased from 4 (4, 5) to 7 (6, 8) mmHg (p<0.0001), heart rate increased from 92 (88, 97) to 147 (122, 165) /min (p<0.0001), contin uous cardiac output dropped from 5.2 (4.7, 5.8) to 4.3 (3.7, 5.0) l/min (p=0.0023), modified shock index increased from 0.99 (0.81, 1.10) to 2.31 (1.99, 2.72), p<0.0001. In conclusion, in stead of continuous cardiac output all of the analyzed parameters can sensitively determine the individual maximal compensatory response to obstructive shock. We assume their monitoring can be used to predict the critical phase of the hemodynamic status in routine practice., J. Kudlička ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Vascular stenosis is often described only by its percentage in both clinical and scientific praxis. Previous studies gave inconclusive results regarding the effect of stenosis eccentricity on its hemodynamic effect. The aim of this experimental study was to investigate and quantify the effect of stenosis severity and eccentricity on the pressure drop. A combination of pressure and flow measurements by Par ticle Imaging Velocimetry (PIV) method was used. Models of the same stenosis significance but with different levels of eccentricity were studied in vitro by PIV. This study has shown that stenosis asymmetry is associated with more profound pressure drop an d flow volume decrease. On the contrary, pressure drop and flow volume decrease were not further significantly influenced by the level of asymmetry. Hemodynamic changes associated with stenosis eccentricity must be taken into account in both clinical and s cientific studies., L. Novakova, J. Kolinsky, J. Adamec, J. Kudlicka, J. Malik., and Obsahuje bibliografii