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Vascular access for hemodialysis and hemodynamics
Válek, Martin ; Lopot, František (advisor) ; Malík, Jan (referee) ; Roček, Miloslav (referee)
The study is based on the program of monitoring of the state of surgically created vascular accesses by measuring the vascular access blood flow (QVA). Besides the comprehensive analysis of factors influencing the value of QVA it discussed in detail hemodynamic changes caused by the presence of non-physiological arteriovenous anastomosis. The study is based on data acquired in the course of more than 10 years during which this program has been routinely used and is based on data from 506 patients with a total of 4,296 measurements of QVA. In patients, QVA is significantly inter- and intraindividually variable. QVA is significantly influenced by multiple factors and corresponds also to the overall health of the patient. No simple factor has been proven to predominantly influence QVA. The study points out the significant long-term physiological variability of QVA (23%) as a parameter that was not taken into account despite its importance in deciding on the correct indication of radiological interventions. The study also analyzes the strong correlation between QVA and cardiac output. It brings a new method of evaluation of the influence of vascular access on myocardium through a calculation of the load of left ventricle and shows that there is a strong non-linear dependency between the flow and the...
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Cerebral hypoxia in chronic kidney disease and its relation to cognitive decline
Kalendová, Lucie ; Malík, Jan (advisor) ; Bednářová, Vladimíra (referee) ; Janečková, Jana (referee)
Cerebral hypoxia in chronic kidney disease and its relation to cognitive decline Dissertation abstract - MUDr. Lucie Kalendová Introduction: Patients with chronic kidney disease in need of regular hemodialysis treatment have high rates of cognitive impairment. In its multifactorial etiology, vascular changes, cerebral ischemia and hypoxia play a major role. In our work we first studied the association between low cerebral oxygenation and cognitive impairment in this population. Subsequently, we focused on one of the possible etiological factors in this association - the presence of a vascular shunt for hemodialysis. Methods: Chronic hemodialysis patients without overt cognitive impairment participated in the studies. We used a near-infrared spectroscopy (NIRS) device named INVOS for monitoring cerebral oxygenation (rSO2). Cognitive function was assessed with the Montreal Cognitive Assessment (MoCA). To assess the effect of vascular shunt, we performed an interventional study based on short-term ultrasound-confirmed manual compression with continuous monitoring of rSO2. Results: In 39 patients (49 % women, age 64 ± 14 years) we observed a significantly lower rSO2 in the subgroup presenting cognitive decline than in patients without this diagnosis (48 ± 9 vs. 57 ± 10; p = 0.01). The association remained...
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Jehlička, Petr ; Piťha, Jan (advisor) ; Urbanová, Zuzana (referee) ; Malík, Jan (referee)
MUDr. JEHLIČKA SUMMARY This study has focused on a new method for the assessment of endothelial dysfunction (ED) using the Deceleration Index (DI). A total of 242 ultrasonographic examinations were performed in 92 children (FH 32, DM1 30, healthy controls 3O). The average DI values were 21.8%(±9.4)in healthy children, 19.9%(±9)in FH and 17.6%(±14)in the DM1 group. There were statistically insignificant differences between the study groups. This was most probably due to the high biological variability of the method employed. The coefficient of variation of DI was 1.02 (0.68 -1.53). Therefore, the clinical usefulness of DI is limited with regards to the individual assessment of ED and thus for the prediction of cardiovascular risk. The association of ADMA and oxLDL with ED and their superior sensitivity compared to DI and FMD has been confirmed in our study. Folic acid supplementation did not lead to a statistically signifiant improvement of DI and FMD. Similarly, plasma levels of ADMA and oxLDL remained unchanged despite a decrease of homocysteine and hsCRP in these children. This finding demonstrates a complicated relationship between ADMA, homocysteine and folic acid. The protective effect of folic acid on ED in high risk children was not confirmed in this study.
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Wall shear stress and its role in progress of atherosclerosis
Chytilová, Eva ; Malík, Jan (advisor) ; Horký, Karel (referee) ; Piťha, Jan (referee)
Atherosclerosis is associated with systemic risk factors such as hypertension, hyperlipidemia, diabetes mellitus and smoking. Nonetheless, atherosclerosis is a focal disease, preferentially affecting predisposed areas. The main local hemodynamic factor is wall shear stress, the frictional force acting tangencially on the endothelial cell surface. The effect of wall shear stress depends on its magnitude and direction, as well as on the characteristic of vessel geometry and blood flow. Wall shear stress is an important determinant of endothelial function and phenotype. Previous research showed that arterial sites with chronically low WSS are more prone to the development of atherosclerotic plaques. Mostly, it is the case of outer wall of arterial bifurcations, where the stroma of vessel wall prevents arterio-constriction in response to low WSS. However, lower WSS was described also in straight arterial segments, such as carotid arteries, in the presence of atherosclerosis risk factors.
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Possibilities of genetic testing in patients with pheochromocytoma and paraganglioma.
Turková, Hana ; Zelinka, Tomáš (advisor) ; Malík, Jan (referee) ; Fryšák, Zdeněk (referee)
1. Abstract Pheochromocytoma/ paraganglioma (FEO/PGL) may be developed on the basis of an inherited genetic mutation of different genes. They are associated with a high risk of developing of secondary hypertension, organ damage and metastatic disease that can be fatal. The aim was to focus on the possibility of genetic testing in patients with FEO/PGL, especially in patients with malignant tumors. The issue FEO/PGL, however, concerns not only the examination and assessment of risks arising therefrom, as well as other therapies and monitoring, including appropriate recommendations for clinical practice. We demonstrated a 20% incidence of cardiovascular (CV) complications before determining the final diagnosis of FEO/PGL, mainly arrhythmic, followed by complications of myocardial ischemia and accentuate atherosclerosis. Elevated levels of vitamin C and decreased levels of malondialdehyde (MDA) following the successful removal of the tumor demonstrated reduction of oxidative stress postoperatively. We found that early postoperative testing of levels of plasma metanephrines to confirm the success of surgical removal of FEO/PGL is already possible, since there was no significant correlation between plasma levels of metanephrines and postoperative examination interval. Distribution of frequency of metastatic...
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Cardiovascular complications in patients with end-stage renal disease.
Valeriánová, Anna ; Malík, Jan (advisor) ; Zemánek, David (referee) ; Piťha, Jan (referee)
Patients with end-stage renal disease frequently suffer from cardiovascular complications. Many factors contribute to their development: hyperkinetic circulation caused by anaemia, fluid retention and by presence of dialysis arteriovenous access; metabolic changes leading to acceleration of atherosclerosis and increase of vascular stiffness and also fluctuation of blood pressure and organ perfusion during haemodialysis, that cause repeated tissue hypoxia. We performed our research on patients in chronic haemodialysis programme. The project studying long-term patency of dialysis access showed that dialysis graft patency is negatively influenced by presence of coronary artery disease and low serum concentrations of cholesterol. In our studies about tissue hypoxia we proved that haemodialysis patients suffer from hypoxia of cerebral tissue and muscle tissue of the dialysis access arm, and that the hypoxia worsens during dialysis. Factors associated with brain hypoxia are presence of heart failure, higher BNP levels and higher erythrocyte distribution width. One of the serious consequences of brain hypoxia is development of cognitive deficit. Among the negative impact of haemodialysis on the heart, we observed left atrial dysfunction, which is a consequence of long-term remodelling and cannot be...
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Structural and hemodynamic characteristics of atherosclerotic plaques in carotid arteries with relation to endovascular manipulation during carotid artery stenting.
Špaček, Miloslav ; Zemánek, David (advisor) ; Malík, Jan (referee) ; Pařenica, Jiří (referee)
Atherosclerotic diseases including stroke are the leading causes of morbidity, mortality as well as disability in industrialized countries. Carotid endarterectomy was long considered the stan- dard approach for the treatment of atherosclerotic carotid disease, one of major causes of stroke. Over time, carotid artery stenting (CAS) has evolved as an alternative approach and is considered equivalent to surgical treatment in selected patients. Particularly in the last years, CAS has gained attention with the increasing knowledge regarding atherosclerotic plaque and cerebrovascular flow. In our study, we focused on patients undergoing CAS and evaluated structural and hemodynamic characteristics of atherosclerotic plaques together with relation to endovascular manipulation. The major part of the study includes transcranial doppler ultrasound evaluation which is able to detect flow in major cerebral arteries as well as to detect microembolizations of atherosclerotic particles during CAS. In eligible patients, we investigated the usefulness of cerebrovascular reserve (CVR) testing to predict severe hemodynamic changes in ipsilateral middle cerebral artery induced by temporary carotid occlusion during proximally protected CAS. CVR was tested by means of a breath-holding test and ophthalmic artery flow...
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Possibilities of genetic testing in patients with pheochromocytoma and paraganglioma.
Turková, Hana ; Zelinka, Tomáš (advisor) ; Malík, Jan (referee) ; Fryšák, Zdeněk (referee)
1. Abstract Pheochromocytoma/ paraganglioma (FEO/PGL) may be developed on the basis of an inherited genetic mutation of different genes. They are associated with a high risk of developing of secondary hypertension, organ damage and metastatic disease that can be fatal. The aim was to focus on the possibility of genetic testing in patients with FEO/PGL, especially in patients with malignant tumors. The issue FEO/PGL, however, concerns not only the examination and assessment of risks arising therefrom, as well as other therapies and monitoring, including appropriate recommendations for clinical practice. We demonstrated a 20% incidence of cardiovascular (CV) complications before determining the final diagnosis of FEO/PGL, mainly arrhythmic, followed by complications of myocardial ischemia and accentuate atherosclerosis. Elevated levels of vitamin C and decreased levels of malondialdehyde (MDA) following the successful removal of the tumor demonstrated reduction of oxidative stress postoperatively. We found that early postoperative testing of levels of plasma metanephrines to confirm the success of surgical removal of FEO/PGL is already possible, since there was no significant correlation between plasma levels of metanephrines and postoperative examination interval. Distribution of frequency of metastatic...
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