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The biological significance of changes in the vascular wall and atherosclerotic plaque for the development of atherosclerotic disease of the coronary arteries
Horváth, Martin ; Hájek, Petr (advisor) ; Poledne, Rudolf (referee) ; Kovárník, Tomáš (referee)
Acute complications of atherosclerosis are typically caused by arterial occlusion due to acute thrombosis forming over a ruptured vulnerable atherosclerotic plaque (VP). Early identification of such VP prior to their rupture could help prevent these events. At the same time, methods for assessing cardiovascular risk are focused on measures at the population level and are not sensitive and specific enough to assess the risk of individual patients. We therefore focused on the possibilities of in vivo detection of VP using biomarkers and invasive imaging methods. First, we focused on the detection of microRNAs (miRs), which have been investigated in recent years as promising biomarkers for a number of diseases, including atherosclerosis. We determined miR levels using quantitative polymerase chain reaction in peripheral venous blood samples from patients in very early phase of ST-elevation myocardial infarction (STEMI), which served as the closest clinical model of acute VP rupture. The results led to the identification of two miRs (miR-331 and miR-151-3p) that were deregulated in STEMI and could be biomarkers of VP. In the next part of the research, we dealt with the possibilities of invasive imaging of VP using intravascular ultrasound and near- infrared spectroscopy (IVUS and NIRS). We confirmed...
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Biomarkers, intravascular ultrasound and near-infrared spectroscopy in the assessment of vulnerable atherosclerotic plaque
Štěchovský, Cyril ; Hájek, Petr (advisor) ; Krajina, Antonín (referee) ; Kaňovský, Jan (referee)
Biomarkers, Intravascular Ultrasound and Near-Infrared Spectroscopy in the Assessment of Vulnerable Atherosclerotic Plaque Abstract The thesis describes pathophysiology of a vulnerable atherosclerotic plaque, detection of the vulnerable plaque in the stenosis of the internal carotid artery (ICA), and optimalization of carotid stenting (CAS) with near-infrared spectroscopy (NIRS) and intravascular ultrasound (IVUS) imaging. NIRS detects lipid core of the vulnerable lipid rich plaque (LRP). We demonstrated safety of NIRS-IVUS imaging during CAS. LRP was detected in one third of ICAs before CAS. Lipid signal was not correlated with plaque morphology (IVUS), biomarkers or clinical variables. CAS caused significant decrease of the lipid signal. Angiography overestimated severity of stenosis of the ICA and vastly underestimated residual stenosis after CAS. Presence of the LRP in the stenosis was neither associated with periprocedural neurological complications of CAS nor long-term adverse cardiovascular events. IVUS identified planimetric features associated with long-term restenosis or stent occlusion. After a median follow-up of 31 months, repeated NIRS-IVUS of the implanted stents showed significant expansion of the stents, diffuse neointimal hyperplasia and further reduction of the lipid signal. We assume,...
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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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Physiological responses on standardized climbing task in sport climbers
Gajdošík, Jan ; Baláš, Jiří (advisor) ; Radvanský, Jiří (referee)
Title: Physiological responses on standardized climbing task in sport climbers Purpose: To determine the effect of height, wall angle, climbing speed and climbing ability on physiological responses in sport climbers. Methods: The study was divided into three parts. 75 sport climbers (36 female and 39 male) completed differing tests on climbing wall and motorized climbing ergometer. Perceived exertion was assessed on a scale suggested by Borg. Indirect calorimetry, venous blood samples and near-infrared spectroscopy were used to assess physiological response, hormonal response and muscle oxygen saturation, respectively. Results: Perceived exertions were higher when climbing to height as opposes to climbing low to the ground on the treadwall (+5,3%; P = 0,013; ηp 2 = 0,149) (Study 1A). The physiological response was higher on the climbing wall as opposed to the treadwall: V̇ O2 (+6%; P = 0,03; ηp 2 = 0,22), SF (+4%; P = 0,04; ηp 2 = 0,20), V̇ E (+9%; P = 0,01; ηp 2 = 0,30) a EC (+16%; P < 0,001; ηp 2 = 0,48). There was an interaction for climbing ability and post- climbing catecholamine concentration (P < 0,01, ηp 2 = 0,28) (Study 1B). With increasing climbing speed greater differences were found for V̇ O2 (P < 0,001, ηp 2 = 0,923) than for StO2 (P < 0,001, ηp 2 = 0,448). Between-subject effect...
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Effect of cold water immersion on intermittent isometric forearm flexor contractions to failure in rock climbers
Kodejška, Jan ; Baláš, Jiří (advisor) ; Stejskal, Pavel (referee) ; Radvanský, Jiří (referee)
Title: Effect of cold water immersion on intermittent isometric forearm flexor contractions to failure in rock climbers Objectives: The aim of this study was to determine the effect of cold water immersion on intermittent isometric forearm flexor contraction to failure in rock climbers. Methods: Thirty-two climbers (15 male and 17 female) completed three intermittent trials to failure, on a climbing-specific handgrip dynamometer, on three separate visits to the laboratory. For each visit a different recovery strategy was employed: passive recovery (PAS), cold water immersion at 8 řC (CWI 8) or 15 řC (CWI 15). The force time integral (FTI - time of contraction multiplied by the force of contraction) was determined to assess intermittent performance. The tissue saturation index (TSI) and total haemoglobin (tHb) during isometric contractions from near-infrared spectroscopy (NIRS) were determined to assess hemodynamic changes. Differences between repeated trials and three recovery protocols, derived parameters NIRS, were assessed using repeated measures ANOVA with Bonferroni corrections. Results: There was no significant difference between conditions after trial one. In response to the PAS recovery condition there was a 10% and 22% decrease in FTI in the second and third trials, respectively. The PAS...
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Physiological responses on standardized climbing task in sport climbers
Gajdošík, Jan ; Baláš, Jiří (advisor) ; Radvanský, Jiří (referee) ; Vajda, Matej (referee)
Title: Physiological responses on standardized climbing task in sport climbers Purpose: To determine the effect of height, wall angle, climbing speed and climbing ability on physiological responses in sport climbers. Methods: The study was divided into three parts. 75 sport climbers (36 female and 39 male) completed differing tests on climbing wall and motorized climbing ergometer. Perceived exertion was assessed on a scale suggested by Borg. Indirect calorimetry, venous blood samples and near-infrared spectroscopy were used to assess physiological response, hormonal response and muscle oxygen saturation, respectively. Results: Perceived exertions were higher when climbing to height as opposes to climbing low to the ground on the treadwall (+5,3%; P = 0,013; ηp 2 = 0,149) (Study 1A). The physiological response was higher on the climbing wall as opposed to the treadwall: V̇ O2 (+6%; P = 0,03; ηp 2 = 0,22), SF (+4%; P = 0,04; ηp 2 = 0,20), V̇ E (+9%; P = 0,01; ηp 2 = 0,30) a EC (+16%; P < 0,001; ηp 2 = 0,48). There was an interaction for climbing ability and post- climbing catecholamine concentration (P < 0,01, ηp 2 = 0,28) (Study 1B). With increasing climbing speed greater differences were found for V̇ O2 (P < 0,001, ηp 2 = 0,923) than for StO2 (P < 0,001, ηp 2 = 0,448). Between-subject effect...
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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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Effect of cold water immersion on intermittent isometric forearm flexor contractions to failure in rock climbers
Kodejška, Jan ; Baláš, Jiří (advisor) ; Stejskal, Pavel (referee) ; Radvanský, Jiří (referee)
Title: Effect of cold water immersion on intermittent isometric forearm flexor contractions to failure in rock climbers Objectives: The aim of this study was to determine the effect of cold water immersion on intermittent isometric forearm flexor contraction to failure in rock climbers. Methods: Thirty-two climbers (15 male and 17 female) completed three intermittent trials to failure, on a climbing-specific handgrip dynamometer, on three separate visits to the laboratory. For each visit a different recovery strategy was employed: passive recovery (PAS), cold water immersion at 8 řC (CWI 8) or 15 řC (CWI 15). The force time integral (FTI - time of contraction multiplied by the force of contraction) was determined to assess intermittent performance. The tissue saturation index (TSI) and total haemoglobin (tHb) during isometric contractions from near-infrared spectroscopy (NIRS) were determined to assess hemodynamic changes. Differences between repeated trials and three recovery protocols, derived parameters NIRS, were assessed using repeated measures ANOVA with Bonferroni corrections. Results: There was no significant difference between conditions after trial one. In response to the PAS recovery condition there was a 10% and 22% decrease in FTI in the second and third trials, respectively. The PAS...
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