Saudi Cultural Missions Theses & Dissertations
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Item Restricted RESISTANT HYPERTENSION – PATHOLOGICAL INSIGHTS FROM CARDIAC MECHANICS(University of Liverpool, 2024-04) Akhmimi, Azhar; Shantsila, Alena; Lip, Gregory; Oxborough, David; Sprung, ToriIntroduction: Patients with resistant hypertension suffer from a high rate of cardiovascular complications and have poor prognosis. Given the poor prognosis in patients with resistant hypertension, early identification of abnormalities in cardiac mechanics, arterial stiffness, endothelial function and autonomic function is of clinical importance to aid in risk stratification and enable timely therapeutic interventions. There are limited data on left ventricular (LV) and left atrial (LA) mechanics, arterial stiffness, endothelial function, and autonomic function assessed by heart rate variability (HRV) in patients with resistant hypertension. Additionally, the relationship between measures of cardiac mechanics, arterial stiffness, endothelial function and autonomic function, as well as the effects of intensified blood pressure (BP) management on these indices, have not yet been investigated in resistant hypertension population. Aims: This study aimed to investigate LV and LA mechanics, arterial stiffness, endothelial function and autonomic function in patients with resistant hypertension, controlled essential hypertension and normotensive controls, and to determine the association between these measures in patients with resistant hypertension. Furthermore, to evaluate the effects of 8 weeks of intensified BP management on LV and LA mechanics, arterial stiffness, endothelial function and autonomic function in patients with resistant hypertension. Methods: A prospective cross-sectional study included 54 participants (17 with resistant hypertension, 18 with controlled hypertension, and 19 normotensive controls), while the longitudinal study included 16 patients with resistant hypertension. Participants underwent transthoracic echocardiography, speckle tracking echocardiography to assess LV and LA mechanics, pulse wave analysis to evaluate arterial stiffness determined by aortic augmentation index (AIx), flow-mediated dilatation (FMD) to assess endothelial function, and HRV to evaluate autonomic function. Results: Patients with resistant hypertension had higher office and central BP, pronounced cardiac remodelling, impaired LV and LA mechanics, increased AIx and lower FMD compared to controlled hypertension and normotensive controls. Several HRV variables were significantly reduced in resistant hypertension compared to normotensive controls. Lower FMD was associated with worse LV longitudinal deformation and reduced HRV indices were related to increased LV twist among patients with resistant hypertension. Following 8 weeks of optimising antihypertensive treatment, patients with resistant hypertension exhibited significant reductions in office and central BP, AIx, as well as significant improvements in LV and LA mechanics, FMD, and total power (TP) index of HRV compared to baseline. Conclusion: Patients with resistant hypertension show evidence of greater cardiac remodelling with concomitant impairment of their LV and LA mechanics, increased arterial stiffness and worsened endothelial function compared to controlled hypertension and normotensive controls. Patients with resistant hypertension exhibited impairment in several HRV indices compared to normotensive controls. Intensive BP management for 8 weeks in patients with resistant hypertension has a favourable impact on LV and LA mechanics, arterial stiffness, endothelial function, and the TP spectrum of HRV. The assessment of cardiac mechanics, arterial stiffness, endothelial and autonomic function in patients with resistant hypertension may have valuable prognostic and therapeutic implications.13 0Item Restricted Systemic Inflammation, Arterial Stiffness, and Vascular Endothelial Dysfunction in Patients with Chronic Lung Disease(University of Dundee, 2024-05-22) Arafah, Abdullah M.; Khan, FaiselChronic lung disease (CLD) is considered a heterogeneous, complex, and multicomponent condition. Types of CLD include bronchiectasis, chronic obstructive pulmonary disease (COPD), and asthma. Cardiovascular events and peripheral vascular disease are highly prevalent among patients who are known to have CLD. It is increasingly acknowledged that cardiovascular comorbidities contribute to the disease’s severity. The underlying mechanisms that link CLD and cardiovascular disease (CVD) are inadequately understood. Systemic inflammation is a key component that could describe the link between CLD and CVD. Changes in vascular endothelial function accompany the increased cardiovascular events in CLD. Atherosclerosis and calcification of macrovascular and microvascular lead to further decrease vascular compliance. These structural changes in the vascular wall contribute to increased arterial stiffness observed in patients with CLD. Endothelial dysfunction and arterial stiffness are early signs of vascular disease and the development of cardiovascular events. Chronic systemic inflammation plays a vital role in linking CLD to the development of endothelial dysfunction and arterial stiffness. Therefore, this study aims to investigate the association between CLD and CVD. To successfully achieve the aims of this project, four work packages were employed, including a systematic review, a retrospective study, a Mendelian randomisation study, and a cross-section study involving the BRIDGE study. The systematic review study related to arterial stiffness in patients with CLD using various pulse wave velocity (PWV) methods, which assessed and summarised the outcomes of all relevant studies regarding the link between CLD and CVD. The retrospective study analysed anonymous data from the SUMMIT study to assess the vascular function in patients with CLD in the presence of CVD and type 2 diabetes mellitus, and shows a significantly greater PWV; p-value = 0.015 and carotid intima-media thickness (CIMT) in the CLD patients; p-value = 0.001. The Mendelian randomisation study investigated potential genetic causal links between CLD and arterial stiffness, which shows a significant association; p-value = 0.021. The cross-section study and BRIDGE study utilised biomarkers to determine if there are shared pathways that contribute to the development and progression of CLD and CVD, and shows significant differences in PWV, and microvascular function; p-value = 0.001, blood biomarkers include adiponectin, VCAM-1, GDF-15, coagulation factor III, syndecan-1, and matrix metalloproteinase (MMP-10); p-value = 0.001. In conclusion, this study revealed a significant association between CLD and CVD. Therefore, monitoring CVD risk, including assessment of endothelial dysfunction and arterial stiffness, in patients with CLD might be helpful for risk stratification and for identifying future CVD pathologies and disease progression. This emphasises the need to identify and manage comorbid CLD and CVD to target new or existing therapeutic approaches to control systemic inflammation and improve overall lung and cardiovascular health.9 0Item Restricted Advanced Ultrasound Applications for Assessing Arteriovenous Fistula Surgery Outcomes in End Stage Renal Failure(Imperial College London, 2024-03-01) Faqihi, Wael; Aslam, MohammedArteriovenous fistulas are critical for facilitating hemodialysis, yet a considerable proportion fail to mature, presenting challenges in predicting their outcomes. This study explores the impact of arterial stiffness and endothelial dysfunction on AVF maturation utilising advanced measurement techniques. A prospective cohort observational study was conducted involving 76 end-stage renal failure patients undergoing AVF surgery. Various assessments, including 2DSWE, 2DSST, LDF, and FMD, were performed to evaluate arterial properties and endothelial function preoperatively. Additionally, intraoperative BVF measurements were taken using Transonic vascular flow probes. Results revealed a 22% AVF failure rate, with hypertension, diabetes, and cardiovascular disease prevalent among the cohort. Higher arterial stiffness was observed in the failure group, while the mature group exhibited better endothelial function. Intraoperative BVF emerged as a significant predictor of immediate maturation outcomes, with defined cutoff values. The developed AVF prediction model demonstrated good performance. These findings underscore the potential of advanced measurement techniques in understanding AVF maturation dynamics and highlight the importance of intraoperative BVF assessment in guiding clinical decisions. Further validation in larger clinical trials is warranted to consolidate these findings.18 0