Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | Department of Health Technology and Informatics | en_US |
| dc.contributor.advisor | Ying, Michael (HTI) | en_US |
| dc.creator | Cheng, Yangyang | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/14447 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | en_US |
| dc.rights | All rights reserved | en_US |
| dc.title | Assessment and investigation of cerebral large and small vessel diseases and coexisting cardiovascular dysfunction among middle-aged and older adults | en_US |
| dcterms.abstract | Background and purpose | en_US |
| dcterms.abstract | Brain vascular diseases, including intracranial atherosclerosis (ICAS) and cerebral small vessel disease (cSVD), a highly prevalent observation on head magnetic resonance imaging (MRI), have been demonstrated to be associated with cardiovascular disease. However, certain physiological mechanisms between cardiac dysfunction and cerebral vascular diseases have not been clarified, and much less is known about the clinical value of typical cardiac metrics for identifying people who are at a higher risk of cerebrovascular events. | en_US |
| dcterms.abstract | Atherosclerosis is a systemic disease that typically affects the cardiac and cerebral vasculatures. For the brain, being the end-organ of cumulative vascular damage, is profoundly influenced by cardiac function, evidence indicates that heart rate variability and autonomic dysregulation contribute to cerebral hypoperfusion, endothelial dysfunction, and subsequent vascular cognitive impairment. Given this intrinsic link, this thesis aims to elucidate the interplay between cardiac dysfunction indicated by ECG dispersion mapping and cerebral large- and small-vessel diseases revealed through 3.0T MRI, while exploring novel cardiac metrics as potential early biomarkers for cerebrovascular diseases, offering opportunities for timely intervention and prevention. | en_US |
| dcterms.abstract | Methods and Materials | en_US |
| dcterms.abstract | This community-based study consecutively recruited dwelling individuals aged more than 45 years or older. All of the study participants had no history of stroke or other severe vascular disease and completed all the examination processes of the study, including baseline questionnaire, MRI examinations-magnetic resonance angiography (MRA), and high-resolution MRI (HR-MRI), and 3-minute ECG dispersion mapping (ECG-DM). The detailed imaging features of intracranial atherosclerotic lesions were assessed by MRA and HR-MRI, including irregularity and smooth plaque, eccentricity or concentricity, positive or negative plaque burden, luminal stenosis, etc. The association between ICAS features and cSVD imaging markers was assessed to stratify risk factors in sub-healthy community-dwelling adults. The extent of cardiac dysfunction was evaluated by ECG-DM monitoring. Cardiac function was classified as either heart rate variability (HRV) or myocardium micro-ischemic metabolic impairment. HRV was assessed by frequency-domain (high-frequency, HF; and low-frequency, LF) and time-domain (the standard deviation of the NN intervals, SDNN; and the root mean square successive difference of intervals, RMSSD). The myocardium function was assessed using a series of metrics, including the myocardial micro-alteration index (MMI), atrium deviation, and ventricle deviation, which were automatically evaluated by ECG-DM monitoring. | en_US |
| dcterms.abstract | Results | en_US |
| dcterms.abstract | This study investigated the relationship between intracranial atherosclerotic stenosis (ICAS), cerebral small vessel disease (cSVD), and cardiac dysfunction in 272 community subjects. Non-stenotic ICAS was found in 65.8% of the 272 participants, with the middle cerebral arteries (MCAs) being the most frequent site, followed by the basilar and vertebral arteries. Moreover, our results demonstrated that the prevalence and severity of ICAS positively correlated with the presence and burden of cSVD imaging markers. Specifically, eccentric plaque morphology on vessel wall imaging was identified as an independent risk predictor of higher burden of white matter hyperintensities (OR, 1.47; 95% CI, 1.04 – 2.10; p=0.036). In terms of cerebral large and small vessel diseases and cardiac dysfunction, the study also revealed that lower HRV (OR, 1.55; 95% CI, 1.10 – 2.18; p=0.012) and atrium deviation (OR, 1.85; 95% CI, 1.10 – 3.14; p=0.022) were predictive risk factors for the presence of ICAS. Lastly, in the analysis of the correlations between cSVD (WMHs and CMBs) and cardiac dysfunction, independent associations were found between WMH burden and both ventricle(OR 3.1, 95% CI 1.37 – 7.29, p= 0.007) and atrium (OR 2.1, 95% CI 1.07 – 4.21, p=0.030) myocardial metabolic oxygen impairment; whereas the presence of CMBs were independently predicted by a higher myocardial micro-alteration index (MMI, OR 1.69, 95% CI 1.18 – 2.41, p= 0.004) and lower HRV (time-domain SDNN, OR 0.56, 95% CI 0.35 – 0.91, p= 0.019). | en_US |
| dcterms.abstract | Conclusions | en_US |
| dcterms.abstract | The study findings addressed three research questions related to cerebral large arteries and small vessel disease. Firstly, the study findings indicated a potential correlation between ICAS and cSVD, and the results further elucidated that eccentric atherosclerotic plaque is an independent risk factor for a greater burden of WMH. This highlights a distinction and correlation between two types of intracranial vascular lesions and suggests the potential for targeted prevention of lesion formation and cerebrovascular diseases. Secondly, the associations with cardiac dysfunction between cerebral large-arterial atherosclerosis and small vessel disease are different. Irregular heart rate variability and atrium hypoxia were more closely associated with features indicative of a higher risk of large artery atherosclerosis. These cardiac indicators are crucial for the early identification of adults who are at high risk for ICAS, thereby enabling clinicians to prioritize early diagnosis, optimize treatment strategies, implement preventive measures, and minimize adverse outcomes of cerebrovascular events. Thirdly, the study showed a robust dose-response relationship of the presence and burden of white matter hyperintensities and cerebral microbleeds with abnormal variation in heart rate and myocardial micro-alteration impairment. Myocardial oxidative metabolic impairment is significantly associated with the severity of WMHs, and reduced heart rate and myocardial micro-alteration abnormalities could be considered risk predictors for the incidence of CMBs. Overall, this PhD study elucidated that cardiac dysfunction may have distinct pathophysiological roles in both cerebral large and small vessel diseases by influencing the cerebrovascular beds. | en_US |
| dcterms.extent | xxii, 151 pages : color illustrations | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2026 | en_US |
| dcterms.educationalLevel | Ph.D. | en_US |
| dcterms.educationalLevel | All Doctorate | en_US |
| dcterms.accessRights | open access | en_US |
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