published_or_final_version / Community Medicine / Master / Master of Public Health

MMed, Community Health, Faculty of Health Sciences, University of the Witwatersrand, 2009 / Introduction Adverse outcomes of pregnancy are global health problems that are much more pronounced in developing countries. The risk factors associated with adverse outcomes of pregnancy are multifactorial. In South Africa, the population prevalence and associated risk factors of maternal and perinatal mortality are routinely documented, but there are gaps in the data on other pregnancy adverse outcomes. This study was aimed at determining the prevalence rates and related risk factors of preterm births and pregnancy loss in an urban population in South Africa. Methods The study was a cross-sectional analytical community study of women 18 to 49 years of age, living in the Potchefstroom municipality. It was conducted from August 2007 to April 2008. Participants were selected using a systematic random sampling strategy; 1 210 women participated. An adapted reproductive health questionnaire was used to collect sociodemographic, environmental, occupational and reproductive health data. Results Prevalence of pregnancy loss and preterm births were estimated to be 5.6% [95% CI: 5.57% - 5.63%] and 13.4% [95% CI: 13.36% - 13.44%], respectively. Pregnancy loss was associated with psychological stress and working during pregnancy; preterm birth was associated with White, Coloured and Indian race, primary and high school education, psychological stress and chronic disease; and antenatal care use was protective against both pregnancy loss and preterm birth. Conclusion The prevalence of pregnancy loss found in this study was lower than would be expected in the general South African population; while the preterm birth prevalence, although lower than that of other developing and middle income countries, could be improved. Generally, there are common risk factors for pregnancy loss and for preterm births. Some of the existing evidence on risk factors was supported by the findings of this study. Improvement of surveillance and health information systems for pregnancy loss and preterm births would provide essential information on the burden of these outcomes in South Africa and would subsequently guide policy, research and prioritisation of effective control programmes.

Background and objectives In low resource settings, ultrasound scans may not be available for amniotic fluid volume (AFV) assessment as part of fetal evaluation for suspected prolonged pregnancies (≥41 weeks’ gestation). The objectives of this study were: 1) to describe AFV measurements using ultrasound in women with suspected prolonged pregnancies, and to relate these measurements to maternal and fetal factors; 2) to evaluate different clinical palpation methods for estimating AFV; and 3) to determine the ability of clinical palpation to estimate AFV and predict oligohydramnios, using ultrasound-based amniotic fluid index (AFI) as a gold standard, accounting for the influence of maternal and fetal factors. Methods The study included women referred to Chris Hani Baragwanath Academic Hospital from midwife-run antenatal clinics because of concern about prolonged pregnancy (gestational age ≥41 weeks). On arrival at hospital, the women had real-time ultrasound assessment of AFI by an experienced ultrasonographer. The researcher, blinded to the AFI result, estimated AFV by abdominal palpation using ballottability of fetal parts, uterine fluctuance, uterine irritability, easily felt fetal parts, and a general impression of AFV. After recording the palpation findings, the researcher made a best estimate of gestational age for each woman based on the last menstrual period, early pregnancy ultrasound scans if available, or other relevant clinical information. Oligohydramnios was defined as an AFI <5 cm. Results One hundred women participated, of whom 45 had a best estimate gestational age ≥41 weeks. The mean AFI was 8.1±4.3 cm; 23 women had an AFI <5 cm. Twenty women were HIV infected. In univariable and multivariable linear regression analysis, HIV infection and gestational age were inversely associated with AFI at a P value <0.05. On abdominal palpation, the symphysis-fundal height, uterine fundal fetal parts ballottement, and presenting part ballottement were significantly positively associated with AFI on univariable and multivariable linear regression analysis. For the binary outcome of oligohydramnios, only presenting part ballottement was associated with an AFI <5 cm (negatively), both crudely, and adjusted for gestational age and HIV infection using logistic regression analysis. For women with a fetal head fully palpable (‘five fifths’) above the pubic symphysis (n=55), an inability to ballot the presenting part had a sensitivity of 73%, specificity of 64%, and a negative predictive value of 90% for an AFI <5 cm. Conclusion While fetal part ballottement and symphysis-fundal height measurement showed significant associations with AFI, the predictive value of clinical palpation for oligohydramnios was poor. However, in settings where real-time ultrasound technology is unavailable, the assessment of presenting part ballottement may be of value in women with suspected prolonged pregnancy. In clinical settings similar to those in this study, a ballottable fetal head gives 90% assurance of normal AFV.

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For a number of years a history of sudden onset of coma, followed later by death, was noted amongst Africans at King Edward VIII hospital, Durban. Necropsy, where performed, revealed no cause in many of these patients. In 1957 after cerebrospinal fluid had been examined in some of the cases it was seen that the only abnormality present was a low cerebrospinal sugar. Hypoglycaemia was suspected and blood sugar estimation confirmed it. Further investigation failed to reveal the cause of the hypoglycaemia and in some cases because of a "flat" glucose tolerance curve organic hyperinsulinism was suspected. In one case total pancreatectomy was performed but thorough macroscopical and histological investigation failed to reveal a tumour or hyperplasia, and the patient subsequently suffered from diabetes. In August 1958, I admitted an African female patient, of 26 years, to the ward in coma.

大动脉闭塞性疾病是脑卒中常见病因，包括颅内外狭窄性血管病变。本研究旨在分析卒中患者颅内外大动脉狭窄斑块的血管造影特征以及相关治疗方案。进一步了解颅内斑块的形态学变化，以及颅外大动脉狭窄的血管造影特征和侧枝循环状态，对于研究其发病机制及临床治疗有指导意义。 / 研究目的 / 研究1：通过前瞻性纵向研究，利用三维旋转血管造影（3D-RA），探讨颅内斑块形态学变化。 / 研究2：通过病例对照研究分析症状性放射性闭塞性血管病变(ORV)的血管造影特征及侧枝循环状态。 / 研究3：通过病例对照研究分析放射性血管病变（RIV）患者进行颈动脉支架治疗（CAS）后血管造影特征及临床预后。 / 研究方法 / 研究1：24例颅内重度狭窄(>70%)的急性缺血性卒中患者，严格控制其危险因素，应用3D-RA研究其发病时及12个月后颅内斑块的形态学变化。 / 研究2：分析96例ORV以及115例非放疗所致严重颈动脉狭窄（>70%）的缺血性卒中患者血管造影特点，比较其病变分布，形态学改变及侧枝循环状态。 / 研究3：比较63例ORV以及87例动脉粥样硬化性颈动脉狭窄的卒中患者的血管造影及预后。主要终点事件包括短暂性脑缺血发作，卒中和死亡。次要终点事件为24个月时支架内再狭窄。 / 结果 / 研究1：颅内动脉粥样硬化性斑块的厚长比不能预测其稳定性。12个月的血管造影提示：13例（50%)斑块逆转；10例（38.5%)斑块无明显变化；3例（11.5%)斑块进展。 / 研究2：ORV更多累及颈总动脉，多见双侧颈动脉受累（54% vs 22%)或出现闭塞（30% vs 9%），常见椎动脉受累(28% vs 14%)（均P<0.05）。ORV常见代偿性软脑膜动脉、前后交通动脉开放，及逆向眼动脉血流。 / 研究3：两组间围手术期并发症，长期生存率和卒中复发率无统计学差异。 / 结论 / 研究1：3D-RA可评价颅内斑块形态学变化；颅内光滑斑块亦可为易损斑块。严格控制危险因素可能逆转斑块。 / 研究2： ORV患者更多见颈动脉及椎基底动脉狭窄-闭塞性病变，并伴随侧枝循环开放。侧枝循环代偿功能减退可能诱导ORV患者发生卒中。 / 研究3：RIV患者与对照组相比，CAS的耐受性和临床预后无明显差异。 / Large artery occlusive disease, encompassing stenosis in intracranial and extracranial vasculature, is the most common stroke subtype worldwide. In this thesis, we aimed to investigate angiographic plaque morphology and treatments in stroke patients attributed to intracranial and/or extracranial stenosis. A better understanding of intracranial plaque morphology, angiographic characteristics and collateral circulations of extracranial occlusive vasculopathy may help clarify pathogenesis and formulate treatment. / Objectives / Study 1: In this prospective longitudinal study, we investigated the intracranial plaque morphology of acute stroke patients by three-dimensional rotational angiography (3D-RA). / Study 2: We aimed to delineate the angiographic attributes and collateral circulations in symptomatic occlusive radiation vasculopathy (ORV) patients by a case-controlled study. / Study 3: We investigated the angiographic and clinical outcome of carotid artery stenting (CAS) in stroke patients attributed to ORV. / Methods / Study 1: Twenty-four patients with acute strokes attributed to a >70% intracranial stenosis were recruited to undergo 3D-RA at baseline and in 12 months after an intensive control of atherosclerotic risks. We described the degree of stenosis and morphology that might be associated with plaque vulnerability. / Study 2: We performed digital subtraction angiograms (DSA) in 96 patients who had first-ever ischemic strokes attributed to ORV, and 115 referent patients who had no radiotherapy (RT) but symptomatic high-grade (>70%) atherosclerotic carotid stenoses. We compared the lesions’ distribution, morphology, and the resultant alteration of collateral flows in both patient groups. / Study 3: We compared the angiographic and clinical outcome of CAS in 63 symtomatic ORV patients and 87 patients with spontaneous atheromatous carotid stenoses. Primary end-points were transient ischemic attack, stroke and death of all causes. Secondary end-point was instent restenosis in 24 months. / Results / Study 1: Inracranial atherosclerotic plaque is a dynamic lesion.Thickness-to-length ratio may not indicate plaque vulnerability. In 12-month angiogram, 13 patients (50%) had plaque regression, 10 (38.5%) had static plaque, and 3 (11.5%) had plaque progression. / Study 2: Compared with spontaneous atheromatous carotid disease, ORV lesions diffusely involved common carotid artery, and were more frequently bilateral (54% vs 22%), associated with complete occlusion in one or both carotid arteries (30% vs 9%), vertebral artery steno-occlusions (27% vs 14%) (all p<0.05). ORV patients showed more established collateral circulations through leptomeningeal arteries, anterior communicating artery, posterior communicating artery and retrograde flow in ophthalmic artery. / Study 3: We found no significant differences in the frequency of periprocedural complications, the rates of patient survival and stroke recurrence between ORV and control groups. / Conclusions / Study 1: Evaluation of intracranial plaque morphology is feasible with 3D-RA. Smooth plaques might also be vulnerable in intracranial vasculature. Intensive risk factor control may halt progression of intracranial plaques. / Study 2: ORV patients had more steno-occlusions over carotid and vertebral arteries amid mature collateral circulations at initial stroke presentation. Decompensation of collateral flows may precipitate stroke in ORV. / Study 3: The durability and clinical outcome of CAS in ORV patients were comparable to those in patients with spontaneous atherosclerotic carotid stenosis. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Zou, Xinying. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 101-119). / Abstract also in Chinese. / ABSTRACT --- p.i / 摘要 --- p.vi / DECLARATION OF ORIGINALITY --- p.ix / ACKNOWLEDGEMENTS --- p.x / PUBLICATIONS AND PRESENTATIONS --- p.xii / LIST OF ABBREVIATIONS --- p.xiv / LIST OF TABLES --- p.xvii / LIST OF FIGURES --- p.xviii / TABLE OF CONTENTS --- p.xx / Chapter CHAPTER 1 --- INTRODUCTION AND LITERATURE REVIEW --- p.1 / Chapter 1.1 --- An overview of large artery occlusive disease in ischemic stroke --- p.1 / Chapter 1.2 --- Vulnerable plaque and plaque morphology in ischemic stroke --- p.3 / Chapter 1.2.1 --- Definition of vulnerable plaque and plaque morphology --- p.4 / Chapter 1.2.2 --- Imaging of vulnerable plaques --- p.5 / Chapter 1.2.3 --- Factors affecting plaque stability or arterial luminal narrowing --- p.7 / Chapter 1.2.3.1 --- Stenosis severity --- p.7 / Chapter 1.2.3.2 --- Thickness and length of plaque --- p.8 / Chapter 1.2.3.3 --- Mechanical stress, shear stress and hemodynamics on plaque stability --- p.9 / Chapter 1.2.3.4 --- Plaque eccentricity --- p.10 / Chapter 1.2.3.5 --- Plaque surface morphology --- p.11 / Chapter 1.2.4 --- Morphological characteristics of symptomatic plaque --- p.11 / Chapter 1.2.4.1 --- Carotid plaque morphology --- p.11 / Chapter 1.2.4.2 --- Intracranial plaque morphology --- p.12 / Chapter 1.2.5 --- Treatment of vulnerable intracranial stenosis --- p.12 / Chapter 1.3 --- Occlusive radiation vasculopathy (ORV) --- p.13 / Chapter 1.3.1 --- Epidemiology of ORV --- p.13 / Chapter 1.3.2 --- Pathogenesis and Pathophysiology of ORV --- p.14 / Chapter 1.3.3 --- Imaging and angiographic characteristics of ORV --- p.16 / Chapter 1.3.4 --- Collateralization in ORV --- p.18 / Chapter 1.3.5 --- Angioplasty and stenting for ORV --- p.19 / Chapter CHAPTER 2 --- OBJECTIVES --- p.22 / Chapter CHAPTER 3 --- RECRUITMENT OF STUDY PARTICIPANTS --- p.24 / Chapter CHAPTER 4 --- REGRESSION OF SYMPTOMATIC INTRACRANIAL PLAQUE BY INTENSIVE RISK FACTOR CONTROL: A LONGITUDIANL STUDY ON PLAQUE MORPHOLOGY BY 3D-ROTATIONAL ANGIOGRAPHY --- p.28 / Chapter 4.1. --- Background and objectives --- p.28 / Chapter 4.2 --- Methods --- p.32 / Chapter 4.2.1 --- Participants --- p.32 / Chapter 4.2.2 --- Risk factors and intensive control --- p.33 / Chapter 4.2.3 --- Evaluation of intracranial stenosis --- p.33 / Chapter 4.2.3.1 --- DSA and 3D-RA protocol --- p.33 / Chapter 4.2.3.2 --- Severity of stenosis --- p.34 / Chapter 4.2.3.3 --- Analysis of morphological characteristics on 3D-RA --- p.34 / Chapter 4.2.3.4 --- Plaque regression --- p.35 / Chapter 4.2.4 --- Statistical analysis --- p.36 / Chapter 4.3 --- Results --- p.36 / Chapter 4.4 --- Discussion --- p.54 / Chapter CHAPTER 5 --- ANGIOGRAPHY DISTINCTIONS AND COLLATERALIZATION IN SYMPTOMATIC CRANIO-CERVICAL OCCLUSIVE RADIATION VASCULOPATHY: A CASE-REFERENT STUDY --- p.58 / Chapter 5.1 --- Background and objectives --- p.58 / Chapter 5.2 --- Methods --- p.59 / Chapter 5.2.1 --- ORV and referent patients --- p.60 / Chapter 5.2.2 --- Evaluation of vascular lesions and collateral status --- p.61 / Chapter 5.2.3 --- Statistical analysis --- p.64 / Chapter 5.3 --- Results --- p.64 / Chapter 5.4 --- Discussion --- p.81 / Chapter CHAPTER 6 --- SAFETY AND CLINICAL OUTCOME OF CAROTID ARTERY STENTING IN STROKE PATIENTS WITH OCCLUSIVE RADIATION VASCULOPATHY --- p.86 / Chapter 6.1. --- Background and objectives --- p.86 / Chapter 6.2 --- Methods --- p.87 / Chapter 6.2.1 --- Participants --- p.87 / Chapter 6.2.2 --- Baseline clinical assessment --- p.87 / Chapter 6.2.3 --- Carotid artery stenting (CAS) --- p.88 / Chapter 6.2.4 --- Follow-up and end-points --- p.89 / Chapter 6.2.5 --- Statistical analysis --- p.89 / Chapter 6.3. --- Results --- p.90 / Chapter 6.4. --- Discussion --- p.96 / Chapter CHAPTER 7 --- CONCLUSIONS --- p.98 / REFERENCES --- p.101