No description available.

This thesis aims to evaluate the blood flow velocity in the Brachial artery during reactive hyperemia. Primarily to appraise the information it might contain regarding cardiovascular function and cardiovascular risk. Ultrasonographic doppler measurements of the Brachial artery were made on the 1016 men and women aged 70 included in the prospective investigation of the vasculature in Uppsala seniors (PIVUS) study. Analysis of the blood flow velocity in the forearm was made in comparison to established methods of estimating endothelial function, clinical markers of cardiovascular risk, the Framingham risk score and global atherosclerosis determined by whole body magnetic resonance angiography. Systolic blood flow velocity was positively related to cardiovascular risk whereas the diastolic velocity was inversely correlated. However, the systolic to diastolic blood flow velocity (SDFV) ratio was more closely associated with cardiovascular risk than its components apart. Ultrasonographic markers of Carotid atherosclerosis were related to the SDFV ratio. Concentric left ventricular remodeling and left ventricular mass index were also associated with the SDFV ratio, but not to its numerator or denominator separately. A similar pattern was found when assessing SDFV ratio in relation to global atherosclerosis, as well as to established markers of arterial compliance and vasodilation. In conclusion, during reactive hyperemia of the Brachial artery, the systolic to diastolic blood flow velocity ratio appears to contain information of additional value than its components separately, independently of established cardiovascular risk factors. Possibly, the SDFV ratio could offer a promising means to estimate cardiovascular risk in aging populations. / PIVUS

Cardiac physiology and hypertrophy are regulated by the phosphorylation status of most proteins, which is controlled by the opposing reactions of protein kinases and phosphatases (PP). The type 2A protein phosphatase family is comprised of PP2A, PP4 and PP6, due to the high amino acid homology of their catalytic subunits (PP2ACα/β, PP4C and PP6C). The activity and expression of this family are partly regulated by alpha4, a common regulatory protein that is essential in type 2A phosphatase holoenzyme biogenesis. In the heart, more than 98% of protein dephosphorylation is mediated by serine/ threonine protein phosphatases, of which type 2A protein phosphatases along with protein phosphatase 1, contr ibute approximately 90%. Currently, the role(s) of type 2A protein phosphatases and their regulation by alpha4 in the heart is poorly defined and requires detailed investigation. In this study, quantitative PCR analysi s demonstrated that PP2ACβ mRNA was most abundant in H9c2 cardiomyocytes and neonatal rat ventricular myocytes (NRVM) whilst, in adult rat ventricular myocytes (ARVM), PP2ACα mRNA was the most abundantly transcribed. Surprisingly, immunoblotting analysis, using catalytic subunit-specific antibodies, identified the expression of all type 2A protein phosphatase catalytic subunits in H9c2 cardiomyocytes and NRVM, however, ARVM only expressed PP2AC and PP6C protein. PP4C protein expression was only detectable in ARVM following proteasomal inhibition with compound MG132. Using siRNA to selectively knockdown type 2A protein phosphatase catalytic subunits, it was revealed that PP2ACα alone dephosphorylates CaV1.2-Ser1928. The data also suggested that PP2ACα, PP2ACβ and PP4C dephosphorylate phospholemman at both Ser63 and Ser68 in cardiomyocytes. siRNA-mediated knockdown of alpha4 protein expression rapidly reduced the expression of all type 2A catalytic subunits. Interestingly, expression of both PP2AC and alpha4 protein expression was elevated in pressure overload-induced left ventricular (LV) hypertrophy. Even though PP6C expression was unchanged, expression of PP6C regulatory subunits (i) SIT4-associated protein 1 (SAP1) and (ii) ankyrin repeat domain (ANKRD) 28 and 44 proteins were upregulated, whereas SAP2 expression was downregulated in hypertrophied LV tissue. Co-immunoprecipitation experiments revealed that the cellular association between alpha4 protein and PP2AC or PP6C subunits was either unchanged or reduced in hypertrophied LV tissue, respectively. Exposure of cardiomyocytes to hydrogen peroxide increased levels of H2AX phosphorylation (γH2AX), indicating hydrogen peroxide-induced DNA damage, which was unaffected by the knockdown of PP6C, however, levels of both total H2AX and γH2AX were diminished by the knockdown of alpha4 protein. The novel findings in this study collectively, demonstrate the differences in th e expression, stability, substrate specificity and altered alpha4-mediated regulation of the type 2A protein phosphatases in normal and hypertrophied myocardium and provide new insights into the molecular mechanisms involved in cardiac calcium homeostasis and DNA repair and thereby help to identify potential targets for the development of new and improved therapies against cardiac pathological hypertrophy.

Apolipoprotein (apo) A-V is the most recently discovered member of a protein family responsible for the structure and metabolic fate of plasma lipoproteins. While most of the apolipoproteins are well characterized with regard to structure, interactions and function, the role of apoA-V is not well understood. ApoA-V is synthesized only in liver and is present in blood at much lower concentration than the other apolipoproteins. Although apoA-V is firmly established as an important determinant for plasma triacylglycerol (TG) metabolism, the mechanism is unclear. ApoA-V has been suggested to act through 1) an intracellular mechanism affecting lipoprotein assembly and secretion, 2) direct or indirect activation of lipoprotein lipase (LPL), or 3) interaction with endocytotic lipoprotein receptors. Two other novel players involved in the clearance of lipoproteins are angiopoietin-like protein (ANGPTL) 3 and 4. Previous studies have shown that the coiled-coil domain (ccd) of ANGPTL3 and -4 can inactivate lipoprotein lipase (LPL). The functional site of action of LPL is at the capillary endothelium, but the enzyme is synthesized mostly in adipocytes and myocytes and has to be transported by trancytosis to the luminal side of endothelial cells. Both ANGPTLs are present in tissues and in the circulating blood, but it is not known were the inactivation of LPL normally takes place. The aim of this thesis was to investigate the mechanism by which apoA-V exerts its effect on TG metabolism and to investigate in further detail how ANGPTLs act on the LPL system. Binding of apoA-V to receptors involved in lipoprotein metabolism was investigated by surface plasmon resonance technique (SPR). ApoA-V was found to bind to the LDL receptor related protein 1 (LRP1) and to the mosaic type 1 receptor sorLA. Binding could be competed by receptor associated protein (RAP) or by heparin, and was calcium dependent. We concluded that apoA-V binds to the LA-repeats of these receptors. In further experiments apoA-V was shown to increase binding of TG-rich chylomicrons to the receptors. This demonstrated a possible mechanism for the TG-lowering effect of apoA-V in vivo. A putative binding region in apoA-V for heparin and receptors was investigated by site-directed mutagenesis. Two positively charged amino acid residues were changed (Arg210Glu/Lys211Gln), resulting in decreased binding to heparin and to LRP1 and thus the localization of one important functional region in apoA-V. Since the receptor sorLA also contains a Vsp10p domain, another Vsp10p domain family member, sortilin, was investigated. ApoA-V was found to interact also with this receptor. In experiments with human embryonic kidney cells transfected with sorLA or sortilin, apoA-V was found to bind to cell surfaces and to be rapidly internalized while co-localized with the receptors on the way to lysosomes for degradation. Additional apoA-V mutants, identified in patients with severe hypertriglyceridemia, were investigated with regard to effects in vitro on LPL activity and receptor binding. The most severe mutants displayed null binding to LRP1, whereas the effect on LPL activity was retained. These results suggest that lack of receptor interaction mirrors the loss of biological function in a better way than the in vitro effect on LPL activity. We noted that ccd-ANGPTL3 and -4 did not prevent the LPL-mediated uptake of chylomicron-like lipoproteins in primary murine hepatocytes. Therefore LPL activity was measured after pre-incubation with ccd-ANGPTL3 or 4 in the presence or absence of TG-rich lipoproteins. Physiological concentrations of lipoproteins were found to protect LPL from inactivation by ccd-ANGPTLs. Investigation by SPR demonstrated that the ccd-ANGPTLs did not bind to the lipoproteins. Other experiments showed that less than 1% of ANGPTL4 in human serum was bound to TG-rich lipoproteins. This implies that the known binding of LPL to TG-rich lipoproteins stabilizes the enzyme and protects it from inactivation by ANGPTLs. We conclude that the normal levels of ANGPTLs in plasma are too low to affect the LPL-system and that inactivation of the enzyme by ANGPTLs is more likely to occur locally in the extracellular interstitium of tissues where LPL is en route to its endothelial binding sites and where the concentrations of the TG-rich lipoproteins are low.

We developed a spatially-tracked single neuron transcriptomics map of an intrinsic cardiac ganglion, the right atrial ganglionic plexus (RAGP) that is a critical mediator of sinoatrial node (SAN) activity. This 3D representation of RAGP used neuronal tracing to extensively map the spatial distribution of the subset of neurons that project to the SAN. RNA-seq of laser capture microdissected neurons revealed a distinct composition of RAGP neurons compared to the central nervous system and a surprising finding that cholinergic and catecholaminergic markers are coexpressed, suggesting multipotential phenotypes that can drive neuroplasticity within RAGP. High-throughput qPCR of hundreds of laser capture microdissected single neurons confirmed these findings and revealed a high dimensionality of neuromodulatory factors that contribute to dynamic control of the heart. Neuropeptide-receptor coexpression analysis revealed a combinatorial paracrine neuromodulatory network within RAGP informing follow-on studies on the vagal control of RAGP to regulate cardiac function in health and disease.

Inflammatory arthropathies and systemic rheumatic diseases (IASRDs) commonly involve the cardiovascular system, and are associated with high morbidity and mortality. Mechanisms of cardiovascular involvement in these clinical entities are not fully understood. Cardiovascular magnetic resonance (CMR) is the single imaging modality capable of assessing non-invasively cardiac function, strain, ischaemia, altered vascular function, perfusion, oedema/inflammation and fibrosis. Furthermore, magnetic resonance spectroscopy (MRS) can give further insights into the status of myocardial energetics and lipidosis. The pathophysiological mechanisms and phenotype of cardiovascular disease (CVD) in IASRDs need further clarification. CMR is an ideal tool for the early identification and monitoring of cardiac manifestations in patients with IASRDs. Hence, the aims of this D.Phil project were to (i) utilise CMR and MRS to study disease mechanisms in patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and systemic sclerosis (SSc), and (ii) to assess the role of anti-cytokine therapies in abrogation of cardiovascular complications and effects on cardiovascular function in patients with RA, ankylosing spondylitis (AS) and psoriatic arthritis (PsA). First, we used CMR to assess myocardial structure and function in RA, SLE and SSc patients with no known cardiovascular symptoms. Patients and controls were stratified by the presence of traditional cardiovascular risk factors (CVRFs). Our data demonstrated no differences in overall left ventricular (LV) systolic function, size and mass between patients and matched controls. There were, however, impairments in regional function and myocardial deformation, which is most severe in RA, SLE and SSc patients with CVRFs. We also found evidence of impaired vascular function in RA, SLE and SSc, using pulse wave velocity (PWV) and aortic distensibility, and again, showed that patients with CVRFs demonstrated the most severe aberrations, while patients without CVRFs and controls with CVRFs had an intermediate phenotype. Abnormalities in vascular and regional function were most severe in patients with SSc. Also, we showed that impaired vascular function correlated with abnormal systolic myocardial strain and diastolic strain rate in all groups of IASRDs studied. These data have implications for the clinical care of patients with RA, SLE and SSc and show that there is extensive cardiovascular involvement in asymptomatic patients. These results also suggest that early identification and stratification of CVD in IASRDs, with non-invasive techniques like CMR, may permit earlier intervention, thus potentially reducing the effect of CVD on morbidity and mortality in IASRDs. Lastly, these data highlight the importance of early detection and aggressive management of co-existent traditional CVRFs, as they confer incremental risk of CVD in patients with IASRDs. Second, we used CMR for comprehensive phenotyping of tissue characteristics in patients with RA, SLE and SSc. Our data confirmed that subclinical myocardial changes are common in patients with IASRDs (even with apparently normal hearts), which can be detected using multiparametric CMR. In addition to focal areas of fibrosis (detected by late gadolinium enhancement [LGE]), there were also areas of focal myocardial oedema or inflammation (detected by T2-weighted imaging). Further, using more sensitive techniques such as native T1 mapping and extracellular volume (ECV) quantification, we were able to demonstrate even more areas of myocardial involvement in IASRD patients than conventional CMR techniques can reveal, with patients showing significantly larger areas of T1 abnormality and expanded ECV, which likely represent a combination of low grade inflammation and diffuse myocardial fibrosis that are well-described disease processes in this cohort. We also found that T1 and ECV measures were associated with subtle myocardial systolic and diastolic dysfunction. The results of this study suggest that CMR, particularly T1 and ECV quantification, can be used for early detection of subclinical myocardial involvement in IASRD patients, potentially serving as an early screening tool before overt LV dysfunction or irreversible myocardial damage occurs. Third, we utilised CMR to study myocardial perfusion in patients with RA, SLE and SSc. We found that myocardial perfusion was impaired in asymptomatic IASRD with no overt heart disease. Non-segmental, subendocardial perfusion defects consistent with microvascular dysfunction were present in 47%, 31% and 41% of RA, SLE and SSc patients, respectively. Furthermore, there was a significant correlation between MPRI and systolic and diastolic regional function in all groups of patients. In RA and SSc, there was also a correlation between myocardial perfusion reserve index (MPRI) and disease activity. SSc patients had the greatest burden of ECV expansion, and in this group ECV also correlated with MPRI. These data led us to hypothesise that myocardial ischaemia likely leads to impaired myocardial relaxation and diffuse fibrosis, which predate overt dysfunction in contractility. Fourth, we investigated the effect of TNF-alpha inhibitors on myocardial and vascular function and structure in RA, AS and PsA patients. We confirmed that anti-TNF therapy was associated with improvements in serum inflammatory parameters like CRP and ESR, as well as with improved clinical measures of disease activity. Anti-TNF therapy, however, was not related to a change in left ventricular size, mass and global systolic function. We found that inhibition of TNF-alpha activity does result in better myocardial strain and strain rate, likely reflecting an improvement in myocardial inflammatory burden. Moreover, these findings were also supported by improvements in T2 weighted measures, native T1 values and ECV calculations. There was, however, no significant change in myocardial perfusion following anti-TNF therapy. These results support the hypothesis that during episodes of disease activity, myocardial oedema is present in patients with IASRDS and that by reducing the systemic inflammatory response, improvements in myocardial and vascular function can be achieved. Finally, we used CMR and MRS in asymptomatic RA and SLE patients (with normal hearts on echocardiography) to investigate cardiac metabolic status in this cohort. We found that myocardial energetics were impaired in patients, despite preserved overall ejection fraction. Interestingly, abnormal myocardial energetics were associated with presence of LGE, decreased myocardial perfusion, expanded ECV, volume fraction of T1 >990ms (which represents >2 standard deviations above the mean T1 value at 1.5T) and left atrial size. We did not find any difference in myocardial and hepatic lipid content between patients and controls. These data clearly demonstrate that abnormalities in cardiac energetics are present in IASRD patients even before the development of overt cardiac dysfunction, and may be driven by microvascular function and fibrosis.

Abstract Both qualitative and quantitative limitations of two-dimensional (2DE) imaging have lead to the emergence of the three-dimensional echo (3DE) technique. Until recently the development of 3DE technology has been slow due to inferior image quality and longer processing and acquisition times compared with 2DE. However, in recent times 3DE technology has advanced to “real-time” (RT3D) and has become feasible as a standard clinical tool. The overall hypothesis of the studies undertaken in this thesis is that the increased accuracy of left ventricular (LV) assessment using RT3D justifies its use in clinical decision-making based on both single and sequential measurements in routine echocardiographic practice. It shows the increased accuracy and feasibility of 3DE using online and offline techniques and opacification, and evaluates the prognostic implications of LV measurements globally and regionally using 3DE compared with 2DE. Further, it assesses the accuracy of LV assessment using 3DE and demonstrates its superior accuracy to 2DE in cross-sectional studies. The thesis initially reviews the use of physiologic parameters used for clinical decision making and looks at the principles of incremental value in diagnostic testing. The assessment of ventricular structure and function is discussed as well as the current problems with clinical echocardiography, which have lead to the evolution and development of 3DE. The second chapter describes the methodologies used in this thesis, with particular emphasis on new technologies used in the studies. Chapter 3 looks at the role of experience as a barrier to incorporation of 3DE into standard practice. We tested attendees before and after an intensive interactive training course to evaluate the learning curve. An interactive teaching course with rehearsal and direct mentoring appears to overcome this limitation and may improve the uptake of the 3DE technique. Chapters 4 to 6 validate the use of 3DE by comparing it to 2DE and magnetic resonance imaging (MRI) with respect to online and offline techniques, the use of left ventricular opacification (LVO) and the serial follow-up of patients. The availability of automated on-line software may increase the feasibility of real-time 3DE for LV volume calculation in clinical practice. Chapter 4 looks at the comparison of off- and on-line approaches with magnetic resonance imaging. Online measurement of LV volumes was found to be feasible and more accurate than with 2DE, however the offline approach was more accurate - although more time-consuming. Chapter 5 involves two studies which sought to validate 3DE in a multicentre setting. They examine the variability of LV measurements across multiple sites and to validate 3DE against MRI. The first study found that the semi-automated measurement of 3DE reduces the variation of LV volume between centers. The second study provides information on the role of different potential sources of error and provides guidelines for future users on how to minimize these errors as well as how to interpret their findings. The next chapter further validates 3DE with use of LVO as a technique to improve the accuracy of LV volume measurements. We sought to examine the accuracy of non-contrast and contrast enhanced 2DE and 3DE for calculation of LV volumes and ejection fraction (EF), relative to cardiac magnetic resonance imaging. 2DE with LVO was analogous to 3DE in accurate categorization of LV function. However, 3DE with LVO was feasible and superior to other non-contrast and contrast enhanced techniques in patients with previous infarction. Chapter 7 examines the technical details of regional volume measurements. The use of a fixed external frame of reference in analyses of regional wall motion in the apical four-chamber view is prone to a systematic error and the use of a floating-axis analysis corrects for this, but this is based on landmarks by MRI (apex, annulus) and center of mass by 3DE. The axis is likely to be influenced by reverse remodeling after intervention and therefore we sought to evaluate 3DE regional volume assessment vs. cardiac MRI over follow-up. The use of a center-line based on center of mass with RT3D may contribute to problems with use of this modality to track regional volumes over time. Although global 3DE volumes compare well with MRI volumes, new developments in image quality and automated software will be needed before changes in regional volumes can be reliably followed with 3DE. 2DE ESE is limited by sampling in standard imaging planes and suboptimal acquisition may cause poor matching of pre- and post-stress images. 3DE may avoid these orientation problems and contraction front mapping (CFM) may also provide a method for defining the temporal homogeneity of contraction. Chapter 8 examines the incremental benefit of 3DE CFM to 2DE and 3DE, using coronary angiography as the reference standard. It found that analysis of the temporal distribution of contraction may be an alternate means than 3DE wall motion assessment for identification of ischemia for ESE. Another significant validation needed for 3DE is not only for the LV but for the right ventricle (RV). The non-geometric nature of the RV makes it difficult to measure. Chapter 9 shows that 3DE is superior to 2DE for follow-up of RV function by validation vs. cardiac MRI. It was found that 3DE was indeed more accurate than 2DE approaches and reduces test-retest variation of RV volumes and EF measurements in follow-up RV assessment. Chapter 10 investigates the accuracy and reproducibility of the use of 3DE for serial follow-up of LV measurements. Echocardiographic follow-up of LV volumes is difficult because of the test-retest variation of 2DE. In this follow-up study, sequential 3DE measurements of change of volumes and EF were similar to those obtained using MRI, but 2DE overestimated change in EDV. As MRI is expensive, of limited availability and cannot be performed on patients with implanted devices, 3DE appears to be an effective long-term follow-up imaging tool for when sequential measurement of LV volumes is sought to guide management decisions. Chapter 11 investigates whether 3DE is more predictive of outcome than 2DE. In this outcome study, 3DE measurements of ESV and EF showed a stronger prediction of outcomes than 2DE. 3DE now appears to be the measurement of choice for when LV volumes and EF are sought to guide management decisions. In conclusion, the work reported in this thesis demonstrates that 3DE increases the accuracy of LV assessment and justifies its use in clinical decision-making based on both single and sequential measurements in routine echocardiographic practice.

<p>Consequences of atherosclerosis may result in a number of diseases of the cardiovascular system that represent serious health problems and major causes of morbidity and mortality worldwide. Although it is initially considered as disease of fibro-lipid and thrombus deposition in the arterial wall, it also involves an ongoing inflammatory response.</p><p>Normally, the inflammatory response is considered as a protective defence mechanism of the body. However, if the inflammation gets out of proportion to the threat it is dealing with, it may then result in a sustained chronic disorder and thus may underlie the initial stage of atherogenesis. The work of this thesis focuses on the expression of cytokines/chemokines and the vascular transcriptional response to inflammation, i.e. LPS in atherosclerosis. This has mainly been studied in animal models of atherosclerosis; consequently, we set out to investigate these events using human material in vitro (human carotid lesions).</p><p>Employing quantitative analysis, we were able to detect a significant induction of protein and mRNA of the cytokines IL-1β, IL-6, IL-10 and TNF-α and the chemokines IL-8 and MCP-1 by LPS in both atherosclerotic and non-atherosclerotic vessels. In contrast, LPS induction of TNF-α, IL-1β and IL-10 was solely observed in the lesions, but not in normal arteries. In addition, the impact of IL-1 gene polymorphism on the risk of myocardial infarction (MI) was estimated by DNA genotyping of 387 survivors of a first MI and 387 sex and age-matched control subjects. We found no statistically significant differences in either genotypic distribution or allelic frequencies of IL-1β (-511) or IL-1Ra (VNTR) polymorphisms between first-time survivors of myocardial infarction and their age-matched healthy controls. Incontrast, our results demonstrated a strong association between the IL-1Ra genotype and severity of angiographically determined coronary artery disease in post-MI patients. To further investigate the vascular response to inflammation, we used gene array analysis to evaluate the human vascular transcriptional response to LPS of non-atherosclerotic human renal arteries compared to carotid lesions. In LPS treated renal arteries, 54% of the transcripts gave a detectable signal, where 4% were upregulated and 3.8% down-regulated. In the LPS stimulated carotid lesions, 44% of transcripts were detected. In this latter group, 5.1% of transcripts were increased and 3.3% decreased. Interestingly, a newly identified virus-inducible antiviral protein, CMV inducible gene ₅/viperin (Cig₅), was among the most strongly induced gene in both normal and atherosclerotic biopsies. Single gene analysis revealed viperin in the endothelium of human atherosclerotic lesions. Further, viperin was induced in vascular cells by inflammatory stimuli and CMV infection.</p><p>In conclusion we show that atherosclerotic vessels produce more proinflammatory cytokines/chemokines than normal vessels. Interestingly, our results indicate that LPS enhances the expression of cytokines/chemokines in a similar pattern both in lesions and normal arteries. However, the response is stronger in atherosclerotic lesions. Furthermore, our results suggest that genetic polymorphisms within the IL-1Ra loci may influence the severity of CAD. Finally, the CMV inducible gene ₅/viperin have been identified as a putative culprit molecule in vascular inflammation and atherosclerosis.</p>

Background: Patients with sleep apnea have frequent apneas and hypopneas during sleep. Apneas can be either central or obstructive. The apnea-hypopnea index (AHI) is the mean number of apneas and hypopneas per hour of sleep. Aims: 1) To evaluate the effect of a mandibular advancement device on obstructive apneas and sleep; 2) to evaluate the influence of body position on central apnea frequency; 3) to investigate whether obstructive or central apnea is related to mortality in patients with stroke; and 4) to investigate sleep and sleeping positions in women. Methods: Subjects were investigated during whole-night sleep respiratory recordings, either polysomnography including continuous recordings of EEG, EOG, EMG, airflow, respiratory effort, ECG, pulse oximetry and body position, or simplified sleep apnea recordings without EEG, EOG and EMG. Results: The frequency of obstructive apneas, hypopneas and arousals decreased and rapid eye movement (REM) sleep increased in patients with mild, moderate and severe sleep apnea during treatment with a mandibular advancement device. Central apneas were more prevalent in the supine position compared with the non-supine position in patients with Cheyne-Stokes respiration. The mean ± SD central AHI was 41 ± 13 in the supine position and 26 ± 12 in the non-supine position, p&lt;0.001. Stroke patients with obstructive sleep apnea ran an increased risk of death during 10 ± 0.6 years of follow-up with an adjusted hazard ratio of 1.76 (95% CI 1.05-2.95) compared with controls, independent of hypertension, age, body mass index, gender, smoking, diabetes mellitus, atrial fibrillation, Mini-Mental State Examination and Barthel-ADL. Central apnea was not related to early death. Total sleep time, sleep efficiency, rapid eye movement sleep, slow wave and time in the supine position decreased with age in women. Sleep quality in women was reduced with age, body mass index, obstructive sleep apnea, smoking, alcohol and hypertension. Conclusions: Obstructive sleep apneas and arousals are reduced and REM sleep is increased using a mandibular advancement device in patients with mild, moderate and severe sleep apnea. The frequency of central apneas and hypopneas is increased in the supine position in patients with Cheyne-Stokes respiration. Stroke patients with obstructive sleep apnea run an increased risk of early death. Central sleep apnea was not related to early death among the present patients. Normal values for sleep stages and sleeping positions are presented in a population-based sample of women. Age, body mass index, obstructive sleep apnea, smoking, alcohol and hypertension reduce sleep quality in women.

Carotid stenosis is one of several causes of ischemic stroke and entails a high risk of ischemic stroke recurrence. Removal of a carotid stenosis by carotid endarterectomy results in a risk reduction for ischemic stroke, but the magnitude of risk reduction depends on several factors. If the delay between the last symptom and carotid endarterectomy is less than 2 weeks, the absolute risk reduction is &gt;10%, regardless of age, sex, or if the degree of carotid stenosis is 50–69% or 70–99%. Thus, speed is the key. However, if many patients suffers an ischemic stroke recurrence within the first 2 weeks of the presenting event, an additional benefit is likely be obtained if carotid endarterectomy is performed even earlier than within 2 week after the presenting event. Carotid endarterectomy for asymptomatic carotid stenoses carries a small risk reduction for stroke. Screening for asymptomatic carotid stenosis requires a prevalence of &gt;5% in the examined population, i.e., higher than in the general population; however, directed screening in groups with a prevalence of &gt;5% is beneficial. The aims of this thesis were to investigate the length of the delay to carotid endarterectomy, determine the risk of recurrent stroke before carotid endarterectomy, and determine if a calcification in the area of the carotid arteries seen on dental panoramic radiographs is a valid selection method for directed ultrasound screening to detect asymptomatic carotid stenosis. Consecutive patients with a symptomatic carotid stenosis who underwent a preoperative evaluation aimed at carotid endarterectomy at Umeå Stroke Centre between January 1, 2004–March 31, 2006 (n=275) were collected retrospectively and between August 1, 2007–December 31, 2009 (n=230) prospectively. In addition, 117 consecutive persons, all preliminarily eligible for asymptomatic carotid endarterectomy and with a calcification in the area of the carotid arteries seen on panoramic radiographs, were prospectively examined with carotid ultrasound. The median delay between the presenting event and carotid endarterectomy was 11.7 weeks in the first half year of 2004, dropped to 6.9 weeks in the first quarter year of 2006, and had dropped to 3.6 weeks in the second half year of 2009. The risk of ipsilateral ischemic stroke recurrence was 4.8% within 2 days, 7.9% within 1 week, and 11.2% within 2 weeks of the presenting event. For patients with a stroke or transient ischemic attack as the presenting event, this risk was 6.0% within 2 days, 9.7% within 1 week, and 14.3% within 2 weeks of the presenting event. For the 10 patients with a near-occlusion, the risk of ipsilateral ischemic stroke recurrence was 50% at 4 weeks after the presenting event. Among the 117 persons with a calcification in the area of the carotid arteries seen on panoramic radiographs, eight had a 50–99% carotid stenosis, equalling a prevalence of 6.8% (not statistically significantly over the pre-specified 5% threshold). Among men, the prevalence of 50–99% carotid stenosis was 12.5%, which was statistically significantly over the pre-specified 5% threshold. In conclusion: The delay to carotid endarterectomy was longer than 2 weeks. Additional benefit is likely to be gained by performing carotid endarterectomy within a few days of the presenting event instead of at 2 weeks because many patients suffer a stroke recurrence within a few days; speed is indeed the key. The finding that near-occlusion entails an early high risk of stroke recurrence stands in sharp contrast to previous studies; one possible explaination is that this was a high-risk period missed in previous studies. The incidental finding of a calcification in the area of the carotid arteries on a panoramic radiograph is a valid indication for carotid ultrasound screening in men who are otherwise eligible for asymptomatic carotid endarterectomy.