Potential impact of single-risk-factor versus total risk management for the prevention of cardiovascular events in Seychelles.

OBJECTIVE: To assess the prevalence of cardiovascular (CV) risk factors in Seychelles, a middle-income African country, and compare the cost-effectiveness of single-risk-factor management (treating individuals with arterial blood pressure >/= 140/90 mmHg and/or total serum cholesterol >/= 6.2 mmol/l) with that of management based on total CV risk (treating individuals with a total CV risk >/= 10% or >/= 20%).METHODS: CV risk factor prevalence and a CV risk prediction chart for Africa were used to estimate the 10-year risk of suffering a fatal or non-fatal CV event among individuals aged 40-64 years. These figures were used to compare single-risk-factor management with total risk management in terms of the number of people requiring treatment to avert one CV event and the number of events potentially averted over 10 years. Treatment for patients with high total CV risk (>/= 20%) was assumed to consist of a fixed-dose combination of several drugs (polypill). Cost analyses were limited to medication.FINDINGS: A total CV risk of >/= 10% and >/= 20% was found among 10.8% and 5.1% of individuals, respectively. With single-risk-factor management, 60% of adults would need to be treated and 157 cardiovascular events per 100 000 population would be averted per year, as opposed to 5% of adults and 92 events with total CV risk management. Management based on high total CV risk optimizes the balance between the number requiring treatment and the number of CV events averted.CONCLUSION: Total CV risk management is much more cost-effective than single-risk-factor management. These findings are relevant for all countries, but especially for those economically and demographically similar to Seychelles.

Frailty and risk for heart failure in older adults: The health, aging, and body composition study.

OBJECTIVE: The aim of this study was to assess the association between frailty and risk for heart failure (HF) in older adults. BACKGROUND: Frailty is common in the elderly and is associated with adverse health outcomes. Impact of frailty on HF risk is not known. METHODS: We assessed the association between frailty, using the Health ABC Short Physical Performance Battery (HABC Battery) and the Gill index, and incident HF in 2825 participants aged 70 to 79 years. RESULTS: Mean age of participants was 74 ± 3 years; 48% were men and 59% were white. During a median follow up of 11.4 (7.1-11.7) years, 466 participants developed HF. Compared to non-frail participants, moderate (HR 1.36, 95% CI 1.08-1.71) and severe frailty (HR 1.88, 95% CI 1.02-3.47) by Gill index was associated with a higher risk for HF. HABC Battery score was linearly associated with HF risk after adjusting for the Health ABC HF Model (HR 1.24, 95% CI 1.13-1.36 per SD decrease in score) and remained significant when controlled for death as a competing risk (HR 1.30; 95% CI 1.00-1.55). Results were comparable across age, sex, and race, and in sub-groups based on diabetes mellitus or cardiovascular disease at baseline. Addition of HABC Battery scores to the Health ABC HF Risk Model improved discrimination (change in C-index, 0.014; 95% CI 0.018-0.010) and appropriately reclassified 13.4% (net-reclassification-improvement 0.073, 95% CI 0.021-0.125; P = .006) of participants (8.3% who developed HF and 5.1% who did not). CONCLUSIONS: Frailty is independently associated with risk of HF in older adults.

Peri-operative management of antiplatelet therapy in patients with coronary artery disease. Joint position paper by members of the working group on Perioperative Haemostasis of the Society on Thrombosis and Haemostasis Research (GTH), the working group on Perioperative Coagulation of the Austrian Society for Anesthesiology, Resuscitation and Intensive Care (ÖGARI) and the Working Group Thrombosis of the European Society for Cardiology (ESC).

An increasing number of patients suffering from cardiovascular disease, especially coronary artery disease (CAD), are treated with aspirin and/or clopidogrel for the prevention of major adverse events. Unfortunately, there are no specific, widely accepted recommendations for the perioperative management of patients receiving antiplatelet therapy. Therefore, members of the Perioperative Haemostasis Group of the Society on Thrombosis and Haemostasis Research (GTH), the Perioperative Coagulation Group of the Austrian Society for Anesthesiology, Reanimation and Intensive Care (ÖGARI) and the Working Group Thrombosis of the European Society of Cardiology (ESC) have created this consensus position paper to provide clear recommendations on the perioperative use of anti-platelet agents (specifically with semi-urgent and urgent surgery), strongly supporting a multidisciplinary approach to optimize the treatment of individual patients with coronary artery disease who need major cardiac and non-cardiac surgery. With planned surgery, drug eluting stents (DES) should not be used unless surgery can be delayed for ≥12 months after DES implantation. If surgery cannot be delayed, surgical revascularisation, bare-metal stents or pure balloon angioplasty should be considered. During ongoing antiplatelet therapy, elective surgery should be delayed for the recommended duration of treatment. In patients with semi-urgent surgery, the decision to prematurely stop one or both antiplatelet agents (at least 5 days pre-operatively) has to be taken after multidisciplinary consultation, evaluating the individual thrombotic and bleeding risk. Urgently needed surgery has to take place under full antiplatelet therapy despite the increased bleeding risk. A multidisciplinary approach for optimal antithrombotic and haemostatic patient management is thus mandatory.

Association of major and minor ECG abnormalities with coronary heart disease events.

CONTEXT: In populations of older adults, prediction of coronary heart disease (CHD) events through traditional risk factors is less accurate than in middle-aged adults. Electrocardiographic (ECG) abnormalities are common in older adults and might be of value for CHD prediction. OBJECTIVE: To determine whether baseline ECG abnormalities or development of new and persistent ECG abnormalities are associated with increased CHD events. DESIGN, SETTING, AND PARTICIPANTS: A population-based study of 2192 white and black older adults aged 70 to 79 years from the Health, Aging, and Body Composition Study (Health ABC Study) without known cardiovascular disease. Adjudicated CHD events were collected over 8 years between 1997-1998 and 2006-2007. Baseline and 4-year ECG abnormalities were classified according to the Minnesota Code as major and minor. Using Cox proportional hazards regression models, the addition of ECG abnormalities to traditional risk factors were examined to predict CHD events. MAIN OUTCOME MEASURE: Adjudicated CHD events (acute myocardial infarction [MI], CHD death, and hospitalization for angina or coronary revascularization). RESULTS: At baseline, 276 participants (13%) had minor and 506 (23%) had major ECG abnormalities. During follow-up, 351 participants had CHD events (96 CHD deaths, 101 acute MIs, and 154 hospitalizations for angina or coronary revascularizations). Both baseline minor and major ECG abnormalities were associated with an increased risk of CHD after adjustment for traditional risk factors (17.2 per 1000 person-years among those with no abnormalities; 29.3 per 1000 person-years; hazard ratio [HR], 1.35; 95% CI, 1.02-1.81; for minor abnormalities; and 31.6 per 1000 person-years; HR, 1.51; 95% CI, 1.20-1.90; for major abnormalities). When ECG abnormalities were added to a model containing traditional risk factors alone, 13.6% of intermediate-risk participants with both major and minor ECG abnormalities were correctly reclassified (overall net reclassification improvement [NRI], 7.4%; 95% CI, 3.1%-19.0%; integrated discrimination improvement, 0.99%; 95% CI, 0.32%-2.15%). After 4 years, 208 participants had new and 416 had persistent abnormalities. Both new and persistent ECG abnormalities were associated with an increased risk of subsequent CHD events (HR, 2.01; 95% CI, 1.33-3.02; and HR, 1.66; 95% CI, 1.18-2.34; respectively). When added to the Framingham Risk Score, the NRI was not significant (5.7%; 95% CI, -0.4% to 11.8%). CONCLUSIONS: Major and minor ECG abnormalities among older adults were associated with an increased risk of CHD events. Depending on the model, adding ECG abnormalities was associated with improved risk prediction beyond traditional risk factors.

Improving cardiovascular and renal outcomes in gout: what should we target?

Epidemiological and experimental studies have shown that hyperuricaemia and gout are intricately linked with hypertension, metabolic syndrome, chronic kidney disease and cardiovascular disease. A number of studies suggest that hyperuricaemia and gout are independent risk factors for the development of these conditions and that these conditions account, in part, for the increased mortality rate of patients with gout. In this Review, we first discuss the links between hyperuricaemia, gout and these comorbidities, and present the mechanisms by which uric acid production and gout might favour the development of cardiovascular and renal diseases. We then emphasize the potential benefit of urate-lowering therapies on cardiovascular and renal outcomes in patients with hyperuricaemia. The mechanisms that link elevated serum uric acid levels and gout with these comorbidities seem to be multifactorial, implicating low-grade systemic inflammation and xanthine oxidase (XO) activity, as well as the deleterious effects of hyperuricaemia itself. Patients with asymptomatic hyperuricaemia should be treated by nonpharmacological means to lower their SUA levels. In patients with gout, long-term pharmacological inhibition of XO is a treatment strategy that might also reduce cardiovascular and renal comorbidities, because of its dual effect of lowering SUA levels as well as reducing free-radical production during uric acid formation.

Aortic remodelling in Fabry disease

Aims To evaluate thoracic aortic dilation in patients with Fabry disease (FD). Methods and results A cohort of 106 patients with FD (52 males; 54 females) from three European centres were studied. The diameter of the thoracic aorta was assessed at three levels (sinus of Valsalva, ascending aorta, and descending aorta) using echocardiograms and cardiovascular magnetic resonance imaging. Aortic dilation at the sinus of Valsalva was found in 32.7% of males and 5.6% of females; aneurysms were present in 9.6% of males and 1.9% of females. No aortic dilation was observed in the descending aorta. There was no correlation between aortic diameter at the sinus of Valsalva and cardiovascular risk factors. Conclusion Fabry disease should be considered as a cardiovascular disease that affects the heart and arterial vasculature, including the thoracic aorta. Thus, patients with FD should be closely monitored for the presence, and possible progression and complications of aortic dilation. Clinical Trial Registration: Protocol 101/01. Ethics committee, Faculty of Medicine, Lausanne.

A simple score for estimating ischemic heart disease in patients with non-traumatic chest pain in primary care

Background: Modelling epidemiological knowledge in validated clinical scores is a practical mean of integrating EBM to usual care. Existing scores about cardiovascular disease have been largely developed in emergency settings, but few in primary care. Such a toll is needed for general practitioners (GP) to evaluate the probability of ischemic heart disease (IHD) in patients with non-traumatic chest pain. Objective: To develop a predictive model to use as a clinical score for detecting IHD in patients with non-traumatic chest-pain in primary care. Methods: A post-hoc secondary analysis on data from an observational study including 672 patients with chest pain of which 85 had IHD diagnosed by their GP during the year following their inclusion. Best subset method was used to select 8 predictive variables from univariate analysis and fitted in a multivariate logistic regression model to define the score. Reliability of the model was assessed using split-group method. Results: Significant predictors were: age (0-3 points), gender (1 point), having at least one cardiovascular risks factor (hypertension, dyslipidemia, diabetes, smoking, family history of CVD; 3 points), personal history of cardiovascular disease (1 point), duration of chest pain from 1 to 60 minutes (2 points), substernal chest pain (1 point), pain increasing with exertion (1 point) and absence of tenderness at palpation (1 point). Area under the ROC curve for the score was of 0.95 (IC95% 0.93; 0.97). Patients were categorised in three groups, low risk of IHD (score under 6; n = 360), moderate risk of IHD (score from 6 to 8; n = 187) and high risk of IHD (score from 9-13; n = 125). Prevalence of IHD in each group was respectively of 0%, 6.7%, 58.5%. Reliability of the model seems satisfactory as the model developed from the derivation set predicted perfectly (p = 0.948) the number of patients in each group in the validation set. Conclusion: This clinical score based only on history and physical exams can be an important tool in the practice of the general physician for the prediction of ischemic heart disease in patients complaining of chest pain. The score below 6 points (in more than half of our population) can avoid demanding complementary exams for selected patients (ECG, laboratory tests) because of the very low risk of IHD. Score above 6 points needs investigation to detect or rule out IHD. Further external validation is required in ambulatory settings.

Cytokines and hs-CRP levels in individuals treated with low-dose aspirin for cardiovascular prevention: a population-based study (CoLaus Study).

Pro-inflammatory cytokines and high-sensitive C-reactive protein (hs-CRP) are associated with increased risk for cardiovascular disease. Low-dose aspirin for CV prevention is reported to have anti-inflammatory effects. The aim of this study was to determine the association between pro-inflammatory cytokines and hs-CRP levels and low-dose aspirin use for cardiovascular prevention in a population-based cohort (CoLaus Study). We assessed blood samples in 6085 participants (3201 women) aged 35-75years. Medications' use and indications were recorded. Among aspirin users (n=1'034; 17%), overall low-dose users (351; 5.8%) and low-dose for cardiovascular prevention users (324; 5.3%) were selected for analysis. Pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α were assessed by a multiplex particle-based flow cytometric assay and hs-CRP by an immunometric assay. Cytokines and hs-CRP were presented in quartiles. Multivariate analysis adjusting for sex, age, smoking status, body mass index, diabetes mellitus and immunomodulatory drugs showed no association between cytokines and hs-CRP levels and low-dose aspirin use for cardiovascular prevention, either comparing the topmost vs. the three other quartiles (OR 95% CI, 0.84 (0.59-1.18), 1.03 (0.78-1.32), 1.10 (0.83-1.46), 1.00 (0.67-1.69) for IL-1β, IL-6, TNF-α and hs-CRP, respectively), or comparing the topmost quartile vs. the first one (OR 95% CI, 0.87 (0.60-1.26), 1.19 (0.79-1.79), 1.26 (0.86-1.84), 1.06 (0.67-1.69)). Low-dose aspirin use for cardiovascular prevention does not impact plasma pro-inflammatory cytokine and hs-CRP levels in a population-based cohort.

HBV or HCV coinfections and risk of myocardial infarction in HIV-infected individuals: the D:A:D Cohort Study.

BACKGROUND: Data on a link between HCV or HBV infection and the development of cardiovascular disease among HIV-negative and HIV-positive individuals are conflicting. We sought to investigate the association between HBV or HCV infection and myocardial infarction in HIV-infected individuals. METHODS: The prospective observational database of the D:A:D collaboration of 11 cohorts of HIV-infected individuals, including 212 clinics in Europe, the United States and Australia was used. Multivariate Poisson regression was used to assess the effect of HCV or HBV infection on the development of myocardial infarction after adjustment for potential confounders, including cardiovascular risk factors, diabetes mellitus and exposure to antiretroviral therapy. RESULTS: Of 33,347 individuals, 517 developed a myocardial infarction over 157,912 person-years, with an event rate of 3.3 events/1,000 person-years (95% confidence interval [CI] 3.0-3.6). Event rates (95% CIs) per 1,000 person-years in those who were HCV-seronegative and HCV-seropositive were 3.3 (3.0-3.7) and 2.7 (2.2-3.3), respectively, and for those who were HBV-seronegative, had inactive infection or had active infection were 3.2 (2.8-3.5), 4.2 (3.1-5.2) and 2.8 (1.8-3.9), respectively. After adjustment, there was no association between HCV seropositivity (rate ratio 0.86 [95% CI 0.62-1.19]), inactive HBV infection (rate ratio 1.07 [95% CI 0.79-1.43]) or active HBV infection (rate ratio 0.78 [95% CI 0.52-1.15]) and the development of myocardial infarction. CONCLUSIONS: We found no association between HBV or HCV coinfection and the development of myocardial infarction among HIV-infected individuals.

Atherosclerosis screening by noninvasive imaging for cardiovascular prevention: a systematic review.

BACKGROUND: Noninvasive imaging of atherosclerosis is being increasingly used in clinical practice, with some experts recommending to screen all healthy adults for atherosclerosis and some jurisdictions mandating insurance coverage for atherosclerosis screening. Data on the impact of such screening have not been systematically synthesized. OBJECTIVES: We aimed to assess whether atherosclerosis screening improves cardiovascular risk factors (CVRF) and clinical outcomes. DESIGN: This study is a systematic review. DATA SOURCES: We searched MEDLINE and the Cochrane Clinical Trial Register without language restrictions. STUDY ELIGIBILITY CRITERIA: We included studies examining the impact of atherosclerosis screening with noninvasive imaging (e.g., carotid ultrasound, coronary calcification) on CVRF, cardiovascular events, or mortality in adults without cardiovascular disease. RESULTS: We identified four randomized controlled trials (RCT, n=709) and eight non-randomized studies comparing participants with evidence of atherosclerosis on screening to those without (n=2,994). In RCTs, atherosclerosis screening did not improve CVRF, but smoking cessation rates increased (18% vs. 6%, p=0.03) in one RCT. Non-randomized studies found improvements in several intermediate outcomes, such as increased motivation to change lifestyle and increased perception of cardiovascular risk. However, such data were conflicting and limited by the lack of a randomized control group. No studies examined the impact of screening on cardiovascular events or mortality. Heterogeneity in screening methods and studied outcomes did not permit pooling of results. CONCLUSION: Available evidence about atherosclerosis screening is limited, with mixed results on CVRF control, increased smoking cessation in one RCT, and no data on cardiovascular events. Such screening should be validated by large clinical trials before widespread use.

Cytokines and hs-CRP levels in individuals treated with aspirin for cardiovascular prevention: a population-based study (CoLaus Study)

Backgrounds: Pro-inflammatory cytokines and high-sensitive C-reactive protein (hs-CRP) are associated with increased risk for cardiovascular disease. Low-dose aspirin for cardiovascular (CV) prevention is reported to have anti-inflammatory effects. The aim of this study was to determine the association between cytokines and hs-CRP levels and low-dose aspirin use for CV prevention in a population-based cohort (CoLaus Study). Methods and Results: Blood samples were assessed in 6,085 participants (3,201 women) aged 35-75 years. Medications' use and indications were recorded. Among aspirin users (n=1'034; 17%), overall low-dose (351; 5.8%) and low-dose for CV prevention (324; 5.3%) users were specifically selected for analysis. IL-1beta, IL-6 and TNF-alpha were assessed by a multiplex particle-based flow cytometric assay and hs-CRP by an immunometric assay. Cytokines and hs-CRP were presented in quartiles. Multivariate analysis adjusting for sex, age, smoking status, body mass index, concomitant use of various immunomodulatory drugs, diabetes mellitus showed no association between cytokines and hs-CRP levels and low-dose aspirin use for CV prevention either comparing the topmost vs. the three other quartiles (OR 95% CI, 0.84 (0.59 - 1.18), 1.03 (0.78 - 1.32), 1.10 (0.83 - 1.46), 1.00 (0.67 - 1.69) for IL-1beta, IL-6, TNF-alpha and hs-CRP, respectively), or comparing the topmost quartile vs. the first one (OR 95% CI, 0.87 (0.60 - 1.26), 1.19 (0.79 - 1.79), 1.26 (0.86 - 1.84), 1.06 (0.67 - 1.69)). Conclusions: Low-dose aspirin use for cardiovascular prevention does not seem to impact plasma cytokine and hs-CRP levels in a population-based cohort.

The Atherosclerosis Burden Score (ABS): a Convenient Ultrasound-Based Score of Peripheral Atherosclerosis for Coronary Artery Disease Prediction.

Ultrasonographic detection of subclinical atherosclerosis improves cardiovascular risk stratification, but uncertainty persists about the most discriminative method to apply. In this study, we found that the "atherosclerosis burden score (ABS)", a novel straightforward ultrasonographic score that sums the number of carotid and femoral arterial bifurcations with plaques, significantly outperformed common carotid intima-media thickness, carotid mean/maximal thickness, and carotid/femoral plaque scores for the detection of coronary artery disease (CAD) (receiver operating characteristic (ROC) curve area under the curve (AUC) = 0.79; P = 0.027 to <0.001 with the other five US endpoints) in 203 patients undergoing coronary angiography. ABS was also more correlated with CAD extension (R = 0.55; P < 0.001). Furthermore, in a second group of 1128 patients without cardiovascular disease, ABS was weakly correlated with the European Society of Cardiology chart risk categories (R (2) = 0.21), indicating that ABS provided information beyond usual cardiovascular risk factor-based risk stratification. Pending prospective studies on hard cardiovascular endpoints, ABS appears as a promising tool in primary prevention.

A common BACE1 polymorphism is a risk factor for sporadic Creutzfeldt-Jakob disease

The β site APP cleaving enzyme 1 (BACE1) is the rate-limiting β-secretase enzyme in the amyloidogenic processing of APP and Aβ formation, and therefore it has a prominent role in Alzheimer"s disease (AD) pathology. Recent evidence suggests that the prion protein (PrP) interacts directly with BACE1 regulating its β-secretase activity. Moreover, PrP has been proposed as the cellular receptor involved in the impairment of synaptic plasticity and toxicity caused by Aβ oligomers. Provided that common pathophysiologic mechanisms are shared by Alzheimer"s and Creutzfeldt-Jakob (CJD) diseases, we investigated for the first time to the best of our knowledge a possible association of a common synonymous BACE1 polymorphism (rs638405) with sporadic CJD (sCJD). Our results indicate that BACE1 C-allele is associated with an increased risk for developing sCJD, mainly in PRNP M129M homozygous subjects with early onset. These results extend the very short list of genes (other than PRNP) involved in the development of human prion diseases; and support the notion that similar to AD, in sCJD several loci may contribute with modest overall effects to disease risk. These findings underscore the interplay in both pathologies of APP, Aβ oligomers, ApoE, PrP and BACE1, and suggest that aging and perhaps vascular risk factors may modulate disease pathologies in part through these key players

Development of cardiovascular magnetic resonance imaging techniques for improved characterization of atherosclerotic disease

Atherosclerosis is a chronic cardiovascular disease that involves the thicken¬ing of the artery walls as well as the formation of plaques (lesions) causing the narrowing of the lumens, in vessels such as the aorta, the coronary and the carotid arteries. Magnetic resonance imaging (MRI) is a promising modality for the assessment of atherosclerosis, as it is a non-invasive and patient-friendly procedure that does not use ionizing radiation. MRI offers high soft tissue con¬trast already without the need of intravenous contrast media; while modifica¬tion of the MR pulse sequences allows for further adjustment of the contrast for specific diagnostic needs. As such, MRI can create angiographic images of the vessel lumens to assess stenoses at the late stage of the disease, as well as blood flow-suppressed images for the early investigation of the vessel wall and the characterization of the atherosclerotic plaques. However, despite the great technical progress that occurred over the past two decades, MRI is intrinsically a low sensitive technique and some limitations still exist in terms of accuracy and performance. A major challenge for coronary artery imaging is respiratory motion. State- of-the-art diaphragmatic navigators rely on an indirect measure of motion, per¬form a ID correction, and have long and unpredictable scan time. In response, self-navigation (SM) strategies have recently been introduced that offer 100% scan efficiency and increased ease of use. SN detects respiratory motion di¬rectly from the image data obtained at the level of the heart, and retrospectively corrects the same data before final image reconstruction. Thus, SN holds po-tential for multi-dimensional motion compensation. To this regard, this thesis presents novel SN methods that estimate 2D and 3D motion parameters from aliased sub-images that are obtained from the same raw data composing the final image. Combination of all corrected sub-images produces a final image with reduced motion artifacts for the visualization of the coronaries. The first study (section 2.2, 2D Self-Navigation with Compressed Sensing) consists of a method for 2D translational motion compensation. Here, the use of com- pressed sensing (CS) reconstruction is proposed and investigated to support motion detection by reducing aliasing artifacts. In healthy human subjects, CS demonstrated an improvement in motion detection accuracy with simula¬tions on in vivo data, while improved coronary artery visualization was demon¬strated on in vivo free-breathing acquisitions. However, the motion of the heart induced by respiration has been shown to occur in three dimensions and to be more complex than a simple translation. Therefore, the second study (section 2.3,3D Self-Navigation) consists of a method for 3D affine motion correction rather than 2D only. Here, different techniques were adopted to reduce background signal contribution in respiratory motion tracking, as this can be adversely affected by the static tissue that surrounds the heart. The proposed method demonstrated to improve conspicuity and vi¬sualization of coronary arteries in healthy and cardiovascular disease patient cohorts in comparison to a conventional ID SN method. In the third study (section 2.4, 3D Self-Navigation with Compressed Sensing), the same tracking methods were used to obtain sub-images sorted according to the respiratory position. Then, instead of motion correction, a compressed sensing reconstruction was performed on all sorted sub-image data. This process ex¬ploits the consistency of the sorted data to reduce aliasing artifacts such that the sub-image corresponding to the end-expiratory phase can directly be used to visualize the coronaries. In a healthy volunteer cohort, this strategy improved conspicuity and visualization of the coronary arteries when compared to a con¬ventional ID SN method. For the visualization of the vessel wall and atherosclerotic plaques, the state- of-the-art dual inversion recovery (DIR) technique is able to suppress the signal coming from flowing blood and provide positive wall-lumen contrast. How¬ever, optimal contrast may be difficult to obtain and is subject to RR variability. Furthermore, DIR imaging is time-inefficient and multislice acquisitions may lead to prolonged scanning times. In response and as a fourth study of this thesis (chapter 3, Vessel Wall MRI of the Carotid Arteries), a phase-sensitive DIR method has been implemented and tested in the carotid arteries of a healthy volunteer cohort. By exploiting the phase information of images acquired after DIR, the proposed phase-sensitive method enhances wall-lumen contrast while widens the window of opportunity for image acquisition. As a result, a 3-fold increase in volumetric coverage is obtained at no extra cost in scanning time, while image quality is improved. In conclusion, this thesis presented novel methods to address some of the main challenges for MRI of atherosclerosis: the suppression of motion and flow artifacts for improved visualization of vessel lumens, walls and plaques. Such methods showed to significantly improve image quality in human healthy sub¬jects, as well as scan efficiency and ease-of-use of MRI. Extensive validation is now warranted in patient populations to ascertain their diagnostic perfor¬mance. Eventually, these methods may bring the use of atherosclerosis MRI closer to the clinical practice. Résumé L'athérosclérose est une maladie cardiovasculaire chronique qui implique le épaississement de la paroi des artères, ainsi que la formation de plaques (lé¬sions) provoquant le rétrécissement des lumières, dans des vaisseaux tels que l'aorte, les coronaires et les artères carotides. L'imagerie par résonance magné¬tique (IRM) est une modalité prometteuse pour l'évaluation de l'athérosclérose, car il s'agit d'une procédure non-invasive et conviviale pour les patients, qui n'utilise pas des rayonnements ionisants. L'IRM offre un contraste des tissus mous très élevé sans avoir besoin de médias de contraste intraveineux, tan¬dis que la modification des séquences d'impulsions de RM permet en outre le réglage du contraste pour des besoins diagnostiques spécifiques. À ce titre, l'IRM peut créer des images angiographiques des lumières des vaisseaux pour évaluer les sténoses à la fin du stade de la maladie, ainsi que des images avec suppression du flux sanguin pour une première enquête des parois des vais¬seaux et une caractérisation des plaques d'athérosclérose. Cependant, malgré les grands progrès techniques qui ont eu lieu au cours des deux dernières dé¬cennies, l'IRM est une technique peu sensible et certaines limitations existent encore en termes de précision et de performance. Un des principaux défis pour l'imagerie de l'artère coronaire est le mou¬vement respiratoire. Les navigateurs diaphragmatiques de pointe comptent sur une mesure indirecte de mouvement, effectuent une correction 1D, et ont un temps d'acquisition long et imprévisible. En réponse, les stratégies d'auto- navigation (self-navigation: SN) ont été introduites récemment et offrent 100% d'efficacité d'acquisition et une meilleure facilité d'utilisation. Les SN détectent le mouvement respiratoire directement à partir des données brutes de l'image obtenue au niveau du coeur, et rétrospectivement corrigent ces mêmes données avant la reconstruction finale de l'image. Ainsi, les SN détiennent un poten¬tiel pour une compensation multidimensionnelle du mouvement. A cet égard, cette thèse présente de nouvelles méthodes SN qui estiment les paramètres de mouvement 2D et 3D à partir de sous-images qui sont obtenues à partir des mêmes données brutes qui composent l'image finale. La combinaison de toutes les sous-images corrigées produit une image finale pour la visualisation des coronaires ou les artefacts du mouvement sont réduits. La première étude (section 2.2,2D Self-Navigation with Compressed Sensing) traite d'une méthode pour une compensation 2D de mouvement de translation. Ici, on étudie l'utilisation de la reconstruction d'acquisition comprimée (compressed sensing: CS) pour soutenir la détection de mouvement en réduisant les artefacts de sous-échantillonnage. Chez des sujets humains sains, CS a démontré une amélioration de la précision de la détection de mouvement avec des simula¬tions sur des données in vivo, tandis que la visualisation de l'artère coronaire sur des acquisitions de respiration libre in vivo a aussi été améliorée. Pourtant, le mouvement du coeur induite par la respiration se produit en trois dimensions et il est plus complexe qu'un simple déplacement. Par conséquent, la deuxième étude (section 2.3, 3D Self-Navigation) traite d'une méthode de cor¬rection du mouvement 3D plutôt que 2D uniquement. Ici, différentes tech¬niques ont été adoptées pour réduire la contribution du signal du fond dans le suivi de mouvement respiratoire, qui peut être influencé négativement par le tissu statique qui entoure le coeur. La méthode proposée a démontré une amélioration, par rapport à la procédure classique SN de correction 1D, de la visualisation des artères coronaires dans le groupe de sujets sains et des pa¬tients avec maladies cardio-vasculaires. Dans la troisième étude (section 2.4,3D Self-Navigation with Compressed Sensing), les mêmes méthodes de suivi ont été utilisées pour obtenir des sous-images triées selon la position respiratoire. Au lieu de la correction du mouvement, une reconstruction de CS a été réalisée sur toutes les sous-images triées. Cette procédure exploite la cohérence des données pour réduire les artefacts de sous- échantillonnage de telle sorte que la sous-image correspondant à la phase de fin d'expiration peut directement être utilisée pour visualiser les coronaires. Dans un échantillon de volontaires en bonne santé, cette stratégie a amélioré la netteté et la visualisation des artères coronaires par rapport à une méthode classique SN ID. Pour la visualisation des parois des vaisseaux et de plaques d'athérosclérose, la technique de pointe avec double récupération d'inversion (DIR) est capa¬ble de supprimer le signal provenant du sang et de fournir un contraste posi¬tif entre la paroi et la lumière. Pourtant, il est difficile d'obtenir un contraste optimal car cela est soumis à la variabilité du rythme cardiaque. Par ailleurs, l'imagerie DIR est inefficace du point de vue du temps et les acquisitions "mul- tislice" peuvent conduire à des temps de scan prolongés. En réponse à ce prob¬lème et comme quatrième étude de cette thèse (chapitre 3, Vessel Wall MRI of the Carotid Arteries), une méthode de DIR phase-sensitive a été implémenté et testé

Cardiovascular dysfunction in children conceived by assisted reproductive technologies.

Epidemiological studies demonstrate a relationship between pathological events during foetal development and future cardiovascular risk and the term 'foetal programming of cardiovascular disease' has been coined to describe this phenomenon. The use of assisted reproductive technologies (ARTs) is growing exponentially and 2-5% of children are now born by this procedure. Emerging evidence indicates that ART represents a novel important example of foetal programming. Assisted reproductive technology may modify the cardiovascular phenotype in two ways: (i) ART involves manipulation of the early embryo which is exquisitely sensitive to environmental insults. In line with this concern, ART alters vascular and cardiac function in children and studies in mice show that ART alters the cardiovascular phenotype by epigenetic alterations related to suboptimal culture conditions. (ii) Assisted reproductive technology markedly increases the risk of foetal insults that augment cardiovascular risk in naturally conceived individuals and are expected to have similar consequences in the ART population. Given the young age of the ART population, it will take another 20-30 years before data on cardiovascular endpoints will be available. What is clear already, however, is that ART emerges as an important cardiovascular risk factor. This insight requires us to revise notions on ART's long-term safety and to engage on a debate on its future. There is an urgent need to better understand the mechanisms underpinning ART-induced alteration of the cardiovascular phenotype, improve the procedure and its long-term safety, and, while awaiting this aim, not to abandon medicine's fundamental principle of doing no harm (to future children) and use ART parsimoniously.