Reconstruction active et passive en vision par ordinateur

Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal

Near-Infrared Spectroscopy (NIRS): A Novel Tool for Intravascular Coronary Imaging

Acute coronary syndrome (ACS) arising from plaque rupture is the leading cause of mortality worldwide. Near-infrared spectroscopy (NIRS) combined with intravascular ultrasound (NIRS-IVUS) is a novel catheter-based intravascular imaging modality that provides a chemogram of the coronary artery wall, which enables the detection of lipid core and specific quantification of lipid accumulation measured as the lipid-core burden index (LCBI) in patients undergoing coronary angiography. Recent studies have shown that NIRS-IVUS can identify vulnerable plaques and vulnerable patients associated with increased risk of adverse cardiovascular events, whereas an increased coronary plaque LCBI may predict a higher risk of future cardiovascular events and periprocedural events. NIRS is a promising tool for the detection of vulnerable plaques in CAD patients, PCI-guidance procedures, and assessment of lipid-lowering therapies. Previous trials have evaluated the impact of statin therapy on coronary NIRS defined lipid cores, whereas NIRS could further be used as a surrogate end point of future ACS in phase II clinical trials evaluating novel anti-atheromatous drug therapies. Multiple ongoing studies address the different potential clinical applications of NIRS-IVUS imaging as a valuable tool for coronary plaque characterization and predictor of future coronary events in CAD patients

Quality of life with ivabradine in patients with angina pectoris

Background—To explore the effect of ivabradine on angina-related quality of life (QoL) in patients participating in the Study Assessing the Morbidity–Mortality Benefits of the If Inhibitor Ivabradine in Patients with Coronary Artery Disease (SIGNIFY) QoL substudy. Methods and Results—QoL was evaluated in a prespecified subgroup of SIGNIFY patients with angina (Canadian Cardiovascular Society class score, ≥2 at baseline) using the Seattle Angina Questionnaire and a generic visual analogue scale on health status. Data were available for 4187 patients (2084 ivabradine and 2103 placebo). There were improvements in QoL in both treatment groups. The primary outcome of change in physical limitation score at 12 months was 4.56 points for ivabradine versus 3.40 points for placebo (E, 0.96; 95% confidence interval, –0.14 to 2.05; P=0.085). The ivabradine−placebo difference in physical limitation score was significant at 6 months (P=0.048). At 12 months, the visual analogue scale and the other Seattle Angina Questionnaire dimensions were higher among ivabradine-treated patients, notably angina frequency (P<0.001) and disease perception (P=0.006). Patients with the worst QoL at baseline (ie, those in the lowest tertile of score) had the best improvement in QoL for 12 months, with improvements in physical limitation and a significant reduction in angina frequency (P=0.034). The effect on QoL was maintained over the study duration, and ivabradine patients had better scores on angina frequency at every visit to 36 months. Conclusions—Treatment with ivabradine did not affect the primary outcome of change in physical limitation score at 12 months. It did produce consistent improvements in other self-reported QoL parameters related to angina pectoris, notably in terms of angina frequency and disease perception

Critical Appraisal of C-Reactive Protein Throughout the Spectrum of Cardiovascular Disease

Clinicians involved in the care of patients with cardiovascular conditions have recently been confronted with an important body of literature linking inflammation and cardiovascular disease. Indeed, the level of systemic inflammation as measured by circulating levels of C-reactive protein (CRP) has been linked to prognosis in patients with atherosclerotic disease, congestive heart failure, atrial fibrillation, myocarditis, aortic valve disease and heart transplantation. In addition, a number of basic science reports suggest an active role for CRP in the pathophysiology of cardiovascular diseases. This article explores the potential role of CRP in disease initiation, progression, and clinical manifestations and reviews its role in the prediction of future events in clinical practice. Therapeutic interventions to decrease circulating levels of CRP are also reviewed

Prevalence of anginal symptoms and myocardial ischemia and their effect on clinical outcomes in outpatients with stable coronary artery disease: data from the international observational CLARIFY registry

Importance: In the era of widespread revascularization and effective antianginals, the prevalence and prognostic effect of anginal symptoms and myocardial ischemia among patients with stable coronary artery disease (CAD) are unknown.<p></p> Objective: To describe the current clinical patterns among patients with stable CAD and the association of anginal symptoms or myocardial ischemia with clinical outcomes.<p></p> Design, Setting, and Participants: The Prospective Observational Longitudinal Registry of Patients With Stable Coronary Artery Disease (CLARIFY) registry enrolled outpatients in 45 countries with stable CAD in 2009 to 2010 with 2-year follow-up (median, 24.1 months; range, 1 day to 3 years). Enrollees included 32 105 outpatients with prior myocardial infarction, chest pain, and evidence of myocardial ischemia, evidence of CAD on angiography, or prior revascularization. Of these, 20 291 (63.2%) had undergone a noninvasive test for myocardial ischemia within 12 months of enrollment and were categorized into one of the following 4 groups: no angina or ischemia (n = 13 207 [65.1%]); evidence of myocardial ischemia without angina (silent ischemia) (n = 3028 [14.9%]); anginal symptoms alone (n = 1842 [9.1%]); and angina and ischemia (n = 2214 [10.9%]).<p></p> Exposures: Stable CAD.<p></p> Main Outcome and Measure: The composite of cardiovascular (CV)–related death or nonfatal myocardial infarction.<p></p> Results: Overall, 4056 patients (20.0%) had anginal symptoms and 5242 (25.8%) had evidence of myocardial ischemia on results of noninvasive testing. Of 469 CV-related deaths or myocardial infarctions, 58.2% occurred in patients without angina or ischemia, 12.4% in patients with ischemia alone, 12.2% in patients with angina alone, and 17.3% in patients with both. The hazard ratios for the primary outcome relative to patients without angina or ischemia and adjusted for age, sex, geographic region, smoking status, hypertension, diabetes mellitus, and dyslipidemia were 0.90 (95% CI, 0.68-1.20; P = .47) for ischemia alone, 1.45 (95% CI, 1.08-1.95; P = .01) for angina alone, and 1.75 (95% CI, 1.34-2.29; P <.001) for both. Similar findings were observed for CV-related death and for fatal or nonfatal myocardial infarction.<p></p> Conclusions and Relevance: In outpatients with stable CAD, anginal symptoms (with or without ischemia on noninvasive testing) but not silent ischemia appear to be associated with an increased risk for adverse CV outcomes. Most CV events occurred in patients without angina or ischemia

Beneficial effects of reconstituted high-density lipoprotein (rHDL) on circulating CD34+ cells in patients after an acute coronary syndrome

Background: High-density lipoproteins (HDL) favorably affect endothelial progenitor cells (EPC). Circulating progenitor cell level and function are impaired in patients with acute coronary syndrome (ACS). This study investigates the short-term effects of reconstituted HDL (rHDL) on circulating progenitor cells in patients with ACS. Methods and Findings: The study population consisted of 33 patients with recent ACS: 20 patients from the ERASE trial (randomized to receive 4 weekly intravenous infusions of CSL-111 40 mg/kg or placebo) and 13 additional patients recruited as controls using the same enrolment criteria. Blood was collected from 16 rHDL (CSL-111)-treated patients and 17 controls at baseline and at 6–7 weeks (i.e. 2–3 weeks after the fourth infusion of CSL-111 in ERASE). CD34+ and CD34+/kinase insert domain receptor (KDR+) progenitor cell counts were analyzed by flow cytometry. We found preserved CD34+ cell counts in CSL-111-treated subjects at follow-up (change of 1.6%), while the number of CD34+ cells was reduced (-32.9%) in controls (p = 0.017 between groups). The level of circulating SDF-1 (stromal cell-derived factor-1), a chemokine involved in progenitor cell recruitment, increased significantly (change of 21.5%) in controls, while it remained unchanged in CSL-111-treated patients (p = 0.031 between groups). In vitro exposure to CSL-111 of early EPC isolated from healthy volunteers significantly increased CD34+ cells, reduced early EPC apoptosis and enhanced their migration capacity towards SDF-1. Conclusions: The relative increase in circulating CD34+ cells and the low SDF-1 levels observed following rHDL infusions in ACS patients point towards a role of rHDL in cardiovascular repair mechanisms

Simple risk models to predict cardiovascular death in patients with stable coronary artery disease

Aims: Risk estimation is important to motivate patients to adhere to treatment and to identify those in whom additional treatments may be warranted and expensive treatments might be most cost effective. Our aim was to develop a simple risk model based on readily available risk factors for patients with stable coronary artery disease (CAD). Methods and results: Models were developed in the CLARIFY registry of patients with stable CAD, first incorporating only simple clinical variables and then with the inclusion of assessments of left ventricular function, estimated glomerular filtration rate, and haemoglobin levels. The outcome of cardiovascular death over ∼5 years was analysed using a Cox proportional hazards model. Calibration of the models was assessed in an external study, the CORONOR registry of patients with stable coronary disease. We provide formulae for calculation of the risk score and simple integer points-based versions of the scores with associated look-up risk tables. Only the models based on simple clinical variables provided both good c-statistics (0.74 in CLARIFY and 0.80 or over in CORONOR), with no lack of calibration in the external dataset. Conclusion: Our preferred model based on 10 readily available variables [age, diabetes, smoking, heart failure (HF) symptom status and histories of atrial fibrillation or flutter, myocardial infarction, peripheral arterial disease, stroke, percutaneous coronary intervention, and hospitalization for HF] had good discriminatory power and fitted well in an external dataset. Study registration: The CLARIFY registry is registered in the ISRCTN registry of clinical trials (ISRCTN43070564)

Differences in outcomes in patients with stable coronary artery disease managed by cardiologists versus noncardiologists Results from the international prospective CLARIFY registry

INTRODUCTION Clinical outcomes of patients with stable coronary artery disease (CAD) may differ between those primarily managed by cardiologists versus noncardiologists. OBJECTIVES Our main objective was to analyze the clinical outcomes of outpatients with stable CAD in relation to the specialty of the managing physicians. PATIENTS AND METHODS We studied 32 468 outpatients with stable CAD included in the CLARIFY registry, with up to 4 years of follow-up data. Cardiologists provided medical care in 84.1% and noncardiologists in 15.9% of the patients. Primary outcome was the composite of cardiovascular death, nonfatal myocardial infarction (MI), or stroke. RESULTS Important differences in management as well as demographic and clinical characteristics were observed between the groups at baseline. Patients treated by cardiologists were younger and more of them had dyslipidemia, hypertension, and diabetes. The use of beta-blockers and thienopyridines, as well as history of percutaneous coronary intervention were more frequent in this group. More patients treated by noncardiologists had a history of MI as well as concomitant peripheral artery disease and asthma or chronic obstructive pulmonary disease. They also had lower left ventricular ejection fraction and more often received lipid-lowering drugs. After adjustment for baseline differences, patients treated by cardiologists had a lower risk of the primary outcome (adjusted hazard ratio, 0.80;95% confidence interval, 0.68-0.94;P = 0.0067) and of most secondary outcomes, but greater risk of bleeding. CONCLUSIONS Outpatients with stable CAD managed by cardiologists had a lower rate of cardiovascular outcomes than those managed by noncardiologists. We did not find clear evidence that cardiologists provided superior guideline -based treatment, so the differences in outcome were most likely due to unquantifiable differences in patient characteristics