1,721,027 research outputs found
Myocardial infarction with no obstructive coronary artery disease: angiographic and clinical insights in patients with premature presentation
No full textBackground - Premature myocardial infarction (MI) is an increasingly prevalent cause of morbidity and mortality worldwide. A subset of patients, predominantly young women, present with MI with no obstructive coronary artery disease (MINOCA), a nomenclature gaining recognition. However, few data exist on presentation and prognosis according to the severity of coronary artery disease (CAD).
Methods - We studied patients with premature (younger than 55 years of age) acute MI enrolled in a large cohort in 24 centres across Canada. Baseline clinical, psychosocial, and coronary anatomy characteristics as well as 12-month outcomes were compared between patients with MINOCA (< 50% stenosis) and patients with MI with obstructive CAD (≥ 50% stenosis; MICAD).
Results - From a cohort of 1210 patients with acute coronary syndrome, we examined 998 MI patients with available angiography core lab readings: 82 (8.2%) had a MINOCA and 916 (91.8%) had a MICAD. Forty percent of patients with MINOCA were women compared with one-third with MICAD. The prevalence of traditional risk factors and chest pain at presentation was lower in MINOCA patients, yet 37% had a ST-elevation MI and 10% presented with a cardiac arrest. No evident etiology was detected in > 70% of MINOCA, but 10% presented with either spontaneous coronary dissection or Takotsubo cardiomyopathy. Although combined major adverse cardiovascular events and all-cause readmission rate was lower in the MINOCA group (14% vs 25%; adjusted hazard ratio, 0.51; 95% confidence interval, 0.28-0.93), it was not negligible.
Conclusions - Patients with MINOCA present with high-risk features despite the absence of obstructive CAD. A search for etiology and eventual treatment provides a rich avenue for improving prognosis in young women with premature MI
The Learning Curve and Annual Procedure Volume Standards for Optimum Outcomes of Transcatheter Aortic Valve Replacement: Findings from an International Registry
Full text linkTranscatheter aortic valve replacement (TAVR) is a technically complex procedure. Despite increasing use of TAVR across institutions, incomplete knowledge exists to describe the learning curve and minimum annual volumes for this procedure. We hypothesize that TAVR has a prolonged learning curve, as well as a high minimal annual volume to maintain competency. In this study, we analyzed data from 16 international centers comprising 3403 patients from the inception of their TAVR programs. The study identified an important learning curve, with higher mortality for the first 225 cases compared to those performed after > 300 case volume, and higher combined major complications up until a 300-case volume. In addition, the 30-day mortality was higher for centers performingM.Sc
CLINICAL CHARACTERISTICS AND OUTCOMES IN PATIENTS WITH INFECTIVE ENDOCARDITIS (IE)
Full text linkInfective endocarditis (IE) is a serious medical condition with significant morbidity and mortality. We sought to determine the clinical characteristics, microbiological profile and long-term outcome of IE patients at a tertiary care Canadian hospital. A total of 307 confirmed IE cases were included from, January 2008 to June 2016. The mean age of study population was 58 ±16 years, including 66% males. A native cardiac valve (NVE) was affected in 238 patients (77.5%) and Staphylococcus aureus was isolated in 98 cases (32%). Surgery was performed in 190 patients (61.8%), with 120 early surgeries (63%) during index hospitalization. At a median follow up of 235 days (IQR 45-1012 days), 90 patients had died (29%); 44.4% from medical and 20% from surgical cohort, p=0.001. On multivariate analysis, age (OR 1.04 95%CI 1.02-1.07, p=0.000), heart failure (OR 3.62 95%CI 1.06-12.41, p=0.04) and septic shock (OR 2.89 95%CI 1.18-7.08, p=0.02) were predictors of mortality.M.Sc
CLINICAL CHARACTERISTICS AND OUTCOMES IN PATIENTS WITH INFECTIVE ENDOCARDITIS (IE)
No full textInfective endocarditis (IE) is a serious medical condition with significant morbidity and mortality. We sought to determine the clinical characteristics, microbiological profile and long-term outcome of IE patients at a tertiary care Canadian hospital. A total of 307 confirmed IE cases were included from, January 2008 to June 2016. The mean age of study population was 58 ±16 years, including 66% males. A native cardiac valve (NVE) was affected in 238 patients (77.5%) and Staphylococcus aureus was isolated in 98 cases (32%). Surgery was performed in 190 patients (61.8%), with 120 early surgeries (63%) during index hospitalization. At a median follow up of 235 days (IQR 45-1012 days), 90 patients had died (29%); 44.4% from medical and 20% from surgical cohort, p=0.001. On multivariate analysis, age (OR 1.04 95%CI 1.02-1.07, p=0.000), heart failure (OR 3.62 95%CI 1.06-12.41, p=0.04) and septic shock (OR 2.89 95%CI 1.18-7.08, p=0.02) were predictors of mortality.M.Sc
The Learning Curve and Annual Procedure Volume Standards for Optimum Outcomes of Transcatheter Aortic Valve Replacement: Findings from an International Registry
No full textTranscatheter aortic valve replacement (TAVR) is a technically complex procedure. Despite increasing use of TAVR across institutions, incomplete knowledge exists to describe the learning curve and minimum annual volumes for this procedure. We hypothesize that TAVR has a prolonged learning curve, as well as a high minimal annual volume to maintain competency. In this study, we analyzed data from 16 international centers comprising 3403 patients from the inception of their TAVR programs. The study identified an important learning curve, with higher mortality for the first 225 cases compared to those performed after > 300 case volume, and higher combined major complications up until a 300-case volume. In addition, the 30-day mortality was higher for centers performingM.Sc
Natural History of Functional Tricuspid Regurgitation after Device Closure of Atrial Septal Defect
Full text linkFunctional tricuspid regurgitation (TR) is a significant complication in patients diagnosed with atrial septal defect (ASD) and occurs due to right-heart volume overload from the left to right shunting of blood at the atrial level. A reduction in the severity of TR after ASD closure has been reported, however, the frequency, timing and magnitude of TR reduction after ASD device closure has not been well established. Moreover, the factors which may affect the TR severity after ASD closure are poorly understood. An improved understanding of these parameters has important implications for the management of patients being considered for ASD device closure. In the present prospective longitudinal cohort study, I aim to examine the chronological change in TR severity after transcatheter ASD device closure and to determine predictors of moderate to severe TR persistence. The present study included a total of 84 patients who underwent successful transcatheter ASD device closure at St Michael’s Hospital (Toronto, Canada) between 2007 and 2018 and who underwent serial clinical and echocardiographic follow-up up to nine years (mean follow up = 1095 days). The mean age of the study cohort was 48±15 years (32% male). The results showed that the prevalence of moderate to severe TR reduced from 31% at baseline to 13% at day 7, 12% at 2 months and 6% at 6 months. This reduction in TR was associated with similar reduction in dimensions of both right atrium and right ventricle. The univariate predictors of persistent moderate to severe TR after ASD closure included female gender (p=0.034), history of hypertension (p=0.033), elevated RVSP (p<0.001) and moderate to severe TR (p<0.001) at baseline. The multivariate predictors of persistent moderate to severe TR during follow up included elevated RVSP (p=0.009) and moderate to severe TR at baseline (p=0.044). These findings indicate that patients diagnosed with ASD should be considered for ASD device closure before development of moderate to severe TR or elevation of pulmonary artery pressures to achieve optimum reduction in post procedural TR.M.Sc
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Arterial repair after balloon angioplasty and stenting: Role of extracellular matrix and adventitial microvessels in the development of intimal hyperplasia and restenosis
Full text linkThe development of restenosis after percutaneous coronary intervention (PCI) is a major limitation of such procedures and is associated with significant cost and morbidity. Although, the role of smooth muscle cells and vascular intima in arterial repair after PCI has been well investigated, limited information is available regarding the function of extracellular matrix (ECM) and vascular adventitia in this repair response. The research presented in this thesis focuses on these two important aspects of arterial repair (i.e. ECM turnover and changes in adventitial microvessels) in an attempt to identify new targets for therapeutic intervention. Although, collagen and elastin accumulation in the vessel wall has been identified as a critical component of the arterial repair response after PCI, therapeutic implications of these changes remain unclear. In view of the antifibrotic effects of cryotherapy application during tissue repair observed in skin and liver, intravascular cryotherapy was applied after balloon angioplasty in rabbit iliac arteries and effects on collagen accumulation and intimal hyperplasia determined at 72 hours and at 10 weeks. Cryotherapy application produced average vessel wall temperature of -26°C (range, -20°C to -45°C). Despite greater lumen areas noted immediately, both collagen content and intimal hyperplasia was increased two-fold in cryotherapy treated arteries compared to balloon only injured arteries. In addition, marked cell loss and morphologic changes in the form of cartilage and bone formation were noted in cryotherapy treated arteries suggesting that contrary to earlier observations in skin and liver tissue, intravascular cryotherapy after angioplasty increased intimal hyperplasia and induced fibrosis and chondro-metaplasia with no beneficial effects on restenosis. Inhibition of collagen accumulation in the arterial wall after PCI may also be achieved by inhibition of platelet derived growth factor (PDGF) and transforming growth factor beta (TGF beta), two profibrotic growth factors with increased expression after arterial injury. Decorin is a small leucine rich proteoglycan with potent in vitro activity against PDGF and TGF beta and demonstrated antifibrotic properties in animal models. Adenoviral mediated decorin overexpression was achieved in a rabbit carotid angioplasty model to investigate the role of decorin in the prevention of restenosis. Decorin overexpression after angioplasty inhibited both collagen content and intimal area at ten weeks compared to placebo (beta-galactosidase transfected) or injured non-transfected controls. These findings suggest a potential therapeutic role of decorin in the prevention of intimal hyperplasia and restenosis after PCI. (Abstract shortened by UMI.).Ph.D
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
