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The best American sports writing 2017
An anthology of top-selected sports writing from the past year is culled from hundreds of national, regional, and specialty publications as well as a variety of leading sports blogs.
BOOK
Deep-learning cardiac motion analysis for human survival prediction
Motion analysis is used in computer vision to understand the behaviour of moving objects in sequences of images. Optimizing the interpretation of dynamic biological systems requires accurate and precise motion tracking as well as efficient representations of high-dimensional motion trajectories so that these can be used for prediction tasks. Here we use image sequences of the heart, acquired using cardiac magnetic resonance imaging, to create time-resolved three-dimensional segmentations using a fully convolutional network trained on anatomical shape priors. This dense motion model formed the input to a supervised denoising autoencoder (4Dsurvival), which is a hybrid network consisting of an autoencoder that learns a task-specific latent code representation trained on observed outcome data, yielding a latent representation optimized for survival prediction. To handle right-censored survival outcomes, our network used a Cox partial likelihood loss function. In a study of 302 patients, the predictive accuracy (quantified by Harrell’s
C
-index) was significantly higher (
P
= 0.0012) for our model
C
= 0.75 (95% CI: 0.70–0.79) than the human benchmark of
C
= 0.59 (95% CI: 0.53–0.65). This work demonstrates how a complex computer vision task using high-dimensional medical image data can efficiently predict human survival.
A fully convolutional neural network is used to create time-resolved three-dimensional dense segmentations of heart images. This dense motion model forms the input to a supervised system called 4Dsurvival that can efficiently predict human survival.
Journal Article
British Thoracic Society Guideline for the initial outpatient management of pulmonary embolism (PE)
Correspondence to Dr Luke S G E Howard, National Pulmonary Hypertension Service, Hammersmith Hospital, Imperial College Healthcare NHS Trust, London, W12 0HS, UK; l.howard@imperial.ac.uk Summary of recommendations Outcomes of outpatient care for low-risk pulmonary embolism (PE) Recommendations Patients with PE should be assessed for suitability for management as outpatients (OPs). Chronic kidney disease (CKD) stages 4 or 5 (estimated glomerular filtration rate (eGFR)<30 mL/min) or severe liver disease. Grade C Where RV dilatation has been identified on CT scanning or echocardiography in patients who are suitable for OP management, consider measuring laboratory cardiac biomarkers (B-type natriuretic peptide (BNP), N-terminal pro B-type natriuretic peptide (NT-proBNP), high-sensitivity troponin I or T (hsTnI or hsTnT)). If no consultant is available, then patients may be reviewed by a senior trainee (ST3 or above; ST4 in the case of Emergency Medicine) by a staff grade or similar substantive career grade doctor, advanced nurse practitioner or clinical nurse specialist designated to undertake this role within the department with consultant advice available.
Journal Article
Evidence of Dysfunction of Endothelial Progenitors in Pulmonary Arterial Hypertension
Severe pulmonary arterial hypertension (PAH) is characterized by the formation of plexiform lesions and concentric intimal fibrosis in small pulmonary arteries. The origin of cells contributing to these vascular lesions is uncertain. Endogenous endothelial progenitor cells are potential contributors to this process.
To determine whether progenitors are involved in the pathobiology of PAH.
We performed immunohistochemistry to determine the expression of progenitor cell markers (CD133 and c-Kit) and the major homing signal pathway stromal cell-derived factor-1 and its chemokine receptor (CXCR4) in lung tissue from patients with idiopathic PAH, familial PAH, and PAH associated with congenital heart disease. Two separate flow cytometric methods were employed to determine peripheral blood circulating numbers of angiogenic progenitors. Late-outgrowth progenitor cells were expanded ex vivo from the peripheral blood of patients with mutations in the gene encoding bone morphogenetic protein receptor type II (BMPRII), and functional assays of migration, proliferation, and angiogenesis were undertaken. measurements and main results: There was a striking up-regulation of progenitor cell markers in remodeled arteries from all patients with PAH, specifically in plexiform lesions. These lesions also displayed increased stromal cell-derived factor-1 expression. Circulating angiogenic progenitor numbers in patients with PAH were increased compared with control subjects and functional studies of late-outgrowth progenitor cells from patients with PAH with BMPRII mutations revealed a hyperproliferative phenotype with impaired ability to form vascular networks.
These findings provide evidence of the involvement of progenitor cells in the vascular remodeling associated with PAH. Dysfunction of circulating progenitors in PAH may contribute to this process.
Journal Article
Thrombolysis for PE: less is more?
While the National Institute for Health and Care Excellence (NICE) Clinical Guideline 144 makes it clear that thrombolysis should not be administered to patients outside the context of haemodynamic instability,1 the European Society of Cardiology (ESC) guidelines leave open the possibility that we ‘consider’ reperfusion therapy in some patients with intermediate-high risk PE.2 While NICE guidance does not perhaps reflect the complexity of different presentations of PE, the ESC guidelines leave us with a great deal of uncertainty when making major clinical decisions. [...]we may be able to improve the benefit:risk profile of reperfusion therapy with better patient selection. While PEITHO used the intermediate-high risk patient group, recent data have suggested that this group of patients does not have a significantly higher mortality than the intermediate-low risk patients.4 Various studies have shown that combinations of risk factors that include biomarkers and deep vein thrombosis identified on leg vein Doppler may identify normotensive patients at the highest risk of adverse outcomes who would benefit from reperfusion.5 6 Furthermore, a deeper look into the PEITHO data shows that younger patients were at lower risk of adverse events. [...]including these patients in the overall analysis may have contaminated the overall findings; however, since they were negative, this criticism is invalid.
Journal Article
BTS guidelines for the initial outpatient management of pulmonary embolism: there’s no place like home
This article provides an overview of the highlights and key points of the new BTS guideline for the initial outpatient management of pulmonary embolism.
Journal Article
Reduced plasma levels of small HDL particles transporting fibrinolytic proteins in pulmonary arterial hypertension
BackgroundAberrant lipoprotein metabolism has been implicated in experimental pulmonary hypertension, but the relevance to patients with pulmonary arterial hypertension (PAH) is inconclusive.ObjectiveTo investigate the relationship between circulating lipoprotein subclasses and survival in patients with PAH.MethodsUsing nuclear magnetic resonance spectroscopy, 105 discrete lipoproteins were measured in plasma samples from two cohorts of patients with idiopathic or heritable PAH. Data from 1124 plasma proteins were used to identify proteins linked to lipoprotein subclasses. The physical presence of proteins was confirmed in plasma lipoprotein subfractions separated by ultracentrifugation.ResultsPlasma levels of three lipoproteins from the small high-density lipoprotein (HDL) subclass, termed HDL-4, were inversely related to survival in both the discovery (n=127) and validation (n=77) cohorts, independent of exercise capacity, comorbidities, treatment, N-terminal probrain natriuretic peptide, C reactive protein and the principal lipoprotein classes. The small HDL subclass rich in apolipoprotein A-2 content (HDL-4-Apo A-2) exhibited the most significant association with survival. None of the other lipoprotein classes, including principal lipoprotein classes HDL and low-density lipoprotein cholesterol, were prognostic. Three out of nine proteins identified to associate with HDL-4-Apo A-2 are involved in the regulation of fibrinolysis, namely, the plasmin regulator, alpha-2-antiplasmin, and two major components of the kallikrein–kinin pathway (coagulation factor XI and prekallikrein), and their physical presence in the HDL-4 subfraction was confirmed.ConclusionReduced plasma levels of small HDL particles transporting fibrinolytic proteins are associated with poor outcomes in patients with idiopathic and heritable PAH.
Journal Article
Echocardiographic assessment of pulmonary hypertension: a guideline protocol from the British Society of Echocardiography
Pulmonary hypertension is defined as a mean arterial pressure of ≥25 mmHg as confirmed on right heart catheterisation. Traditionally, the pulmonary arterial systolic pressure has been estimated on echo by utilising the simplified Bernoulli equation from the peak tricuspid regurgitant velocity and adding this to an estimate of right atrial pressure. Previous studies have demonstrated a correlation between this estimate of pulmonary arterial systolic pressure and that obtained from invasive measurement across a cohort of patients. However, for an individual patient significant overestimation and underestimation can occur and the levels of agreement between the two is poor. Recent guidance has suggested that echocardiographic assessment of pulmonary hypertension should be limited to determining the probability of pulmonary hypertension being present rather than estimating the pulmonary artery pressure. In those patients in whom the presence of pulmonary hypertension requires confirmation, this should be done with right heart catheterisation when indicated. This guideline protocol from the British Society of Echocardiography aims to outline a practical approach to assessing the probability of pulmonary hypertension using echocardiography and should be used in conjunction with the previously published minimum dataset for a standard transthoracic echocardiogram.
Journal Article
Changing Demographics, Epidemiology, and Survival of Incident Pulmonary Arterial Hypertension
Incident pulmonary arterial hypertension was underrepresented in most pulmonary hypertension registries and may have a different disease profile to prevalent disease.
To determine the characteristics and outcome of a purely incident, treatment-naive cohort of idiopathic, heritable, and anorexigen-associated pulmonary arterial hypertension and to determine the changes in presentations and survival over the past decade in the United Kingdom and Ireland.
All consecutive newly diagnosed patients from 2001 to 2009 were identified prospectively.
A total of 482 patients (93% idiopathic, 5% heritable, and 2% anorexigen-associated pulmonary arterial hypertension) were diagnosed, giving rise to an estimated incidence of 1.1 cases per million per year and prevalence of 6.6 cases per million in 2009. Younger patients (age ≤ 50 yrs) had shorter duration of symptoms, fewer comorbidities, better functional and exercise capacity, higher percent diffusing capacity of carbon monoxide, more severe hemodynamic impairment, but better survival compared with older patients. In comparison with the earlier cohorts, patients diagnosed in 2007-2009 were older, more obese, had lower percent diffusing capacity of carbon monoxide,(,) and more comorbidities, but better survival. Registry to Evaluate Early and Long-Term Pulmonary Arterial Hypertension Disease Management (REVEAL) equation, REVEAL risk score, and Pulmonary Hypertension Connection Registry survival equation accurately predicted survival of our incident cohort at 1 year.
This study highlights the influence of age on phenotypes of incident pulmonary arterial hypertension and has shown the changes in demographics and epidemiology over the past decade in a national setting. The results suggest that there may be two subtypes of patients: the younger subtype with more severe hemodynamic impairment but better survival, compared with the older subtype who has more comorbidities.
Journal Article