Publications by authors named "William Bradlow"

26 Publications

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Improved characterisation of clinical text through ontology-based vocabulary expansion.

J Biomed Semantics 2021 04 12;12(1). Epub 2021 Apr 12.

Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.

Background: Biomedical ontologies contain a wealth of metadata that constitutes a fundamental infrastructural resource for text mining. For several reasons, redundancies exist in the ontology ecosystem, which lead to the same entities being described by several concepts in the same or similar contexts across several ontologies. While these concepts describe the same entities, they contain different sets of complementary metadata. Linking these definitions to make use of their combined metadata could lead to improved performance in ontology-based information retrieval, extraction, and analysis tasks.

Results: We develop and present an algorithm that expands the set of labels associated with an ontology class using a combination of strict lexical matching and cross-ontology reasoner-enabled equivalency queries. Across all disease terms in the Disease Ontology, the approach found 51,362 additional labels, more than tripling the number defined by the ontology itself. Manual validation by a clinical expert on a random sampling of expanded synonyms over the Human Phenotype Ontology yielded a precision of 0.912. Furthermore, we found that annotating patient visits in MIMIC-III with an extended set of Disease Ontology labels led to semantic similarity score derived from those labels being a significantly better predictor of matching first diagnosis, with a mean average precision of 0.88 for the unexpanded set of annotations, and 0.913 for the expanded set.

Conclusions: Inter-ontology synonym expansion can lead to a vast increase in the scale of vocabulary available for text mining applications. While the accuracy of the extended vocabulary is not perfect, it nevertheless led to a significantly improved ontology-based characterisation of patients from text in one setting. Furthermore, where run-on error is not acceptable, the technique can be used to provide candidate synonyms which can be checked by a domain expert.
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http://dx.doi.org/10.1186/s13326-021-00241-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8042947PMC
April 2021

Transthoracic echocardiography of hypertrophic cardiomyopathy in adults: a practical guideline from the British Society of Echocardiography.

Echo Res Pract 2021 Mar 1. Epub 2021 Mar 1.

W Bradlow, Cardiology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, B15 2TH, United Kingdom of Great Britain and Northern Ireland.

Hypertrophic cardiomyopathy (HCM) is common, inherited and characterised by unexplained thickening of the myocardium. The British Society of Echocardiography (BSE) has recently published a minimum dataset for transthoracic echocardiography detailing the core views needed for a standard echocardiogram. For patients with confirmed or suspected HCM, additional views and measurements are necessary. This guideline, therefore, supplements the minimum dataset and describes a tailored, stepwise approach to the echocardiographic examination, and echocardiography's position in the diagnostic pathway, before advising on the imaging of disease complications and invasive treatments.
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http://dx.doi.org/10.1530/ERP-20-0042DOI Listing
March 2021

Persisting Adverse Ventricular Remodeling in COVID-19 Survivors: A Longitudinal Echocardiographic Study.

J Am Soc Echocardiogr 2021 May 1;34(5):562-566. Epub 2021 Feb 1.

Department of Cardiology, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom; Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.

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http://dx.doi.org/10.1016/j.echo.2021.01.020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8008825PMC
May 2021

A fast, accurate, and generalisable heuristic-based negation detection algorithm for clinical text.

Comput Biol Med 2021 Mar 16;130:104216. Epub 2021 Jan 16.

College of Medical and Dental Sciences, Institute of Cancer and Genomic Sciences, University of Birmingham, UK; Institute of Translational Medicine, University Hospitals Birmingham, NHS Foundation Trust, UK; NIHR Experimental Cancer Medicine Centre, UK; NIHR Surgical Reconstruction and Microbiology Research Centre, UK; NIHR Biomedical Research Centre, UK; MRC Health Data Research UK (HDR UK) Midlands, UK; University Hospitals Birmingham NHS Foundation Trust, Edgbaston, Birmingham, UK.

Negation detection is an important task in biomedical text mining. Particularly in clinical settings, it is of critical importance to determine whether findings mentioned in text are present or absent. Rule-based negation detection algorithms are a common approach to the task, and more recent investigations have resulted in the development of rule-based systems utilising the rich grammatical information afforded by typed dependency graphs. However, interacting with these complex representations inevitably necessitates complex rules, which are time-consuming to develop and do not generalise well. We hypothesise that a heuristic approach to determining negation via dependency graphs could offer a powerful alternative. We describe and implement an algorithm for negation detection based on grammatical distance from a negatory construct in a typed dependency graph. To evaluate the algorithm, we develop two testing corpora comprised of sentences of clinical text extracted from the MIMIC-III database and documents related to hypertrophic cardiomyopathy patients routinely collected at University Hospitals Birmingham NHS trust. Gold-standard validation datasets were built by a combination of human annotation and examination of algorithm error. Finally, we compare the performance of our approach with four other rule-based algorithms on both gold-standard corpora. The presented algorithm exhibits the best performance by f-measure over the MIMIC-III dataset, and a similar performance to the syntactic negation detection systems over the HCM dataset. It is also the fastest of the dependency-based negation systems explored in this study. Our results show that while a single heuristic approach to dependency-based negation detection is ignorant to certain advanced cases, it nevertheless forms a powerful and stable method, requiring minimal training and adaptation between datasets. As such, it could present a drop-in replacement or augmentation for many-rule negation approaches in clinical text-mining pipelines, particularly for cases where adaptation and rule development is not required or possible.
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http://dx.doi.org/10.1016/j.compbiomed.2021.104216DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7910278PMC
March 2021

Incidence of sudden cardiac death in the young: a systematic review.

BMJ Open 2020 10 7;10(10):e040815. Epub 2020 Oct 7.

Warwick Medical School, University of Warwick Warwick Medical School, Coventry, UK.

Objective: To summarise studies describing incidence of sudden cardiac death in a general population of young individuals to inform screening policy.

Design: Systematic review.

Data Sources: Database searches of MEDLINE, EMBASE and the Cochrane library (all inception to current) on 29 April 2019 (updated 16 November 2019), and forward/backward citation tracking of eligible studies.

Study Eligibility Criteria: All studies that reported incidence of sudden cardiac death in young individuals (12-39 years) in a general population, with no restriction on language or date. Planned subgroups were incidence by age, sex, race and athletic status (including military personnel).

Data Extraction: Two reviewers independently assessed study eligibility, extracted study data and assessed risk of bias using the Joanna Briggs Institute critical appraisal checklist for prevalence studies.

Analysis: Reported incidence of sudden cardiac death in the young per 100 000 person-years.

Results: 38 studies that reported incidence across five continents. We identified substantial heterogeneity in population, sudden cardiac death definition, and case ascertainment methods, precluding meta-analysis. Median reported follow-up years was 6.97 million (IQR 2.34 million-23.70 million) and number of sudden cardiac death cases was 64 (IQR 40-251). In the general population, the median of reported incidence was 1.7 sudden cardiac death per 100 000 person-years (IQR 1.3-2.6, range 0.75-11.9). Most studies (n=14, 54%) reported an incidence between one and two cases per 100 000 person-years. Incidence was higher in males and older individuals.

Conclusions: This systematic review identified variability in the reported incidence of sudden cardiac death in the young across studies. Most studies reported an incidence between one and two cases per 100 000 person-years.

Prospero Registration Number: CRD42019120563.
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http://dx.doi.org/10.1136/bmjopen-2020-040815DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7542928PMC
October 2020

Monitoring indirect impact of COVID-19 pandemic on services for cardiovascular diseases in the UK.

Heart 2020 12 5;106(24):1890-1897. Epub 2020 Oct 5.

The University of Edinburgh Usher Institute of Population Health Sciences and Informatics, Edinburgh, UK

Objective: To monitor hospital activity for presentation, diagnosis and treatment of cardiovascular diseases during the COVID-19) pandemic to inform on indirect effects.

Methods: Retrospective serial cross-sectional study in nine UK hospitals using hospital activity data from 28 October 2019 (pre-COVID-19) to 10 May 2020 (pre-easing of lockdown) and for the same weeks during 2018-2019. We analysed aggregate data for selected cardiovascular diseases before and during the epidemic. We produced an online visualisation tool to enable near real-time monitoring of trends.

Results: Across nine hospitals, total admissions and emergency department (ED) attendances decreased after lockdown (23 March 2020) by 57.9% (57.1%-58.6%) and 52.9% (52.2%-53.5%), respectively, compared with the previous year. Activity for cardiac, cerebrovascular and other vascular conditions started to decline 1-2 weeks before lockdown and fell by 31%-88% after lockdown, with the greatest reductions observed for coronary artery bypass grafts, carotid endarterectomy, aortic aneurysm repair and peripheral arterial disease procedures. Compared with before the first UK COVID-19 (31 January 2020), activity declined across diseases and specialties between the first case and lockdown (total ED attendances relative reduction (RR) 0.94, 0.93-0.95; total hospital admissions RR 0.96, 0.95-0.97) and after lockdown (attendances RR 0.63, 0.62-0.64; admissions RR 0.59, 0.57-0.60). There was limited recovery towards usual levels of some activities from mid-April 2020.

Conclusions: Substantial reductions in total and cardiovascular activities are likely to contribute to a major burden of indirect effects of the pandemic, suggesting they should be monitored and mitigated urgently.
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http://dx.doi.org/10.1136/heartjnl-2020-317870DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7536637PMC
December 2020

Impact of Right Ventricular Dysfunction on Mortality in Patients Hospitalized With COVID-19, According to Race.

CJC Open 2021 Jan 20;3(1):91-100. Epub 2020 Sep 20.

Department of Cardiology, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Edgbaston, Birmingham, United Kingdom.

Background: Epidemiologic studies suggest that Black, Asian, and minority ethnic (BAME) patients may be at risk of worse outcomes from coronavirus disease-2019 (COVID-19), but the pathophysiological drivers for this association are unknown. This study sought to investigate the relationship between findings on echocardiography, mortality, and race in COVID-19 pneumonia.

Methods: This was a multicentre, retrospective, observational study including 164 adults (aged 61 ± 13 years; 78% male; 36% BAME) hospitalized with COVID-19 undergoing echocardiography between March 16 and May 9, 2020 at 3 days (interquartile range 2-5) from admission. The primary outcome was all-cause mortality.

Results: After a median follow-up of 31 days (interquartile range 14-42 days), 66 (40%) patients had died. The right ventricle was dilated in 62 (38%) patients, and 58 (35%) patients had right ventricular (RV) systolic dysfunction. Only 2 (1%) patients had left ventricular (LV) dilatation, and 133 (81%) had normal or hyperdynamic LV systolic function. Reduced tricuspid annulus planar systolic excursion was associated with elevated D-dimer (ρ = -0.18,  = 0.025) and high-sensitivity cardiac Troponin (ρ = -0.30, < 0.0001). Reduced RV systolic function (hazard ratio 1.80; 95% confidence interval, 1.05-3.09;  = 0.032) was an independent predictor of all-cause mortality after adjustment for demographic and clinical risk factors. Comparing white and BAME individuals, there were no differences in echocardiography findings, biomarkers, or mortality.

Conclusions: In patients hospitalized with COVID-19 pneumonia, reduced RV systolic function is prevalent and associated with all-cause mortality. There is, however, no racial variation in the early findings on echocardiography, biomarkers, or mortality.
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http://dx.doi.org/10.1016/j.cjco.2020.09.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7502228PMC
January 2021

Echocardiographic Findings in Patients With COVID-19 Pneumonia.

Can J Cardiol 2020 08 28;36(8):1203-1207. Epub 2020 May 28.

Department of Cardiology, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom.

The aim of this study was to characterize the echocardiographic phenotype of patients with COVID-19 pneumonia and its relation to biomarkers. Seventy-four patients (59 ± 13 years old, 78% male) admitted with COVID-19 were included after referral for transthoracic echocardiography as part of routine care. A level 1 British Society of Echocardiography transthoracic echocardiography was used to assess chamber size and function, valvular disease, and likelihood of pulmonary hypertension. The chief abnormalities were right ventricle (RV) dilatation (41%) and RV dysfunction (27%). RV impairment was associated with increased D-dimer and C-reactive protein levels. In contrast, left ventricular function was hyperdynamic or normal in most (89%) patients.
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http://dx.doi.org/10.1016/j.cjca.2020.05.030DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7255734PMC
August 2020

Variation in cardiovascular magnetic resonance myocardial contouring: Insights from an international survey.

J Magn Reson Imaging 2019 10 17;50(4):1336-1338. Epub 2019 Feb 17.

Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.

Level Of Evidence: 5 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2019;50:1336-1338.
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http://dx.doi.org/10.1002/jmri.26689DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6767425PMC
October 2019

Surgical management of left ventricular outflow obstruction in hypertrophic cardiomyopathy.

Echo Res Pract 2015 Mar 9;2(1):R37-44. Epub 2015 Mar 9.

Department of Cardiology, New Queen Elizabeth Hospital Birmingham , Mindelsohn Way, Edgbaston, Birmingham, B15 2GW , UK.

Hypertrophic cardiomyopathy is the single most common form of inherited heart disease. Left ventricular outflow tract obstruction (LVOTO) is a recognised feature of this condition which arises when blood leaving the outflow tract is impeded by systolic anterior motion of the mitral valve. In an important minority of patients, breathlessness, chest pain and syncope may result and persist despite the use of medications. In suitable candidates, surgery may relieve obstruction and its associated symptoms, and normalise life expectancy. Refinements in surgical techniques have marked improvements in the understanding of mechanisms underlying LVOTO. In this review, we hope to provide the reader with an understanding of how contemporary surgical practice has developed, which patients should be considered for surgery, and what results are anticipated. The role echocardiography plays in this area is highlighted throughout.
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http://dx.doi.org/10.1530/ERP-15-0005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4676463PMC
March 2015

Malposition of pacing lead into the left ventricle: a rare complication of pacemaker insertion.

BMJ Case Rep 2014 Jul 22;2014. Epub 2014 Jul 22.

Department of Cardiology, Birmingham Queen Elizabeth Hospital, Birmingham, West Midland, UK.

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http://dx.doi.org/10.1136/bcr-2013-202131DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4112331PMC
July 2014

Mechanical mitral valve thrombosis in rheumatic valve disease.

BMJ Case Rep 2014 Feb 26;2014. Epub 2014 Feb 26.

Department of Cardiology, University Hospital Birmingham, Birmingham, West Midlands, UK.

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http://dx.doi.org/10.1136/bcr-2013-201918DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3939409PMC
February 2014

Noninvasive imaging for the diagnosis and prognosis of pulmonary hypertension.

Expert Rev Cardiovasc Ther 2014 Jan 9;12(1):71-86. Epub 2013 Dec 9.

Department of Cardiology, Queen Elizabeth Hospital, Edgbaston, Birmingham B15 2TH, UK.

Pulmonary hypertension (PH) is a major cause of morbidity and mortality, but it often presents with nonspecific symptoms, thereby delaying diagnosis and treatment. While invasive cardiac catheterization is essential to confirm the diagnosis, patients with breathlessness are commonly encountered in clinical practice creating a demand for noninvasive screening methods. Preliminary investigations such as the electrocardiogram and chest radiograph lack sensitivity even in advanced cases. Echocardiography is used to screen patients; however, over-reliance on a single estimation of pulmonary artery systolic pressure is unwise, instead multiple parameters should be assessed. Once a diagnosis of PH is made, radionuclide imaging should be performed to exclude chronic thromboembolic disease, and computed tomography is vital for eliminating parenchymal lung disease as a potential etiology. Currently, the primary contribution of cardiac MRI is the accurate assessment of right ventricular size and function. In this respect, cardiac MRI may be supportive during diagnosis of PH, but the main importance of this is in defining prognosis although new outcome variables are anticipated.
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http://dx.doi.org/10.1586/14779072.2014.867806DOI Listing
January 2014

Right ventricular systolic dysfunction in young adults born preterm.

Circulation 2013 Aug;128(7):713-20

Oxford Cardiovascular Clinical Research Facility, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX39DU, UK.

Background: Young adults born preterm have distinct differences in left ventricular mass, function, and geometry. Animal studies suggest that cardiomyocyte changes are evident in both ventricles after preterm birth; therefore, we investigated whether these young adults also have differences in their right ventricular structure and function.

Methods And Results: We studied 102 preterm-born young adults followed up prospectively since birth and 132 term-born control subjects born to uncomplicated pregnancies. We quantified right ventricular structure and function by cardiovascular magnetic resonance on a 1.5-T Siemens scanner using Argus and TomTec postprocessing software. Preterm birth was associated with a small right ventricle (end diastolic volume, 79.8±13.2 versus 88.5±11.8 mL/m(2); P<0.001) but greater right ventricular mass (24.5±3.5 versus 20.4±3.4 g/m2; P<0.001) compared with term-born controls, with the severity of differences proportional to gestational age (r=-0.47, P<0.001). Differences in right ventricular mass and function were proportionally greater than previously reported for the left ventricle. This was most apparent for systolic function; young adults born preterm had significantly lower right ventricular ejection fraction (57±8% versus 60±5%; P=0.006). Indeed, 21% had values below the lower limit observed in the term-born adults and 6% had mild systolic dysfunction (<45%). Postnatal ventilation accounted for some of the variation in mass but not function.

Conclusions: Preterm birth is associated with global myocardial structural and functional differences in adult life, including smaller right ventricular size and greater mass. The changes are greater in the right ventricle than previously observed in the left ventricle, with potentially clinically significant impairment in right ventricular systolic function.
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http://dx.doi.org/10.1161/CIRCULATIONAHA.113.002583DOI Listing
August 2013

Severe vasospastic angina complicated by multiple pulseless electrical activity arrests.

Lancet 2013 Aug;382(9890):478

Oxford Heart Centre, John Radcliffe Hospital, Oxford, UK. Electronic address:

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http://dx.doi.org/10.1016/S0140-6736(13)61096-XDOI Listing
August 2013

Endovascular stent-associated infection with Staphylococcus lugdunensis.

BMJ Case Rep 2013 Feb 18;2013. Epub 2013 Feb 18.

Department of Infectious Diseases and Microbiology, Oxford University Hospitals NHS Trust, Oxford, UK.

An elderly woman presented febrile 5 days after stenting of multiple coronary arteries. Echocardiography showed a thickening of the aortic root, raising the possibility of stent infection. Four  of four blood culture bottles grew Staphylococcus lugdunensis and repeat echo showed an aortic root abscess. Despite appropriate antibiotic treatment, the patient died. A 24-year-old man with a ventricular septal defect presented febrile 4 weeks after stenting of an aortic coarctation. Initial transoesophageal echo found no vegetations around the stent or elsewhere. Four of six blood culture bottles grew S lugdunensis. Following an episode of hypoxia, the imaging was repeated and a new large vegetation was seen on the pulmonary valve with two thin-walled cavities in the lungs on a CT pulmonary angiogram. The patient was treated with a long course of appropriate antibiotic therapy and discharged from hospital 6 weeks later.
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http://dx.doi.org/10.1136/bcr-2012-008357DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3603815PMC
February 2013

PET-diagnosed lead infection in ARVC.

Eur Heart J Cardiovasc Imaging 2012 Jun 8;13(6):538. Epub 2012 Feb 8.

Department of Cardiology, John Radcliffe Hospital, Headley Way, Oxford, UK.

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http://dx.doi.org/10.1093/ehjci/jes016DOI Listing
June 2012

Cardiovascular magnetic resonance in pulmonary hypertension.

J Cardiovasc Magn Reson 2012 Jan 18;14. Epub 2012 Jan 18.

Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, London, UK.

Pulmonary hypertension represents a group of conditions characterized by higher than normal pulmonary artery pressures. Despite improved treatments, outcomes in many instances remain poor. In recent years, there has been growing interest in the use of cardiovascular magnetic resonance (CMR) in patients with pulmonary hypertension. This technique offers certain advantages over other imaging modalities since it is well suited to the assessment of the right ventricle and the proximal pulmonary arteries. Reflecting the relatively sparse evidence supporting its use, CMR is not routinely recommended for patients with pulmonary hypertension. However, it is particularly useful in patient with pulmonary arterial hypertension associated with congenital heart disease. Furthermore, it has proven informative in a number of ways; illustrating how right ventricular remodeling is favorably reversed by drug therapies and providing explicit confirmation of the importance of the right ventricle to clinical outcome. This review will discuss these aspects and practical considerations before speculating on future applications.
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http://dx.doi.org/10.1186/1532-429X-14-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3305675PMC
January 2012

Role of cardiovascular magnetic resonance as a gatekeeper to invasive coronary angiography in patients presenting with heart failure of unknown etiology.

Circulation 2011 Sep 6;124(12):1351-60. Epub 2011 Sep 6.

Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, London, UK.

Background: In patients presenting with new-onset heart failure of uncertain etiology, the role of coronary angiography (CA) is unclear. Although conventionally performed to differentiate underlying coronary artery disease from dilated cardiomyopathy, CA is associated with a risk of complications and may not detect an ischemic cause resulting from arterial recanalization or an embolic episode. In this study, we assessed the diagnostic accuracy of a cardiovascular magnetic resonance (CMR) protocol incorporating late gadolinium enhancement (LGE) and magnetic resonance CA as a noninvasive gatekeeper to CA in determining the etiology of heart failure in this subset of patients.

Methods And Results: One hundred twenty consecutive patients underwent CMR and CA. The etiology was ascribed by a consensus panel that used the results of the CMR scans. Similarly, a separate consensus group ascribed an underlying cause by using the results of CA. The diagnostic accuracy of both strategies was compared against a gold-standard panel that made a definitive judgment by reviewing all clinical data. The study was powered to show noninferiority between the 2 techniques. The sensitivity of 100%, specificity of 96%, and diagnostic accuracy of 97% for LGE-CMR were equivalent to CA (sensitivity, 93%; specificity, 96%; and diagnostic accuracy, 95%). As a gatekeeper to CA, LGE-CMR was also found to be a cheaper diagnostic strategy in a decision tree model when United Kingdom-based costs were assumed. The economic merits of this model would change, depending on the relative costs of LGE-CMR and CA in any specific healthcare system.

Conclusion: This study showed that LGE-CMR is a safe, clinically effective, and potentially economical gatekeeper to CA in patients presenting with heart failure of uncertain etiology.
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http://dx.doi.org/10.1161/CIRCULATIONAHA.110.011346DOI Listing
September 2011

Pericardiocentesis in contemporary practice.

J Invasive Cardiol 2011 Jun;23(6):234-9

Cardiology Department, Royal Berkshire Hospital, Reading, United Kingdom.

Objective: Pericardiocentesis is a life-saving procedure associated with a small, but significant, risk of major complication. An apical or subcostal approach may be used, although the relative complication rates are not reported. In modern practice, an increasing proportion of pericardial effusions occur as a result of catheter-laboratory related complications. This study examines current practice and analyzes the complications of pericardial drainage according to the route of approach.

Design: Historical cohort study.

Setting: Four Oxfordshire hospitals, including the John Radcliffe Hospital, a tertiary referral center.

Patients: Local databases were searched to identify percutaneous pericardiocenteses carried out between November 2002 and October 2009.

Results: A total of 188 pericardiocenteses were performed in 163 patients. Malignancy (55; 33.7%) and catheter-based cardiac procedures (45; 23.9%) were the most common causes of pericardial effusions requiring drainage. 50.0% of all pericardiocenteses were performed in patients who had received anticoagulant or antiplatelet agents the same day. This rose to 93.7% in patients whose effusions occurred as a complication of a catheter-based procedure. Nine complications occurred during the study period, giving an overall complication rate of 4.8%. Six of the complications occurred via the subcostal route and all 4 complications requiring surgery occurred via the subcostal route.

Conclusion: The numbers of iatrogenic pericardial effusions occurring as a complication of catheter-based procedures mean that a significant proportion of pericardiocenteses are being performed in anticoagulated patients. This may alter the risk profile. Although complication rates were low for both routes, all major complications requiring surgery occurred via the subcostal approach. These data suggest an apical approach may be preferable where practical.
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June 2011

Rupture of an aneurysmal aortic diverticulum associated with coarctation and bicuspid aortic valve.

Circulation 2011 Jan;123(1):102-3

Department of Cardiothoracic Surgery, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, United Kingdom.

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http://dx.doi.org/10.1161/CIRCULATIONAHA.110.958355DOI Listing
January 2011

Understanding late gadolinium enhancement in pulmonary hypertension.

Circ Cardiovasc Imaging 2010 Jul;3(4):501-3

Cardiovascular Magnetic Resonance Unit and Department of Pathology, Royal Brompton Hospital, Sydney Street, Chelsea, London, UK.

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http://dx.doi.org/10.1161/CIRCIMAGING.109.919779DOI Listing
July 2010

Simvastatin as a treatment for pulmonary hypertension trial.

Am J Respir Crit Care Med 2010 May;181(10):1106-13

Experimental Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London, United Kingdom.

Rationale: In animal models of pulmonary hypertension, simvastatin has been shown to reduce pulmonary artery pressure and induce regression of associated right ventricular (RV) hypertrophy.

Objectives: To assess the therapeutic value of simvastatin in patients with pulmonary arterial hypertension (PAH).

Methods: Forty-two patients with PAH were randomized to receive either simvastatin (80 mg/d) or placebo in addition to current care for 6 months, and thereafter offered open-label simvastatin. The primary outcome was change in RV mass, assessed by cardiac magnetic resonance (CMR).

Measurements And Main Results: At 6 months, RV mass decreased by 5.2 +/- 11 g in the statin group (P = 0.045) and increased 3.9 +/- 14 g in the placebo group. The treatment effect was -9.1 g (P = 0.028). N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels decreased significantly in the statin group (-75 +/- 167 fmol/ml; P = 0.02) but not the placebo group (49 +/- 224 fmol/ml; P = 0.43; overall treatment effect -124 fmol/ml; P = 0.041). There were no significant changes in other outcome measures (including 6-minute walk test, cardiac index, and circulating cytokines). From 6 to 12 months, both RV mass and NT-proBNP increased toward baseline values in 16 patients on active treatment who continued with simvastatin but remained stable in 18 patients who switched from placebo to simvastatin. Two patients required a reduction in dose but not cessation of simvastatin.

Conclusions: Simvastatin added to conventional therapy produces a small and transient early reduction in RV mass and NT-proBNP levels in patients with PAH, but this is not sustained over 12 months.
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http://dx.doi.org/10.1164/rccm.2009111-699ocDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2874452PMC
May 2010

Measuring the heart in pulmonary arterial hypertension (PAH): implications for trial study size.

J Magn Reson Imaging 2010 Jan;31(1):117-24

Cardiovascular Magnetic Resonance Unit, Royal Brompton Hospital, London, UK.

Purpose: To calculate the sample size for a theoretical pulmonary arterial hypertension (PAH) randomized controlled trial (RCT) by using cardiovascular magnetic resonance (CMR) imaging to determine the repeatability of measures between two scans.

Materials And Methods: Two same-day examinations from 10 PAH patients were analyzed manually and semiautomatically. Study size was calculated from the standard deviation (SD) of repeatability. Different approaches to right-ventricle (RV) mass were investigated, agreement between methods tested and interobserver reproducibility measured by Bland-Altman analysis to explore how the PAH heart might be best measured.

Results: Repeatability was good for almost all manually-measured indices but poor for semiautomated measurement of RV mass and left-ventricle (LV) end-diastolic volume (EDV). Thus, for an RCT (power, 80%; significance level, 5%) analyzing "outcome" indices (RVEDV, LVEDV, RV ejection fraction, and RV mass; anticipated change: 10 mL, 10 mL, 3%, and 10 g, respectively) manually, 34 patients are required compared to 78 if analysis is semiautomated. RV mass was repeatable if the interventricular septum was divided between ventricles or if wholly apportioned to the LV. Limits of agreement between manual and semiautomated analyses were unsatisfactory for RV measures and interobserver reproducibility was worse for semiautomated than manual analysis.

Conclusion: Manual is more robust than semiautomated analysis and at present should be favored in RCTs in PAH as it leads to lower sample size requirements.
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http://dx.doi.org/10.1002/jmri.22011DOI Listing
January 2010

Assessing normal pulse wave velocity in the proximal pulmonary arteries using transit time: a feasibility, repeatability, and observer reproducibility study by cardiovascular magnetic resonance.

J Magn Reson Imaging 2007 May;25(5):974-81

Imperial College, and Cardiovascular MR Unit, Royal Brompton Hospital, Sydney Street, London, United Kingdom.

Purpose: To calculate pulse wave velocity (PWV) in the proximal pulmonary arteries (PAs) by cardiovascular magnetic resonance (CMR) using the transit-time method, and address respiratory variation, repeatability, and observer reproducibility.

Materials And Methods: A 1.9-msec interleaved phase velocity sequence was repeated three times consecutively in 10 normal subjects. Pulse wave (PW) arrival times (ATs) were determined for the main and branch PAs. The PWV was calculated by dividing the path length traveled by the difference in ATs. Respiratory variation was considered by comparing acquisitions with and without respiratory gating.

Results: For navigated data the mean PWVs for the left PA (LPA) and right PA (RPA) were 2.09 +/- 0.64 m/second and 2.33 +/- 0.44 m/second, respectively. For non-navigated data the mean PWVs for the LPA and RPA were 2.14 +/- 0.41 m/second and 2.31 +/- 0.49 m/second, respectively. No statistically significant difference was found between respiratory non-navigated data and navigated data. Repeated on-table measurements were consistent (LPA non-navigated P = 0.95, RPA non-navigated P = 0.91, LPA navigated P = 0.96, RPA navigated P = 0.51). The coefficients of variation (CVs) were 12.2% and 12.5% for intra- and interobserver assessments, respectively.

Conclusion: One can measure PWV in the proximal PAs using transit-time in a reproducible manner without respiratory gating.
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http://dx.doi.org/10.1002/jmri.20888DOI Listing
May 2007

Images in cardiovascular medicine. Ovarian malignancy presenting as multiple intracardiac masses.

Circulation 2006 Mar;113(10):e399-400

Cardiovascular Division, North Shore Hospital, Waitemata Health, Auckland, New Zealand.

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http://dx.doi.org/10.1161/CIRCULATIONAHA.105.565630DOI Listing
March 2006