Publications by authors named "Robert MacKenzie-Ross"

Background: The world symposium on pulmonary hypertension (PH) has proposed that PH be defined as a mean pulmonary artery pressure (mPAP) > 20 mmHg as assessed by right heart catheterisation (RHC). Transthoracic echocardiography (TTE) is an established screening tool used for suspected PH. International guidelines recommend a multi-parameter assessment of the TTE PH probability although effectiveness has not been established using real world data.

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Autoimmunity is believed to play a role in idiopathic pulmonary arterial hypertension (IPAH). It is not clear whether this is causative or a bystander of disease and if it carries any prognostic or treatment significance. To study autoimmunity in IPAH using a large cross-sectional cohort.

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This investigation validated the inert gas rebreathing (IGR) technique and determined IGR prognostic ability compared to invasive cardiac output measurements in patients with pulmonary hypertension. IGR compared with thermodilution cardiac output demonstrated a moderate bias. IGR technique demonstrated long-term prognostic value comparable to invasive cardiac output in pulmonary hypertension patients.

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Unlabelled: Introduction and objectivesThe ongoing respiratory sequelae of COVID-19 pneumonia remain unclear, and the ideal follow-up of these patients is still a work in progress. We describe our experience of using a pre-follow-up multidisciplinary team (MDT) to decide the follow-up stream in patients hospitalised for COVID-19 pneumonia.

Methods: We reviewed all patients with a clinico-radiological diagnosis of COVID-19 admitted to hospital during a 3-month period and assigned a follow-up stream based on British Thoracic Society guidance.

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Article Synopsis
  • The study conducts a systematic review to evaluate how artificial intelligence (AI) can be used in cross-sectional imaging for diagnosing acquired pulmonary arterial hypertension (PAH).
  • A total of three retrospective observational studies were analyzed, showing high accuracy in AI models applied to cardiac MRI, with one model achieving an area under the curve (AUC) of 0.97 for idiopathic PAH.
  • The findings suggest that AI could provide effective, non-invasive support in diagnosing PAH, though more research is needed in this field for improved early detection and application in other imaging methods.
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- Approximately 25% of patients with pulmonary arterial hypertension (PAH) have been found to harbor rare mutations in disease-causing genes. To identify missing heritability in PAH we integrated deep phenotyping with whole-genome sequencing data using Bayesian statistics. - We analyzed 13,037 participants enrolled in the NIHR BioResource - Rare Diseases (NBR) study, of which 1,148 were recruited to the PAH domain.

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Recently, rare heterozygous mutations in were identified in patients with pulmonary arterial hypertension (PAH). encodes the circulating BMP (bone morphogenetic protein) type 9, which is a ligand for the BMP2 receptor. Here we determined the functional impact of mutations and characterized plasma BMP9 and BMP10 levels in patients with idiopathic PAH.

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A 29-year-old female patient presented with chest pain, breathlessness and syncope on the background of constitutional symptoms, oral ulceration and a rash. Multiple investigations were performed, including a CT pulmonary angiogram (CTPA) that was initially felt to show imaging features consistent with a diagnosis of chronic thromboembolic disease (CTED). The patient was referred to a tertiary pulmonary hypertension centre and the possibility of pulmonary vasculitis was raised.

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While traffic and air pollution exposure is associated with increased mortality in numerous diseases, its association with disease severity and outcomes in pulmonary arterial hypertension (PAH) remains unknown.Exposure to particulate matter with a 50% cut-off aerodynamic diameter ≤2.5 μm (PM), nitrogen dioxide (NO) and indirect measures of traffic-related air pollution (distance to main road and length of roads within buffer zones surrounding residential addresses) were estimated for 301 patients with idiopathic/heritable PAH recruited in the UK National Cohort Study of Idiopathic and Heritable PAH.

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Background: Rare genetic variants cause pulmonary arterial hypertension, but the contribution of common genetic variation to disease risk and natural history is poorly characterised. We tested for genome-wide association for pulmonary arterial hypertension in large international cohorts and assessed the contribution of associated regions to outcomes.

Methods: We did two separate genome-wide association studies (GWAS) and a meta-analysis of pulmonary arterial hypertension.

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Pulmonary arterial hypertension (PAH) is a rare disorder with a poor prognosis. Deleterious variation within components of the transforming growth factor-β pathway, particularly the bone morphogenetic protein type 2 receptor (BMPR2), underlies most heritable forms of PAH. To identify the missing heritability we perform whole-genome sequencing in 1038 PAH index cases and 6385 PAH-negative control subjects.

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Background: Pulmonary arterial hypertension (PAH) is a rare disease with an emerging genetic basis. Heterozygous mutations in the gene encoding the bone morphogenetic protein receptor type 2 () are the commonest genetic cause of PAH, whereas biallelic mutations in the eukaryotic translation initiation factor 2 alpha kinase 4 gene () are described in pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis. Here, we determine the frequency of these mutations and define the genotype-phenotype characteristics in a large cohort of patients diagnosed clinically with PAH.

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Background: Chronic thromboembolic pulmonary hypertension results from incomplete resolution of pulmonary emboli. Pulmonary endarterectomy (PEA) is potentially curative, but residual pulmonary hypertension following surgery is common and its impact on long-term outcome is poorly understood. We wanted to identify factors correlated with poor long-term outcome after surgery and specifically define clinically relevant residual pulmonary hypertension post-PEA.

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Background: Symptoms of theophylline toxicity and factors that augment the risk of developing it are well documented in the literature. However these appear to be poorly considered in clinical practice. This case underlines the challenges in recognising and managing theophylline toxicity; moreover the requirement for improved application of knowledge of its pharmacokinetics to our practice.

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Aims: Endothelin-1 levels are raised in chronic thromboembolic pulmonary hypertension. Our aim in this study was to identify the presence of endothelin receptors in patients with CTEPH by analysing tissue removed at pulmonary endarterectomy.

Main Methods: Pulmonary endarterectomy tissue cross-sections were analysed using autoradiography with [(125)I]-ET-1 using ligands selective for ETA or ETB to determine sub-type distribution.

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Pressure-volume loops describe dynamic ventricular performance, relevant to patients with and at risk of pulmonary hypertension. We used conductance catheter-derived pressure-volume loops to measure right ventricular (RV) mechanics in patients with chronic thromboembolic pulmonary arterial obstruction at different stages of pathological adaptation. Resting conductance catheterization was performed in 24 patients: 10 with chronic thromboembolic pulmonary hypertension (CTEPH), 7 with chronic thromboembolic disease without pulmonary hypertension (CTED), and 7 controls.

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Introduction: Persistent obstruction in the pulmonary artery following acute pulmonary embolism (PE) can give rise to both chronic thromboembolic pulmonary hypertension (CTEPH) and chronic thromboembolic disease without PH (CTED). We hypothesised that cardiopulmonary exercise testing (CPET) may be able to differentiate patients with CTEPH and CTED following unresolved PE which may help guide patient assessment.

Materials And Methods: Fifteen patients with CTEPH and 15 with CTED all diagnosed after PE underwent CT pulmonary angiography, CPET and resting right heart catheterisation.

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This study analyzed the relationship between pulmonary vascular resistance (PVR) and pulmonary arterial compliance (Ca) in patients with idiopathic pulmonary arterial hypertension (IPAH) and proximal chronic thromboembolic pulmonary hypertension (CTEPH). It has recently been shown that the time constant of the pulmonary circulation (RC time constant), or PVR × Ca, remains unaltered in various forms and severities of pulmonary hypertension, with the exception of left heart failure. We reasoned that increased wave reflection in proximal CTEPH would be another cause of the decreased RC time constant.

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Background: The Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) is a disease-specific assessment tool used for the evaluation and follow-up of patients with pulmonary hypertension (PH). We describe a novel use for this questionnaire in its potential to predict clinical deterioration (CD) in two patient cohorts with subtypes of PH, idiopathic pulmonary arterial hypertension (IPAH), and chronic thromboembolic pulmonary hypertension (CTEPH) during an 8-year period.

Methods: We retrospectively analyzed CAMPHOR scores obtained at baseline and at follow-up visits in patients under the care of our unit over an 8-year period to assess CD and survival, as well as 6-min walk distance (6MWD) and New York Heart Association (NYHA) class.

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The past decade has seen increased application of 18-flurodeoxyglucose positron emission tomography ((18)FDG-PET) imaging to help diagnose and monitor disease, particularly in oncology, vasculitis and atherosclerosis. Disordered glycolytic metabolism and infiltration of plexiform lesions by inflammatory cells has been described in idiopathic pulmonary arterial hypertension (IPAH). We hypothesized that increased (18)FDG uptake may be present in the lungs, large pulmonary arteries and right ventricle of patients with pulmonary hypertension, and that this uptake would be related to markers of immune activation.

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Background: Anaemia is common in left heart failure and is associated with a poorer outcome. Many patients with pulmonary arterial hypertension (PAH) are anaemic or iron-deficient. This study was performed to investigate the prevalence of iron deficiency in PAH and to identify possible causes.

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