Publications by authors named "Dunbar D Ivy"

Background: Risk assessment in pulmonary arterial hypertension (PAH) is fundamental to guiding treatment and improved outcomes. Clinical models are excellent at identifying high-risk patients, but leave uncertainty amongst moderate-risk patients.

Research Question: Can a multiple blood biomarker model of PAH, using previously described biomarkers, improve risk discrimination over current models?

Study Design And Methods: Using a multiplex enzyme-linked immunosorbent assay, we measured N-terminal pro-B-type natriuretic peptide (NT-proBNP), soluble suppressor of tumorigenicity, IL-6, endostatin, galectin 3, hepatoma derived growth factor, and insulin-like growth factor binding proteins (IGFBP1-7) in training (n = 1,623), test (n = 696), and validation (n = 237) cohorts.

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Background: Mutations in the T-Box 4 (TBX4) gene are a lesser-known cause of heritable pulmonary arterial hypertension (PAH). Patients with heritable PAH typically have worse outcomes when compared with patients with idiopathic PAH, yet little is known about the phenotypical presentation of this mutation.

Objective: This article reviews the pattern of chest CT findings in pediatric patients with PAH and TBX4 mutations and compares their radiographic presentation with those of age-matched patients with PAH but without TBX4 mutations.

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Pulmonary hypertension (PH) is a significant health problem that contributes to high morbidity and mortality in diverse cardiac, pulmonary, and systemic diseases in children. Evidence-based advances in PH care have been challenged by a paucity of quality endpoints for assessing clinical course and the lack of robust clinical trial data to guide pharmacologic therapies in children. While the landmark adult AMBITION trial demonstrated the benefit of up-front combination PH therapy with ambrisentan and tadalafil, it remains unknown whether upfront combination therapy leads to more rapid and sustained clinical benefits in children with various categories of PH.

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Background: Pulmonary arterial hypertension (PAH) is a heterogeneous and complex pulmonary vascular disease associated with substantial morbidity. Machine-learning algorithms (used in many PAH risk calculators) can combine established parameters with thousands of circulating biomarkers to optimise PAH prognostication, but these approaches do not offer the clinician insight into what parameters drove the prognosis. The approach proposed in this study diverges from other contemporary phenotyping methods by identifying patient-specific parameters driving clinical risk.

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Background: Germline mutation in bone morphogenetic protein type II (BMPR2) is the most common cause of idiopathic/heritable pulmonary hypertension in pediatric patients. Despite the discovery of this gene there are no known descriptions of the CT or CT angiography findings in these children.

Objective: To correlate the clinical presentation, pathology and chest CT findings in pediatric patients with pulmonary hypertension caused by mutations in the BMPR2 gene.

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Pulmonary arterial hypertension (PAH) is a progressive disease characterized by sustained elevations of pulmonary artery pressure. To date, we lack circulating, diagnostic, and prognostic markers that correlate to clinical and functional parameters. In this study, we performed mass spectrometry-based proteomics analysis to identify circulating biomarkers of PAH.

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The pro-inflammatory cytokine interleukin (IL)-6 has been associated with outcomes in small pulmonary arterial hypertension (PAH) cohorts composed largely of patients with severe idiopathic PAH (IPAH). It is unclear whether IL-6 is a marker of critical illness or a mechanistic biomarker of pulmonary vascular remodelling. We hypothesised that IL-6 is produced by pulmonary vascular cells and sought to explore IL-6 associations with phenotypes and outcomes across diverse subtypes in a large PAH cohort.

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Objective: Real-world data (RWD) are increasingly used for pharmacoepidemiology and regulatory innovation. Our objective was to compare adverse drug event (ADE) rates determined from two RWD sources, electronic health records and administrative claims data, among children treated with drugs for pulmonary hypertension.

Materials And Methods: Textual mentions of medications and signs/symptoms that may represent ADEs were identified in clinical notes using natural language processing.

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Purpose Of Review: The purpose of this review is to detail the advanced echocardiographic studies that evaluated outcomes in pediatric PH using these advanced imaging techniques: (1) right heart size and function (using 2D and 3D echocardiography), (2) myocardial mechanics, and (3) right ventricular (RV) to pulmonary arterial coupling.

Recent Findings: Advanced echocardiographic imaging tools in pediatric PH include RV/left ventricular ratio, 3D echocardiographic assessment of RV volumes and ejection fraction, right atrial and RV strain, and RV-pulmonary arterial coupling ratio that allow for evaluation of clinical outcomes in this patient population. The right atrial to RV axis provides insights to RV diastolic function that has been poorly understood in pediatrics.

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The right ventricle and left ventricle are physically coupled through the interventricular septum. Therefore, changes in the geometry and mechanics of one ventricle can directly affect the function of the other. In treatment of pediatric pulmonary arterial hypertension, the left ventricle is often overlooked, with clinical focus primarily on improving right ventricular function.

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Different treatment options for pulmonary hypertension have emerged in recent years, and evidence-based management strategies have improved quality of life and survival in adults. In children with pulmonary vascular disease, therapeutic algorithms are not so clearly defined; this study determined current treatment initiation in children with pulmonary hypertension in participating centres of a registry. Through the multinational Tracking Outcomes and Practice in Pediatric Pulmonary Hypertension registry, patient demographics, diagnosis, and treatment as judged and executed by the local physician were collected.

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The introduction of prostanoid therapy has revolutionized the treatment of pulmonary arterial hypertension (PAH). However, continuous intravenous prostacyclin infusion poses significant risks and challenges, particularly in children. Inhaled treprostinil has been shown to be safe and efficacious in adults.

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What Is Already Known About This Subject: * Exposure to bosentan was lower in paediatric pulmonary arterial hypertension (PAH) patients treated with the marketed adult formulation at a dose of about 2 mg kg(-1) when compared with adult PAH patients. * In healthy adult subjects, bosentan pharmacokinetics are less than dose-proportional at doses of >or=500 mg.

What This Study Adds: * The pharmacokinetics of a new paediatric bosentan formulation were characterized in paediatric PAH patients.

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We describe 5 patients who presented with musculoskeletal abnormalities in the neonatal period. All patients were initially suspected to have Larsen syndrome or Beals syndrome but were subsequently diagnosed with a TGFBR2 mutation diagnostic of Loeys-Dietz syndrome. Patients had progressive aortic enlargement, which necessitated surgical intervention for 3 patients and resulted in the death of 1 patient.

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Background: Pulmonary arterial hypertension (PAH) can lead to significant cardiac dysfunction and is considered to be associated with an increased risk of perioperative cardiovascular complications.

Methods: We reviewed the medical records of children with PAH who underwent anesthesia or sedation for noncardiac surgical procedures or cardiac catheterizations from 1999 to 2004. The incidence, type, and associated factors of complications occurring intraoperatively through 48 h postoperatively were examined.

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A biaxial bubble test has been designed to ascertain the mechanical properties of rat pulmonary arteries. The analytical procedure used to estimate stress and strain from the resulting test data is presented along with some analytical results. The bubble test was performed by loading a flat piece of rat pulmonary artery into a test fixture beneath a circular opening; the material was subsequently pressurized from below, producing a "bubble" of deformed material.

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