Publications by authors named "Kim O' Connor"

Background: Residual mitral regurgitation (MR) is associated with worse outcomes after transcatheter edge-to-edge mitral valve repair (TEER). Shear stress induced by MR leads to altered von Willebrand factor activity (vWF:Act) and increased closure time with adenosine diphosphate (CT-ADP).

Objectives: The purpose of this study was to investigate the use of CT-ADP to monitor MR during TEER and the association between the vWF, residual MR, and clinical events post-TEER.

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  • Dermatologic issues are a significant part of primary care, appearing in about one-third of visits.
  • The review focuses on common skin conditions like alopecia, facial rashes, and various types of dermatitis, highlighting new and emerging treatment options.
  • It aims to enhance primary care providers’ prescribing confidence and awareness of potential side effects associated with more aggressive dermatological treatments.
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Background: Blood collection from donors on testosterone therapy (TT) is restricted to red blood cell (RBC) concentrates to avoid patient exposure to supraphysiological testosterone (T). The objective of this study was to identify TT-related changes in RBC characteristics relevant to transfusion effectiveness in patients.

Study Design: This was a two-part study with cohorts of patients and blood donors on TT.

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Cardiac troponin is extensively used as a biomarker in modern medicine due to its diagnostic capability for myocardial injury, as well as its predictive and prognostic value for cardiac diseases. However, heterophile antibodies, antitroponin antibodies, and macrotroponin complexes can be observed both in seemingly healthy individuals and patients with cardiac diseases, potentially leading to false positive or disproportionate elevation of cTn (cardiac troponin) assay results and introducing discrepancies in clinical interpretations with impact on medical management. In this review article, we describe the possible mechanisms of cTn release and the sources of variations in the assessment of circulating cTn levels.

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  • Transcatheter valve-in-valve replacement (ViV-TAVR) is compared to redo-surgical aortic valve replacement (Redo-SAVR) for patients with failed aortic bioprostheses, focusing on their hemodynamic and clinical outcomes.
  • The study analyzed data from 184 patients, showing that ViV-TAVR had a significantly lower success rate in achieving optimal hemodynamic results shortly after the procedure compared to Redo-SAVR.
  • Long-term results indicated that Redo-SAVR had notably lower mortality rates over 8 years, despite a transiently higher 30-day mortality rate when compared to ViV-TAVR.
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The use of transcatheter edge-to-edge mitral valve repair (TEER) in symptomatic patients with severe mitral regurgitation (MR) has dramatically increased over the last few years. Current guidelines consider TEER as a reasonable option in symptomatic patients with primary or chronic secondary severe MR with high or prohibitive surgical risk and favorable anatomy. However, several anatomical and morphological mitral features have restricted the use of this mini-invasive technique in its early experience.

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Background: Primary mitral regurgitation (MR) is a heterogeneous clinical disease requiring integration of echocardiographic parameters using guideline-driven recommendations to identify severe disease.

Objectives: The purpose of this preliminary study was to explore novel data-driven approaches to delineate phenotypes of MR severity that benefit from surgery.

Methods: The authors used unsupervised and supervised machine learning and explainable artificial intelligence (AI) to integrate 24 echocardiographic parameters in 400 primary MR subjects from France (n = 243; development cohort) and Canada (n = 157; validation cohort) followed up during a median time of 3.

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Background: The optimal timing for mitral valve (MV) surgery in asymptomatic patients with primary mitral regurgitation (MR) remains a matter of debate. Myocardial contraction fraction (MCF) - the ratio of the left ventricular (LV) stroke volume to that of the myocardial volume - is a volumetric measure of LV myocardial shortening independent of size or geometry.

Aim: To assess the relationship between MCF and outcome in patients with significant chronic primary MR due to prolapse managed in contemporary practice.

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The optimal timing for mitral valve (MV) surgery in asymptomatic patients with primary mitral regurgitation (MR) remains controversial. We aimed at evaluating the relation between left ventricular ejection time (LVET) and outcome in patients with moderate or severe chronic primary MR because of prolapse. Clinical, Doppler echocardiographic, and outcome data prospectively collected from 302 patients (median age 61 [54 to 74] years, 34% women) with moderate or severe primary MR were analyzed.

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Introduction: Percutaneous left atrial appendage closure (LAAC) is an alternative to oral anticoagulants (OAC) in patients with non-valvular atrial fibrillation (AF) and contraindication to long-term OAC. Combined strategy with percutaneous LAAC at the same time of other cardiac structural or electrophysiological procedures has emerged as an alternative to a staged strategy.

Aim: To describe our experience with combined LAAC procedures using Watchman™ devices.

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Background: Optimal timing for intervention remains uncertain in asymptomatic patients with primary mitral regurgitation (MR). We aimed to assess the prognostic value of a new cardiac damage staging classification in patients with asymptomatic moderate or severe primary MR.

Methods: Clinical, Doppler-echocardiographic, and outcome data prospectively collected in 338 asymptomatic patients (64 ± 15 years, 68% men) with at least moderate primary MR were retrospectively analyzed.

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Background Or Purpose: We report our single-center experience with percutaneous left atrial appendage closure (LAAC) in patients with non-valvular atrial fibrillation (NVAF) and primary hemostasis disorders (HD).

Methods: Consecutive patients with primary HD who underwent a percutaneous LAAC were included. Baseline characteristics, procedural data, and clinical outcomes were prospectively collected and compared with the overall LAAC cohort without HD.

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  • Dilated cardiomyopathy (DCM) is a significant cause of heart failure in younger patients, with recent findings identifying toxic cardiomyopathy (TCM) from substance abuse as a notable trigger.
  • A study of 553 patients revealed that 19% had TCM, commonly linked to substances like amphetamines and cocaine, with a majority achieving event-free survival and some recovering heart function with proper treatment.
  • Mechanical support, such as left ventricular assist devices (LVADs), was beneficial for select patients, highlighting the need for personalized treatment approaches.
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  • The study investigates how different imaging methods for measuring mitral valve area (MVA) relate to post-surgical outcomes in patients undergoing transcatheter mitral valve repair.
  • It finds that patients with a mean transmitral gradient (TMG) over 5 mm Hg after the procedure have smaller pre-procedural MVAs, indicating a higher risk for mortality within one year.
  • Additionally, MVA indexed to body surface area and left ventricular stroke volume showed significant associations with elevated post-procedural TMG, with specific threshold values suggested for better patient outcomes.
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Objective: Whether patients with severe aortic stenosis (AS) and significant functional mitral regurgitation (MR) should undergo isolated aortic (aortic valve replacement [AVR]) or double aortic-mitral valve procedure (DVP) remains controversial. We sought to determine outcomes of such patients undergoing surgical (surgical aortic valve replacement [SAVR]) and transcatheter AVR (TAVR) or DVP, identify echocardiographic parameters predictive of significant residual MR after isolated AVR, and determine its impact on long-term survival.

Methods: Data prospectively collected from 736 consecutive patients with severe AS and significant MR undergoing AVR or DVP were retrospectively analyzed.

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Aims: We explored the early effects of bariatric surgery on subclinical myocardial function in individuals with severe obesity and preserved left ventricular (LV) ejection fraction.

Methods: Thirty-eight patients with severe obesity [body mass index (BMI) ≥35 kg/m] and preserved LV ejection fraction (≥50%) who underwent bariatric surgery (biliopancreatic diversion with duodenal switch [BPD-DS]) (Surgery group), 19 patients with severe obesity managed with usual care (Medical group), and 18 age and sex-matched non-obese controls (non-obese group) were included. Left ventricular global longitudinal strain (LV GLS) was evaluated with echocardiography speckle tracking imaging.

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Background: In patients undergoing left atrial appendage (LAA) closure, an accurate sizing of the LAA is key to optimize device sizing, procedural success and reduce complications. Previous studies have shown that intraprocedural volume loading increases LAA dimensions and improves device sizing. However, the safety and effects on LAA and device sizing of administering a fluid bolus during pre-procedural transesophageal echocardiography (TEE) are unknown.

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Preclinical animal studies are essential to the development of safe and effective stem cell therapies. Bioluminescence imaging (BLI) is a powerful tool in animal studies that enables the real-time longitudinal monitoring of stem cells in vivo to elucidate their regenerative properties. This review describes the application of BLI in preclinical stem cell research to address critical challenges in producing successful stem cell therapeutics.

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Historical as well as current species distribution data are needed to track changes in biodiversity. Species distribution data are found in a variety of sources, each of which has its own distinct bias toward certain taxa, time periods or places. We present GalliForm, a database that comprises 186687 galliform occurrence records linked to 118907 localities in Europe and Asia.

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Background: The impact of antithrombotic therapy on coagulation system activation after left atrial appendage closure (LAAC) remains unknown. This study sought to compare changes in coagulation markers associated with short-term oral anticoagulation (OAC) versus antiplatelet therapy (APT) following LAAC.

Methods: Prospective study including 78 atrial fibrillation patients undergoing LAAC with the Watchman device.

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Background: Severely obese patients have decreased cardiorespiratory fitness (CRF) and poor functional capacity. Bariatric surgery-induced weight loss improves CRF, but the determinants of this improvement are not well known. We aimed to assess the determinants of CRF before and after bariatric surgery and the impact of an exercise training program on CRF after bariatric surgery.

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