Publications by authors named "Jack Boyd"

Background: Combined heart-liver transplantation (CHLT) is a definitive therapy reserved for patients with concomitant heart failure and advanced liver disease. A limited number of centers perform CHLT, and even fewer use the en bloc implantation technique. Here we review clinical outcomes and immunoprotective effects following CHLT and describe our institution's more than two decades of experience in performing the en bloc technique.

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Computational simulations of coronary artery blood flow, using anatomical models based on clinical imaging, are an emerging non-invasive tool for personalized treatment planning. However, current simulations contend with two related challenges - incomplete anatomies in image-based models due to the exclusion of arteries smaller than the imaging resolution, and the lack of personalized flow distributions informed by patient-specific imaging. We introduce a data-enabled, personalized and multi-scale flow simulation framework spanning large coronary arteries to myocardial microvasculature.

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Blood vessels are subjected to complex biomechanical loads, primarily from pressure-driven blood flow. Abnormal loading associated with vascular grafts, arising from altered hemodynamics or wall mechanics, can cause acute and progressive vascular failure and end-organ dysfunction. Perturbations to mechanobiological stimuli experienced by vascular cells contribute to remodeling of the vascular wall via activation of mechanosensitive signaling pathways and subsequent changes in gene expression and associated turnover of cells and extracellular matrix.

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Article Synopsis
  • Large language models (LLMs) can perform various language tasks without specific training data, but their inaccurate and potentially harmful outputs limit their use in clinical settings.
  • A study evaluated Almanac, an LLM framework designed for medical guidance, by comparing it with standard LLMs like ChatGPT-4, based on responses to 314 clinical questions from a panel of healthcare experts.
  • Results indicated that Almanac significantly outperformed standard LLMs in factuality, completeness, user satisfaction, and safety, highlighting the need for thorough testing of these models before clinical application.
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Introduction: Adequate peri-operative care is essential to ensuring a satisfactory outcome in cardiac surgery. In this study, we look at the impact of evidence-based protocols implemented at Stanford Hospital.

Methods: This study is a single-center, retrospective analysis.

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Article Synopsis
  • Large-language models have shown strong performance in tasks like summarization and dialogue generation, but their use in clinical medicine is hindered by inaccuracies and harmful outputs.
  • The study introduces Almanac, a model enhanced with retrieval features for providing medical guidelines and treatment recommendations, which was tested using clinical scenarios evaluated by physicians.
  • Findings indicate that Almanac improved factuality by an average of 18% and also enhanced completeness and safety, highlighting the model's potential in clinical decision-making when properly tested and implemented.
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Saphenous vein grafts (SVGs) are the most widely used conduit in coronary artery bypass grafting (CABG) surgery; however, SVG failures due to neointimal hyperplasia present a significant long-term limitation to the effectiveness of myocardial revascularization. This review will provide a comprehensive overview of the biological mechanisms of vein graft failure, including compensatory endothelial proliferation, extracellular matrix deposition, and adventitial disruption. We will discuss historical and emerging strategies for vein graft failure prevention with a focus on the role of mechanical vein graft support using external stenting.

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Introduction: The risk, cost, and adverse outcomes associated with packed red blood cell (RBC) transfusions in patients with cardiopulmonary failure requiring extracorporeal membrane oxygenation (ECMO) have raised concerns regarding the overutilization of RBC products. It is, therefore, necessary to establish optimal transfusion criteria and protocols for patients supported with ECMO. The goal of this study was to establish specific criteria for RBC transfusions in patients undergoing ECMO.

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Obesity, characterized by chronic low-grade inflammation of the adipose tissue, is associated with adverse coronavirus disease 2019 (COVID-19) outcomes, yet the underlying mechanism is unknown. To explore whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection of adipose tissue contributes to pathogenesis, we evaluated COVID-19 autopsy cases and deeply profiled the response of adipose tissue to SARS-CoV-2 infection in vitro. In COVID-19 autopsy cases, we identified SARS-CoV-2 RNA in adipocytes with an associated inflammatory infiltrate.

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Objective: To complete the first in-human study of the automated line clearance Thoraguard chest tube system. The study focuses on the viability and efficacy of the device in comparison with conventional models as well as secondary matters such as patient experience and ease of use.

Methods: This was a single-center, prospective, open-label study involving adult patients (n = 27) who underwent nonemergent, first-time, cardiac surgery.

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Objectives: Cardiothoracic (CT) surgeons with National Institutes of Health (NIH) R01 funding face a highly competitive renewal process. The factors that contribute to successful grant renewal for CT surgeons remain poorly defined. We hypothesized that renewed basic science grants are associated with high research output and scholarly impact during the preceding award cycle.

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Vein grafts, the most commonly used conduits in multi-vessel coronary artery bypass grafting surgery, have high intermediate- and long-term failure rates. The abrupt and marked increase in hemodynamic loads on the vein graft is a known contributor to failure. Recent computational modeling suggests that veins can more successfully adapt to an increase in mechanical load if the rate of loading is gradual.

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Background: A PhD degree can offer significant research experience, but previous studies yielded conflicting conclusions on the relationship between a PhD degree and future research output. We compared the impact of a PhD degree versus research fellowship (RF) training on research productivity in cardiothoracic surgeons, hypothesizing that training pathways may influence potential associations.

Methods: CT surgeons practicing at all accredited United States CT surgery training programs in 2018 who pursued dedicated time for research (n = 597), including earning a PhD degree (n = 92) or completing a non-PhD RF (n = 505), were included.

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Introduction: There is growing concern regarding the attrition of surgeon-scientists. To understand the decline of basic science research (BSR), it is essential to examine trends in research conducted by trainees. We hypothesized that, over recent decades, cardiothoracic (CT) surgery trainees have published fewer BSR articles.

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Background: The objective of this work was to delineate career progression and research productivity of women practicing cardiothoracic surgery in the academic setting.

Methods: Cardiothoracic surgeons at the 79 accredited US cardiothoracic surgery training programs in 2020 were included in this cross-sectional analysis. Data regarding subspecialization, training, practice history, and publications were gathered from public sources including department websites, CTSNet, and Scopus.

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The revolutions in AI hold tremendous capacity to augment human achievements in surgery, but robust integration of deep learning algorithms with high-fidelity surgical simulation remains a challenge. We present a novel application of reinforcement learning (RL) for automating surgical maneuvers in a graphical simulation. In the Unity3D game engine, the Machine Learning-Agents package was integrated with the NVIDIA FleX particle simulator for developing autonomously behaving RL-trained scissors.

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Article Synopsis
  • Coronary artery disease (CAD) is now recognized not just as a lipid disorder but also as a condition marked by chronic inflammation, particularly involving immune cell activity in atherosclerotic plaques.
  • Researchers employed single-cell technology to explore the immune microenvironment of coronary plaques at various maturity stages, revealing a significant presence of activated αβ T cells alongside macrophages.
  • Findings indicated these T cells, which show clonal expansion and specificity to several viral epitopes, are likely involved in autoimmune responses contributing to the disease, with some exhibiting pro-inflammatory properties that may further encourage plaque progression.
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Severe primary graft dysfunction (PGD) is the leading cause of early postoperative mortality following orthotopic heart transplantation (OHT). Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has been used as salvage therapy. This study aimed to evaluate the outcomes in adult OHT recipients who underwent VA-ECMO for severe PGD.

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Introduction: The National Institutes of Health (NIH) recently developed the relative citation ratio (RCR), calculated as article citations benchmarked to NIH-funded publications in the same field. Here, we characterized the scholarly impact of academic cardiothoracic (CT) surgeons and their research using the RCR.

Materials And Methods: Using a database of 992 CT surgeons, we calculated the RCR for all articles published by each surgeon since 1980 using the NIH iCite database.

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Purpose: Patients with myocardial bridges (MBs) have a higher prevalence of atherosclerosis. Wall shear stress (WSS) has previously been correlated with plaque in coronary artery disease patients, but such correlations have not been investigated in symptomatic MB patients. The aim of this paper was to use a multi-scale computational fluid dynamics (CFD) framework to simulate hemodynamics in MB patient, and investigate the co-localization of WSS and plaque.

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Aim: This clinical practice guideline for the evaluation and diagnosis of chest pain provides recommendations and algorithms for clinicians to assess and diagnose chest pain in adult patients.

Methods: A comprehensive literature search was conducted from November 11, 2017, to May 1, 2020, encompassing randomized and nonrandomized trials, observational studies, registries, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Additional relevant studies, published through April 2021, were also considered.

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Aim: This clinical practice guideline for the evaluation and diagnosis of chest pain provides recommendations and algorithms for clinicians to assess and diagnose chest pain in adult patients.

Methods: A comprehensive literature search was conducted from November 11, 2017, to May 1, 2020, encompassing randomized and nonrandomized trials, observational studies, registries, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Additional relevant studies, published through April 2021, were also considered.

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