Publications by authors named "Stock U"

Background: We evaluated the potential benefits of renin-angiotensin-aldosterone system inhibitors (RAASi) in patients with left ventricular assist device support.

Methods And Results: A total of 165 consecutive patients undergoing left ventricular assist device implant and alive at 6-month on support were studied. RAASi status after 6-month visit along with clinical reasons for nonprescription/uptitration were retrospectively assessed.

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Heart valve disease is a major cause of mortality and morbidity worldwide with no effective medical therapy and no ideal valve substitute emulating the extremely sophisticated functions of a living heart valve. These functions influence survival and quality of life. This has stimulated extensive attempts at tissue engineering "living" heart valves.

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Objectives: The aim of this study was to develop a method to quantify the peel force in an in vitro model simulating repair of ascending aortic dissections with tissue glue (Bioglue).

Methods: This study adapted an adhesive T-Peel test for the determination of the peel strength of adhesives by measuring the peeling force of a T-shaped bonded tissue. Measurements were performed on iatrogenic dissected ascending porcine aorta, which has been repaired with Bioglue using different pressure levels.

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Article Synopsis
  • The study looks at how the time lungs spend without blood flow (ischemia) affects patients after lung transplants in the UK.
  • Researchers examined 1,565 lung transplants over 12 years and found that longer ischemic times were linked to a higher risk of death, especially when a heart-lung machine was used during surgery.
  • However, if the surgery didn't use this machine, the time without blood flow didn’t seem to harm the patients as much. This suggests that using the heart-lung machine might be risky for lung transplant outcomes.
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Background: The United Kingdom (UK) was one of the first countries to pioneer heart transplantation from donation after circulatory death (DCD) donors. To facilitate equity of access to DCD hearts by all UK heart transplant centers and expand the retrieval zone nationwide, a Joint Innovation Fund (JIF) pilot was provided by NHS Blood and Transplant (NHSBT) and NHS England (NHSE). The activity and outcomes of this national DCD heart pilot program are reported.

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The coronavirus (COVID-19) pandemic disrupted all surgical specialties significantly and exerted additional pressures on the overburdened United Kingdom (UK) National Health Service. Healthcare professionals in the UK have had to adapt their practice. In particular, surgeons have faced organisational and technical challenges treating patients who carried higher risks, were more urgent and could not wait for prehabilitation or optimisation before their intervention.

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Recurrent myocardial ischemia can lead to left ventricular (LV) dysfunction in patients with coronary artery disease (CAD). In this observational cohort study, we assessed for chronic metabolomic and transcriptomic adaptations within LV myocardium of patients undergoing coronary artery bypass grafting. During surgery, paired transmural LV biopsies were acquired on the beating heart from regions with and without evidence of inducible ischemia on preoperative stress perfusion cardiovascular magnetic resonance.

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Introduction: Thrombosis and bleeding are major complications in patients supported with left ventricular assist devices (LVADs). We aimed to assess the incidence of bleeding and thrombosis in patients supported with a HeartWare left ventricular assist device (HVAD), their predictive factors and their impact on mortality.

Methods: A single centre retrospective observational study of patients supported with HVAD over 5 years from January 2015 to October 2020.

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Objectives: This study aims to characterize the material properties of ascending thoracic aortic aneurysmal tissue, using regional biomechanical assessment of both tensile and dissection propagation peel strength.

Methods: Thirty-four aneurysm specimens (proximal thoracic aorta) were harvested en-bloc from patients undergoing surgery for aneurysm replacement. Specimens were processed into regional samples of similar shapes covering the whole aneurysm isosurface, according to a structured protocol, in both orientations (longitudinal and circumferential).

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Objective: Due to severely limited donor heart availability, durable mechanical circulatory support remains the only treatment option for many patients with end-stage heart failure. However, treatment complexity persists due to its univentricular support modality and continuous contact with blood. We investigated the function and safety of reBEAT (AdjuCor GmbH), a novel, minimal invasive mechanical circulatory support device that completely avoids blood contact and provides pulsatile, biventricular support.

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Article Synopsis
  • Hyperlactatemia, or elevated lactate levels, is frequently observed in patients after heart transplantation, with all studied patients showing levels above 2 mmol/l.
  • A study involving 143 heart transplant patients found that while nonsurvivors had higher maximum lactate levels and worse lactate clearance, these factors did not correlate with 1-year mortality.
  • The minimum lactate level emerged as a significant predictor of mortality, proving more effective in assessing patient prognosis than maximum lactate or lactate clearance metrics.
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Objectives: In addition to excess mortality due to COVID-19, the pandemic has been characterised by excess mortality due to non-COVID diagnoses and consistent reports of patients delaying seeking medical treatment. This study seeks to compare the outcomes of cardiac surgery during and before the COVID-19 pandemic.

Design: Our institutional database was interrogated retrospectively to identify all patients undergoing one of three index procedures during the first six months of the pandemic and the corresponding epochs of the previous five years.

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Objectives: Venovenous extracorporeal membrane oxygenation (VV-ECMO) is increasingly being used in acutely deteriorating patients with end-stage lung disease as a bridge to transplantation (BTT). It can allow critically ill recipients to remain eligible for lung transplants (LTx) while reducing pretransplant deconditioning. We analyzed early- and midterm postoperative outcomes of patients on VV-ECMO as a BTT and the impact of preoperative VV-ECMO on posttransplant survival outcomes.

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Acute kidney injury (AKI) after lung transplantation (LTx) is a common complication. We aimed to assess whether donation after circulatory death (DCD) is associated with an increased risk of AKI and renal replacement therapy (RRT) in the early postoperative period compared to the donation after brain death (DBD). Retrospective data on a cohort (N = 95) of LTx patients (DCD n = 17, DBD n = 78) characterized by no use of ex-vivo lung perfusion were analyzed for the incidence of AKI within 30 postoperative days and incidence of RRT within 7 and 30 days.

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A heart transplant is the gold standard treatment for end stage heart failure. Preservation of the donor heart during its transfer from the hospital of the donor to that of the recipient has a significant impact on the outcome of the transplant procedure. Icebox storage is a conventional method utilized for this purpose that may not provide uniform cooling of the donor heart and does not allow monitoring of the temperature of the donor heart during preservation.

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Recent advances in the management of patients with adult congenital heart disease (ACHD) have led to an increased number of patients who may develop heart failure and require heart transplantation (HTx). The purpose of this study was to evaluate early and mid-term postoperative outcomes after HTx with the use of Organ Care System (OCS) in a cohort of ACHD patients transplanted at our tertiary center. All consecutive HTx performed from January 2015 to January 2019 at our institution were analyzed.

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Background: Despite clear clinical benefits, there is limited evidence regarding possible complications of the novel mechanical support device Impella. Aortic and mitral valve regurgitation or injury are rare but potential complications following implantation of the Impella device.

Methods: To evaluate valvular complications after the Impella device implantation, we have performed a comprehensive search of literature on multiple sites on this topic.

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Article Synopsis
  • * Mechanical circulatory support (MCS) devices can help stabilize patients, making it possible to delay surgery until their condition improves.
  • * This case study focuses on using central venoarterial extracorporeal membrane oxygenation to support a patient with a large VSD, discussing the different types of MCS, their benefits, and drawbacks.
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Donation after circulatory death (DCD) has the potential to expand the lung donor pool. We aimed to assess whether DCD affected the need for perioperative extracorporeal membrane oxygenation (ECMO) and perioperative outcomes in lung transplantation (LTx) as compared to donation after brain death (DBD). All consecutive LTxs performed between April 2017 and March 2019 at our tertiary center were analyzed.

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The Impella (Abiomed, Danvers, MA, USA) has become an important adjunct treatment modality in bridging patients with end-stage heart failure to recovery or orthotopic heart transplantation (HTx). We compared the outcome of patients directly bridged to HTx with the Impella 5.0 versus patients without mechanical circulatory support (MCS).

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Venoarterial extracorporeal membrane oxygenation (VA-ECMO) serves as a conventional short-term mechanical circulatory assist to support heart and lung functions. The short-term ventricular assist devices (ST-VAD) can, on the contrary, offer only circulatory support. A combination of VAD and oxygenator (Oxy-VAD) could help overcome this potential disadvantage.

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Background: We investigated changes in estimated glomerular filtration rate (eGFR) after left ventricular assist device (LVAD) implant and the impact on long-term outcomes.

Methods: A retrospective analysis was conducted for 255 patients with LVADs, divided into 2 groups based on preimplant eGFR (<60 or >60 mL/min/1.73 m) and into 6 grades (grade 1, >90 mL/min/1.

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Appropriate mechanical properties and fast endothelialization of synthetic grafts are key to ensure long-term functionality of implants. We used a newly developed biostable polyurethane elastomer (TPCU) to engineer electrospun vascular scaffolds with promising mechanical properties (E-modulus: 4.8 ± 0.

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