ABSTRACT
An implantable left ventricular assist device (LVAD) is indicated as a bridge to transplantation or recovery in the United Kingdom (UK). The mechanism of action of the LVAD results in a unique state of haemodynamic stability with diminished arterial pulsatility. The clinical assessment of an LVAD recipient can be challenging because non-invasive blood pressure, pulse and oxygen saturation measurements may be hard to obtain. As a result of this unusual situation and complex interplay between the device and the native circulation, resuscitation of LVAD recipients requires bespoke guidelines. Through collaboration with key UK stakeholders, we assessed the current evidence base and developed guidelines for the recognition of clinical deterioration, inadequate circulation and time-critical interventions. Such guidelines, intended for use in transplant centres, are designed to be deployed by those providing immediate care of LVAD patients under conditions of precipitous clinical deterioration. In summary, the Joint British Societies and Transplant Centres LVAD Working Group present the UK guideline on management of emergencies in implantable LVAD recipients for use in advanced heart failure centres. These recommendations have been made with a UK resuscitation focus but are widely applicable to professionals regularly managing patients with implantable LVADs.
Subject(s)
Clinical Deterioration , Heart Failure , Heart Transplantation , Heart-Assist Devices , Humans , Emergencies , Heart Failure/therapyABSTRACT
OBJECTIVE: In Australia, less than one quarter of children aged 5-12 years meet national physical activity (PA) guidelines. Before school care operates as part of Out of School Hours Care (OSHC) services and provide opportunities for children to meet their daily PA recommendations. The aim of this study was to explore factors associated with children meeting 15 min of moderate-to-vigorous-intensity physical activity (MVPA) while attending before school care. METHODS: A cross-sectional study was conducted in 25 services in New South Wales, Australia. Each service was visited twice between March and June 2021. Staff behaviours and PA type and context were captured using staff interviews and the validated System for Observing Staff Promotion of Physical Activity and Nutrition (SOSPAN) time sampling tool. Child PA data were collected using Actigraph accelerometers and associations between program practices and child MVPA analysed. RESULTS: PA data were analysed for 654 children who spent an average of 39.2% (±17.6) of their time sedentary; 45.4% (±11.4) in light PA; and 14.9% (±11.7) in MVPA. Only 17% of children (n = 112) reached ≥15 min MVPA, with boys more likely to achieve this. Children were more likely to meet this recommendation in services where staff promoted and engaged in PA; PA equipment was available; children were observed in child-led free play; and a written PA policy existed. CONCLUSIONS: Before school care should be supported to improve physical activity promotion practices by offering staff professional development and guidance on PA policy development and implementation practices.
Subject(s)
Exercise , Sedentary Behavior , Male , Humans , Cross-Sectional Studies , Schools , Australia , AccelerometryABSTRACT
Lava fountains are a common manifestation of basaltic volcanism. While magma degassing plays a clear key role in their generation, the controls on their duration and intermittency are only partially understood, not least due to the challenges of measuring the most abundant gases, H2O and CO2. The 2021 Fagradalsfjall eruption in Iceland included a six-week episode of uncommonly periodic lava fountaining, featuring ~ 100-400 m high fountains lasting a few minutes followed by repose intervals of comparable duration. Exceptional conditions on 5 May 2021 permitted close-range (~300 m), highly time-resolved (every ~ 2 s) spectroscopic measurement of emitted gases during 16 fountain-repose cycles. The observed proportions of major and minor gas molecular species (including H2O, CO2, SO2, HCl, HF and CO) reveal a stage of CO2 degassing in the upper crust during magma ascent, followed by further gas-liquid separation at very shallow depths (~100 m). We explain the pulsatory lava fountaining as the result of pressure cycles within a shallow magma-filled cavity. The degassing at Fagradalsfjall and our explanatory model throw light on the wide spectrum of terrestrial lava fountaining and the subsurface cavities associated with basaltic vents.
ABSTRACT
Introduction Evidence based blood pressure (BP) targets in acute ischemic stroke are lacking. Previous observational studies have focused on single baseline BP and clinical outcomes, without consideration for dynamic changes. We aim to determine the association between BP parameters including variability, peak, nadir, median and mean during stroke and infarct growth (primary outcome), risk of haemorrhagic transformation and functional outcome (secondary outcomes). Methods Suspected stroke patients were prospectively recruited from a single comprehensive stroke centre. Multimodal computed tomography imaging was used to define infarct core. BP was recorded as per national stroke guidelines during the initial 24-hours. Infarct growth and evidence of parenchymal haemorrhage were determined by follow-up magnetic resonance imaging at 24 hours. Functional outcome at 3-months was assessed using the modified Rankin Scale. Subgroup analysis was performed according to stroke etiology and treatment for the association between BP, infarct volume growth and risk of hemorrhagic transformation. The association between BP parameters and outcomes were determined using regression modelling. Results A total of 229 patients were included in this study. The median age was 67.4, 64.4% were male and the baseline National Institutes of Health Stroke Scale was 8. Blood pressure variability (BPV) was independently associated with increased infarct growth (multivariate coefficient 1.60, 95% CI 0.27-2.94, P=0.019) and an increased odds of parenchymal haemorrhage (adjusted OR 1.21, 95% CI 1.02-1.44, P= 0.028). The odds of a favourable outcome at 90 days were inversely associated with BPV on simple, but not adjusted logistic regression. On subgroup analysis, only in patients with large vessel occlusions undergoing endovascular clot retrieval was BPV associated with infarct growth (multivariate adjusted coefficient 2.62, 95% CI 0.53-4.70, P=0.014) and an increased odds of hemorrhagic transformation (adjusted OR 1.26, 95% CI 1.01-1.57, P=0.045). Conclusions: An increase in BPV was associated with infarct expansion, increased risk of haemorrhagic transformation, and was negatively associated with favourable functional outcomes at 3-months.
ABSTRACT
Artificial intelligence (AI) has the potential to improve diagnostic accuracy. Yet people are often reluctant to trust automated systems, and some patient populations may be particularly distrusting. We sought to determine how diverse patient populations feel about the use of AI diagnostic tools, and whether framing and informing the choice affects uptake. To construct and pretest our materials, we conducted structured interviews with a diverse set of actual patients. We then conducted a pre-registered (osf.io/9y26x), randomized, blinded survey experiment in factorial design. A survey firm provided n = 2675 responses, oversampling minoritized populations. Clinical vignettes were randomly manipulated in eight variables with two levels each: disease severity (leukemia versus sleep apnea), whether AI is proven more accurate than human specialists, whether the AI clinic is personalized to the patient through listening and/or tailoring, whether the AI clinic avoids racial and/or financial biases, whether the Primary Care Physician (PCP) promises to explain and incorporate the advice, and whether the PCP nudges the patient towards AI as the established, recommended, and easy choice. Our main outcome measure was selection of AI clinic or human physician specialist clinic (binary, "AI uptake"). We found that with weighting representative to the U.S. population, respondents were almost evenly split (52.9% chose human doctor and 47.1% chose AI clinic). In unweighted experimental contrasts of respondents who met pre-registered criteria for engagement, a PCP's explanation that AI has proven superior accuracy increased uptake (OR = 1.48, CI 1.24-1.77, p < .001), as did a PCP's nudge towards AI as the established choice (OR = 1.25, CI: 1.05-1.50, p = .013), as did reassurance that the AI clinic had trained counselors to listen to the patient's unique perspectives (OR = 1.27, CI: 1.07-1.52, p = .008). Disease severity (leukemia versus sleep apnea) and other manipulations did not affect AI uptake significantly. Compared to White respondents, Black respondents selected AI less often (OR = .73, CI: .55-.96, p = .023) and Native Americans selected it more often (OR: 1.37, CI: 1.01-1.87, p = .041). Older respondents were less likely to choose AI (OR: .99, CI: .987-.999, p = .03), as were those who identified as politically conservative (OR: .65, CI: .52-.81, p < .001) or viewed religion as important (OR: .64, CI: .52-.77, p < .001). For each unit increase in education, the odds are 1.10 greater for selecting an AI provider (OR: 1.10, CI: 1.03-1.18, p = .004). While many patients appear resistant to the use of AI, accuracy information, nudges and a listening patient experience may help increase acceptance. To ensure that the benefits of AI are secured in clinical practice, future research on best methods of physician incorporation and patient decision making is required.
ABSTRACT
Childhood muscle-related cancer rhabdomyosarcoma is a rare disease with a 50-year unmet clinical need for the patients presented with advanced disease. The rarity of â¼350 cases per year in North America generally diminishes the viability of large-scale, pharmaceutical industry driven drug development efforts for rhabdomyosarcoma. In this study, we performed a large-scale screen of 640,000 compounds to identify the dihydropyridine (DHP) class of anti-hypertensives as a priority compound hit. A structure-activity relationship was uncovered with increasing cell growth inhibition as side chain length increases at the ortho and para positions of the parent DHP molecule. Growth inhibition was consistent across n = 21 rhabdomyosarcoma cell line models. Anti-tumor activity in vitro was paralleled by studies in vivo. The unexpected finding was that the action of DHPs appears to be other than on the DHP receptor (i.e., L-type voltage-gated calcium channel). These findings provide the basis of a medicinal chemistry program to develop dihydropyridine derivatives that retain anti-rhabdomyosarcoma activity without anti-hypertensive effects.
Subject(s)
Dihydropyridines , Rhabdomyosarcoma , Humans , Child , Calcium Channel Blockers/pharmacology , Calcium Channel Blockers/chemistry , Structure-Activity Relationship , Antihypertensive Agents/pharmacology , Calcium Channels, L-Type/metabolism , Rhabdomyosarcoma/drug therapy , Dihydropyridines/pharmacologyABSTRACT
Outcomes are excellent for the majority of patients with Wilms tumors (WT). However, there remain WT subgroups for which the survival rate is approximately 50% or lower. Acknowledging that the composition of this high-risk group has changed over time reflecting improvements in therapy, we introduce the authors' view of the historical and current approach to the classification and treatment of high-risk WT. For this review, we consider high-risk WT to include patients with newly diagnosed metastatic blastemal-type or diffuse anaplastic histology, those who relapse after having been initially treated with three or more different chemotherapeutics, or those who relapse more than once. In certain low- or low middle-income settings, socio-economic factors expand the definition of what constitutes a high-risk WT. As conventional therapies are inadequate to cure the majority of high-risk WT patients, advancement of laboratory and early-phase clinical investigations to identify active agents is urgently needed.
Subject(s)
Kidney Neoplasms , Wilms Tumor , Humans , Kidney Neoplasms/pathology , Neoplasm Staging , Wilms Tumor/pathology , Prognosis , RecurrenceABSTRACT
BACKGROUND: Systemic therapy for metastatic clear cell sarcoma (CCS) bearing EWSR1-CREB1/ATF1 fusions remains an unmet clinical need in children, adolescents, and young adults. METHODS: To identify key signaling pathway vulnerabilities in CCS, a multi-pronged approach was taken: (i) genomic and transcriptomic landscape analysis, (ii) integrated chemical biology interrogations, (iii) development of CREB1/ATF1 inhibitors, and (iv) antibody-drug conjugate testing (ADC). The first approach encompassed DNA exome and RNA deep sequencing of the largest human CCS cohort yet reported consisting of 47 patient tumor samples and 8 cell lines. RESULTS: Sequencing revealed recurrent mutations in cell cycle checkpoint, DNA double-strand break repair or DNA mismatch repair genes, with a correspondingly low to intermediate tumor mutational burden. DNA multi-copy gains with corresponding high RNA expression were observed in CCS tumor subsets. CCS cell lines responded to the HER3 ADC patritumab deruxtecan in a dose-dependent manner in vitro, with impaired long term cell viability. CONCLUSION: These studies of the genomic, transcriptomic and chemical biology landscape represent a resource 'atlas' for the field of CCS investigation and drug development. CHK inhibitors are identified as having potential relevance, CREB1 inhibitors non-dependence of CCS on CREB1 activity was established, and the potential utility of HER3 ADC being used in CCS is found.
Subject(s)
Sarcoma, Clear Cell , Child , Adolescent , Young Adult , Humans , Sarcoma, Clear Cell/genetics , Sarcoma, Clear Cell/metabolism , Sarcoma, Clear Cell/pathology , Transcriptome , Genomics , Base Sequence , RNA , Oncogene Proteins, Fusion/geneticsABSTRACT
Outcomes are excellent for the majority of patients with Wilms tumors (WT). However, there remain WT subgroups for which the survival rate is approximately 50% or lower. Acknowledging that the composition of this high-risk group has changed over time reflecting improvements in therapy, we introduce the authors' view of the historical and current approach to the classification and treatment of high-risk WT. For this review, we consider high-risk WT to include patients with newly diagnosed metastatic blastemal-type or diffuse anaplastic histology, those who relapse after having been initially treated with three or more different chemotherapeutics, or those who relapse more than once. In certain low- or low middle-income settings, socio-economic factors expand the definition of what constitutes a high-risk WT. As conventional therapies are inadequate to cure the majority of high-risk WT patients, advancement of laboratory and early-phase clinical investigations to identify active agents is urgently needed.
Subject(s)
Kidney Neoplasms , Wilms Tumor , Humans , Kidney Neoplasms/pathology , Neoplasm Staging , Wilms Tumor/pathology , Prognosis , RecurrenceABSTRACT
BACKGROUND: While genomic variations can provide valuable information for health care and ancestry, the privacy of individual genomic data must be protected. Thus, a secure environment is desirable for a human DNA database such that the total data are queryable but not directly accessible to involved parties (eg, data hosts and hospitals) and that the query results are learned only by the user or authorized party. OBJECTIVE: In this study, we provide efficient and secure computations on panels of single nucleotide polymorphisms (SNPs) from genomic sequences as computed under the following set operations: union, intersection, set difference, and symmetric difference. METHODS: Using these operations, we can compute similarity metrics, such as the Jaccard similarity, which could allow querying a DNA database to find the same person and genetic relatives securely. We analyzed various security paradigms and show metrics for the protocols under several security assumptions, such as semihonest, malicious with honest majority, and malicious with a malicious majority. RESULTS: We show that our methods can be used practically on realistically sized data. Specifically, we can compute the Jaccard similarity of two genomes when considering sets of SNPs, each with 400,000 SNPs, in 2.16 seconds with the assumption of a malicious adversary in an honest majority and 0.36 seconds under a semihonest model. CONCLUSIONS: Our methods may help adopt trusted environments for hosting individual genomic data with end-to-end data security.
ABSTRACT
BACKGROUND: Out of School Hours Care (OSHC) offers structured care to elementary/primary-aged children before and after school, and during school holidays. The promotion of physical activity in OSHC is important for childhood obesity prevention. The aim of this systematic review was to identify correlates of objectively measured physical activity and sedentary behaviour in before and after school care. METHODS: A systematic search was conducted in Scopus, ERIC, MEDLINE (EBSCO), PsycINFO and Web of Science databases up to December 2021. Study inclusion criteria were: written in English; from a peer-reviewed journal; data from a centre-based before and/or after school care service; children with a mean age < 13 years; an objective measure of physical activity or sedentary behaviour; reported correlations and significance levels; and if an intervention study design these correlates were reported at baseline. Study quality was assessed using the Office of Health Assessment and Translation Risk of Bias Rating Tool for Human and Animal Studies. The PRISMA guidelines informed the reporting, and data were synthesised according to shared correlations and a social ecological framework. RESULTS: Database searches identified 4559 papers, with 18 cross-sectional studies meeting the inclusion criteria.There were a total of 116 physical activity correlates and 64 sedentary behaviour correlates identified. The most frequently reported correlates of physical activity were child sex (males more active), staff engaging in physical activity, an absence of elimination games, and scheduling physical activity in daily programming (all more positively associated). The most frequently reported correlates of sedentary behaviour were child sex (females more sedentary) and age (older children more sedentary). CONCLUSIONS: Encouraging physical activity engagement of female children, promoting positive staff behaviours, removing elimination elements from games, and scheduling more time for physical activity should be priorities for service providers. Additional research is needed in before school care services.
Subject(s)
Pediatric Obesity , Sedentary Behavior , Male , Child , Female , Humans , Adolescent , Aged , Cross-Sectional Studies , Exercise , SchoolsABSTRACT
BACKGROUND: Metastatic epithelioid sarcoma (EPS) remains a largely unmet clinical need in children, adolescents and young adults despite the advent of EZH2 inhibitor tazemetostat. METHODS: In order to realise consistently effective drug therapies, a functional genomics approach was used to identify key signalling pathway vulnerabilities in a spectrum of EPS patient samples. EPS biopsies/surgical resections and cell lines were studied by next-generation DNA exome and RNA deep sequencing, then EPS cell cultures were tested against a panel of chemical probes to discover signalling pathway targets with the most significant contributions to EPS tumour cell maintenance. RESULTS: Other biologically inspired functional interrogations of EPS cultures using gene knockdown or chemical probes demonstrated only limited to modest efficacy in vitro. However, our molecular studies uncovered distinguishing features (including retained dysfunctional SMARCB1 expression and elevated GLI3, FYN and CXCL12 expression) of distal, paediatric/young adult-associated EPS versus proximal, adult-associated EPS. CONCLUSIONS: Overall results highlight the complexity of the disease and a limited chemical space for therapeutic advancement. However, subtle differences between the two EPS subtypes highlight the biological disparities between younger and older EPS patients and emphasise the need to approach the two subtypes as molecularly and clinically distinct diseases.
Subject(s)
DNA-Binding Proteins , Sarcoma , Adolescent , Child , Chromosomal Proteins, Non-Histone/genetics , Chromosomal Proteins, Non-Histone/metabolism , Chromosomal Proteins, Non-Histone/therapeutic use , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , DNA-Binding Proteins/therapeutic use , Genomics , Humans , Sarcoma/drug therapy , Sarcoma/genetics , Sarcoma/pathology , Transcription Factors/genetics , Transcription Factors/metabolism , Transcription Factors/therapeutic use , Young AdultABSTRACT
Correctly diagnosing a rare childhood cancer such as sarcoma can be critical to assigning the correct treatment regimen. With a finite number of pathologists worldwide specializing in pediatric/young adult sarcoma histopathology, access to expert differential diagnosis early in case assessment is limited for many global regions. The lack of highly-trained sarcoma pathologists is especially pronounced in low to middle-income countries, where pathology expertise may be limited despite a similar rate of sarcoma incidence. To address this issue in part, we developed a deep learning convolutional neural network (CNN)-based differential diagnosis system to act as a pre-pathologist screening tool that quantifies diagnosis likelihood amongst trained soft-tissue sarcoma subtypes based on whole histopathology tissue slides. The CNN model is trained on a cohort of 424 centrally-reviewed histopathology tissue slides of alveolar rhabdomyosarcoma, embryonal rhabdomyosarcoma and clear-cell sarcoma tumors, all initially diagnosed at the originating institution and subsequently validated by central review. This CNN model was able to accurately classify the withheld testing cohort with resulting receiver operating characteristic (ROC) area under curve (AUC) values above 0.889 for all tested sarcoma subtypes. We subsequently used the CNN model to classify an externally-sourced cohort of human alveolar and embryonal rhabdomyosarcoma samples and a cohort of 318 histopathology tissue sections from genetically engineered mouse models of rhabdomyosarcoma. Finally, we investigated the overall robustness of the trained CNN model with respect to histopathological variations such as anaplasia, and classification outcomes on histopathology slides from untrained disease models. Overall positive results from our validation studies coupled with the limited worldwide availability of sarcoma pathology expertise suggests the potential of machine learning to assist local pathologists in quickly narrowing the differential diagnosis of sarcoma subtype in children, adolescents, and young adults.
Subject(s)
Rhabdomyosarcoma, Embryonal , Rhabdomyosarcoma , Adolescent , Animals , Child , Humans , Machine Learning , Mice , Neural Networks, Computer , Pathologists , Rhabdomyosarcoma/diagnosis , Rhabdomyosarcoma, Embryonal/pathology , Young AdultABSTRACT
AIMS: The aim of the study was to explore whether, and how, professional nurse educator identity is co-constructed by a community of practice. DESIGN: A critical participatory action research (PAR) methodology was used as it extends the principles of action research by seeking purposeful and sustainable social change that recognizes participants as researchers and generators of knowledge. METHODS: Twenty-two sector-based nurse educators employed as either nurse educators or clinical nurse educators participated in the critical PAR. Multiple methods of data generation were pursued in a cyclic and sequential manner consistent in an action research process. Three distinct phases of the research across 2015-2017 involved the generation of data before, during and after the establishment of a nurse educator community of practice. A social constructionist lens of analysis was used to explore the social and relational outcomes. The COREQ checklist was used to appraise the study report. RESULTS: A sustained period of community of practice engagement enhanced the participants' relationships and shifted their perceived professional identities towards being validated nurse educators with a stronger collective sense of their roles. CONCLUSION: For this group of nurse educators, participation in the research resulted in collective meaning-making, praxis, knowledge generation and the co-construction of their professional identities.
Subject(s)
Faculty, Nursing , Health Services Research , HumansABSTRACT
PURPOSE: There are marked gender differences in all etiologies of advanced heart failure. We sought to determine whether there is evidence of gender-specific decision making for transplant assessments, and how gender effects outcomes. METHODS: Retrospective analysis of adult heart transplant assessments at a single UK center between April 2015 and March 2020. RESULTS: Females were 32% of referrals (N = 137 females, 285 males), with marked differences between diagnoses - 11% ischemic and 43% of adult congenital. Females were younger, shorter, weighed less, and had lower pulmonary pressures. Females were much less likely to receive a ventricular assist device (13%). Blood type "O" females were relatively more likely compared to males to receive a transplant (45%). Comparing males and females who received a ventricular assist device, both had similar levels of high pulmonary pressures, indicating consistent decision-making based on hemodynamics to implant a device. Overall survival was better for females (in noncongenital patients), and this was due to female patients who were not accepted for transplant or a ventricular assist device being more often "too well for transplant," rather than in males when they were more often "unsuitable." CONCLUSIONS: Marked gender differences exist at all stages of the heart transplant assessment pathway. Appropriate decision-making based on clinical grounds is shown with less transplants in male blood type "O"s and hemodynamic criteria for ventricular assist device implantation in both genders. Further studies are needed to determine if there is a wider community bias in advanced heart failure treatments for females.
Subject(s)
Heart Failure , Heart Transplantation , Heart-Assist Devices , Adult , Female , Heart Failure/surgery , Heart Transplantation/adverse effects , Heart-Assist Devices/adverse effects , Humans , Male , Retrospective Studies , Sex Factors , Treatment Outcome , United Kingdom/epidemiologyABSTRACT
The survival of childhood Wilms tumor is currently around 90%, with many survivors reaching reproductive age. Chemotherapy and radiotherapy are established risk factors for gonadal damage and are used in both COG and SIOP Wilms tumor treatment protocols. The risk of infertility in Wilms tumor patients is low but increases with intensification of treatment including the use of alkylating agents, whole abdominal radiation or radiotherapy to the pelvis. Both COG and SIOP protocols aim to limit the use of gonadotoxic treatment, but unfortunately this cannot be avoided in all patients. Infertility is considered one of the most important late effects of childhood cancer treatment by patients and their families. Thus, timely discussion of gonadal damage risk and fertility preservation options is important. Additionally, irrespective of the choice for preservation, consultation with a fertility preservation (FP) team is associated with decreased patient and family regret and better quality of life. Current guidelines recommend early discussion of the impact of therapy on potential fertility. Since most patients with Wilms tumors are prepubertal, potential FP methods for this group are still considered experimental. There are no proven methods for FP for prepubertal males (testicular biopsy for cryopreservation is experimental), and there is just a single option for prepubertal females (ovarian tissue cryopreservation), posing both technical and ethical challenges. Identification of genetic markers of susceptibility to gonadotoxic therapy may help to stratify patient risk of gonadal damage and identify patients most likely to benefit from FP methods.
Subject(s)
Fertility Preservation , Infertility , Kidney Neoplasms , Neoplasms , Wilms Tumor , Child , Female , Fertility Preservation/adverse effects , Fertility Preservation/methods , Humans , Infertility/complications , Kidney Neoplasms/complications , Kidney Neoplasms/therapy , Male , Neoplasms/drug therapy , Quality of Life , Wilms Tumor/therapyABSTRACT
OBJECTIVES: Ventricular assist device (VAD) for systemic right ventricular (RV) failure patients post-atrial switch, for transposition of the great arteries (TGA), and those with congenitally corrected TGA has proven useful to reduce transpulmonary gradient and bridge-to-transplantation. The purpose of this study is to describe our experience of VAD in systemic RV failure and our move towards concomitant tricuspid valve replacement (TVR). METHODS: This is a single-centre retrospective study of consecutive adult patients receiving HeartWare VAD for systemic RV failure between 2010 and 2019. From 2017, concomitant TVR was performed routinely. Demographic, clinical variables and echocardiographic and haemodynamic measurements pre- and post-VAD implantation were recorded. Complications on support, heart transplantation and survival rates were described. RESULTS: Eighteen patients underwent VAD implantation. Moderate or severe systemic tricuspid regurgitation was present in 83.3% of patients, and subpulmonic left ventricular impairment in 88.9%. One-year survival was 72.2%. VAD implantation was technically feasible and successful in all but one. Post-VAD, transpulmonary gradient fell from 16 (15-22) to 10 (7-13) mmHg (P = 0.01). Patients with TVR (n = 6) also demonstrated a reduction in mean pulmonary and wedge pressures. Furthermore, subpulmonic left ventricular end-diastolic dimension (44.3 vs 39.6 mm; P = 0.03) and function improved in this group. After 1 year of support, 72.2% of patients were suitable for transplantation. CONCLUSIONS: VAD is an effective strategy as bridge-to-candidacy and bridge-to-transplantation in patients with end-stage systemic RV failure. Concomitant TVR at the time of implant is associated with better early haemodynamic and echocardiographic results post-VAD.
Subject(s)
Heart Failure , Heart-Assist Devices , Transposition of Great Vessels , Tricuspid Valve Insufficiency , Adult , Heart Ventricles/diagnostic imaging , Heart Ventricles/surgery , Humans , Retrospective Studies , Treatment Outcome , Tricuspid Valve/diagnostic imaging , Tricuspid Valve/surgery , Tricuspid Valve Insufficiency/complicationsABSTRACT
Deposits from explosive submarine eruptions have been found in the deep sea, 1-4 km below the surface, with both flow and fall deposits extending several km's over the seafloor. A model of a turbulent fountain suggests that after rising 10-20 m above the vent, the erupting particle-laden mixture entrains and mixes with sufficient seawater that it becomes denser than seawater. The momentum of the resulting negatively buoyant fountain is only sufficient to carry the material 50-200 m above the seafloor and much of the solid material then collapses to the seafloor; this will not produce the far-reaching fall deposits observed on the seabed. However, new laboratory experiments show that particle sedimentation at the top of the fountain enables some of the hot, buoyant water in the fountain to separate from the collapsing flow and continue rising as a buoyant plume until it forms a radially spreading intrusion higher in the water column. With eruption rates of 10[Formula: see text]-10[Formula: see text] [Formula: see text], we estimate that this warm water may rise a few 100's m above the fountain. Some of the finer grained pyroclasts can be carried upwards by this flow and as they spread out in the radial intrusion, they gradually sediment to form a fall deposit which may extend 1000's m from the source. Meanwhile, material collapsing from the dense fountain forms aqueous pyroclastic flows which may also spread 1000's m from the vent forming a flow deposit on the seabed. Quantification of the controls on the concurrent fall and flow deposits, and comparison with field observations, including from the 2012 eruption of Havre Volcano in the South Pacific, open the way to new understanding of submarine eruptions.