82 research outputs found

    How successful is successful? Aortic arch shape after successful aortic coarctation repair correlates with left ventricular function

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    OBJECTIVES: Even after successful aortic coarctation repair, there remains a significant incidence of late systemic hypertension and other morbidities. Independently of residual obstruction, aortic arch morphology alone may affect cardiac function and outcome. We sought to uncover the relationship of arch 3-dimensional shape features with functional data obtained from cardiac magnetic resonance scans. METHODS: Three-dimensional aortic arch shape models of 53 patients (mean age, 22.3 ± 5.6 years) 12 to 38 years after aortic coarctation repair were reconstructed from cardiac magnetic resonance data. A novel validated statistical shape analysis method computed a 3-dimensional mean anatomic shape of all aortic arches and calculated deformation vectors of the mean shape toward each patient's arch anatomy. From these deformations, 3-dimensional shape features most related to left ventricular ejection fraction, indexed left ventricular end-diastolic volume, indexed left ventricular mass, and resting systolic blood pressure were extracted from the deformation vectors via partial least-squares regression. RESULTS: Distinct arch shape features correlated significantly with left ventricular ejection fraction (r = 0.42, P = .024), indexed left ventricular end-diastolic volume (r = 0.65, P < .001), and indexed left ventricular mass (r = 0.44, P = .014). Lower left ventricular ejection fraction, larger indexed left ventricular end-diastolic volume, and increased indexed left ventricular mass were identified with an aortic arch shape that has an elongated ascending aorta with a high arch height-to-width ratio, a relatively short proximal transverse arch, and a relatively dilated descending aorta. High blood pressure seemed to be linked to gothic arch shape features, but this did not achieve statistical significance. CONCLUSIONS: Independently of hemodynamically important arch obstruction or residual aortic coarctation, specific aortic arch shape features late after successful aortic coarctation repair seem to be associated with worse left ventricular function. Analyzing 3-dimensional shape information via statistical shape modeling can be an adjunct to long-term risk assessment in patients after aortic coarctation repair

    Looks Do Matter! Aortic Arch Shape After Hypoplastic Left Heart Syndrome Palliation Correlates With Cavopulmonary Outcomes

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    BACKGROUND: Aortic arch reconstruction after hypoplastic left heart syndrome (HLHS) palliation can vary widely in shape and dimensions between patients. Arch morphology alone may affect cardiac function and outcome. We sought to uncover the relationship of arch three-dimensional shape features with functional and short-term outcome data after total cavopulmonary connection (TCPC). METHODS: Aortic arch shape models of 37 patients with HLHS (age, 2.89 ± 0.99 years) were reconstructed from magnetic resonance data before TCPC completion. A novel, validated statistical shape analysis method was used to compute a three-dimensional anatomic mean shape from the cohort and calculate the deformation vectors of the mean shape toward each patient's specific anatomy. From these deformations, three-dimensional shape features most related to ventricular ejection fraction, indexed end-diastolic volume, and superior cavopulmonary pressure were extracted by partial least-square regression analysis. Shape patterns relating to intensive care unit and hospital lengths of stay after TCPC were assessed. RESULTS: Distinct deformation patterns, which result in an acutely mismatched aortic root and ascending aorta, and a gothic-like transverse arch, correlated with increased indexed end-diastolic volume and higher superior cavopulmonary pressure but not with ejection fraction. Specific arch morphology with pronounced transverse arch and descending aorta mismatch also correlated with longer intensive care unit and hospital lengths of stay after TCPC completion. CONCLUSIONS: Independent of hemodynamically important arch obstruction, altered aortic morphology in HLHS patients appears to have important associations with higher superior cavopulmonary pressure and with short-term outcomes after TCPC completion as highlighted by statistical shape analysis, which could act as adjunct to risk assessment in HLHS

    Evaluation of high-dose rifampin in patients with new, smear-positive tuberculosis (HIRIF): study protocol for a randomized controlled trial.

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    BACKGROUND: Evidence has existed for decades that higher doses of rifampin may be more effective, but potentially more toxic, than standard doses used in tuberculosis treatment. Whether increased doses of rifampin could safely shorten treatment remains an open question. METHODS/DESIGN: The HIRIF study is a phase II randomized trial comparing rifampin doses of 20 and 15 mg/kg/day to the standard 10 mg/kg/day for the first 2 months of tuberculosis treatment. All participants receive standard doses of companion drugs and a standard continuation-phase treatment (4 months, 2 drugs). They are followed for 6 months post treatment. Study participants are adults with newly diagnosed, previously untreated, smear positive (≥2+) pulmonary tuberculosis. The primary outcome is rifampin area under the plasma concentration-time curve (AUC0-24) after at least 14 days of study treatment/minimum inhibitory concentration. 180 randomized participants affords 90 % statistical power to detect a difference of at least 14 mcg/mL*hr between the 20 mg/kg group and the 10 mg/kg group, assuming a loss to follow-up of up to 17 %. DISCUSSION: Extant evidence suggests the potential for increased doses of rifampin to shorten tuberculosis treatment duration. Early studies that explored this potential using intermittent, higher dosing were derailed by toxicity. Given the continued large, global burden of tuberculosis with nearly 10 million new cases annually, shortened regimens with existing drugs would offer an important advantage to patients and health systems. TRIAL REGISTRATION: This trial was registered with clinicaltrials.gov (registration number: NCT01408914 ) on 2 August 2011

    Ecosystem Resilience and Threshold Response in the Galápagos Coastal Zone

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    Background: The Intergovernmental Panel on Climate Change (IPCC) provides a conservative estimate on rates of sea-level rise of 3.8 mm yr⁻¹ at the end of the 21st century, which may have a detrimental effect on ecologically important mangrove ecosystems. Understanding factors influencing the long-term resilience of these communities is critical but poorly understood. We investigate ecological resilience in a coastal mangrove community from the Galápagos Islands over the last 2700 years using three research questions: What are the 'fast and slow' processes operating in the coastal zone? Is there evidence for a threshold response? How can the past inform us about the resilience of the modern system?Methodology/Principal Findings: Palaeoecological methods (AMS radiocarbon dating, stable carbon isotopes (δ13C)) were used to reconstruct sedimentation rates and ecological change over the past 2,700 years at Diablas lagoon, Isabela, Galápagos. Bulk geochemical analysis was also used to determine local environmental changes, and salinity was reconstructed using a diatom transfer function. Changes in relative sea level (RSL) were estimated using a glacio-isostatic adjustment model. Non-linear behaviour was observed in the Diablas mangrove ecosystem as it responded to increased salinities following exposure to tidal inundations. A negative feedback was observed which enabled the mangrove canopy to accrete vertically, but disturbances may have opened up the canopy and contributed to an erosion of resilience over time. A combination of drier climatic conditions and a slight fall in RSL then resulted in a threshold response, from a mangrove community to a microbial mat.Conclusions/Significance: Palaeoecological records can provide important information on the nature of non-linear behaviour by identifying thresholds within ecological systems, and in outlining responses to 'fast and slow' environmental change between alternative stable states. This study highlights the need to incorporate a long-term ecological perspective when designing strategies for maximizing coastal resilience.</p

    Unofficial policy: access to housing, housing information and social services among homeless drug users in Hartford, Connecticut

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    BACKGROUND: Much research has shown that the homeless have higher rates of substance abuse problems than housed populations and that substance abuse increases individuals' vulnerability to homelessness. However, the effects of housing policies on drug users' access to housing have been understudied to date. This paper will look at the "unofficial" housing policies that affect drug users' access to housing. METHODS: Qualitative interviews were conducted with 65 active users of heroin and cocaine at baseline, 3 and 6 months. Participants were purposively sampled to reflect a variety of housing statuses including homeless on the streets, in shelters, "doubled-up" with family or friends, or permanently housed in subsidized, unsubsidized or supportive housing. Key informant interviews and two focus group interviews were conducted with 15 housing caseworkers. Data were analyzed to explore the processes by which drug users receive information about different housing subsidies and welfare benefits, and their experiences in applying for these. RESULTS: A number of unofficial policy mechanisms limit drug users' access to housing, information and services, including limited outreach to non-shelter using homeless regarding housing programs, service provider priorities, and service provider discretion in processing applications and providing services. CONCLUSION: Unofficial policy, i.e. the mechanisms used by caseworkers to ration scarce housing resources, is as important as official housing policies in limiting drug users' access to housing. Drug users' descriptions of their experiences working with caseworkers to obtain permanent, affordable housing, provide insights as to how access to supportive and subsidized housing can be improved for this population

    Long-term sustainability of a physical activity and nutrition intervention for rural adults with or at risk of metabolic syndrome.

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    OBJECTIVE: To determine longer-term (18-month) sustainability of a six-month physical activity and nutrition intervention for 50-69-year-olds with or at risk of metabolic syndrome residing in a rural Australian community. METHODS: Participants (n=151) were followed-up at 12 and 18 months post-intervention. Changes in nutrition behaviours (fat and fibre barometer); physical activity behaviours (IPAQ); anthropometry (waist-hip ratio, weight, BMI), blood pressure, blood parameters (triglycerides, glucose, LDL-, HDL-, non-HDL, total-cholesterol) were analysed using t-tests and repeated measures ANOVA. RESULTS: Across three time points (6, 12 and 18 months) marginal decrease was observed for waist circumference (p=0.001), a modest increase was observed for diastolic blood pressure (p=0.010) and other outcome measures remained stable. CONCLUSION: Maintenance and ongoing improvement of health behaviours in the longer-term is challenging. Future studies must look for ways to embed interventions into communities so they are sustainable and investigate new approaches to reduce the risk of chronic disease. Implications for public health: Metabolic syndrome is a major health issue in Australia and worldwide. Early identification and management are required to prevent the progression to chronic disease. This 18-month follow-up showed that outcomes measures remained relatively stable; however, there is a need to investigate opportunities for embedded community interventions to support long-term health behaviour change

    Shaping public opinion on the issue of childbirth; a critical analysis of articles published in an Australian newspaper

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    <p>Abstract</p> <p>Background</p> <p>The Australian government has announced a major program of reform with the move to primary maternity care, a program of change that appears to be at odds with current general public perceptions regarding how maternity care is delivered.</p> <p>Methods</p> <p>A critical discourse analysis of articles published in 'The Age', a newspaper with national distribution, subsequent to the release of the discussion paper by the Australian Government in 2008 was undertaken. The purpose was to identify how Australian maternity services are portrayed and what purpose is served by this representation to the general public.</p> <p>Results</p> <p>Findings from this critical discourse analysis revealed that Australian maternity services are being portrayed to the general public as an inflexible outdated service struggling to meets the needs of pregnant women and in desperate need of reform. The style of reporting employed in this newspaper involved presenting to the reader the range of expert opinion relevant to each topic, frequently involving polarised positions of the experts on the issue.</p> <p>Conclusions</p> <p>The general public are presented with a conflict, caught between the need for changes that come with the primary maternity model of care and fear that these change will undermine safe standards. The discourse; 'Australia is one of the safest countries in which to give birth or be born, what is must be best', represents the situation where despite major deficiencies in the system the general public may be too fearful of the consequences to consider a move away from reliance on traditional medical-led maternity care.</p

    Using Cognitive Pre-Testing Methods in the Development of a New Evidenced-Based Pressure Ulcer Risk Assessment Instrument

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    Background: Variation in development methods of Pressure Ulcer Risk Assessment Instruments has led to inconsistent inclusion of risk factors and concerns about content validity. A new evidenced-based Risk Assessment Instrument, the Pressure Ulcer Risk Primary Or Secondary Evaluation Tool - PURPOSE-T was developed as part of a National Institute for Health Research (NIHR) funded Pressure Ulcer Research Programme (PURPOSE: RP-PG-0407-10056). This paper reports the pre-test phase to assess and improve PURPOSE-T acceptability, usability and confirm content validity. Methods: A descriptive study incorporating cognitive pre-testing methods and integration of service user views was undertaken over 3 cycles comprising PURPOSE-T training, a focus group and one-to-one think-aloud interviews. Clinical nurses from 2 acute and 2 community NHS Trusts, were grouped according to job role. Focus group participants used 3 vignettes to complete PURPOSE-T assessments and then participated in the focus group. Think-aloud participants were interviewed during their completion of PURPOSE-T. After each pre-test cycle analysis was undertaken and adjustment/improvements made to PURPOSE-T in an iterative process. This incorporated the use of descriptive statistics for data completeness and decision rule compliance and directed content analysis for interview and focus group data. Data were collected April 2012-June 2012. Results: Thirty-four nurses participated in 3 pre-test cycles. Data from 3 focus groups, 12 think-aloud interviews incorporating 101 PURPOSE-T assessments led to changes to improve instrument content and design, flow and format, decision support and item-specific wording. Acceptability and usability were demonstrated by improved data completion and appropriate risk pathway allocation. The pre-test also confirmed content validity with clinical nurses. Conclusions: The pre-test was an important step in the development of the preliminary PURPOSE-T and the methods used may have wider instrument development application. PURPOSE-T proposes a new approach to pressure ulcer risk assessment, incorporating a screening stage, the inclusion of skin status to distinguish between those who require primary prevention and those who require secondary prevention/treatment and the use of colour to support pathway allocation and decision making. Further clinical evaluation is planned to assess the reliability and validity of PURPOSE-T and it’s impact on care processes and patient outcomes

    "The contribution of chronic diseases to the prevalence of dependence among older people in Latin America, China and India: a 10/66 Dementia Research Group population-based survey"

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    <p>Abstract</p> <p>Background</p> <p>The number of older people is set to increase dramatically worldwide. Demographic changes are likely to result in the rise of age-related chronic diseases which largely contribute to years lived with a disability and future dependence. However dependence is much less studied although intrinsically linked to disability. We investigated the prevalence and correlates of dependence among older people from middle income countries.</p> <p>Methods</p> <p>A one-phase cross-sectional survey was carried out at 11 sites in seven countries (urban sites in Cuba, Venezuela, and Dominican Republic, urban and rural sites in Peru, Mexico, China and India). All those aged 65 years and over living in geographically defined catchment areas were eligible. In all, 15,022 interviews were completed with an informant interview for each participant. The full 10/66 Dementia Research Group survey protocol was applied, including ascertainment of depression, dementia, physical impairments and self-reported diagnoses. Dependence was interviewer-rated based on a key informant's responses to a set of open-ended questions on the participant's needs for care. We estimated the prevalence of dependence and the independent contribution of underlying health conditions. Site-specific prevalence ratios were meta-analysed, and population attributable prevalence fractions (PAPF) calculated.</p> <p>Results</p> <p>The prevalence of dependence increased with age at all sites, with a tendency for the prevalence to be lower in men than in women. Age-standardised prevalence was lower in all sites than in the USA. Other than in rural China, dementia made the largest independent contribution to dependence, with a median PAPF of 34% (range 23%-59%). Other substantial contributors were limb impairment (9%, 1%-46%), stroke (8%, 2%-17%), and depression (8%, 1%-27%).</p> <p>Conclusion</p> <p>The demographic and health transitions will lead to large and rapid increases in the numbers of dependent older people particularly in middle income countries (MIC). The prevention and control of chronic neurological and neuropsychiatric diseases and the development of long-term care policies and plans should be urgent priorities.</p
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