507 research outputs found

    Thermomechanical response of NiTi shape-memory nanoprecipitates in TiV alloys

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    We study the properties of NiTi shape-memory nanoparticles coherently embedded in TiV matrices using three-dimensional atomistic simulations based on the modified embedded-atom method. To this end, we develop and present a suitable NiTiV potential for our simulations. Employing this potential, we identify the conditions under which the martensitic phase transformation of such a nanoparticle is triggered—specifically, how these conditions can be tuned by modifying the size of the particle, the composition of the surrounding matrix, or the temperature and strain state of the system. Using these insights, we establish how the transformation temperature of such particles can be influenced and discuss the practical implications in the context of shape-memory strengthened alloys

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    Clinical characteristics of emergency department heart failure patients initially diagnosed as non-heart failure

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    BACKGROUND: Since previous studies suggest the emergency department (ED) misdiagnosis rate of heart failure is 10–20% we sought to describe the characteristics of ED patients misdiagnosed as non-decompensated heart failure in the ED. METHODS: We analyzed a prospective convenience sample of 439 patients at 4 emergency departments who presented with signs or symptoms of decompensated heart failure. Patients with a cardiology criterion standard diagnosis of decompensated heart failure and an ED diagnosis of decompensated heart failure were compared to patients with a criterion standard of decompensated heart failure but no ED diagnosis of decompensated heart failure. Two senior cardiology fellows retrospectively determined the patient's heart failure status during their acute ED presentation. The Mann-Whitney u-test for two groups, the Kruskall-Wallis test for multiple groups, or Chi-square tests, were used as appropriate. RESULTS: There were 173 (39.4%) patients with a criterion standard diagnosis of decompensated heart failure. Among those with this criterion standard diagnosis of decompensated heart failure, discordant patients without an ED diagnosis of decompensated heart failure (n = 58) were more likely to have a history of COPD (p = 0.017), less likely to have a previous history of heart failure (p = 0.014), and less likely to have an elevated b-type natriuretic peptide (BNP) level (median 518 vs 764 pg/ml; p = 0.038) than those who were given a concordant ED diagnosis of decompensated heart failure. BNP levels were higher in those with a criterion standard diagnosis of decompensated heart failure than in those without a criterion standard diagnosis (median 657 vs 62.7 pg/ml). However, 34.6% of patients with decompensated heart failure had BNP levels in the normal (<100 pg/ml; 6.1%) or indeterminate range (100–500 pg/ml; 28.5%). CONCLUSION: We found the ED diagnoses of decompensated heart failure to be discordant with the criterion standard in 14.3% of patients, the vast majority of which were due to a failure to diagnose heart failure when it was present. Patients with a previous history of COPD, without a previous history of heart failure and with lower BNP levels were more likely to have an ED misdiagnosis of non-decompensated heart failure. Readily available, accurate, objective ED tests are needed to improve the early diagnosis of decompensated heart failure in ED patients

    B-type natriuretic peptide levels predict extent and severity of coronary disease in non-ST elevation coronary syndromes and normal left ventricular systolic function.

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    BACKGROUND: B-type natriuretic peptide (BNP) has been used recently as a biological marker in patients with coronary artery disease (CAD) with ST-elevation, as well as without ST-elevation. BNP is able to predict systolic dysfunction, adding new prognostic information to existing traditional markers. However is not known if there is a relation between the quantity of BNP levels and the severity of coronary artery disease. METHODS: This study compared B-type natriuretic peptide (BNP) levels in patients with stable angina (SA) and acute coronary syndromes (ACS) without ST-elevation in relation to angiographic lesions using TIMI and Gensini Scores. We studied 282 patients with CAD without ST elevation and preserved systolic function. BNP samples were measured in all recruited patients within 24 hours of hospitalization. RESULTS: BNP values were progressively increased in relation to the severity of diagnosis: SA (52.6±49.4 pg/mL ) UA (243.3±212 pg/mL) NSTE-ACS (421.7±334 pg/mL) (p<0.0001 and p<0.007 respectively). No statistically significant difference was observed between patients with SA and controls (21.2±6.8 pg/mL). The analysis of BNP levels in relation to the number of involved vessels demonstrated significantly increased levels in patients with multivessel disease compared to patients with 1 or 2 vessel disease (1-86.2±46.3 pg/mL; 2-127±297 pg/mL; 3-295±318 pg/mL; 4-297±347 pg/mL p<0.001 and p<0.003). Evaluation of BNP using Gensini Score showed a strong relation between BNP and coronary disease extension (r=0.38 p<0.0001).This trend was maintained in all CAD groups (SA=r 0.54; UA r=0.36 NSTE-ACS r=0.28). CONCLUSIONS: Circulating BNP levels appear elevated in ACS with diffuse coronary involvement, even in the absence of systolic dysfunction. BNP is also associated with multi-vessel disease and the extension of coronary disease

    Cardiac magnetic resonance in heart failure with preserved ejection fraction:myocyte, interstitium, microvascular, and metabolic abnormalities

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    Heart failure (HF) with preserved ejection fraction (HFpEF) is a chronic cardiac condition whose prevalence continues to rise, with high social and economic burden, but with no specific approved treatment. Patients diagnosed with HFpEF have a high prevalence of comorbidities and exhibit a high misdiagnosis rate. True HFpEF is likely to have multiple pathophysiological causes - with these causes being clinically ill-defined due to limitations of current measurement techniques. Myocyte, interstitium, microvascular, and metabolic abnormalities have been regarded as key components of the pathophysiology and potential therapeutic targets. Cardiac magnetic resonance (CMR) has the capability to look deeper with a number of tissue characterization techniques which are closer to the underlying specific abnormalities and which could be linked to personalized medicine for HFpEF. This review aims to discuss the potential role of CMR to better define HFpEF phenotypes and to infer measurable therapeutic targets

    Hemodynamic-GUIDEd management of Heart Failure (GUIDE-HF)

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    In that study, incremental reductions in the PA pressures in the monitored arm were associated with both reduction in the frequency of HFH and improvements in health-related quality of life among patients with both preserved (HFpEF) and reduced ejection fraction (HFrEF).3,4 Additionally, hemodynamic-guided HF management in the subset of HFrEF patients treated with guideline-directed medical therapy (GDMT) was associated with a strong trend toward improved survival compared to traditional clinical management.4,7 Consistent benefit is demonstrated in several retrospective studies from the CHAMPION Trial.10-13 as well as extensive analysis of “real-world� experience.6,14 and in Medicare claims data managed in a commercial setting.5,15 Whether the benefits of PA pressure guided therapy can be extended to a broader pool of patients with milder (NYHA class II) or more severe (NYHA class IV) HF or to those without recent hospitalization for HF but with elevation in natriuretic peptide levels remains unclear. Remotely uploaded PA pressure information from the control group will be blocked from investigator review. [...]other than medication changes resulting from information from RHC procedures, control group subjects will not have pressure-based medication changes over time and should be managed instead according to routine practice as informed by published clinical guidelines. Thresholds for NT-proBNP/BNP corrected for BMI using a 4% reduction per BMI unit over 25 kg/m2 Subjects ≥18 y of age able and willing to provide informed consent Chest circumference of 15) at implant RHC, a history of noncompliance, or any condition that would preclude CardioMEMS PA Sensor implantation Table I Inclusion and exclusion criteria PA pressure goals PA diastolic: 8-20 mm Hg PA mean: 10-25 mm Hg PA systolic: 15-35 mm Hg Optimization phas

    Remote monitoring and follow-up of cardiovascular implantable electronic devices in the Netherlands: An expert consensus report of the Netherlands Society of Cardiology

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    Remote monitoring of cardiac implanted electronic devices (CIED: pacemaker, cardiac resynchronisation therapy device and implantable cardioverter defibrillator) has been developed for technical control and follow-up using transtelephonic data transmission. In addition, automatic or patient-triggered alerts are sent to the cardiologist or allied professional who can respond if necessary with various interventions. The advantage of remote monitoring appears obvious in impending CIED failures and suspected symptoms but is less likely in routine follow-up of CIED. For this follow-up the indications, quality of care, cost-effectiveneness and patient satisfaction have to be determined before remote CIED monitoring can be applied in daily practice. Nevertheless remote CIED monitoring is expanding rapidly in the Netherlands without professional agreements about methodology, responsibilities of all the parties involved and that of the device patient, and reimbursement. The purpose of this consensus document on remote CIED monitoring and follow-up is to lay the base for a nationwide, uniform implementation in the Netherlands. This report describes the technical communication, current indications, benefits and limitations of remote CIED monitoring and follow-up, the role of the patient and device manufacturer, and costs and reimbursement. The view of cardiology experts and of other disciplines in conjunction with literature was incorporated in a preliminary series of recommendations. In addition, an overview of the questions related to remote CIED monitoring that need to be answered is given. This consensus document can be used for future guidelines for the Dutch profession

    Use of procalcitonin for the diagnosis of pneumonia in patients presenting with a chief complaint of dyspnoea: results from the BACH (Biomarkers in Acute Heart Failure) trial

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    Biomarkers have proven their ability in the evaluation of cardiopulmonary diseases.We investigated the utility of concentrations of the biomarker procalcitonin (PCT) alone and with clinical variables for the diagnosis of pneumonia in patients presenting to emergency departments (EDs) with a chief complaint of shortness of breath. The BACH trial was a prospective, international, study of 1641 patients presenting to EDs with dyspnoea. Blood samples were analysed for PCT and other biomarkers. Relevant clinical data were also captured. Patient outcomes were assessed at 90 days. The diagnosis of pneumonia was made using strictly validated guidelines. A model using PCT was more accurate [area under the curve (AUC) 72.3%] than any other individual clinical variable for the diagnosis of pneumonia in all patients, in those with obstructive lung disease, and in those with acute heart failure (AHF). Combining physician estimates of the probability of pneumonia with PCT values increased the accuracy to .86% for the diagnosis of pneumonia in all patients. Patients with a diagnosis of AHF and an elevated PCT concentration (.0.21 ng/mL) had a worse outcome if not treated with antibiotics (P ¼ 0.046), while patients with low PCT values (,0.05 ng/mL) had a better outcome if they did not receive antibiotic therapy (P ¼ 0.049). Procalcitonin may aid in the diagnosis of pneumonia, particularly in cases with high diagnostic uncertainty. Importantly, PCT may aid in the decision to administer antibiotic therapy to patients presenting with AHF in which clinical uncertainty exists regarding a superimposed bacterial infection

    Biomarkers Enhance Discrimination and Prognosis of Type 2 Myocardial Infarction

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    Background: The observed incidence of type 2 myocardial infarction (T2MI) is expected to increase with the implementation of increasingly sensitive cardiac troponin (cTn) assays. However, it remains to be determined how to diagnose, risk stratify and treat patients with T2MI. We aimed to discriminate and risk-stratify T2MI using biomarkers. Methods: Patients presenting to the Emergency Department with chest pain, enrolled in the CHOPIN study, were retrospectively analyzed. Two cardiologists adjudicated type 1 MI (T1MI) and T2MI. The prognostic ability of several biomarkers alone or in combination to discriminate T2MI from T1MI was investigated using receiver operating characteristic (ROC) curve analysis. The biomarkers analyzed were cTnI, copeptin, mid-regional pro-atrial natriuretic peptide (MRproANP), C-terminal pro-endothelin-1 (CT-proET1), mid-regional pro-adrenomedullin (MRproADM) and procalcitonin. Prognostic utility of these biomarkers for all-cause mortality and major adverse cardiovascular event (MACE: a composite of acute MI, unstable angina pectoris, reinfarction, heart failure, and stroke) at 180-day follow-up was also investigated. Results: Among the 2071 patients, T1MI and T2MI were adjudicated in 94 and 176 patients, respectively. Patients with T1MI had higher levels of baseline cTnI, while those with T2MI had higher baseline levels of MR-proANP, CT-proET1, MR-proADM, and procalcitonin. The area under the ROC curve (AUC) for the diagnosis of T2MI was higher for CT-proET1, MRproADM and MR-proANP (0.765, 0.750, and 0.733, respectively) than for cTnI (0.631). Combining all biomarkers resulted in a similar accuracy to a model using clinical variables and cTnI (0.854 versus 0.884, p = 0.294). Addition of biomarkers to the clinical model yielded the highest AUC (0.917). Other biomarkers, but not cTnI, were associated with mortality and MACE at 180-day among all patients, with no interaction between the diagnosis of T1MI or T2MI. Conclusions: Assessment of biomarkers reflecting pathophysiologic processes occurring with T2MI might help differentiate it from T1MI. Additionally, all biomarkers measured, except cTnI, were significant predictors of prognosis, regardless of type of MI
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