222 research outputs found

    On the motion of a heavy rigid body in an ideal fluid with circulation

    Full text link
    Chaplygin's equations describing the planar motion of a rigid body in an unbounded volume of an ideal fluid involved in a circular flow around the body are considered. Hamiltonian structures, new integrable cases, and partial solutions are revealed, and their stability is examined. The problems of non-integrability of the equations of motion because of a chaotic behavior of the system are discussed.Comment: 25 pages, 4 figure

    Utilizing Risk Scores in Determining the Optimal Revascularization Strategy for Complex Coronary Artery Disease

    Get PDF
    Percutaneous coronary intervention (PCI) of multivessel and/or left main stem disease have been shown to be potentially legitimate revascularization alternatives in appropriately selected patients. Risk stratification is an important component in guiding patients to identify the most appropriate revascularization modality (PCI or coronary artery bypass grafting [CABG]) in conjunction with the Heart Team. The aim of this paper is to give the clinician a concise overview of the important established and evolving contemporary risk models in aiding this decision-making process. Risk models, based on clinical and anatomical variables alone, the novel concept of functional anatomical risk scores, and risk models combining aspects from both clinical and anatomical scores, are all discussed. The emerging concepts of the patient-empowered risk/benefit tradeoff between PCI and CABG to help personalize the choice of revascularization modality are also explored

    Cardiovascular magnetic resonance for the assessment of patients undergoing transcatheter aortic valve implantation: a pilot study

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Before trans-catheter aortic valve implantation (TAVI), assessment of cardiac function and accurate measurement of the aortic root are key to determine the correct size and type of the prosthesis. The aim of this study was to compare cardiovascular magnetic resonance (CMR) and trans-thoracic echocardiography (TTE) for the assessment of aortic valve measurements and left ventricular function in high-risk elderly patients submitted to TAVI.</p> <p>Methods</p> <p>Consecutive patients with severe aortic stenosis and contraindications for surgical aortic valve replacement were screened from April 2009 to January 2011 and imaged with TTE and CMR.</p> <p>Results</p> <p>Patients who underwent both TTE and CMR (n = 49) had a mean age of 80.8 ± 4.8 years and a mean logistic EuroSCORE of 14.9 ± 9.3%. There was a good correlation between TTE and CMR in terms of annulus size (R<sup>2 </sup>= 0.48, p < 0.001), left ventricular outflow tract (LVOT) diameter (R<sup>2 </sup>= 0.62, p < 0.001) and left ventricular ejection fraction (LVEF) (R<sup>2 </sup>= 0.47, p < 0.001) and a moderate correlation in terms of aortic valve area (AVA) (R<sup>2 </sup>= 0.24, p < 0.001). CMR generally tended to report larger values than TTE for all measurements. The Bland-Altman test indicated that the 95% limits of agreement between TTE and CMR ranged from -5.6 mm to + 1.0 mm for annulus size, from -0.45 mm to + 0.25 mm for LVOT, from -0.45 mm<sup>2 </sup>to + 0.25 mm<sup>2 </sup>for AVA and from -29.2% to 13.2% for LVEF.</p> <p>Conclusions</p> <p>In elderly patients candidates to TAVI, CMR represents a viable complement to transthoracic echocardiography.</p

    Validation and reference values of the EORTC QLQ-CML24 questionnaire to assess health-related quality of life in patients with chronic myeloid leukemia

    Get PDF
    Health-related quality of life (HRQOL) assessment is important to facilitate decisions in the current treatment landscape of chronic myeloid leukemia (CML). Therefore, the availability of a validated HRQOL questionnaire, specifically developed for CML patients treated with tyrosine kinase inhibitors (TKIs), may enhance quality of research in this area. We performed an international study including 782 CML patients to assess the validity of the EORTC QLQ-CML 24 questionnaire, and to generate HRQOL reference values to facilitate interpretation of results in future studies. Internal consistency, assessed with Cronbach’s alpha coefficients, ranged from 0.66 to 0.83. In the confirmatory factor analysis, all standardized factor loadings exceeded the threshold of 0.40 (range 0.49–0.97), confirming the hypothesized scale structure. Reference values stratified by age and sex were also generated. Our findings support the use of the EORTC QLQ-CML 24, in conjunction with the EORTC QLQ-C30, as a valuable measure to assess HRQOL in CML patients

    Roadmap consensus on carotid artery plaque imaging and impact on therapy strategies and guidelines: An international, multispecialty, expert review and position statement

    Get PDF
    Current guidelines for primary and secondary prevention of stroke in patients with carotid atherosclerosis are based on the quantification of the degree of stenosis and symptom status. Recent publications have demonstrated that plaque morphology and composition, independent of the degree of stenosis, are important in the risk stratification of carotid atherosclerotic disease. This finding raises the question as to whether current guidelines are adequate or if they should be updated with new evidence, including imaging for plaque phenotyping, risk stratification, and clinical decision-making in addition to the degree of stenosis. To further this discussion, this roadmap consensus article defines the limits of luminal imaging and highlights the current evidence supporting the role of plaque imaging. Furthermore, we identify gaps in current knowledge and suggest steps to generate high-quality evidence, to add relevant information to guidelines currently based on the quantification of stenosis

    Physicians’ Perceptions of Clinical Utility of a Digital Health Tool for Electronic Patient-Reported Outcome Monitoring in Real-Life Hematology Practice. Evidence From the GIMEMA-ALLIANCE Platform

    Get PDF
    Digital health tools are increasingly being used in cancer care and may include electronic patient-reported outcome (ePRO) monitoring systems. We examined physicians’ perceptions of usability and clinical utility of a digital health tool (GIMEMA-ALLIANCE platform) for ePRO monitoring in the real-life practice of patients with hematologic malignancies. This tool allows for the collection and assessment of ePROs with real-time graphical presentation of results to medical staff. Based on a predefined algorithm, automated alerts are sent to medical staff. Participating hematologists completed an online survey on their experience with the platform. Of the 201 patients invited to participate between December 2020 and June 2021 (cut-off date for current analysis), 180 (90%) agreed to enter the platform and had a median age of 57 years. Twenty-three hematologists with a median age of 42 years and an average of 17 years of experience in clinical practice were surveyed. All hematologists agreed or strongly agreed that the platform was easy to use, and 87%, agreed or strongly agreed that ePROs data were useful to enhance communication with their patients. The majority of physicians (78%) accessed the platform at least once per month to consult the symptom and health status profile of their patients. The frequency of access was independent of physician sex (p=0.393) and years of experience in clinical practice (p=0.404). In conclusion, our preliminary results support the clinical utility, from the perspective of the treating hematologist, of integrating ePROs into the routine cancer care of patients with hematologic malignancies

    Modelling chemistry and biology after implantation of a drug-eluting stent. Part I: Drug transport

    Get PDF
    Drug-eluting stents have been used widely to prevent restenosis of arteries following percutaneous balloon angioplasty. Mathematical modelling plays an important role in optimising the design of these stents to maximise their efficiency. When designing a drug-eluting stent system, we expect to have a sufficient amount of drug being released into the artery wall for a sufficient period to prevent restenosis. In this paper, a simple model is considered to provide an elementary description of drug release into artery tissue from an implanted stent. From the model, we identified a parameter regime to optimise the system when preparing the polymer coating. The model provides some useful order of magnitude estimates for the key quantities of interest. From the model, we can identify the time scales over which the drug traverses the artery wall and empties from the polymer coating, as well as obtain approximate formulae for the total amount of drug in the artery tissue and the fraction of drug that has released from the polymer. The model was evaluated by comparing to in-vivo experimental data and good agreement was found

    Revascularization for Unprotected Left Main Coronary Artery Disease: An Evolution in Clinical Decision Making

    Get PDF
    Coronary artery bypass grafting (CABG) has been considered the standard therapy for unprotected (nonrevascularized) left main coronary disease (ULM). However, increasing experience with ULM percutaneous coronary intervention (PCI) has resulted in high procedural success and favorable early and late clinical outcomes. In particular, reduction in clinical restenosis with drug-eluting stents, evolution of procedural technique, and demonstration of favorable outcomes from comparative trials with CABG have promoted consideration of PCI as an alternative revascularization strategy in selected patients with ULM disease. This review summarizes the results from comparative studies examining PCI versus CABG for ULM disease, discusses changing indications for ULM PCI and identifies outstanding issues that must be considered before further advancing treatment recommendations

    Observational study of chronic myeloid leukemia italian patients who discontinued tyrosine kinase inhibitors in clinical practice

    Get PDF
    It is judged safe to discontinue treatment with tyrosine kinase inhibitors (TKI) for chronic myeloid leukemia (CML) in experimental trials on treatment-free remission (TFR). We collected a total of 293 Italian patients with chronic phase CML who discontinued TKI in deep molecular response. Seventy-two percent of patients were on treatment with imatinib, and 28% with second generation TKI at the time of discontinuation. Median duration of treatment with the last TKI was 77 months [Interquartile Range (IQR) 54;111], median duration of deep molecular response was 46 months (IQR 31;74). Duration of treatment with TKI and duration of deep molecular response were shorter with second generation TKI than with imatinib (P&lt;0.001). Eighty-eight percent of patients discontinued as per clinical practice, and reasons for stopping treatment were: toxicity (20%), pregnancy (6%), and shared decision between treating physician and patient (62%). After a median follow up of 34 months (range, 12-161) overall estimated TFR was 62% (95%CI: 56;68). At 12 months, TFR was 68% (95%CI: 62;74) for imatinib, 73% (95%CI: 64;83) for second generation TKI. Overall median time to restart treatment was six months (IQR 4;11). No progressions occurred. Although our study has the limitation of a retrospective study, our experience within the Italian population confirms that discontinuation of imatinib and second generation TKI is feasible and safe in clinical practice
    corecore