Surgical intervention and its role in Takayasu arteritis

Vascular surgery remains an important option in the management of Takayasu arteritis (TA). Its use is predominantly confined to the treatment of symptomatic organ ischaemia or life-threatening aneurysm formation. In most cases, this follows the failure of medical therapy to prevent arterial injury. Open surgery and endovascular approaches are used. The choice between them, at least in part, is determined by the site and nature of the lesion. Open surgery, although more invasive, offers enhanced duration of arterial patency, whereas for endovascular intervention, primary angioplasty without stenting is preferred, with stenting reserved for primary or secondary angioplasty failures. Although there is increasing interest in the role of stent grafts and tailor-made endovascular stents, long-term outcomes remain to be reported. Interventional outcomes are improved and complications reduced by therapeutic control of disease activity before and after surgery. The wider use of combined immunosuppression and the introduction of biologic therapy for refractory TA may reduce future requirements for surgical intervention

Takayasu arteritis: criteria for surgical intervention should not be ignored.

Takayasu aortoarteritis is a rare, chronic granulomatous panarteritis with significant morbidity amongst young patients. Current challenges include a lack of awareness about the condition, delays in diagnosis due to its varied presentation, and suboptimal methods for assessing disease activity. The development of noninvasive imaging including magnetic resonance angiography and positron emission tomography is aiding earlier diagnosis. Early initiation of immunosuppressive treatment is crucial to control active inflammation and minimize arterial injury. Recent studies investigating biological agents such as tumour necrosis factor- α antagonists are encouraging. Surgical revascularization should only be undertaken following careful consideration, as restenosis is common. The indications for considering intervention include uncontrolled hypertension due to renal artery stenosis, severe symptomatic coronary artery or cerebrovascular disease, severe aortic regurgitation, stenotic or occlusive lesions resulting in critical limb ischemia, and aneurysms at risk of rupture. In these cases, the risk benefit ratio for intervention is good. Open surgery, at present, has better outcomes compared to endovascular techniques. However, technological advances in endovascular treatment are continually improving. Controlling disease activity prior to and following revascularization is key to preventing complications. A multidisciplinary approach to the diagnosis and management of Takayasu arteritis is essential to achieve satisfactory patient outcomes

Recent results on magnetic plasma turbulence

Magnetic plasma turbulence is observed over a broad range of scales in the solar wind. We discuss the results of high-resolution numerical simulations of magnetohydrodynamic (MHD) turbulence that models plasma motion at large scales and the results of numerical simulations of kinetic-Alfvén turbulence that models plasma motion at small, sub-proton scales. The simulations, with numerical resolutions up to 20483 mesh points in the MHD case and 5123 points in kinetic-Alfvén case and statistics accumulated over 30 to 150 eddy turnover times, constitute, to the best of our knowledge, the largest statistical sample of steadily driven three dimensional MHD and kinetic-Alfvén turbulence to date.This work was supported by the NSF/DoE partnership grant NSF-ATM-1003451 at the University of New Hampshire, the NSF sponsored Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas at the University of Chicago and the University of Wisconsin - Madison, the US DoE awards DE-FG02- 07ER54932, DE-SC0003888, DE-SC0001794, the NSF grants PHY-0903872 and AGS-1003451, and the DoE INCITE 2010 Award. This research used resources of the Argonne Leadership Computing Facility at Argonne National Laboratory, supported by the DoE Office of Science under contract DE-AC02-06CH11357. The studies were also supported by advanced computing resources provided by the NSF XSEDE allocation TG-PHY110016 at the National Institute for Computational Sciences and the PADS resource (NSF grant OCI-0821678) at the Computation Institute, a joint institute of Argonne National Laboratory and the University of Chicago

Why business angels reject investment opportunities: Is it personal?

A major focus of research on business angels has examined their decision-making processes and investment criteria. As business angels reject most of the opportunities that they receive, this article explores the reasons informing such decisions. In view of angel heterogeneity, investment opportunities might be expected to be rejected for differing reasons. Two sources of data are used to examine this issue. Face-to-face interviews with 30 business angels in Scotland and Northern Ireland provided information on typical ‘deal killers’. This was complemented by an Internet survey of United Kingdom that attracted responses from 238 UK business angels. The findings confirm that the main reason for rejection relates to the entrepreneur/management team. However, angel characteristics do not explain the number of reasons given for opportunity rejection nor do they predict the reasons for rejecting investment opportunities. This could be related to the increasing trend for business angels to join organised groups which, in turn, leads to the development of a shared repertoire of investment approaches. We suggest the concept of ‘communities-of-practice’ as an explanation for this finding

A model of plasma heating by large-scale flow

PublishedIn this work, we study the process of energy dissipation triggered by a slow large-scale motion of a magnetized conducting fluid. Our consideration is motivated by the problem of heating the solar corona, which is believed to be governed by fast reconnection events set off by the slow motion of magnetic field lines anchored in the photospheric plasma. To elucidate the physics governing the disruption of the imposed laminar motion and the energy transfer to small scales, we propose a simplified model where the large-scale motion of magnetic field lines is prescribed not at the footpoints but rather imposed volumetrically. As a result, the problem can be treated numerically with an efficient, highly accurate spectral method, allowing us to use a resolution and statistical ensemble exceeding those of the previous work. We find that, even though the large-scale deformations are slow, they eventually lead to reconnection events that drive a turbulent state at smaller scales. The small-scale turbulence displays many of the universal features of field-guided magnetohydrodynamic turbulence like a well-developed inertial range spectrum. Based on these observations, we construct a phenomenological model that gives the scalings of the amplitude of the fluctuations and the energy-dissipation rate as functions of the input parameters. We find good agreement between the numerical results and the predictions of the model.This research was supported by the NSF Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas at the University of Chicago, by the US DOE award no. DE-SC0003888, by the NASA grant no. NNX11AE12G, and by the National Science Foundation under grant no. NSF PHY11-25915 and no. AGS-1261659. SB and JM appreciate the hospitality and support of the Kavli Institute for Theoretical Physics, University of California, Santa Barbara, where part of this work was conducted. Simulations were performed at the Texas Advanced Computing Center (TACC) at the University of Texas at Austin under the NSF-Teragrid Projects TG-AST140015 & TG-PHY120042 and by the National Institute for Computational Sciences

ANCA in systemic sclerosis, when vasculitis overlaps with vasculopathy: a devastating combination of pathologies

In patients with systemic sclerosis (SSc), the coexistence of ANCA-associated vasculitis (SSc-AAV) has been reported to be associated with a severe disease course, including significant pulmonary and renal involvement. The presence of ANCA is not uncommon in patients with SSc and therefore clinicians must maintain a high index of clinical suspicion about SSc-AAV. p-ANCA and anti-MPO antibodies are the most common antibodies observed. Patients typically present with clinical features of microscopic polyangiitis or renal-limited vasculitis There are multiple areas of potential interaction in the pathogenesis of SSc and AAV which can exacerbate/compound vascular disease. In addition, similar patterns of major internal organ involvement (e.g., lung and kidneys) are seen in both conditions. We highlight a diagnostic approach to SSc-AAV and the paucity of data to inform management. As such, SSc-AAV is typically treated as per isolated AAV which can potentially be hazardous in patients with SSc (e.g., the association between high-dose steroid and scleroderma renal crisis). We propose that this rare clinical entity warrants rigorous investigation including definition of a therapeutic strategy to ameliorate the potentially devastating combination of pathologies in SSc-AAV

The EuroHeart Failure Survey programme—a survey on the quality of care among patients with heart failure in Europe Part 2: treatment

National surveys suggest that treatment of heart failure in daily practice differs from guidelines and is characterized by underuse of recommended medications. Accordingly, the Euro, Heart Failure Survey was conducted to ascertain how patients hospitalized for heart failure are managed in Europe and if national variations occur in the treatment of this condition. Methods The survey screened discharge summaries of 11 304 patients over a 6-week period in 115 hospitals from 24 countries belonging to the ESC to study their medical treatment. Results Diuretics (mainly loop diuretics) were prescribed in 86.9% followed by ACE inhibitors (61.8%), beta-blockers (36.9%), cardiac glycosides (35.7%), nitrates (32.1%), calcium. channel blockers (21.2%) and spironolactone (20.5%). 44.6% of the population used four or more different drugs. Only 17.2% were under the combination of diuretic, ACE inhibitors and beta-blockers. Important local variations were found in the rate of prescription of ACE inhibitors and particularly beta-blockers. Daily dosage of ACE inhibitors and particularly of beta-blockers was on average below the recommended target dose. Modelling-analysis of the prescription of treatments indicated that the aetiology of heart failure, age, co-morbid factors and type of hospital ward influenced the rate of prescription. Age 70 years, in patients with respiratory disease and increased in cardiology wards, in ischaemic heart failure and in mate subjects. Prescription of cardiac glycosides was significantly increased in patients with supraventricular tachycardia/atrial fibrillation. Finally, the rate of prescription of antithrombotic agents was increased in the presence of supraventricular arrhythmia, ischaemic heart disease, mate subjects but was decreased in patients over 70. Conclusion Our results suggest that the prescription of recommended medications including ACE inhibitors and beta-blockers remains limited and that the daily dosage remains tow, particularly for beta-blockers. The survey also identifies several important factors including age, gender, type of hospital ward, co morbid factors which influence the prescription of heart failure medication at discharge

The EuroHeart Failure survey programme—a survey on the quality of care among patients with heart failure in Europe Part 1: patient characteristics and diagnosis

The European Society of Cardiology (ESC) has published guidelines for the investigation of patients with suspected heart failure and, if the diagnosis is proven, their subsequent management. Hospitalisation provides a key point of care at which time diagnosis and treatment may be refined to improve outcome for a group of patients with a high morbidity and mortality. However, little international data exists to describe the features and management of such patients. Accordingly, the EuroHeart Failure survey was conducted to ascertain if appropriate tests were being performed with which to confirm or refute a diagnosis of heart failure and how this influenced subsequent management. Methods The survey screened consecutive deaths and discharges during 2000-2001 predominantly from medical wards over a 6-week period in 115 hospitals from 24 countries belonging to the ESC, to identify patients with known or suspected heart failure. Results A total of 46,788 deaths and discharges were screened from which 11,327 (24%) patients were enrolled with suspected or confirmed heart failure. Forty-seven percent of those enrolled were women. Fifty-one percent of women and 30% of men were aged >75 years. Eighty-three percent of patients had a diagnosis of heart failure made on or prior to the index admission. Heart failure was the principal reason for admission in 40%. The great majority of patients (>90%) had had an ECG, chest X-ray, haemoglobin and electrolytes measured as recommended in ESC guidelines, but only 66% had ever had an echocardiogram. Left ventricular ejection fraction had been measured in 57% of men and 41% of women, usually by echocardiography (84%) and was <40% in 51% of men but only in 28% of women. Forty-five percent of women and 22% of men were reported to have normal left ventricular systolic function by qualitative echocardiographic assessment. A substantial proportion of patients had alternative explanations for heart failure other than left ventricular systolic or diastolic dysfunction, including valve disease. Within 12 weeks of discharge, 24% of patients had been readmitted. A total of 1408 of 10,434 (13.5%) patients died between admission and 12 weeks follow-up. Conclusions Known or suspected heart failure comprises a large proportion of admissions to medical wards and such patients are at high risk of early readmission and death. Many of the basic investigations recommended by the ESC were usually carried out, although it is not clear whether this was by design or part of a general routine for all patients being admitted regardless of diagnosis. The investigation most specific for patients with suspected heart failure (echocardiography) was performed less frequently, suggesting that the diagnosis of heart failure is still relatively neglected. Most men but a minority of women who underwent investigation of cardiac function had evidence of moderate or severe left ventricular dysfunction, the main target of current advances in the treatment of heart failure. Considerable diagnostic uncertainty remains for many patients with suspected heart failure, even after echocardiography, which must be resolved in order to target existing and new therapies and services effectively. (C) 2003 Published by Elsevier Science Ltd on behalf of The European Society of Cardiology