Atrial fibrillation as a contributing factor in the diagnostic algorithm for coronary subclavian steal syndrome and cardiac tamponade following coronary artery bypass graft surgery: a case study

Coronary subclavian steal syndrome (CSSS) is a complication of coronary artery bypass graft (CABG) surgery in patients with coexistent significant subclavian artery stenosis (SAS). It is characterized by a retrograde blood flow through the left internal mammary artery graft from the coronary to subclavian circulation, leading to myocardial ischemia. Current screening for CSSS includes bilateral blood pressure measurement for the detection of a significant inter-arm blood pressure difference. However, the commonly used automated sphygmomanometers have limited accuracy in patients with atrial fibrillation. Consequently, these patients are often underdiagnosed. We present a case of a 73-year-old man with a medical history of atrial fibrillation, peripheral artery disease, and CABG surgery four months before the current event, who came to the emergency department due to progressive dyspnea. The initial diagnostic management showed a large circulatory pericardial effusion, so the patient was admitted to the coronary care unit and underwent pericardial drainage. In the following days, due to a sudden high increase in cardiac troponin, the patient underwent an urgent coronary angiography, which revealed severe left SAS with functional CABG, indicating the occurrence of CSSS. Percutaneous transluminal angioplasty was then performed with an optimal angiographic result. The patient was discharged in good condition with adequate medicament therapy and instructions. This case report highlights atrial fibrillation as a contributing factor for the diagnosis of CSSS and pericardial tamponade after CABG surgery. Furthermore, we suggest a diagnostic approach that can reduce the incidence of both these severe complications.

Coronary subclavian steal syndrome (CSSS) occurs in the presence of subclavian artery stenosis (SAS) or occlusion and represents a reversal of blood flow in the left internal mammary artery (LIMA) bypass graft, which leads to coronary ischemia. It presents as a complication in 2.5–4.5% of patients undergoing coronary artery bypass graft (CABG) surgery. The prevalence is even higher in patients with peripheral artery disease (PAD), who have a 5-fold increased risk of SAS (1,2). It commonly presents as stable angina triggered by left upper extremity activity, but can also manifest as an acute coronary syndrome, acute heart failure, ventricular arrhythmia, or even sudden cardiac death (3). Digital subtraction angiography, the current gold standard in the imaging of CSSS, has lately been increasingly replaced by other diagnostic tools, such as duplex ultrasound (DUS), computed tomography angiography (CTA), and magnetic resonance angiography. The current guidelines recommend the endovascular approach as the first-line treatment of CSSS and vascular surgery as the second option (4).     

Ferroxidase hephaestin's cell-autonomous role in the retinal pigment epithelium

Hephaestin (Heph) is a ferroxidase protein that converts ferrous to ferric iron to facilitate cellular iron export by ferroportin. Many tissues express either Heph or its homologue, ceruloplasmin (Cp), but the retina expresses both. In mice, a combined systemic mutation of Heph and systemic knockout of Cp (Cp(-/-), Heph(sla/sla)) causes retinal iron accumulation and retinal degeneration, with features of human age-related macular degeneration; however, the role of Heph and Cp in the individual retinal cells is unclear. Herein, we used conditional knockout mice to study Heph's role in retinal pigment epithelial (RPE) and photoreceptor cells. Loss of both Heph and Cp from RPE cells alone results in RPE cell iron accumulation and degeneration. We found, however, that RPE iron accumulation in these conditional knockout mice is not as great as in systemic knockout mice. Photoreceptor-specific Heph knockout indicates that the additional iron in the RPE cells does not result from loss of ferroxidases in the photoreceptors, and Cp and Heph play minor roles in photoreceptors. Instead, loss of ferroxidases in other retinal cells causes retinal iron accumulation and transfer of iron to the RPE cells. Cp and Heph are necessary for iron export from the retina but are not essential for iron import into the retina. Thus, our studies, revise how we think about iron import and export from the retina.     

Magnetic resonance imaging spectrum of medulloblastoma

Introduction  

Two medulloblastoma variants were recently added to the WHO classification of CNS tumours. We retrospectively analysed the imaging findings of 37 classic and 27 cases of variant medulloblastomas to identify imaging characteristics that might suggest a particular MB subtype.     

Wicked spell or magic bullet? A review of the clinical supervision literature 2001-2007

Clinical supervision has become an established part of nursing. Implemented in various different ways it has attracted attention from the research, educator and practice communities. The literature reported and analysed in this paper describes work that may benefit professional practice but there continue to be questions about application and method. Two new messages arise from the literature. The first underscores the responsibility of health care organisations to sustain and develop clinical supervision and the second points to the potential benefit that clinical supervision may have on patient outcomes.