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The article presents a review of research on the relationship between music and emotion, focusing on research approaches and methodology, models of emotion, and types of musical stimuli studied. Topics discussed include discrete and dimensional emotional models, studies based on classical music stimuli, and self-report approaches to the study of emotions. The authors discuss problems with prevalent approaches to music and emotion studies and suggest strategies for future research.

An overview of the computational prediction of emotional responses to music is presented. Communication of emotions by music has received a great deal of attention during the last years and a large number of empirical studies have described the role of individual features (tempo, mode, articulation, timbre) in predicting the emotions suggested or invoked by the music. However, unlike the present work, relatively few studies have attempted to model continua of expressed emotions using a variety of musical features from audio-based representations in a correlation design. The construction of the computational model is divided into four separate phases, with a different focus for evaluation. These phases include the theoretical selection of relevant features, empirical assessment of feature validity, actual feature selection, and overall evaluation of the model. Existing research on music and emotions and extraction of musical features is reviewed in terms of these criteria. Examples drawn from recent studies of emotions within the context of film soundtracks are used to demonstrate each phase in the construction of the model. These models are able to explain the dominant part of the listeners' self-reports of the emotions expressed by music and the models show potential to generalize over different genres within Western music. Possible applications of the computational models of emotions are discussed. [ABSTRACT FROM AUTHOR]

Electronic structures and spectroscopic properties of mixed-ligand cyclometallated iridium complexes with general formula [Ir(NˆC)2(NˆN)]+ (NˆC = 2-phenylpyridine, NˆN = Hcmbpy = 4-carboxyl-4′-methyl-2,2′-bipyridine, 1; H2dcbpy = 4,4′-dicarboxyl-2,2′-bipyridine, 2) were studied theoretically. The geometries of the complexes in ground and excited state were optimized at B3LYP and CIS levels, respectively. The absorption and emission of the complexes in CH3CN solutions were calculated by time-dependent density functional theory (TD-DFT) with the PCM solvent model. The calculated absorptions and emissions of the complexes are in good agreement with the measured results. The deprotonation influence on the electronic structure and the optical properties of 2 was also investigated. The results indicate that the deprotonation which occurs on the COOH groups influences the geometries of the complexes in ground and excited state slightly but leads to significant blue-shifts in low energy absorption and emission maximum. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 [ABSTRACT FROM AUTHOR]

Empirical studies of emotions in music have described therole of individual musical features in recognizing particular emotions. However, no attempts have been made as yet to establish if there is a link between particular emotions and a specific genre. Here this is investigated byanalysing nine separate datasets that represent categories ranging from classical (three sets), and film music (two), to popular music (two), and mixed genre (two). Atotal of 39 musical features were extracted from the audio. Models were then constructed from theseto explain self-reports of valence and arousal, by using multiple andRandom Forest regression. The models were fully validated across the datasets, suggesting low generalizability between the genres for valence (16% variance was accounted for) and moderately good generalizability between the genres for arousal (43%). In contrast, the generalizability within genres was considerably higher (43% and 62% respectively), which suggests that emotions, especially those that express valence, operate differently depending on the musical genre. The most reliable musical features of affects across genres were identified, yielding aranked set of features most likely to operate across the genre. In conclusion, the implications of the findings, and the genre-specificity of emotions in music are discussed. [ABSTRACT FROM PUBLISHER]

The phase transition temperatures (PTTs) of poly(N-isopropylacrylamide) (PNIPAM) decreased with increasing concentration of hydroxypropyl cyclodextrins (HPCDs), possibly due to the ability of the cyclodextrin (CD) cavity to facilitate the hydrophobic interact of PNIPAM chains. The capability to decrease the PTT was in the order of HPγCD > HPβCD > HPαCD. However, the PTTs of hydrophobically modified PNIPAM (HmPNIPAM), poly(N-isopropylacrylamide-co-octadecylacrylate), increased with the concentration of HPCDs in a lower concentration range (0–4.0% or 0–8.0%), but it decreased with the concentration in a higher range (4.0–32.0% or 8.0–32.0%). In the lower HPCD concentration range, the interaction of the CD cavity with ODA residues may be prevailing and it will interfere with the hydrophobic interaction of octadecylacrylate residue, leading to an increase in the PTT. In the higher HPCD concentration range, the interaction of the CD cavity with PNIPAM segments may be dominant and it would promote the hydrophobic interaction of the segments, resulting in a decrease in the PTT. [ABSTRACT FROM AUTHOR]

Blood compatibility is the most important aspect for blood-contacting medical devices including cardiovascular stents. In this study, the surface of nickel-titanium (TiNi) stent was coated with diamond-like carbon (DLC) and then subsequently grafted by using zwitterion (N and SO)-linked poly(ethylene glycol) (PEG). We hypothesize that this coupling of zwitterion and PEG may significantly improve blood compatibility of DLC-coated TiNi stent. The surface modified TiNi stents, including PEG-grafted stent (DLC-PEG) and zwitterionic PEG-grafted one (DLC-PEG-N-S) were the main focus on the tests of surface characteristics and blood compatibility. The zwitterionic PEG derivatives were obtained from a series of chemical reactions at room temperature. The results exhibited that as compared to the DLC-PEG, the hydrophilicity was much better with DLC-PEG-N-S and significantly increased atomic percentage of oxygen and nitrogen proved the entity of zwitterions on the surface of DLC-PEG-N-S. Meanwhile, the adsorption of blood proteins such as, human serum albumin (HSA) and fibrinogen was found considerably down-regulated in DLC-PEG-N-S, due mainly to the protein-repellant effect of PEG and zwitterion. Microscopic observation also revealed that as compared with the other substrates without zwitterion, the degree of platelet adhesion was the lowest with DLC-PEG-N-S. In addition, DLC-PEG-N-S retained an extended blood coagulation time as measured by activated partial thromboplastin time (APTT). The present results suggested that surface grafting of zwitterionic PEG derivatives could substantially enhance the blood compatibility of TiNi-DLC stent. In conclusion, anti-fouling properties of PEG and zwitterions are expected to be very useful in advancing overall stent performance. [ABSTRACT FROM AUTHOR]

The primary aim of the present study was to systematically compare perceived emotions in music using two different theoretical frameworks: the discrete emotion model, and the dimensional model of affect. A secondary aim was to introduce a new, improved set of stimuli for the study of music-mediated emotions. A large pilot study established a set of 110 film music excerpts, half were moderately and highly representative examples of five discrete emotions (anger, fear, sadness, happiness and tenderness), and the other half moderate and high examples of the six extremes of three bipolar dimensions (valence, energy arousal and tension arousal). These excerpts were rated in a listening experiment by 116 non-musicians. All target emotions of highly representative examples in both conceptual sets were discriminated by self-ratings. Linear mapping techniques between the discrete and dimensional models revealed a high correspondence along two central dimensions that can be labelled as valence and arousal, and the three dimensions could be reduced to two without significantly reducing the goodness of fit. The major difference between the discrete and categorical models concerned the poorer resolution of the discrete model in characterizing emotionally ambiguous examples. The study offers systematically structured and rich stimulus material for exploring emotional processing. [ABSTRACT FROM PUBLISHER]

While hemodialysis access ligation has been used to manage pacemaker (PM) and implantable cardioverter-defibrillator (ICD) lead-induced central venous stenosis (CVS), percutaneous transluminal balloon angioplasty (PTA) has also been employed to manage this complication. The advantages of PTA include minimal invasiveness and preservation of arteriovenous access for hemodialysis therapy. In this multi-center study we report the patency rates for PTA to manage lead-induced CVS. Consecutive PM/ICD chronic hemodialysis patients with an arteriovenous access referred for signs and symptoms of CVS due to lead-induced CVS were included in this analysis. PTA was performed using the standard technique. Technical and clinical success was examined. Technical success was defined as the ability to successfully perform the procedure. Clinical success was defined as the ability to achieve amelioration of the signs and symptoms of CVS. Both primary and secondary patency rates were also analyzed. Twenty-eight consecutive patients underwent PTA procedure. Technical success was 95%. Postprocedure clinical success was achieved in 100% of the cases where the procedure was successful. The primary patency rates were 18% and 9% at 6 and 12 months, respectively. The secondary patency rates were 95%, 86%, and 73% at 6, 12, and 24 months, respectively. On average, 2.1 procedures/year were required to maintain secondary patency. There were no procedure-related complications. This study finds PTA to be a viable option in the management of PM/ICD lead-induced CVS. Additional studies with appropriate design and sample size are required to conclusively establish the role of PTA in the management of this problem. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to evaluate the clinical outcome of peripheral stent placement after failed balloon angioplasty in patients with grafts who are on hemodialysis. We examined 30 Wallstents that were placed in 26 patients because balloon angioplasty failed or early restenosis (<3 months) occurred within 3 months. We retrospectively reviewed 267 consecutive balloon angioplasties performed in 71 patients with graft access between August 2000 and March 2007. Stent placements accounted for 30 (11.2%) of the 267 balloon angioplasties. The clinical success rate of stent placement was 93.3% (28 of 30 stent placements). The 3-, 6-, and 12-month primary patency rates were 73.3%, 39.3%, and 17.7%, respectively. The 1-, 2-, and 3-year secondary patency rates were 90.2%, 83.8%, and 83.8%, respectively. Primary patency was significantly prolonged by stent placement after early restenosis compared with previous balloon angioplasty alone (P = 0.0059). Primary patency after stent placement was significantly lower than after successful balloon angioplasty without indications for stent placement (P = 0.0279). Secondary patency rates did not significantly differ between stent placement and balloon angioplasty alone. The mean number of reinterventions required to maintain secondary patency after stent placement was significantly larger than that after balloon angioplasty alone (Mann-Whitney U test, P = 0.0419). We concluded that peripheral stent placement for graft access is effective for salvaging vascular access after failed balloon angioplasty and for prolonging patency in early restenosis after balloon angioplasty. However, reinterventions are required to maintain secondary patency after stent placement. Furthermore, peripheral stent placement for graft access cannot achieve the same primary patency as balloon angioplasty alone. [ABSTRACT FROM AUTHOR]

The purpose of this review is to explore the pathophysiology, epidemiology, and interventional treatment of central vein stenosis (CVS) that may result from central vein catheter (CVC) placement. The precise mechanism of CVC-associated CVS remains largely undefined, though anatomic considerations appear to play a prominent pathologic role. The impact of CVC-associated CVS on arteriovenous fistula outcomes is reviewed. The percutaneous treatment of CVS, observation, angioplasty, or angioplasty with stent placement is reviewed, along with potential surgical treatment options. As the treatment outcomes of CVC-associated CVS have been disappointing, catheter avoidance remains the best strategy. [ABSTRACT FROM AUTHOR]

Proximal or “downhill” esophageal varices are a rare complication of superior vena caval (SVC) obstruction. Few reports describe downhill varices in dialysis patients with catheter-related SVC occlusion. We studied a case of downhill esophageal varices in a dialysis patient from our center and reviewed the published literature on presentation, evaluation and treatment in other dialysis patients (MEDLINE database search). Including our current case, we identified eight reports of dialysis patients with downhill varices. All cases were recognized after presentation with gastrointestinal bleeding, in contrast to low reported bleeding rates of downhill varices in non-dialysis patients. Localized edema and superficial venous engorgement (signs of SVC occlusion) were each observed in four of eight patients. The duration of hemodialysis dependence ranged from 2.5 to 23 years, and dialysis access history included multiple central venous catheters when described (seven cases). Central venous imaging by direct, magnetic resonance or computerized tomographic venography documented SVC stenosis in all cases. Management included percutaneous transluminal angioplasty of the SVC with or without stenting in five of eight patients, three of whom developed restenosis during observation. Successful surgical venous bypass was performed in one patient after failed percutaneous venoplasty. Varices were treated with band ligation in four of eight cases without reported complications. Although rare, downhill esophageal varices should be considered in the differential diagnosis of upper gastrointestinal hemorrhage in dialysis patients exposed to central venous catheters. Diagnosis should prompt radiographic evaluation of SVC patency. Treatment requires timely and coordinated care by specialists in endovascular interventions and gastrointestinal endoscopy. [ABSTRACT FROM AUTHOR]

Central vein stenosis is commonly associated with placement of central venous catheters and devices. Central vein stenosis can jeopardize the future of arteriovenous fistula and arteriovenous graft in the ipsilateral extremity. Occurrence of central vein stenosis in association with indwelling intravascular devices including short-term, small-diameter catheters such as peripherally inserted central catheters, long-term hemodialysis catheters, as well as pacemaker wires, has been recognized for over two decades. Placement of multiple catheters, longer duration, location in subclavian vein, and placement on the left-hand side of neck seem to predispose to the development of central vein stenosis. Endothelial injury with subsequent changes in the vessel wall results in development of microthrombi, smooth muscle proliferation, and central vein stenosis. Central vein stenosis is often asymptomatic in nondialysis patients, but can result in edema of ipsilateral extremity and breast when challenged by increased flow from an arteriovenous fistula or arteriovenous graft. Bilateral central vein stenosis or superior vena cava stenosis can produce a clinical picture of superior vena cava syndrome, associated with engorgement of face and neck. Endovascular interventions are the mainstay of management of central vein stenosis. Percutaneous angioplasty and stent placement for elastic and recurring lesions can restore the functionality of the vascular access, at least temporarily. Frequent or multiple interventions are usually required. In recalcitrant cases, surgical bypass of the obstruction is an option. In resistant cases with severe symptoms, occlusion of the functioning vascular access will usually provide relief of symptoms. Further study of mechanisms of development of central vein stenosis and search for a targeted therapy is likely to lead to better ways of managing central vein stenosis. Prevention of central vein stenosis is the key to avoid access failure and other complications from central vein stenosis and relies upon avoidance of central vein stenosis placement and timely placement of arteriovenous fistula in prospective dialysis patient. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the utility of MR and X-ray imaging for characterizing aortic coarctation and flow, and guiding the endovascular catheter to place a stent to repair the coarctation. Materials and Methods: The descending aorta in eight dogs was looped with elastic band and tightened distal to the subclavian artery. Balanced fast field echo (bFFE) and velocity-encoded cine (VEC) MRI sequences were used for device tracking and measuring aortic flow. A T1-weighted fast-field echo sequence (T1-FFE) was used to visualize the coarctation and roadmap the aorta. Nitinol stents were guided by a nitinol guidewire and placed under MR guidance. Results: Aortic coarctation was visible on MR and X-ray imaging. The procedure success rate was 88%. VEC MRI measured the changes in aortic flow (baseline = 1.3 +/- 0.2, coarctation = 0.2 +/- 0.02, and stent placement = 0.8 +/- 0.1 liters/minute). A significant reduction in iliac blood pressure was measured after coarctation, but it was reversed by stent placement. The stent lumen was visible on X-ray fluoroscopy, but not on MRI. Conclusion: Stent deployment to repair aortic coarctation is feasible under MR guidance. The combined use of MR and X-ray imaging is effective for anatomic and functional evaluation of aortic coarctation dilation, which may be crucial for optimal therapy. [ABSTRACT FROM AUTHOR]

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of pharmacoepidemiology and drug safety. Each bibliography is divided into 20 sections: 1 Books, Reviews & Symposia; 2 General; 3 Anti-infective Agents; 4 Cardiovascular System Agents; 5 CNS Depressive Agents; 6 Non-steroidal Anti-inflammatory Agents; 7 CNS Agents; 8 Anti-neoplastic Agents; 9 Haematological Agents; 10 Neuroregulator-Blocking Agents; 11 Dermatological Agents; 12 Immunosuppressive Agents; 13 Autonomic Agents; 14 Respiratory System Agents; 15 Neuromuscular Agents; 16 Reproductive System Agents; 17 Gastrointestinal System Agents; 18 Anti-inflammatory Agents - Steroidal; 19 Teratogens/fetal exposure; 20 Others. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted. [ABSTRACT FROM AUTHOR]

Nitinol stents are thought to exhibit reduced occurrence of artifacts and may be suitable for magnetic resonance imaging (MRI) evaluation of stent localization and in-stent patency even in coronary-sized stent grafts. A 54-year-old male patient presented with a large coronary post-stenotic aneurysm of the right coronary artery (RCA) beside significant stenoses of the left circumflex coronary artery (LCX) and the left anterior descending coronary artery (LAD) with aneurysm formation. After implantation of stent grafts to the LAD and LCX, two polymermembrane-covered nitinol stent grafts were placed into the RCA. A control MR examination 7 days following the RCA intervention showed successful occlusion of the former aneurysm, no post-interventional endoleak, and bright signal within the stent indicating stent patency. Thus, coronary MRI after nitinol stent implantation in coronary aneurysms is feasible for post-interventional early imaging control at least as far as the exclusion of possible endoleaks is concerned. [ABSTRACT FROM AUTHOR]

Background: Active magnetic resonance imaging implants, for example stents, stent grafts or vena cava filters, are constructed as wireless inductively coupled transmit and receive coils. They are built as a resonator tuned to the Larmor frequency of a magnetic resonance system. The resonator can be added to or incorporated within the implant. This technology can counteract the shielding caused by eddy currents inside the metallic implant structure. This may allow getting diagnostic information of the implant lumen (in stent stenosis or thrombosis for example). The electro magnetic rf-pulses during magnetic resonance imaging induce a current in the circuit path of the resonator. A by material fatigue provoked partial rupture of the circuit path or a broken wire with touching surfaces can set up a relatively high resistance on a very short distance, which may behave as a point-like power source, a hot spot, inside the body part the resonator is implanted to. This local power loss inside a small volume can reach 1/4 of the total power loss of the intact resonating circuit, which itself is proportional to the product of the resonator volume and the quality factor and depends as well from the orientation of the resonator with respect to the main magnetic field and the imaging sequence the resonator is exposed to. Methods: First an analytical solution of a hot spot for thermal equilibrium is described. This analytical solution with a definite hot spot power loss represents the worst case scenario for thermal equilibrium inside a homogeneous medium without cooling effects. Starting with this worst case assumptions additional conditions are considered in a numerical simulation, which are more realistic and may make the results less critical. The analytical solution as well as the numerical simulations use the experimental experience of the maximum hot spot power loss of implanted resonators with a definite volume during magnetic resonance imaging investigations. The finite volume analysis calculates the time developing temperature maps for the model of a broken linear metallic wire embedded in tissue. Half of the total hot spot power loss is assumed to diffuse into both wire parts at the location of a defect. The energy is distributed from there by heat conduction. Additionally the effect of blood perfusion and blood flow is respected in some simulations because the simultaneous appearance of all worst case conditions, especially the absence of blood perfusion and blood flow near the hot spot, is very unlikely for vessel implants. Results: The analytical solution as worst case scenario as well as the finite volume analysis for near worst case situations show not negligible volumes with critical temperature increases for part of the modeled hot spot situations. MR investigations with a high rf-pulse density lasting below a minute can establish volumes of several cubic millimeters with temperature increases high enough to start cell destruction. Longer exposure times can involve volumes larger than 100 mm3. Even temperature increases in the range of thermal ablation are reached for substantial volumes. MR sequence exposure time and hot spot power loss are the primary factors influencing the volume with critical temperature increases. Wire radius, wire material as well as the physiological parameters blood perfusion and blood flow inside larger vessels reduce the volume with critical temperature increases, but do not exclude a volume with critical tissue heating for resonators with a large product of resonator volume and quality factor. Conclusion: The worst case scenario assumes thermal equilibrium for a hot spot embedded in homogeneous tissue without any cooling due to blood perfusion or flow. The finite volume analysis can calculate the results for near and not close to worst case conditions. For both cases a substantial volume can reach a critical temperature increase in a short time.… [ABSTRACT FROM AUTHOR]

Purpose To evaluate the signal characteristics of different iliac artery stents in MR angiography (MRA) at 3 T in comparison with 1.5 T. Materials and Methods Sixteen iliac artery stents were implanted in plastic tubes filled with a solution of Gd-DTPA and imaged at 3 T and 1.5 T using a T1-weighted 3D spoiled gradient-echo sequence. Image analysis included a subjective assessment of artifact characteristics, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) measurements in stented and unstented vessel parts, and quantitative measurements of total artifact size. Results The pattern of stent artifacts inside the stents evidently did not differ at 3 T and 1.5 T. The average total size of the artifact areas surrounding the stents was significantly larger at 3 T ( P < 0.03). However, within the stented part of the vessel phantom, the signal of the lumen and its contrast to modeled surrounding tissue was significantly higher at the higher field. The mean SNR of the lumen increased from 95.5 at 1.5 T to 127.3 at 3 T, and the CNR of the vessel increased from 70.3 to 93. Conclusion Assessment of the stent lumen in iliac artery stents in a phantom model is not compromised by imaging at 3 T compared to 1.5 T. The signal gain inside the stented part of the vessel lumen at higher field compensates for the higher degree of stent artifacts seen in stents made of steel or cobalt. J. Magn. Reson. Imaging 2005. © 2005 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Stents that have been implanted to preserve the results of vascular dilatation are frequently affected by in-stent restenosis, which ideally should be followed up by a noninvasive diagnostic modality. Active MRI stents can enable this kind of follow-up, while normal metallic stents can not. The prototype stents investigated in this study were designed as electric resonating circuits without a direct connection to the MR imager, and function as inductively coupled transmit coils. The model of a long solenoid coil is used to describe the additional power loss caused by such resonators. The theoretically estimated temperature increase is verified by measurements for different resonators and discussed for worst-case conditions. The RF power absorption of an active resonator is negligible compared to the total power absorbed during MRI. The local temperature increase observed for prototypes embedded in phantoms is in a range that excludes direct tissue damage. However, ruptures in the conducting structure of a resonator can cause hot spots, which may establish a high local temperature. This hazard can be reduced by designing resonators with a low quality ( Q) factor or by setting the circuit slightly off resonance; however, this would lower the nominal amplification for which the resonator was designed. Magn Reson Med, 2005. © 2005 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Aims Synchrotron radiation angiography (SRA) is a novel tool for minimally invasive coronary artery imaging. The method uses subtraction of two images produced at energies bracketing the iodine K-edge after intravenous infusion of iodinated contrast agent. We investigated the accuracy of SRA for detecting in-stent restenosis (ISR). [ABSTRACT FROM PUBLISHER]

The endovascular treatment of atherosclerotic intracranial arterial stenoses has previously been based on balloon dilatation or the deployment of a balloon expandable stent. Both methods have advantages (balloon: flexibility; balloon expandable stent: high radial force) and drawbacks (balloon: risk of elastic recoil and dissection; balloon expandable stent: limited flexibility, risk of injury to the vessel due to excessive straightening, overexpansion at ends of stent). A new combination of balloon dilatation, followed by the deployment of a self-expanding microstent has been applied in 15 patients with atherosclerotic arterial stenoses, symptomatic despite medical treatment. An anatomically and clinically adequate result was achieved in all patients. The initial degree of stenosis was 72% (mean). Balloon dilatation resulted in an average residual stenosis of 54% (mean), reduced further to a mean of 38% after stent deployment. Arterial dissection, occlusion of the target artery or symptomatic distal emboli was not encountered. In one patient, a side branch occlusion occurred after dilatation of a M1 stenosis, with complete neurological recovery. All patients were either stable or improved 4 weeks after the treatment. Recurrent TIA did not occur in any patient. Balloon dilatation and subsequent deployment of a self-expandable stent for the treatment of symptomatic intracranial arterial stenoses combines the advantages of both techniques and allows a rapid, clinically effective and technically safe treatment of these frequently challenging lesions. [ABSTRACT FROM AUTHOR]

Editorial. Focuses on the significance of interventional radiology in the conservation of vascular access for hemodialysis. Techniques of the interventional radiology; Effectiveness of interventional radiology in the treatment of stenosis and thrombosis; Surgical techniques for stenosis treatment.

Examines the dilatation and declotting of arteriovenous accesses. Accessibility for hemodialysis; Rates for declotting; Occurrence of stenoses and thrombosis once arteriovenous access is constructed.

Summary Non-tunnelled central venous catheters allow for a quick and effective vascular access for patients in urgent need of renal replacement therapy. The high frequency of early and late complications, however, should be sufficient reason for great care with respect to indication, implantation, and surveillance. Unfortunately it is completely unclear which catheter material and design is best suited for hemodialysis access. It is also uncertain whether impregnation of the catheter with antiseptics or antibiotics might help reduce complication rates. In case of emergency, the femoral vein should be preferred. Whenever possible, the right internal jugular vein should be preserved for early implantation of a tunnelled cuffed catheter which should be considered as soon as it becomes clear that renal replacement therapy will be necessary for more than one or two weeks. In patients in whom it is obvious that they are in terminal renal failure requiring chronic hemodialysis, a peripheral arterio-venous access should be created at the time when a tunnelled catheter is inserted. All other catheter patients need regular re-evaluations of their renal function in order to timely identify those in need of a permanent access. In chronic hemodialysis, "permanent catheter" is a contradiction in terms. Hemodialysis via central venous catheters is less effective and reliable than via arterio-venous access. Catheters reduce the success rates of later arterio-venous access procedures, enhance the risk of infection, and as a result of these complications reduce the patients'' life expectancy. The same has to be suspected for totally implantable port devices as long as prospective studies have not proven any significant advantage over tunnelled cuffed catheters. Zusammenfassung Nicht-tunnelierte großlumige zentrale Venenkatheter stellen einen schnell und effektiv nutzbaren Gefäßzugang für die Hämodialyse und Hämofiltration dar. Die hohe Rate von Früh- und Spätkomplikationen sollte jedoch Grund genug für eine sorfältige Indikationsstellung, Implantationstechnik und Überwachung sein. Leider ist bis heute völlig unklar welches Kathetermaterial und -design das geeignetste ist, und ob eine Beschichtung mit Antiseptika oder Antibiotika das Risiko Katheter-assoziierter Bakteriämien senken hilft. In der Notfallsituation bietet sich die V. femoralis als Punktionsort an. Die rechte V. jugularis interna sollte möglichst für die spätere Platzierung eines tunnelierten Katheters reserviert bleiben, die erfolgen sollte, sobald sich abzeichnet, dass die Nierenersatztherapie voraussichtlich länger als nur ein oder zwei Wochen erforderlich sein wird. Bei offensichtlich terminaler Niereninsuffizienz sollte die Anlage eines peripheren arterio-venösen Zugangs möglichst simultan zur Implantation des tunnelierten Katheters durchgeführt werden. Bei unklarer Prognose des Nierenversagens muss die Nierenfunktion regelmäßig überprüft werden, um im Bedarfsfall möglichst frühzeitig einen permanenten arterio-venösen Dialysezugang zu schaffen. Für die chronische Hämodialyse stellt der Begriff „permanenter Katheter" einen Widerspruch in sich dar. Die Nierenersatztherapie über Katheter ist weniger effektiv und zuverlässig als die über einen arterio-venösen Zugang. Der Einsatz von Kathetern erschwert die spätere Anlage eines Dialyseshunt und bedeutet ein nachweislich erhöhtes Infektionsrisiko für ihre Träger. All dies führt zu einer deutlichen Reduktion der Lebenserwartung. Für Portsysteme konnte diesbezüglich bislang kein Vorteil gegenüber Dialysekathetern gezeigt werden. [ABSTRACT FROM AUTHOR]

Shunt thrombosis is a relatively frequent complication of implant grafts but less common in native fistulas; both may undergo mechanical recanalization without thrombolysis. While in native fistulas, simple balloon angioplasty is a very useful tool for short-segment thrombosis, extensive thrombosis in native veins or grafts requires use of different mechanical devices or aspiration catheters. In venous access thrombosis, thrombolysis or fibrinous sheath stripping are percutaneous options. [ABSTRACT FROM AUTHOR]

Introduction: Peak systolic velocity (PSV) measurements of blood flow inside vascular stents allow reliable detection of in-stent restenosis. The purpose of this in vitro study was to evaluate the feasibility of obtaining PSV measurements inside vascular stents made of Stainless Steel and Nitinol, using a velocity encoded MR technique. Materials/methods: In a flow phantom, stents of Stainless Steel and Nitinol were studied. The phantom was integrated into a closed-tubing circuit driven by a MR dedicated pulsatile flow pump. MR imaging was performed on a 1.5 T system. The PSV in the tube without stent was used as the gold standard to determine the accuracy and the variability (paired t-test and Pittman’s test) of the PSV measurements inside the stents. Results: PSV values inside the stents showed percentual difference in mean of −15 to 21% ( P <0.05) at a pump setting of 10 and 20 ml/s. Conclusion: PSV measurements can be accurately obtained inside stents made of Stainless Steel and Nitinol. MR-velocity measurements may be used in patients to non-invasively evaluate stent patency and in-stent re-stenosis. [ABSTRACT FROM AUTHOR]

Purpose: To review the place of interventional radiology in arteriovenous access for hemodialysis. Methods: Prophylactic dilation of stenoses greater than 50% associated with clinical abnormalities such as flow-rate reduction is warranted to prolong access patency. Stents are placed only in selected cases with clearly insufficient results of dilation but they must never overlap major side veins and obviate future access creation. Thrombosed fistulae and grafts can be declotted by purely mechanical methods or in combination with a lytic drug. Results: The success rates are over 90% for dilation, with frequent resort to stents in central veins. Long-term results in the largest series are better in forearm native fistulae compared with grafts (best 1-year primary patency: 51% versus 40%). The success rates for declotting are better in grafts compared with forearm fistulae but early rethrombosis is frequent in grafts so that primary patency rates can be better for native fistulae from the first month's follow-up (best 1-year primary patency: 49% versus 26%). Conclusion: Radiology achieves results comparable with surgery, with minimal invasiveness and better venous preservation. However, wide variations in the results suggest that the degree of commitment of physicians might be as important as the type of technique used. [ABSTRACT FROM AUTHOR]

Purpose: To present the long-term results in superior caval stenting for symptomatic obstruction. Methods: Forty-nine stents were placed in 30 patients: 16 (53%) with malignant lesions, five (17%) with benign lesions and nine (30%) hemodialysis patients. Self-expandable stents were deployed on a first-line basis. Patients were followed clinically as well as by various imaging techniques and survival analysis was performed. Results: Stent deployment was possible in all cases. Reocclusion was seen in 13 patients, of whom eight belonged to the hemodialysis group. Primary and secondary patency rates for malignant, benign and hemodialysis patients were respectively 74%, 50% and 22%, and 74%, 75% and 56% at 1 year. We had 7% complications and one death from iatrogenic superior vena cava injury. Conclusion: Primary stenting of superior caval obstruction is a first-choice treatment method achieving good mid-term patency. Patients with hemodialysis shunts must be closely monitored for early reintervention. [ABSTRACT FROM AUTHOR]

Background. There are no large series reporting the long‐term results after radiological treatment of both stenosis and thrombosis in native fistulas (AVFs) and prosthetic grafts. [ABSTRACT FROM PUBLISHER]