Binocular rivalry reveals differential face processing in congenital prosopagnosia.

Congenital Prosopagnosia (CP) is an innate impairment in face perception with heterogeneous characteristics. It is still unclear if and to what degree holistic processing of faces is disrupted in CP. Such disruption would be expected to lead to a focus on local features of the face. In this study, we used binocular rivalry (BR) to implicitly measure face perception in conditions that favour holistic or local processing. The underlying assumption is that if stimulus saliency affects the perceptual dominance of a given stimulus in BR, one can deduce how salient a stimulus is for a given group (here: participants with and without CP) based on the measured perceptual dominance. A further open question is whether the deficit in face processing in CP extends to the processing of the facial display of emotions. In experiment 1, we compared predominance of upright and inverted faces displaying different emotions (fearful, happy, neutral) vs. houses between participants with CP (N = 21) and with normal face perception (N = 21). The results suggest that CP observers process emotions in faces automatically but rely more on local features than controls. The inversion of faces, which is supposed to disturb holistic processing, affected controls in a more pronounced way than participants with CP. In experiment 2, we introduced the Thatcher effect in BR by inverting the eye and mouth regions of the presented faces in the hope of further increasing the effect of face inversion. However, our expectations were not borne out by the results. Critically, both experiments showed that inversion effects were more pronounced in controls than in CP, suggesting that holistic face processing is less relevant in CP. We find BR to be a useful implicit test for assessing visual processing specificities in neurological participants.

Long-lasting effects of a gaze-contingent intervention on change detection in healthy participants - Implications for neglect rehabilitation.

Patients with spatial neglect show an ipsilesional exploration bias. We developed a gaze-contingent intervention that aims at reducing this bias and tested its effects on visual exploration in healthy participants: During a visual search, stimuli in one half of the search display are removed when the gaze moves into this half. This leads to a relative increase in the exploration of the other half of the search display - the one that can be explored without impediments. In the first experiment, we tested whether this effect transferred to visual exploration during a change detection task (under change blindness conditions), which was the case. In a second experiment, we modified the intervention (to an intermittent application) but the original version yielded more promising results. Thus, in the third experiment, the original version was used to test the longevity of its effects and whether its repeated application produced even stronger results. To this aim, we compared two groups: the first group received the intervention once, the second group repeatedly on three consecutive days. The change detection task was administered before the intervention and at four points in time after the last intervention (directly afterwards, + 1 hour, + 1 day, and +4 days). The results showed long-lasting effects of the intervention, most pronounced in the second group. Here the intervention changed the bias in the visual exploration pattern significantly until the last follow-up. We conclude that the intervention shows promise for the successful application in neglect patients.

Gaze-contingent stimulus removal leads to subsequent changes in overt attentional allocation.

Spatial neglect is a debilitating neurological disorder marked by reduced exploration of contralesional space. We developed an intervention in which eye movements to and within one half of a search display were reduced over the course of several hundred trials. The aim of this study was to determine whether this intervention had an effect on the deployment of attention of healthy participants as a first step towards application in patients. The participants carried out a visual search task during which the stimuli in one half of the search display were removed whenever the participants made eye movements towards it. The stimuli in the other half were unaffected by eye movements. Indeed, this led to a steady relative decrease in fixations within the affected half over the course of the intervention. In five experiments, the performance in different spatial attention paradigms was measured before and after this intervention. In two visual search paradigms (feature and conjunction search), exploration of the affected half decreased compared to the unaffected half. In a Posner task with exogenous cues, a partial effect of the intervention was found. However, an attempt at replicating this effect was not successful. The fifth experiment showed that performance in a line bisection paradigm was not significantly influenced by the intervention. To conclude, the intervention showed the potential to influence the behavior of healthy participants in overt attentional exploration tasks.

Pulse transit time in pregnancy: a new way to diagnose and classify sleep disordered breathing?

STUDY OBJECTIVES: There are significant discrepancies between the prevalence of snoring and that of objectively defined sleep disordered breathing among pregnant women, suggesting subtle airflow limitations that may not be captured by conventional scoring. This study examined the performance of pulse transit time, an indirect measure of arterial stiffness and sympathetic activation, in pregnancy. METHODS: Pregnant women with obesity and snoring and a group of controls without symptoms of sleep disordered breathing were recruited in the first trimester. Women underwent a level III in-laboratory sleep monitoring study including an electrocardiogram and pulse oximetry, and pulse transit time was measured. Sleep disordered breathing was defined as an apnea-hypopnea index at least five events per hour of sleep. Statistical analysis was performed using Spearman correlation, Fisher's exact t-test, and univariate analysis. RESULTS: Of the 222 women, 38 met criteria for sleep disordered breathing. Pulse transit time drops were very prevalent (95% of participants with snoring had > 5 drops per hour). Median apnea-hypopnea index was 0.7 (interquartile range [IQR]: 2.6) events per hour whereas median pulse transit time drop index was 20.70 (IQR: 35.90) events per hour. Pulse transit time index was significantly higher in snorers with apnea-hypopnea index less than five events per hours and participants with apnea-hypopnea index greater than five events per hour compared to controls. Examination of random epochs with pulse transit time drops showed that 95% of pulse transit time drops were associated with airflow limitation. CONCLUSIONS: Pulse transit time ascertains frequent events of sympathetic activation in at-risk women with and without sleep disordered breathing beyond conventional apneas and hypopneas. Pulse transit time may be an important addition to the identification of clinically significant sleep disordered breathing in pregnant women, and may identify more sleep disordered breathing than apnea-hypopnea index.

Differential modulation of visual object processing in dorsal and ventral stream by stimulus visibility.

As a functional organization principle in cortical visual information processing, the influential 'two visual systems' hypothesis proposes a division of labor between a dorsal "vision-for-action" and a ventral "vision-for-perception" stream. A core assumption of this model is that the two visual streams are differentially involved in visual awareness: ventral stream processing is closely linked to awareness while dorsal stream processing is not. In this functional magnetic resonance imaging (fMRI) study with human observers, we directly probed the stimulus-related information encoded in fMRI response patterns in both visual streams as a function of stimulus visibility. We parametrically modulated the visibility of face and tool stimuli by varying the contrasts of the masks in a continuous flash suppression (CFS) paradigm. We found that visibility - operationalized by objective and subjective measures - decreased proportionally with increasing log CFS mask contrast. Neuronally, this relationship was closely matched by ventral visual areas, showing a linear decrease of stimulus-related information with increasing mask contrast. Stimulus-related information in dorsal areas also showed a dependency on mask contrast, but the decrease rather followed a step function instead of a linear function. Together, our results suggest that both the ventral and the dorsal visual stream are linked to visual awareness, but neural activity in ventral areas more closely reflects graded differences in awareness compared to dorsal areas.

Priming in a shape task but not in a category task under continuous flash suppression.

Continuous flash suppression (CFS) is an interocular suppression technique that uses high-contrast masks flashed to one eye to prevent conscious perception of images shown to the other eye. It has become widely used due to its strength and prolonged duration of suppression and its nearly deterministic control of suppression onset and offset. Recently, it has been proposed that action-relevant visual processing ascribed to the dorsal stream remains functional, while processing in the ventral stream is completely suppressed, when stimuli are invisible under CFS. Here we tested the hypothesis that the potentially dorsal-stream-based analysis of prime-stimulus elongation during CFS affects the categorization of manipulable target objects. In two behavioral experiments, we found evidence for priming in a shape task, but none for priming in a category task, when prime stimuli were rendered invisible using CFS. Our results thus support the notion that the representation of CF-suppressed stimuli is more limited than previously thought.

Weighing the evidence for a dorsal processing bias under continuous flash suppression.

With the introduction of continuous flash suppression (CFS) as a method to render stimuli invisible and study unconscious visual processing, a novel hypothesis has gained popularity. It states that processes typically ascribed to the dorsal visual stream can escape CFS and remain functional, while ventral stream processes are suppressed when stimuli are invisible under CFS. This notion of a CFS-specific "dorsal processing bias" has been argued to be in line with core characteristics of the influential dual-stream hypothesis of visual processing which proposes a dissociation between dorsally mediated vision-for-action and ventrally mediated vision-for-perception. Here, we provide an overview of neuroimaging and behavioral studies that either examine this dorsal processing bias or base their conclusions on it. We show that both evidence for preserved ventral processing as well as lack of dorsal processing can be found in studies using CFS. To reconcile the diverging results, differences in the paradigms and their effects are worthy of future research. We conclude that given the current level of information a dorsal processing bias under CFS cannot be universally assumed.

Investigating category- and shape-selective neural processing in ventral and dorsal visual stream under interocular suppression.

Recent behavioral and neuroimaging studies using continuous flash suppression (CFS) have suggested that action-related processing in the dorsal visual stream might be independent of perceptual awareness, in line with the "vision-for-perception" versus "vision-for-action" distinction of the influential dual-stream theory. It remains controversial if evidence suggesting exclusive dorsal stream processing of tool stimuli under CFS can be explained by their elongated shape alone or by action-relevant category representations in dorsal visual cortex. To approach this question, we investigated category- and shape-selective functional magnetic resonance imaging-blood-oxygen level-dependent responses in both visual streams using images of faces and tools. Multivariate pattern analysis showed enhanced decoding of elongated relative to non-elongated tools, both in the ventral and dorsal visual stream. The second aim of our study was to investigate whether the depth of interocular suppression might differentially affect processing in dorsal and ventral areas. However, parametric modulation of suppression depth by varying the CFS mask contrast did not yield any evidence for differential modulation of category-selective activity. Together, our data provide evidence for shape-selective processing under CFS in both dorsal and ventral stream areas and, therefore, do not support the notion that dorsal "vision-for-action" processing is exclusively preserved under interocular suppression.

Training improves visual processing speed and generalizes to untrained functions.

Studies show that manipulating certain training features in perceptual learning determines the specificity of the improvement. The improvement in abnormal visual processing following training and its generalization to visual acuity, as measured on static clinical charts, can be explained by improved sensitivity or processing speed. Crowding, the inability to recognize objects in a clutter, fundamentally limits conscious visual perception. Although it was largely considered absent in the fovea, earlier studies report foveal crowding upon very brief exposures or following spatial manipulations. Here we used GlassesOff's application for iDevices to train foveal vision of young participants. The training was performed at reading distance based on contrast detection tasks under different spatial and temporal constraints using Gabor patches aimed at testing improvement of processing speed. We found several significant improvements in spatio-temporal visual functions including near and also non-trained far distances. A remarkable transfer to visual acuity measured under crowded conditions resulted in reduced processing time of 81 ms, in order to achieve 6/6 acuity. Despite a subtle change in contrast sensitivity, a robust increase in processing speed was found. Thus, enhanced processing speed may lead to overcoming foveal crowding and might be the enabling factor for generalization to other visual functions.

Avaliação parasitológica em amostras de alfaces (Lactuca sativa var. crispa) comercializadas no Município de Quatá, São Paulo, Brasil / Evaluation parasitological in samples of lettuces (Lactuca sativa var. crispa) marketed from the municipality of Quatá, State of São Paulo, Brazil

Existem poucas pesquisas sobre as práticas de fiscalização sanitária na cadeia de produção de hortaliças até o consumidor, especialmente os que são ingeridos crus, pois são passiveis de veicular microorganismo como bactérias, parasitos e fungos, contribuindo para possíveis malefícios à saúde. O objetivo deste trabalho foi verificar qualitativamente a contaminação por parasitos e/ou comensais de interesse médico em folhas de alface (Lactuca sativa) in natura comercializadas no município de Quatá, São Paulo. Um total de 15 amostras foi analisado aleatoriamente em dias alternados nos três diferentes locais que comercializam hortaliças (quitanda, supermercado e a horta comunitária) durante o mês de maio de 2011. Os parasitos e/ou comensais encontrados nas alfaces foram Entamoeba coli (67%), Entamoeba histolytica (20%), Giardia sp (13%) e Ascaris lumbricoides (7%). A análise mostrou a presença de parasitos e/ou comensais em todas as amostras, exceto nas cultivadas na horta o que evidenciou más condições sanitárias, provavelmente pela contaminação no transporte e manuseio por terceiros no supermercado e na quitanda. O monitoramento parasitário das condições higiênicas de hortaliças comercializadas em ambientes urbanos torna-se relevante para tomada de medidas preventivas evitando a continuidade do ciclo parasitário e possíveis complicações futuras à saúde.

There is little research on the practices of sanitary inspection in the chain of production of vegetables to the consumer, especially those eaten raw, they are liable to serve microorganism such as bacteria, fungi and parasites, contributing to possible health hazards. The aim of this study was to assess qualitatively contamination by parasites and / or commensals of medical interest in lettuce leaves (Lactuca sativa) "fresh" market in the municipality of Quatá, São Paulo. A total of 15 random samples were analyzed every other day of the three different places that sell vegetables a grocery store, a supermarket and a vegetable garden during the month of May 2011. The parasites and / or commensals found in lettuce were Entamoeba coli (67%), Entamoeba histolytica (20%), Giardia sp (13%) and Ascaris lumbricoides (7%). The analysis showed the presence of parasites and / or commensals in all samples, except in the cultivated garden which showed poor sanitary conditions, probably due to contamination in the shipping and handling by third parties in supermarket and grocery store. The parasite monitoring sanitary conditions of vegetables sold in urban environments becomes relevant for preventive measures to avoid the continued parasitic cycle and possible future health complications.

Neural processing of visual information under interocular suppression: a critical review.

When dissimilar stimuli are presented to the two eyes, only one stimulus dominates at a time while the other stimulus is invisible due to interocular suppression. When both stimuli are equally potent in competing for awareness, perception alternates spontaneously between the two stimuli, a phenomenon called binocular rivalry. However, when one stimulus is much stronger, e.g., due to higher contrast, the weaker stimulus can be suppressed for prolonged periods of time. A technique that has recently become very popular for the investigation of unconscious visual processing is continuous flash suppression (CFS): High-contrast dynamic patterns shown to one eye can render a low-contrast stimulus shown to the other eye invisible for up to minutes. Studies using CFS have produced new insights but also controversies regarding the types of visual information that can be processed unconsciously as well as the neural sites and the relevance of such unconscious processing. Here, we review the current state of knowledge in regard to neural processing of interocularly suppressed information. Focusing on recent neuroimaging findings, we discuss whether and to what degree such suppressed visual information is processed at early and more advanced levels of the visual processing hierarchy. We review controversial findings related to the influence of attention on early visual processing under interocular suppression, the putative differential roles of dorsal and ventral areas in unconscious object processing, and evidence suggesting privileged unconscious processing of emotional and other socially relevant information. On a more general note, we discuss methodological and conceptual issues, from practical issues of how unawareness of a stimulus is assessed to the overarching question of what constitutes an adequate operational definition of unawareness. Finally, we propose approaches for future research to resolve current controversies in this exciting research area.

Frontoparietal cortex mediates perceptual transitions in bistable perception.

During bistable vision, perception oscillates between two mutually exclusive percepts despite constant sensory input. Greater BOLD responses in frontoparietal cortex have been shown to be associated with endogenous perceptual transitions compared with "replay" transitions designed to closely match bistability in both perceptual quality and timing. It has remained controversial, however, whether this enhanced activity reflects causal influences of these regions on processing at the sensory level or, alternatively, an effect of stimulus differences that result in, for example, longer durations of perceptual transitions in bistable perception compared with replay conditions. Using a rotating Lissajous figure in an fMRI experiment on 15 human participants, we controlled for potential confounds of differences in transition duration and confirmed previous findings of greater activity in frontoparietal areas for transitions during bistable perception. In addition, we applied dynamic causal modeling to identify the neural model that best explains the observed BOLD signals in terms of effective connectivity. We found that enhanced activity for perceptual transitions is associated with a modulation of top-down connectivity from frontal to visual cortex, thus arguing for a crucial role of frontoparietal cortex in perceptual transitions during bistable perception.

Exploring the ideas and expectations of German medical students towards career choices and the speciality of psychiatry.

The aim of this study was to explore the ideas and expectations of medical students toward their career choices and the speciality of psychiatry. A total of 323 students of the Hannover Medical School filled in a questionnaire about their career choices, preferred medical specialization, factors of influence on career choices and attitude towards psychiatry. The three most important factors of influence appeared to be: (1) work-life balance, (2) flexible working hours, (3) career prospects. Although expectations towards the professional life of psychiatrists were quite positive among the students, there was only a small number of students (n = 53 of 318 respondents, 17%) interested in specializing in psychiatry. Important reasons for choosing psychiatry included personal experience with somatic or mental health issues and practical experience in psychiatry. Most of the students experienced clinical exposure to psychiatry but at a much later period in the curriculum. For a career choice of psychiatry as a speciality it seems to be important to start psychiatric education in medical school early. The positive aspects of the professional life in psychiatry, such as flexible working hours, career prospects and good work-life balance should be more emphasized.

Ocorrência de enteroparasitoses na população de um bairro da cidade de Cândido Mota-SP / Occurrence of enteroparasitoses in the population of a neighbourhood in the city of Cândido Mota-SP

Objetivo - Verificar a incidência de parasitoses intestinais na população de um bairro da cidade de Cândido Mota-SP, e verificar a possibilidade de associação entre a ocorrência de parasitoses e as condições socioeconômicas e sanitárias. As parasitoses intestinais são consideradas um problema de saúde pública, principalmente onde as condições de saneamento básico, higiene pessoal e o nível intelectual do indivíduo são precários, o que pode facilitar a transmissão. Métodos - As coletas foram feitas nas residências e as fezes analisadas pelos métodos de Hoffmann et al. e Faust et al., enquanto que o nível socioeconômico foi investigado através de questionário, respondido pelo responsável pela residência. Resultados - Foram analisadas 177 amostras e 35% encontrados: Ascaris lumbricoides, Giardia lamblia, Entamoeba histolytica, Enterobius vermicularis, Strongyloides stercoralis, Trichuris trichiura, com um caso de biparasitismos (Entamoeba coli com Ancylostomidae) e a faixa etária mais jovem foi a mais acometida. Da população estudada, 69% afirmaram não ter nenhum ou muito pouco conhecimento sobre as enteroparasitoses. Conclusão - A grande maioria da população residente no bairro era de baixa renda, com famílias numerosas vivendo em casas pequenas, demonstrando precariedade de higiene pessoal, ambiental e habitacional e o baixo conhecimento sobre as enteroparasitoses. Assim, é de suma importância a conscientização das populações quanto às principais formas de transmissão e profilaxia das enteroparasitoses, visando diminuir os índices apresentados, dando ênfase a trabalhos nas escolas que estimulem os hábitos de higiene pessoal e do ambiente.

Objective - To verify the incidence of intestinal parasitoses in the population of a neighbourhood in the city of Cândido Mota-SP, and the possibility of association between parasitosis conditions and sanitation and socioeconomic conditions. Intestinal parasitoses are considered a public health problem, especially in areas where basic sanitation conditions, personal hygiene and educational level of the individual are precarious, which may favour transmission. Methods - The collections were made in residences and the faeces were analysed through Hoffmann et al. and Faust et al. methods, and the socioeconomic level was investigated through questionnaires, answered by the person responsible for the household. Results - A total of 177 samples were analysed and 35% of them were positive for one or more types of parasites,and the most commonly found were: Ascaris lumbricoides, Giardia lamblia, Entamoeba histolytica, Enterobius vermicularis, Strongyloides stercoralis, Trichuris trichiura, with one case of biparasitism (Entamoeba coli with Ancylostomidae) and the youngest age range was the most affected. Of the studied population 69% claimed not to have or have very little knowledge of enteroparasitoses. Conclusion - Most of the population living in that neighbourhood consisted of low-income, large families living in small houses, showing precarious personal, environmental and residential hygiene, and little knowledge of enteroparasitoses. Therefore, it is essential to create awareness regarding the mainforms of transmission and prophylaxis of enteroparasitoses, aiming to reduce the present rates, emphasizing school work whicher stimulates environmental and personal hygiene habits.

MR angiography of infrapopliteal arteries in patients with peripheral arterial occlusive disease by using Gadofosveset at 3.0 T: diagnostic accuracy compared with selective DSA.

PURPOSE: To prospectively compare the diagnostic accuracy of steady-state, high-spatial-resolution magnetic resonance (MR) angiography of the lower leg, performed with a blood pool contrast agent, with selective digital subtraction angiography (DSA) as the reference standard in patients with symptomatic peripheral arterial disease. MATERIALS AND METHODS: Local ethics committee approval and written informed consent were obtained. In a nonrandomized trial, selective DSA and MR angiography were performed at 3.0 T with a blood pool contrast agent on 22 calves in 20 patients (mean age, 69.4 years +/- 11.3 [standard deviation]), 16 men (mean age, 67.8 years +/- 12.4) and four women (mean age, 75.6 years +/- 3.6 years), to evaluate 352 arterial segments. DSA and MR angiography were performed within 24 hours of each other and directly compared by three experienced, blinded radiologists by using high-spatial-resolution steady-state MR angiograms. Consensus reading for both DSA and MR angiography served as the reference standard. RESULTS: MR angiography was successful and occurred without serious adverse events in all patients. Seven significantly stenosed and 40 occluded segments were rated equally in both modalities. In three cases, the tibial arteries were shown to be occluded or significantly stenosed at DSA but appeared normal or significantly stenosed at MR angiography. The respective average segment sensitivity, specificity, and accuracy were 98.3% (59 of 60), 98% (113.7 of 116), and 98.1% (172.7 of 176) for DSA and 100% (60 of 60), 100% (116 of 116), and 100% (176 of 176) for MR angiography. Steady-state MR angiography was especially useful for the distal peroneal artery and the proximal anterior tibial artery. CONCLUSION: MR angiography performed with blood pool agents has an accuracy comparable with that of selective DSA in the lower leg but with less risk involved. Steady-state imaging performed with blood pool agents facilitates evaluation of MR angiography of infrapopliteal arteries.

Interventional management of hypervascular osseous metastasis: role of embolotherapy before orthopedic tumor resection and bone stabilization.

OBJECTIVE: The purpose of this study was to evaluate, in relation to intraoperative estimated blood loss (EBL), the effectiveness of preoperative transcatheter arterial embolization of hypervascular osseous metastatic lesions before orthopedic resection and stabilization. MATERIALS AND METHODS: Between June 1987 and November 2007, 22 patients underwent transcatheter arterial embolization of tumors of the long bone, hip, or vertebrae before resection and stabilization. Osseous metastatic lesions from renal cell carcinoma, malignant melanoma, leiomyosarcoma, and prostate cancer were embolized. All patients were treated with a coaxial catheter technique with polyvinyl alcohol (PVA) particles alone or a combination of PVA particles and coils. After embolization, each tumor was angiographically graded according to devascularization (grades 1-3) based on tumor blush after contrast injection into the main tumor-feeding arteries. RESULTS: In patients with complete devascularization (grade 1), mean EBL was calculated to be 1,119 mL, whereas in patients with partial embolization (grades 2 and 3) EBL was 1,788 mL and 2,500 mL. With respect to intraoperative EBL, no significant difference between devascularization grades was found (p > 0.05). Moderate correlation (r = 0.51, p = 0.019) was observed between intraoperative EBL and tumor size before embolization. Only low correlation (r = 0.44, p = 0.046) was found between intraoperative EBL and operating time. Major complications included transient palsy of the sciatic nerve and gluteal abscess in one patient. CONCLUSION: The results of this study support the concept that there is no statistically significant difference among amounts of intraoperative EBL with varying degrees of embolization.

Acute lower gastrointestinal hemorrhage: minimally invasive management with microcatheter embolization.

PURPOSE: To evaluate the efficacy of superselective embolization therapy in the management of acute lower gastrointestinal (LGI) hemorrhage, including any bleeding distal to the ligament of Treitz. MATERIALS AND METHODS: Between June and August 2007, 20 patients with acute LGI bleeding underwent superselective transcatheter arterial embolization (TAE) at the authors' institution. The bleeding had different causes. All patients were treated with use of microcatheters. The following embolic agents were used: microcoils (n = 16), polyvinyl alcohol (PVA) particles (n = 2), and a combination of microcoils and PVA particles (n = 2). Outcome measures included technical success (complete cessation of bleeding as documented at completion angiography), clinical success (resolution of signs or symptoms of LGI bleeding within 30 days after TAE), and the rate of major and minor complications. RESULTS: The identified bleeding sources were as follows: jejunal branch, branch of middle colic artery, branch of ileocolic artery, ileal branch, branch of left colic artery, branch of sigmoid artery, branch of the superior rectal artery, and branch of the middle rectal artery. Technical success with effective control of active bleeding was achieved in all patients (100%). Clinical success attributed to TAE was documented in 18 of the 20 patients (90%). Major complications included death due to pulmonary embolism, heart infarction, and multiorgan failure in the 3rd week after TAE; a procedure-related colonic infarction occurred in one patient. A minor complication occurred in one patient who developed a groin hematoma. CONCLUSIONS: Superselective embolization may be used for effective, minimally invasive control of acute LGI bleeding.

Internal iliac artery embolization before endovascular repair of aortoiliac aneurysms with a nitinol vascular occlusion plug.

PURPOSE: To evaluate the acute and midterm effectiveness of a novel vascular occlusion device for embolization of the internal iliac artery (IIA) before endovascular repair of aortoiliac aneurysms. MATERIALS AND METHODS: Between March 2005 and April 2006, nine men (mean age, 75 years +/- 5; range, 66-83 y) with aortoiliac aneurysms underwent bifurcated endovascular stent-graft procedures. All these patients were referred specifically for embolization. Pre- and perioperatively, eight patients underwent unilateral embolization and one underwent bilateral embolization of the IIA to prevent type II endoleak. Via a contralateral femoral approach with a 6-F or 8-F sheath, the embolization procedure was performed with an Amplatzer Vascular Plug, a self-expandable cylindrical device consisting of a nitinol-based wire mesh. Technical success, clinical outcome, and complications were evaluated. Follow-up at 3, 6, and 12 months was performed with clinical and radiologic examinations. RESULTS: IIA embolization was technically successful in all cases and no procedure-related complications occurred. Imaging at discharge and at 3-, 6-, or 12-month follow-up was accomplished in all nine patients. Control computed tomography and magnetic resonance angiography did not reveal retrograde perfusion of the aneurysmal sac, ie, type II endoleak. Three of nine patients (33.3%) reported symptoms of buttock claudication that did not resolve completely. Clinical symptoms such as bowel ischemia or sexual dysfunction were not observed. CONCLUSIONS: The midterm results of this study suggest that preoperative IIA embolization with a nitinol vascular occlusion plug during endovascular treatment of aortoiliac aneurysms is safe and effective.

Initial clinical experience with the 4-F self-expanding XPERT stent system for infrapopliteal treatment of patients with severe claudication and critical limb ischemia.

PURPOSE: To evaluate the primary success and short-term patency associated with a new 4-F sheath-compatible self-expanding nitinol stent after failed conventional angioplasty of distal popliteal and infrapopliteal lesions in severe lifestyle-limiting claudication (LLC) and chronic critical limb ischemia (CLI). MATERIALS AND METHODS: Between May 2003 and July 2005, 35 patients with Rutherford category 3-5 disease (16 patients with CLI, 19 patients with LLC) underwent percutaneous transluminal angioplasty (PTA) and stent implantation. Indications for stent placement were residual stenosis, flow-limiting dissections, or elastic recoil after PTA. Before and after the intervention and during the 6-month follow-up, clinical investigation, color-flow and duplex Doppler ultrasonography, and digital subtraction angiography were performed. Technical success, primary patency at 6 months, clinical improvement as defined by Rutherford with clinical and hemodynamic measures, and complications were evaluated. RESULTS: A total of 22 patients underwent distal popliteal artery stent placement and 13 underwent tibioperoneal artery stent placement. Stent implantation was successfully performed in all patients. After stent placement, the primary cumulative patency rate for the study group at 6 months was 82%. The mean resting ankle-brachial index at baseline was 0.50 +/- 0.16 and significantly increased to 0.90 +/- 0.17 at 12-24 hours after intervention and 0.82 +/- 0.24 at latest follow-up (P < .001 for both). The sustained clinical improvement rate was 80% at the 6-month follow-up. The 6-month limb salvage rate regarding major amputation was 100%. The rate of major complications was 17%. CONCLUSIONS: Infrapopliteal application of the new nitinol stent is a safe, feasible, and effective method with good short-term patency rate in the treatment of severe LLC and chronic CLI.