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Background/objective: The scale for the assessment and rating of ataxia (SARA) is a feasible assessment for the classification and evaluation of therapeutic interventions. In order to provide access to the SARA in German, the aim of this work was to translate the SARA into German and to adapt it according to international guidelines for German-speaking countries., Method: The process involved six steps. The comprehensibility of the scale was assessed using interviews with potential users., Results: A total of nine physiotherapists and six physicians working in various clinical settings were interviewed, seven of them worked in Germany and four each in Austria and Switzerland. The interviews led to a refined version of the translation. The comprehensibility testing revealed no country-specific differences., Conclusion: A German version of the SARA authorized by the co-author of the original publication, is now available. The results provide methodological insights into the translation process of observation-based standardized assessments., (© 2023. The Author(s).)

Aims: Prior studies demonstrated an association between hospital admission blood glucose and mortality in acute myocardial infarction (AMI). Because stress hyperglycemia ratio (SHR) has been suggested as a more reliable marker of stress hyperglycemia this study investigated to what extent SHR in comparison with admission blood glucose is associated with short- and long-term mortality in diabetic and non-diabetic AMI patients., Methods: The analysis was based on 2,311 AMI patients aged 25-84 years from the population-based Myocardial Infarction Registry Augsburg (median follow-up time 6.5 years [IQR: 4.9-8.1]). The SHR was calculated as admission glucose (mg/dl)/(28.7 × HbA1c (%)-46.7). Using logistic and COX regression analyses the associations between SHR and admission glucose and mortality were investigated., Result: Higher admission glucose and higher SHR were significantly and nonlinearly associated with higher 28-day mortality in AMI patients with and without diabetes. In patients without diabetes, the AUC for SHR was significantly lower than for admission glucose (SHR: 0.6912 [95%CI 0.6317-0.7496], admission glucose: 0.716 [95%CI 0.6572-0.7736], p-value: 0.0351). In patients with diabetes the AUCs were similar for SHR and admission glucose. Increasing admission glucose and SHR were significantly nonlinearly associated with higher 5-year all-cause mortality in AMI patients with diabetes but not in non-diabetic patients. AUC values indicated a comparable prediction of 5-year mortality for both measures in diabetic and non-diabetic patients., Conclusions: Stress hyperglycemia in AMI patients plays a significant role mainly with regard to short-term prognosis, but barely so for long-term prognosis, underlining the assumption that it is a transient dynamic disorder that occurs to varying degrees during the acute event, thereby affecting prognosis., (© 2022. The Author(s).)

An in-vitro study was conducted to investigate the general feasibility of using only one pumping chamber of the SynCardia total artificial heart (TAH) as a replacement of the single ventricle palliated by Fontan circulation. A mock circulation loop was used to mimic a Fontan circulation. The combination of both ventricle sizes (50 and 70 cc) and driver (Freedom Driver and Companion C2 Driver) was investigated. Two clinical relevant scenarios (early Fontan; late Fontan) as derived from literature data were set up in the mock loop. The impact of increased transpulmonary pressure gradient, low atrial pressure, and raised central venous pressure on cardiac output was studied. From a hemodynamic point, the single-chambered TAH performed sufficiently in the setting of the Fontan circulation. Increased transpulmonary pressure gradient, from ideal to pulmonary hypertension, decreased the blood flow in combinations by almost 2 L/min. In the early Fontan scenario, a cardiac output of 3-3.5 L/min was achieved using the 50 cc ventricle, driven by the Companion C2 Driver. Even under pulmonary hypertension, cardiac outputs greater than 4 L/min could be obtained with the 70 cc pump chamber in the late Fontan scenario. In the clinically relevant Fontan scenarios, implementation of the single chambered TAH performed successfully from a hemodynamic point of view. The replacement of the failing univentricular heart by a single chamber of the SynCardia TAH may provide an alternative to a complex biventricular repair procedure or ventricular support in Fontan patients., (© 2021. The Author(s).)

Purpose: The presented in-vitro study provides a comparison of various catheters for mechanical treatment of large-burden pulmonary embolism (PE) under standardized conditions, using a new test rig. Dedicated aspiration catheters (JETi®, Penumbra Indigo®, Aspirex®) were compared with standard catheters (Pigtail, Multi-Purpose, Balloon Catheter) applied for embolus fragmentation., Materials and Methods: Emboli prepared from porcine blood were washed into the test rig which consists of anatomical models of the pulmonary artery (PA) and of the right heart in combination with a pulsatile drive system. For all catheters, the duration of the recanalization procedure and the weight percentage (wt%) of the remaining, removed and washed-down clot fractions were evaluated. For aspiration catheters, the aspirated volume was measured., Results: All catheters achieved full or partial recanalization. The aspiration catheters showed a significantly (p < 0.05) lower procedure time (3:15 min ± 4:26 min) than the standard fragmentation catheters (7:19 min ± 4:40 min). The amount of thrombus removed by aspiration was significantly (p < 0.001) higher than that by fragmentation, averaging 86.1 wt% ± 15.6 wt% and 31.7 wt% ± 3.8 wt%, respectively. Nonetheless, most of the residue was fragmented into pieces of ≥ 1 mm and washed down. Only in 2 of 36 tests, a residual thrombus of 11.9 wt% ± 5.1 wt% remained in the central PA., Conclusion: Comparison under standardized in-vitro patho-physiological conditions showed that embolus fragmentation with standard catheters is clearly inferior to aspiration with dedicated catheters in the treatment of large-burden PE, but can still achieve considerable success., Level of Evidence: No level of evidence, experimental study., (© 2021. The Author(s).)

Background: In addition to learning theoretical knowledge, the medical specialist training in surgery necessitates the acquisition of practical surgical competences. Simulation-based teaching concepts represent an alternative to education and advanced training on patients. The aim of this study was to analyze the distribution and implementation of surgical simulators in German hospitals., Methods: The data analysis was carried out based on an individual on-line questionnaire with a total of 19 standardized questions. This was sent to the senior surgeons in hospitals and clinics via the email distributors of specialist societies for surgery in Germany., Results: A total of 267 complete datasets were analyzed (response rate 12%). Of the participants 84% reported that they were active in a teaching hospital. At the time of the investigation 143 surgical simulators were in use at 35% of the hospitals and clinics included in the evaluation. There were clear regional differences between the individual federal states. Of the participants, 21.1% did not have a simulator at the hospital but the acquisition of one was planned. Simulation training was most frequently used by students (41.1%) and physicians during further education (32.5%). Simulators were not integrated into advanced surgical training in 81.8%. Of the participating hospitals, 94% showed an interest in integration into surgical specialist training in the future., Conclusion: The results of this survey confirmed the special importance of simulation-based training for surgical education in German hospitals; however, at the same time there were clear deficits in information concerning user behavior and a deficiency in the perceived integration of simulation training in advanced training for surgery., (© 2021. The Author(s).)

Background: The MTL30 (mortality, transfer, length of stay) was proposed as a surrogate parameter for evaluating the quality of large and potentially complication-prone visceral surgical interventions., Objective: The aim of this study was to find out to what extent the MTL30 can be correlated with the results of the abdominal aortic aneurysm (AAA) registry of the German Institute for Vascular Health Research (DIGG) of the German Society for Vascular Surgery and Vascular Medicine (DGG) and with the case volume of the participating hospitals., Material and Methods: Elective endovascular abdominal aortic aneurysm repair (EVAR) was performed in 14,282 patients and open repair (OAR) in 3923 patients. Case volume of the treating hospitals, hospital mortality, length of stay and transfer to another acute care hospital were determined 30 days after the index intervention., Results: The hospital mortality was 1.3% for EVAR and 4.9% for OAR (p = 0.000), the MTL30 was 5.0% and 14.4%, respectively (p = 0.000). For EVAR, no relationship between case volume and hospital mortality (quintile 1: 1.0%; quintile 5: 1.3%) as well as case volume and MTL30 (quintile 1: 5.3%; quintile 5: 5.3%) could be demonstrated. Also in OAR there was no significant relationship between case volume and hospital mortality (quintile 1: 5.8%, quintile 5: 3.5%; p = 0.505) and case volume and MTL30 (quintile 1: 16.4%, quintile 5: 12.2%, p = 0.110). With a hospital mortality rate of 7.2% (5-10%) the MTL30 for OAR was 17.6%. In both EVAR and OAR, the length of stay correlated significantly with hospital mortality and MTL30., Discussion: A clear relationship between hospital case volume and hospital mortality could not be shown in the AAA registry of the DIGG. The same was true for the MTL30. It remains to be seen whether the MTL30 offers an additional benefit compared to the recording of hospital mortality and inpatient length of stay as a quality parameter., (© 2020. The Author(s).)

Purpose: Monoamniotic twin pregnancies are at high risk of perinatal complications and fetal loss. The objective of this study is to describe the management and outcomes of monoamniotic twin pregnancies in a French university obstetrics department., Methods: Retrospective review of all consecutive monoamniotic twin pregnancies managed between 1992 and 2018 in a level-3 university hospital maternity unit. Antenatal variables, gestational age and other neonatal characteristics at delivery, mode of delivery, and its reason were recorded, together with outcomes, including a composite adverse neonatal outcome., Results: Overall, 46 monoamniotic twin pregnancies (92 fetuses) were identified during the study period. Among them, 27 fetal losses and 2 early neonatal deaths were reported. Congenital abnormalities accounted for 33.3% of the 27 fetal losses, and unexpected fetal deaths for 29.6%. Among the 37 women who gave birth to 65 live infants at 23 or more weeks of gestation, 17 had cesarean and 19 vaginal deliveries. Overall and composite adverse neonatal outcomes did not differ significantly for the 33 children born vaginally and the 31 by cesarean deliveries. The prospective risk of intrauterine death in all 92 fetuses reached its nadir of 1.8% at 33 6/7  weeks., Conclusion: This series confirms the still high risk of fetal and neonatal death of these twins and shows that congenital abnormalities but also unexpected fetal deaths account for the majority of pre- and postnatal mortality. Our data suggest that vaginal delivery of monoamniotic twins is safe and that delivery for uncomplicated monoamniotic twins should be considered around 33 weeks of gestation, but not later than 35 weeks.

Objective: The purpose of this review is to comment on the association between hospital nursing personnel staffing and patient outcomes, including the avoidance of errors and complications., Methods: A literature search was carried out in the Medline database on publications from the last 10 years on nursing personnel staffing., Results: Only overviews and observational studies on the topic were available and no controlled or prospective surveys. Most investigators assumed that there was an inverse relationship between low nursing staff levels of hospital wards and intensive care and adverse outcomes, including higher mortality rates; however, there is no clear significance for this assumption and evidence-based definitive lower limits for nursing staff cannot be given due to a lack of randomized trials. The causes for unfavorable results in the case of inadequate nursing personnel staffing include hygiene deficiencies, orders not followed and unfulfilled nursing and monitoring measures. Furthermore, staff overload leads to staff dissatisfaction and burnout, which also has a negative impact on the results. Most studies required a maximum patient to nurse ratio of 2:1 for the intensive care unit and an average ratio of not more than 8:1 for surgical wards. With respect to these requirements, changing personnel needs must be considered depending on the current state of the patients being cared for, which enabled all investigators to require a flexible roster design; approval for fixed statutory lower limits for nursing staff was low. The level of education of the nursing staff also played an essential role as qualified nursing staff cannot be replaced at will by less qualified assistant staff., Conclusion: The level of training and the number of the nursing personnel influence hospital mortality and adverse outcomes; however, there are no evidence-based lower levels for nursing staff for inpatient care and perhaps this cannot be the case due to the changing complexity of the patients admitted, the comorbidities and possible treatment complications. There is a considerable need for research.

Purpose: WHO sets 24 months as the ideal minimum interpregnancy interval (IPI) to minimize maternal and perinatal adverse outcomes. Some studies suggest that an interval longer than 59 months may affect these outcomes, but little is known about its influence on labor. The primary objective of this study was to compare the cesarean delivery rate between primiparous women with a long IPI and, on the one hand, primiparous women with an ideal minimum IPI of 18-24 months and, on the other hand, with nulliparous women., Methods: This retrospective cohort study of 17 years included nulliparas and primiparas who gave birth to live singleton fetuses in cephalic presentation after 22 weeks of gestation. Women with an IPI < 18 months or from 24 to 59 months were excluded, as were women with planned cesarean. We analyzed three groups: primiparous women with a long IPI defined as > 59 months, primiparous women with an ideal minimum IPI (18-24 months), and nulliparous women., Results: The study included 18,503 women: 1342 women in the "long IPI" group, 1388 in the "ideal minimum IPI" group, and 15,773 in the nulliparous women group. The cesarean delivery rate was significantly higher in the long compared to the ideal minimum IPI group [12.2% vs. 6.3%, respectively; aOR = 2.2 (95% CI 1.6-3.1)], but both groups had similar durations of labor, regardless of mode of delivery. Women in the long IPI group had significantly lower cesarean rates than nulliparous women [12.2% and 14.3%, respectively; aOR = 0.5 (95% CI 0.4-0.7)], and the nulliparous women had a significantly longer mean duration of labor., Conclusions: Primiparas with a long IPI, compared with ideal minimal IPI have a higher risk of cesarean delivery during labor. Compared with nulliparous women, primiparous women with a long IPI had a lower cesarean rate.

Objective: The aim of the study was to develop a specific risk score for the aortic register of the German Institute for Vascular Health Care Research (DIGG) of the German Society for Vascular Surgery and Vascular Medicine (DGG) for the prediction of postoperative mortality in elective treatment of intact abdominal aortic aneurysms (iAAA). The score should also enable a risk-adjusted presentation of the register results in the near future., Methods: The method of binary logistic regression analysis was used to calculate the model. The data from 10,404 patients were included in the analysis, of whom 7870 (75.6%) were treated by endovascular (EVAR) and 2534 (24.4%) by open (OR) aortic repair. It was examined which factors have an independent influence on hospital mortality and the effect size was determined as a score., Results: For EVAR, the influencing factors with their effect sizes (score in brackets) were: age >85 years (2), female gender (2), juxtarenal AAA (5), maximum diameter >65 mm (2), diabetes mellitus (2), American Society of Anesthesiologists (ASA) score >3 (2), cardiac comorbidities (3) and renal insufficiency stage >3 (5). For OR the factors were: age >80 years (2), female gender (2), juxtarenal AAA (2), ASA score >3 (3), previous myocardial infarction (2), renal comorbidities (3) and previous stroke (2). The estimated hospital mortality was calculated for the individual case from the sum of the risk factors (scores). The accuracy of the model (correlation between observed and expected results) was determined using the receiver operating characteristic (ROC) curve. An area under the curve (AUC) of 0.817 (confidence interval 0.789-0.844) demonstrated an excellent discrimination. In a validation group of 3831 patients, the good agreement between observed and calculated results was confirmed., Conclusion: The DIGG risk score can predict risk-adjusted hospital mortality after EVAR and OR of iAAA in the DIGG register. Improvements with respect to the prediction are desirable for OR and should be strived for by extending the model in the future.

Background: Carbon dioxide (CO 2 ) is a very good and validated alternative to iodine-containing contrast media in diagnostic and interventional angiography. Nevertheless, its routinely use is still limited to specialized centers., Objective: The presentation of the current role and limitations of CO 2 in diagnostic and interventional angiography (venous and arterial)., Material and Methods: A comprehensive review of the literature regarding CO 2 angiography (physical features, indications, contraindications, applications) was carried out., Results: The results show that CO 2 can be used as a reliable alternative for diagnostic angiography and to support interventions in many arterial and venous vascular territories. An exception is the intra-arterial use of CO 2 above the diaphragm due to the risk of severe myocardial and cerebral complications, which represents the most important contraindication. Moreover, due to its very low viscosity, CO 2 is more effective than iodine-containing contrast media in detecting bleeding arising from small vessels., Conclusion: The CO 2 angiography is a safe and effective technique and can be used as valid alternative. In several clinical cases it even offers some advantages compared to iodine-containing contrast media.

The answer to the question of whether endovascular techniques extend the barriers to treatment in multimorbid vascular patients depends on the localization of the vascular disease and its stage. In multimorbid vascular patients with limited life expectancy and asymptomatic carotid stenosis, neither an endovascular nor an open procedure is indicated but a conservative best medicinal treatment is to be preferred. In symptomatic carotid stenosis the endovascular procedure is indicated for special anatomical conditions, such as contralateral carotid artery occlusion, contralateral recurrent nerve palsy, recurrent stenosis following endarterectomy, radical neck dissection and radiotherapy in the cervical region. In the treatment of intact abdominal aortic aneurysms (AAA), endovascular procedures reduce the perioperative risk especially in older patients, allowing the indications for intervention in this group of patients to be expanded, provided that the life expectancy of such treated patients is still several years. There is no clear evidence as to whether endovascular repair should be preferred in ruptured AAAs but there are indications that with the establishment of EVAR the proportion of patients receiving treatment has increased in those patients who were previously denied surgery after arrival in hospital. In critical limb ischemia the propagation of endovascular techniques has not so much extended the indications for invasive therapy but instead the endovascular approach has superseded open bypass surgery, which is positively reflected in a lower perioperative morbidity, especially in older frail patients.

Purpose: Assess electromagnetically guided in situ fenestration of juxtarenal aortic stent grafts in an in vivo model., Methods: Using a newly developed electromagnetic guidance system together with a modified, electromagnetically guidable catheter with steerable tip, an electromagnetically trackable guidewire and a custom in situ fenestrateable stent graft, a series of seven animal experiments was performed. In a swine model, stent grafts were placed juxtarenally, covering the renal arteries. Subsequently, the perfusion of the renal arteries was restored using electromagnetically guided in situ fenestration of the graft at the renal ostia followed by covered stent placement. Intervention times and technical success were assessed., Results: The individual components were successfully combined for the animal experiments. Thirteen of fourteen fenestration experiments in seven animals were successful in restoring perfusion through in situ fenestration. Fenestration (catheter introduction-guidewire placement in renal artery across graft) could be achieved in on average 10.5 ± 9.2 min, and subsequent covered stent placement (guidewire placement-covered stent placement) took on average 32.7 ± 17.5 min. No significant differences between left and right side reperfusion times could be detected. Reperfusion in <30 min was achieved in 3/14 attempts., Conclusion: Electromagnetically navigated in situ aortic fenestration for juxtarenal aortic stent grafts was feasible in a healthy animal model. Identified remaining challenges were: shortening the procedure to avoid long warm ischemia times, using an aortic aneurysm animal model, and improving the stability of the stent graft material.

The aim of this retrospective study was to describe the epidemiology and spectrum of infections of admitted pediatric refugees and asylum seekers in a tertiary referral hospital in a high-income country in Europe. We identified recent refugees and asylum seekers < 18 years of age admitted to the University Children's Hospital in Basel, Switzerland, in 2015. A retrospective analysis was performed using electronic patient records. We identified 105 admissions in 93 patients with a median age of 5.7 (IQR 2.6-14.5) years. Eritrea, Syria, and Afghanistan were the most frequent countries of origin. The median duration of admission was 4 (IQR 2-6) days with infections and elective surgical interventions being the most common reason (54.8 and 16.1%, respectively). Most infections were airway, skin, and gastrointestinal in 46.4, 20.2, and 11.9%, respectively. The prevalence of tropical infections was 11.9%. The main pathogens identified were influenza A virus (13.8%), Staphylococcus aureus (10.3%), and rhino/enterovirus (10.3%). Previous medical non-infectious conditions were recorded in 13%., Conclusion: The study revealed a high burden of infections in admitted patients mostly caused by well-known pathogens prevalent also in the local population. Both tropical infections and pre-existing non-infectious conditions are also important in admitted patients. Better epidemiological data is required to optimize health care for this medically most vulnerable population in refugee crises. What is Known: • Pediatric refugees and asylum seekers are the most vulnerable population in refugee crises. • Data on health concerns and needs in this population is scarce. What is New: • This is one of the first studies on the epidemiology of pediatric refugees and asylum seekers treated as inpatients in a European high-income country. • The high burden of infections is mostly caused by well-known pathogens prevalent also in the local population.

Patient blood management is a multimodal concept that aims to detect, prevent and treat anemia, optimize hemostasis, minimize iatrogenic blood loss, and support a patient-centered decision to provide optimal use of allogeneic blood products. Although the World Health Organization (WHO) has already recommended patient blood management as a new standard in 2010, many hospitals have not implemented it at all or only in part in clinical practice. The German Society of Anaesthesiology and Intensive Care Medicine and the German Society of Surgery therefore demand that i) all professionals involved in the treatment should implement important aspects of patient blood management considering local conditions, and ii) the structural, administrative and budgetary conditions should be created in the health care system to implement more intensively many of the measures in Germany.

Purpose: Covered stents have been demonstrated to reduce restenosis; however, the membrane's limited biocompatibility can still lead to thrombus formation. To obtain optimal surface hemocompatibility, endothelialization of the luminal surface has been proposed. However, the effect of delivery procedures, such as crimping and balloon dilatation, on the endothelial layer has not been quantified. This study investigated the impact of such procedures on endothelialized covered stents in vitro., Methods: Using an injection molding technique, bare metal stents were covered with fibrin subsequently, endothelialized and conditioned in a bioreactor under arterial pressure (80-120 mmHg) and shear stress (1 Pa). For each set of experiments, three covered stents were prepared, one being subjected to crimping alone, one to crimping followed by balloon dilatation and one serving as control. The experiment was repeated three times. The endothelial coverage was quantified by scanning electron microscopy (SEM). The functionality of the endothelium after exposure to platelet-rich plasma was evaluated by immunohistochemistry and SEM., Results: The mean endothelial coverage of control, crimped, crimped and balloon-dilated stents was 87.6, 80.1 and 52.1%, respectively, indicating that endothelial cells detached significantly not after crimping (P = 0.465) but following balloon dilatation (P < 0.001). The cells present on the stent's surface, either after crimping or crimping followed by balloon dilatation, expressed eNOS and CD31 and exhibited no platelet adhesion., Conclusion: The simulated delivery procedure resulted in the retention of viable cells on more than half of the luminal surface. The main damage to the layer occurred during balloon dilatation.

Background: Preoperative anemia has a prevalence of approximately 30% and is one of the strongest predictors of perioperative red blood cell (RBC) transfusion. It is rarely treated although it is an independent risk factor for the occurrence of postoperative complications. Additionally, the high variability in the worldwide usage of RBC transfusions is alarming. Due to these serious deficits in patient care, in 2011 the World Health Organization recommended the implementation of a patient blood management (PBM)., Objectives: This article provides information about PBM as a multidimensional and interdisciplinary approach., Material and Methods: A selective literature search was carried out in the Medline and Cochrane library databases including consideration of national and international guidelines., Results: A PBM promotes the medically and ethically appropriate use of all available resources, techniques and materials in favor of an optimized perioperative patient care. Patients' own resources should be specifically protected, strengthened and used and include (i) diagnosis and therapy of preoperative anemia, (ii) minimizing perioperative blood loss, (iii) blood-conserving surgical techniques, (iv) restriction of diagnostic blood sampling, (v) utilization of individual anemia tolerance, (vi) optimal coagulation and hemotherapy concepts and (vii) guideline-based, rational indications for the use of RBC transfusions., Conclusion: A PBM should be advocated as an incentive to evaluate and critically optimize local conditions. An individual, interdisciplinarily structured bundle of different PBM measures has great potential to optimize the quality of patient care and to make it safer.

Purpose: Devices constantly tracking the blood pressure (BP) of hypertensive patients are highly desired to facilitate effective patient management and to reduce hospitalization. We report on experiences gathered in a pilot study that was designed to evaluate the prototype of a newly developed, minimally invasive implantable sensor system for long-term BP monitoring., Methods: The device was implanted in the femoral artery (FA) of 12 sheep via standard FA catheterization under fluoroscopic control. Accuracy of the recorded blood pressure was determined by comparison with a reference catheter, which was positioned in the contralateral FA immediately after implantation. Regular follow-up included angiography, computed tomography (CT), and control of functionality and position of the BP sensor. Animals were euthanized after 6 months. FA segments with in situ pressure sensor underwent macroscopic and histopathologic examinations., Results: All implantations of the novel sensor device in the FA were successful and uneventful. High-quality BP recordings were documented. Bland-Altman plots indicate very good agreement. Comparison with measurements taken from the reference sensor revealed mean differences and standard deviations of -0.56 ± 0.85, 0.29 ± 1.44, and 0.85 ± 2.27 mmHg (diastolic, systolic, and pulse pressure, respectively) after exclusion of one outlier. CT uncovered deficiencies in cable stability that were addressed in a redesign. No thrombus formation, necrosis, or apoptosis were detected., Conclusions: The pilot study proved the technical feasibility of wireless BP measurement in the FA via a novel miniature sensor device.

Purpose: To evaluate heating efficacy of superparamagnetic iron oxide nanoparticles (SPIO) for electromagnetic ablation (EMA) of osteoid osteoma (OO) using an ex vivo model compared to radiofrequency ablation (RFA) and microwave ablation (MWA)., Methods: A model for OO using sliced bovine tibia and sliced muscle tissue was developed. A bone cavity filled with either a mixture of SPIO and agarose or pure agarose (control group) was established. EMA was performed using an experimental system, RFA and MWA using clinically approved systems, and the ablation protocols recommended by the vendor. For temperature measurements, fiberoptic temperature probes were inserted inside the cavity, on the outside of the periosteum, and at a 5 mm distance to the periosteum., Results: Maximum temperatures with or without SPIO in the nidus were as follows: EMA: 79.9 ± 2.5/22.3 ± 0.7 °C; RFA: 95.1 ± 1.8/98.6 ± 0.9 °C; MWA: 85.1 ± 10.8/83.4 ± 9.62 °C. In RFA with or without SPIO significantly higher temperatures were achieved in the nidus compared to all other groups (p < 0.05). In MWA significantly higher temperatures were observed in the 5 mm distance to the periosteum compared to EMA and RFA with or without SPIO (p < 0.05). In MWA temperature decrease between nidus and the 5 mm distance to the periosteum was significantly lower than in RFA with or without SPIO (p < 0.0001). In MWA without SPIO temperature decrease was significantly lower than in the EMA group (p < 0.05)., Conclusion: In the experimental setting, ablation of OO is safe and effective using EMA. It is less invasive than RFA and MWA, and it theoretically allows repeated treatments without repeated punctures. In comparison, the highest temperatures in the nidus are reached using RFA.

Purpose: To test the performance of an expandable bipolar probe as a simple technical solution for extending the coagulation volume., Methods: On the basis of a commercially available monopolar radiofrequency (RF) probe (LeVeen), an expandable bipolar RF probe was developed by integrating a second electrode into the probe shaft. The influence of length on the second electrode, and the distance between both electrodes and generator output was investigated by performing ten ablations for each condition on a freshly excised bovine liver. Macroscopically quantified coagulation volumes, lesion shape characteristics, and procedure durations were recorded. Results of the prototype featuring the optimal configuration were compared to the original LeVeen probe and commonly used bipolar RF probe (CelonLabPower)., Results: Extension of the shaft electrode length, increasing distance between the shaft electrode and the tip electrode, and reduction of generator output resulted in increasing coagulation volumes. The coagulation volumes the prototype generated were significantly smaller and more elliptically shaped than the monopolar probe (9.4 ± 1.5 cm(3) vs. 12.1 ± 1.6 cm(3)), but were larger than the commercially available bipolar RF probe (vs. 7.3 ± 0.5). The procedure duration of the prototype was comparable to the monopolar probe (467 ± 31 s vs. 464 ± 17 s) and shorter than the bipolar probe (vs. 2009 ± 444 s). In comparison to the commercially available bipolar system, the developed prototype exhibited favorable results., Conclusion: The first benchmark testing of the developed bipolar prototype had promising results. However, further optimization of the applicator design and ablation protocol is needed to enlarge the achievable coagulation volume.

Purpose: This study was designed to evaluate CO2 computed tomography angiography (CO2-CTA) of the iliac and lower limb arteries in patients with contraindications for iodinated contrast agent (ICA)., Methods: Five patients with contraindications for ICA were examined using CO2-fluoroscopic enhanced angiography (CO2-FLA) and CO2-CTA using a high-pitch examination protocol. Objective (vessel diameter) and subjective (visual score) image quality parameters were evaluated. Pathological findings in both modalities were compared., Results: CO2-CTA was feasible in all patients without adverse side effects, except for CO2 injection-associated pain. Objective vessel analysis revealed no significant difference in diameters as determined by CO2-CTA and CO2-FLA (0.44 ± 0.4 and 0.46 ± 0.41 mm, p = 0.93). CO2-CTA had on average a higher image-quality score (2.6 ± 1.0 vs. 2.3 ± 1.0, p = 0.009). While for pelvic and upper leg CO2-CTA advantageous (3.1 ± 0.74 vs. 2.7 ± 0.9, p = 0.0014) at good quality scores, for calf vessels no significant improvement was visible (1.9 ± 1.0 vs. 1.7 ± 0.9, p = 0.49) and scores were poorer., Conclusions: CO2-CTA with high-pitch CT was feasible in a limited number of patients. Image-quality scores were on average higher for CO2-CTA than for CO2-FLA, while limited imaging quality in the vessels below the knee needs further work on the CT protocol. An added value of cross-sectional imaging was apparent but needs further quantification.

Purpose: To evaluate the effects of particle size and course of action of superselective bland transcatheter arterial embolization (TAE) on the efficacy of radiofrequency ablation (RFA)., Methods: Twenty pigs were divided into five groups: group 1a, 40-μm bland TAE before RFA; group 1b, 40-μm bland TAE after RFA; group 2a, 250-μm bland TAE before RFA; group 2b, 250-μm bland TAE after RFA and group 3, RFA alone. A total of 40 treatments were performed with a combined CT and angiography system. The sizes of the treated zones were measured from contrast-enhanced CTs on days 1 and 28. Animals were humanely killed, and the treated zones were examined pathologically., Results: There were no complications during procedures and follow-up. The short-axis diameter of the ablation zone in group 1a (mean ± standard deviation, 3.19 ± 0.39 cm) was significantly larger than in group 1b (2.44 ± 0.52 cm; P = 0.021), group 2a (2.51 ± 0.32 cm; P = 0.048), group 2b (2.19 ± 0.44 cm; P = 0.02), and group 3 (1.91 ± 0.55 cm; P < 0.001). The greatest volume of ablation was achieved by performing embolization with 40-μm particles before RFA (group 1a; 20.97 ± 9.65 cm(3)). At histology, 40-μm microspheres were observed to occlude smaller and more distal arteries than 250-μm microspheres., Conclusion: Bland TAE is more effective before RFA than postablation embolization. The use of very small 40-μm microspheres enhances the efficacy of RFA more than the use of larger particles.

The epidemically increasing number of diabetics is resulting in an increasing number of patients with end-stage renal failure who, furthermore, show a high degree of co-morbidity. An increasingly longer survival time with dialysis also means that the group of patients requiring functional dialysis access is continuously growing. The autologous arteriovenous fistula with its high function and low complication rate is the best access form, and should be provided to as many of those patients requiring dialysis as possible. This article discusses the timing of dialysis access, the importance of the medical history and the physical examination, preoperative investigation of the prospective fistula vein, the possibilities of anastomosis, maturation of the fistula and long-term results.

Purpose: To compare the effectiveness of microwave (MW) ablation with radiofrequency (RF) ablation for treating breast tissue in a nonperfused ex vivo model of healthy bovine udder tissue., Materials and Methods: MW ablations were performed at power outputs of 25W, 35W, and 45W using a 915-MHz frequency generator and a 2-cm active tip antenna. RF ablations were performed with a bipolar RF system with 2- and 3-cm active tip electrodes. Tissue temperatures were continuously monitored during ablation., Results: The mean short-axis diameters of the coagulation zones were 1.34 ± 0.14, 1.45 ± 0.13, and 1.74 ± 0.11 cm for MW ablation at outputs of 25W, 35W, and 45W. For RF ablation, the corresponding values were 1.16 ± 0.09 and 1.26 ± 0.14 cm with electrodes having 2- and 3-cm active tips, respectively. The mean coagulation volumes were 2.27 ± 0.65, 2.85 ± 0.72, and 4.45 ± 0.47 cm(3) for MW ablation at outputs of 25W, 35W, and 45W and 1.18 ± 0.30 and 2.29 ± 0.55 cm(3) got RF ablation with 2- and 3-cm electrodes, respectively. MW ablations at 35W and 45W achieved significantly longer short-axis diameters than RF ablations (P < 0.05). The highest tissue temperature was achieved with MW ablation at 45W (P < 0.05). On histological examination, the extent of the ablation zone in MW ablations was less affected by tissue heterogeneity than that in RF ablations., Conclusion: MW ablation appears to be advantageous with respect to the volume of ablation and the shape of the margin of necrosis compared with RF ablation in an ex vivo bovine udder.

Coordination between perception and action is required to interact with the environment successfully. This is already trained by very young infants who perform spontaneous movements to learn how their body interacts with the environment. The strategies used by the infants for this purpose change with age. Therefore, very early progresses in action control made by the infants can be investigated by monitoring the development of spontaneous motor activity. In this paper, an objective method is introduced, which allows the quantitative evaluation of the development of spontaneous motor activity in newborns. The introduced methodology is based on the acquisition of spontaneous movement trajectories of the feet by 3D movement analysis and subsequent calculation of specific movement parameters from them. With these movement-based parameters, it was possible to provide an objective description of age-dependent developmental steps in healthy newborns younger than 6 months. Furthermore, it has been shown that pathologies like infantile cerebral palsy influence development of motor activity significantly. Since the introduced methodology is objective and quantitative, it is suitable to monitor how newborns train their cognitive processes, which will enable them to cope with their environment by motor interaction.

Purpose: Silicon carbide (SiC) is an inert compound material with excellent microwave absorption and heat-conducting properties. The aim of our study was to investigate the heat-enhancing effects of SiC in microwave ablation in an in vitro setting., Materials and Methods: Different concentrations of SiC powder were mixed with 2% gelatin, producing a 20-ml mixture that was then heated with a clinical microwave ablation system (5 min/45 W). Temperature was measured continuously fiberoptically. Additional heating properties were assessed for the most heatable concentrations at different energy settings (10, 20, and 30 W). As reference, 2% gelatin without SiC was heated. Statistical evaluation by analysis of variance with post hoc Student-Newman-Keuls testing was performed., Results: For the different SiC concentrations, maximum temperatures measured were 45.7 ± 1.2°C (0% SiC, control), 50.4 ± 3.6°C (2% SiC), 60.8 ± 1.8°C (10% SiC), 74.9 ± 2.6°C (20% SiC), and 83.4 ± 2.5°C (50% SiC). Differences between all data points were significant (P < 0.05). Maximum temperatures that used 20% SiC were 36.3 ± 2.76°C (10 W), 48.7 ± 4.18°C (20 W), and 50.6 ± 0.68°C (30 W). The use of 50% SiC maximum temperatures resulted in values of 46.2 ± 2.52°C (10 W), 70.1 ± 0.64°C (20 W), and 83.0 ± 4.69°C (30 W). With 20% SiC and 50% SiC mixtures, the 10 W maximum temperatures were significantly lower than at all other power levels, and maximum temperatures with 20 and 30 W were significantly lower when compared with 45 W (P < 0.05)., Conclusions: SiC is a nontoxic, highly effective substance for enhancing microwave-induced heating with a microwave ablation system in vitro. These data suggest its usefulness for enhancement of ablative effects in percutaneous tumor therapy. Further investigations need to be performed to evaluate the ex vivo and in vivo ablation effects and the possible methods for administration of SiC particles.

The combination of radiofrequency ablation (RFA) with direct current (DC) is a promising strategy to improve the efficiency of RFA. However, DC-enhanced monopolar RFA is limited by electrolytic injury at the positive-electrode site. The aim of this study was to investigate the feasibility of the DC-enhanced bipolar RFA. To obviate the need for the subcutaneous positive electrode, the DC circuit was combined with a commercially available bipolar RFA system, in which both poles of the DC circuit are connected to a single RF probe. DC was applied for 15 min and followed by RFA in bovine livers using the following various DC currents: (1) no DC (control), (2) 3V continued until the end of RFA, (3) 5V continued until the end of RFA, (4) 10V continued until the end of RFA, (5) 5V continued in the circuit with reversed pole, (6) 3V stopped after initiation of RFA, and (7) 5V stopped. Coagulation volume, temperatures at a distance of 5, 10, and 15 mm from the RF probe, mean amperage, ablation duration, applied energy, minimum impedance, and degree of tissue charring were assessed and compared (analysis of variance, Student-Newman-Keuls test). All combined DC and RFA groups did increase coagulation volume. The 10V continued group showed significantly lower applied energy, shortest ablation duration, highest minimum impedance, and highest degree of charring with the lowest coagulation volume (p<0.05). DC-enhanced bipolar RFA with both poles of the DC circuit on a single probe appears to be ineffective.

The purpose of this study was to investigate the optimal setting for radiofrequency (RF) ablation combined with direct electrical current (DC) ablation in ex vivo bovine liver. An electrical circuit combining a commercially available RF ablation system with DC was developed. The negative electrode of a rectifier that provides DC was connected to a 3-cm multitined expandable RF probe. A 100-mH inductor was used to prevent electrical leakage from the RF generator. DC was applied for 15 min and followed by RF ablation in freshly excised bovine livers. Electric current was measured by an ammeter. Coagulation volume, ablation duration, and mean amperage were assessed for various DC voltages (no DC, 2.2, 4.5, and 9.0 V) and different RF ablation protocols (stepwise increase from 40 to 80 W, 40 W fixed, and 80 W fixed). Results were compared using Kruskal-Wallis and Mann-Whitney U test. Applying DC with 4.5 or 9.0 V, in combination with 40 W fixed or a stepwise increase of RF energy, resulted in significantly increased zone of ablation size compared with 2.2 V or no DC (P = 0.009). At 4.5 V DC, the stepwise increase of RF energy resulted in the same necrosis size as a 40 W fixed protocol (26.6 +/- 3.9 vs. 26.5 +/- 4.0 ml), but ablation duration was significantly decreased (296 +/- 85 s vs. 423 +/- 104 s; P = 0.028). Mean amperage was significantly lower at 4.5 V compared with 9.0 V (P = 0.028). Combining a stepwise increase of RF energy with a DC voltage of 4.5 V is most appropriate to increase coagulation volume and to minimize procedure time.

Thromboses in the lower extremities are common. Non-invasive examination techniques, such as compression sonography and color-coded duplex sonography, have a high sensitivity and specificity. Relevant complications are in particular post-thrombotic syndrome and pulmonary arterial embolisms. The gold standard in treatment of phlebothrombosis of the leg is immediate anticoagulation therapy and compression treatment with early mobilization whereas lysis therapy, operative thrombectomy or implantation of cava filters are indicated only in isolated cases.

The objective of this study was to assess the technical feasibility of CT-guided magnetic thermoablation for the treatment of malignant kidney tumors in a VX2 tumor rabbit model. VX2 tumors were implanted into the kidneys of five rabbits and allowed to grow for 2 weeks. After preinterventional CT perfusion imaging, CT-guided injection of superparamagnetic iron oxide particles (300 microl) was performed, followed by exposure of the animals to an alternating electromagnetic field for 15 min (approximately 0.32 kA/m). Then animals underwent CT perfusion imaging again. Afterward, animals were sacrificed and kidneys were dissected for macroscopic and histological evaluation. Changes in perfusion before and after exposure to the alternating magnetic field were analyzed. In one animal no tumor growth could be detected so the animal was used for optimization of the ablation procedure including injection technique and peri-interventional cross-sectional imaging (CT, MRI). After image-guided intratumoral injection of ferrofluids, the depiction of nanoparticle distribution by CT correlated well with macroscopic evaluation of the dissected kidneys. MRI was limited due to severe susceptibility artefacts. Postinterventional CT perfusion imaging revealed a perfusion deficiency around the ferrofluid deposits. Histological workup showed different zones of thermal damage adjacent to the ferrofluid deposits. In conclusion, CT-guided magnetic thermoablation of malignant kidney tumors is technically feasible in an animal model and results in a perfusion deficiency indicating tumor necrosis as depicted by CT perfusion imaging and shown in histological evaluation.

Vascular surgery is a young surgical discipline which has experienced a stormy development driven by internal motivation and external constraints. Changes in the field are primarily a result of diverse external influences which are expected to continue into the future. The most significant intrinsic change has been the development of stent graft technology. External influences include extensive demographic changes, rapid progress in endovascular techniques to treat obstructive vascular disease, improved advanced training, state and non-state controls, certification requests without considering the feasibility of professional and structural implementation and changing public expectations. Progress in vascular medicine is stimulated by advances in imaging techniques and subsequent improved endovascular procedures. Nevertheless, external influences have, at least within the 'surgical' sphere of influence, led to formidable innovative efforts on the part of associations representing vascular surgeons. These innovative efforts are concentrated in the Academy of the German Society of Vascular Surgery and Medicine and will determine trends in coming years. The future will reflect their quality.

The purpose of this study was to evaluate the technical and animal experimental feasibility of a percutaneously implantable pulmonary arterial implant for permanent hemodynamic monitoring. Two systems for measuring pulmonary artery pressure (PAP) as well as pulmonary artery occlusion pressure (PAOP) were developed by modifying a commercially available pulmonary artery catheter (PAC). First, a cable-bound catheter-based system was designed by implementation of a capacitive absolute-pressure sensor in the catheter tip. This system was developed further into a completely implantable telemetric system. The devices were tested in an acute setting in a total of 10 sheep. The implant was placed with its tip in the descending pulmonary artery via the right jugular approach. Results were compared with conventional PAC positioned in the contralateral pulmonary artery using Pearson's correlation coefficients and Bland-Altman plots. Implantation of the monitoring systems was uneventful in 10 animals. Data from two fully functional cable-bound and telemetric pressure monitoring systems were available, with a total of 18,506 measurements. There was an excellent correlation between reference data and the data obtained with the implants (r = 0.9944). Bland-Altman plots indicated a very good agreement between the techniques. We report the development and successful initial test of an implantable catheter-based device for long-term measurement of PAP and PAOP. Both devices may be applicable for hemodynamic monitoring. Further long-term studies for assessing reliability and durability of the device are warranted.

The purpose of this study was to compare the effects of magnetic thermal ablation in different porcine tissues using either a singular injection or a continuous infusion of superparamagnetic iron oxide nanoparticles. In the first setting samples of three ferrofluids containing different amounts of iron (1:171, 2:192, and 3:214 mg/ml) were singularly interstitially injected into specimens of porcine liver, kidney, and muscle (n = 5). Then the specimens were exposed to an alternating magnetic field (2.86 kA/m, 190 kHz) generated by a circular coil for 5 min. In the second experimental setup ferrofluid samples were continuously interstitially infused into the tissue specimens during the exposure to the magnetic field. To measure the temperature increase two fiber-optic temperature probes with a fixed distance of 0.5 cm were inserted into the specimens along the puncture tract of the injection needle and the temperature was measured every 15 s. Finally, the specimens were dissected, the diameters of the created thermal lesions were measured, and the volumes were calculated and compared. Compared to continuous infusion, a single injection of ferrofluids resulted in smaller coagulation volumes in all tissues. Significant differences regarding coagulation volume were found in kidney and muscle specimens. The continuous infusion technique led to more elliptically shaped coagulation volumes due to larger diameters along the puncture tract. Our data show the feasibility of magnetic thermal ablation using either a single interstitial injection or continuous infusion for therapy of lesions in muscle, kidney, and liver. Continuous infusion of ferrofluids results in larger zones of necrosis compared to a single injection technique.

Current protocols for surveillance after endovascular repair (EVAR) of abdominal aortic aneurysms are mostly based on costly and time-consuming imaging procedures and aim to detect adverse events such as graft migration, endoleaks or aneurysm sac enlargement. These imaging procedures are either associated with radiation exposure to the patients or may be harmful to the patient due to the use of iodine- or gadolinium-containing contrast agents. Furthermore the advantages of EVAR in the short term might be negated by the necessity for endograft surveillance over years. Thus, alternative modalities for follow-up are being investigated. One of these technologies provides pressure information directly from the aneurysm sac. This noninvasive, telemetric pressure sensing was tested in vitro as well as in first clinical trials and was able to identify successful aneurysm exclusion after EVAR. The telemetric pressure sensors showed a promising efficacy and accuracy in detecting type I and type III endoleaks and will help to clarify the clinical relevance of type II endoleaks. This article provides an overview of the in vitro sensors investigated as well as the first clinical trials and the sensors' potential to change the current endograft surveillance regimes.

The purpose of this study was to evaluate the effectiveness of a newly developed perfused monopolar radiofrequency (RF) probe with an umbrella-shaped array. A perfused umbrella-shaped monopolar RF probe based on a LeVeen electrode (Boston Scientific Corp., Natick, MA, USA) with a 3-cm array diameter was developed. Five different configurations of this electrode were tested: (a) perfusion channel/endhole, (b) perfusion channel/endhole + sideholes, (c) 1 cm insulation removed at the tip, (d) 1 cm insulation removed at the tip + perfusion channel/endhole, and (e) 1 cm insulation removed at the tip + perfusion channel/endhole + sideholes. An unmodified LeVeen electrode served as a reference standard. RF ablations were performed in freshly excised bovine liver using a commercial monopolar RF system with a 200-W generator (RF 3000; Boston Scientific Corp.). Each electrode was tested 10 times applying the vendor's recommended ablation protocol combined with the preinjection of 2 ml 0.9% saline. Volumes and shapes of the lesions were compared. Lesions generated with the original LeVeen electrode showed a mean volume of 12.74 +/- 0.52 cm(3). Removing parts of the insulation led to larger coagulation volumes (22.65 +/- 2.12 cm(3)). Depending on the configuration, saline preinjection resulted in a further increase in coagulation volume (25.22 +/- 3.37 to 31.28 +/- 2.32 cm(3)). Besides lesion volume, the shape of the ablation zone was influenced by the configuration of the electrode used. We conclude that saline preinjection in combination with increasing the active tip length of the umbrella-shaped LeVeen RF probe allows the reliable ablation of larger volumes in comparison to the originally configured electrode.

Purpose: To evaluate the size and quantity of downstream emboli after thrombectomy using the Arrow-Trerotola Percutaneous Thrombolytic Device (PTD) with or without temporary filtration for extensive iliofemoral and iliocaval thrombi in an in vitro flow model., Methods: Iliocaval thrombi were simulated by clotted bovine blood in a flow model (semilucent silicone tubings, diameter 12-16 mm). Five experimental set-ups were performed 10 times each; thrombus particles and distribution were measured in the effluent. First, after retrograde insertion, mechanical thrombectomy was performed using the PTD alone. Then a modified self-expanding tulip-shaped temporary vena cava stent filter was inserted additionally at the beginning of each declotting procedure and removed immediately after the intervention without any manipulation within or at the filter itself. In a third step, the filter was filled with thrombus only. Here, two experiments were performed: Careful closure within the flow circuit without any additional fragmentation procedure and running the PTD within the filter lumen, respectively. In the final set-up, mechanical thrombectomy was performed within the thrombus-filled tubing as well as in the filter lumen. The latter was closed at the end of the procedure and both devices were removed from the flow circuit., Results: Running the PTD in the flow circuit without filter protection led to a fragmentation of 67.9% (+/-7.14%) of the clot into particles < or =500 microm; restoration of flow was established in all cases. Additional placement of the filter safely allowed maceration of 82.9% (+/-5.59%) of the thrombus. Controlled closure of the thrombus-filled filter within the flow circuit without additional mechanical treatment broke up 75.2% (+/-10.49%), while additional mechanical thrombectomy by running the PTD within the occluded filter led to dissolution of 90.4% (+/-3.99%) of the initial clot. In the final set-up, an overall fragmentation rate of 99.6% (+/-0.44%) was achieved., Conclusions: The combined use of the Arrow-Trerotola PTD and a temporary vena cava stent filter proved to be effective for even large clot removal in this experimental set-up.

We report a case of successful percutaneous treatment of a subacute ilio-caval venous thrombosis in a 64-year-old female patient by using a novel combination of a rotatory fragmentation device (percutaneous thrombectomy device: PTD) and large wire basket (temporary Günther basket filter) under temporary caval filter protection using an expandable sheath. Because the patient had multiple myeloma with increased risk for contrast media-induced renal failure, the therapeutic angiographic procedure was performed without iodinated contrast medium. Non-contrast-enhanced MR venography (high-resolution True FISP) confirmed the effective thrombus removal by the percutaneous mechanical thrombectomy procedure.

For arterial reconstructions veins or alloplastic vascular prostheses are used. Nonanastomotic pseudoaneurysms of vascular protheses are a rare event. Breaks of the suture material, structural defects of the transplant fabric or degenerative modifications in the recipient vessel can cause nonanastomotic or anastomotic pseudoaneurysms. Such pseudoaneurysms are known from early clinical application of ePTFE grafts. In the case presented a nonanastomotic rupture of a ePTFE graft is described with partial repair of the rupture site by fibroblasts and connective tissue, which prevented bleeding.

Purpose: To evaluate the effectiveness of ultrasound thrombolysis in occluded hemodialysis access shunts using an in vitro model., Methods: Thrombosed hemodialysis accesses were simulated by clotted bovine blood in a flow model (silicone tubing; inner diameters 4, 6, and 9 mm). After retrograde and antegrade sheath placement (7 Fr), mechanical thrombolysis was performed using an ultrasound probe (Acolysis, Angiosonics, Morrisville, NC, USA). The tip of the device measured 2.2 mm in diameter. During sonication, the catheter was moved slowly back and forth using an over-the-wire system. Thirty complete occlusions [tubing diameters 4 mm (n = 12), 6 mm (n = 12), 9 mm (n = 6)] were treated. Initial thrombus weights were 3.5 (+/- 0.76) g, 7.7 (+/- 1.74) g, and 19.4 (+/- 2.27) g for the three diameters. Maximum sonication time was 15 min for each probe., Results: With this device, we were able to restore a continuous lumen in all 12 occluded 4 approximately mm silicone tubes. No wall-adherent thrombi remained after sonication for 3.5--9.6 min. In hemodialysis access models with diameters of 6 mm, thrombus fragments persisted in 25% (3/12 accesses). These were located in the medial portion of the access loop and near to the puncture sites. However, flow was re-established after 5.0--13.0 min of treatment in all settings. Mechanical dissolution of thrombus material failed in five of six access models with diameters of 9 mm, even though ultrasound energy was applied for the maximum of 15 min., Conclusion: In a clotted hemodialysis shunt model, successful ultrasound thrombolysis was limited to small access diameters and small amounts of thrombus.

Fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) has proven useful in the differentiation of various tumour entities, including breast cancer. In patients with primary breast cancer we performed a 3-h imaging protocol to examine possible improvements in tumour detectability and image contrast. Twenty-nine patients with primary breast cancer with a diameter of >/=2 cm that was demonstrated to be malignant by biopsy or surgery were injected with 370-740 MBq 18F-FDG and scanned in the prone position. Data were acquired 0-40 min, 1.5 h and 3.0 h after injection. After correction for measured attenuation, decay and scatter and iterative reconstruction, standardised uptake values (SUVs) and tumour-to-non-tumour and tumour-to-organ ratios were calculated. Visual analysis was performed using transverse, sagittal and coronal slices as well as 3D reprojection images. Tumour-to-non-tumour and tumour-to-organ ratios were significantly higher for the 3-h images than for the 1.5-h images. SUVs did not increase to the same extent. Lesion detectability was 83% in 1.5-h images compared to 93% in 3-h images. We conclude that tumour contrast in breast cancer is improved by starting the PET acquisition at 3 h p.i. rather than at 1.5 h p.i.

Purpose: The flow pattern in the central pulmonary arteries proximal to large pulmonary emboli was studied experimentally. The currents to which thrombolytic agents are exposed when administered via an intrapulmonary catheter were visualized in order to explain the lack of benefit of local versus systemic administration., Methods: By illumination of suspended microspheres, the flow pattern proximal to an obstructing embolus was visualized in an in vitro pulmonary arterial flow model. In six dogs massive pulmonary embolism was created. A pigtail catheter was positioned in the pulmonary artery immediately proximal to the central edge of the occluding embolus. To allow visualization of the local flow pattern, a small amount of contrast material (4 ml) was injected through the catheter at a high flow rate (25 ml/sec). The course of the radiopaque spot that emerged from the catheter tip within 160 msec was monitored with digital subtraction angiography at a frame rate of 12.5 frames/sec. In two dogs, the study was repeated after embolus fragmentation with the same catheter position., Results: The flow model study revealed formation of a vortex proximal to the occluding embolus. In vivo experiments showed that the radiopaque spot was whirled by the vortex proximal to the embolus and made only evanescent contact with the edge of the embolus. Regardless of the embolus location, the contrast spot was washed into the non-occluded ipsilateral and contralateral pulmonary arteries within 0.40-0.64 sec. After embolus fragmentation, the contrast spot was carried completely into the formerly occluded artery., Conclusion: Flow studies explain why thrombolytic agents administered via a catheter positioned adjacent to the embolus may have no more effect than systemically administered agents. An enhanced local effect is precluded by the rapid washout into the non-occluded pulmonary arteries and subsequent systemic dilution. These results support the practice of direct intrathrombic injection of thrombolytics or local thrombolysis as an adjunct to embolus fragmentation.

Purpose: To evaluate the feasibility of thrombus removal from temporary vena cava filters using a rheolytic thrombectomy device and to assess the embolization rate of this procedure., Methods: Five temporary vena cava filters together with porcine thrombi were placed in a vena cava flow model (semitranslucent silicone tube of 23 mm diameter, pulsatile flow at a mean flow rate of 4 L/min). A rheolytic thrombectomy system (Hydrolyser) was used with a 9 Fr guiding catheter to remove the clots. The effluent was passed through filters of different size and the amount of embolized particles as well as the remaining thrombus were measured., Results: Thrombus removal rates ranged from 85% to 100%. Embolization rates between 47% and 60% were calculated for the different filters., Conclusion: The Hydrolyser is able to remove sufficiently high amounts of thrombus from temporary vena cava filters. However, the amount of embolized particles makes it impossible to utilize this method without special precautions against embolization.

Purpose: To assess the efficacy of catheter fragmentation of massive caval thrombosis and of filter protection against procedure-related pulmonary embolism., Methods: In 10 sheep, a self-expanding tulip-shaped filter made from Wallstent mesh (diameter 25 mm) was introduced from the right jugular approach into the proximal inferior vena cava. Experimentally induced massive iliocaval thrombosis was fragmented by an impeller catheter (expanded diameter 14 mm), which was advanced coaxially through the sheath of the expanded filter. Post-procedural cavography and pulmonary angiography were performed to document the extent of caval recanalization and pulmonary embolism., Results: In all cases, impeller fragmentation cleared the inferior vena cava and the iliac veins of thrombi completely. Fragments washed downstream were trapped in the filter. In two of the first cases, parts of the clots caused pulmonary embolism before the filter was in place. Further events were avoided by a modification of the experimental setup. Except for some small peripheral perfusion defects in two cases, pulmonary angiograms did not show any incidence of pulmonary embolism., Conclusion: Our preliminary results suggest that impeller fragmentation of iliocaval thrombi under tulip filter protection is effective and does not cause significant pulmonary embolism.

Purpose: To test two over-the-wire systems for fragmentation of pulmonary emboli., Methods: In 11 dogs, 22 embolic occlusions of lobar or central pulmonary arteries were performed by injection of preformed emboli through a jugular vein sheath. A commercially available device (thrombolizer) and a modified version of the impeller catheter were introduced via the femoral vein and positioned at the embolus site., Results: Catheter placement at the site of the emboli was possible. In more than half of the cases a hydrophilic or an extra-stiff guidewire was necessary. The thrombolizer did not rotate properly with its original pneumatic drive and required a major modification. When sufficient rotation was provided, both fragmentation catheters were able to clear the occluded main arteries. Side branches were partly obstructed by the resulting fragments. Recanalization led to a reduction of the emboli-induced elevation of the pulmonary arterial pressure by two-thirds. Histology of the recanalized pulmonary artery segments revealed localized (impeller catheter) and widespread (thrombolizer) periarterial hemorrhage., Conclusion: Embolus fragmentation led to a hemodynamic improvement. The impeller catheter was less traumatic compared with the thrombolizer, which was technically insufficient.

Purpose: A new self-expanding tulip sheath was tested for percutaneous wife capturing in a femoro-femoral pull-through maneuver., Methods: In six sheep, a self-expanding tulip sheath was introduced into the right iliac artery. A 5 Fr catheter and an 0.035-inch guidewire were guided into the iliac artery from a left femoral approach. Thirty-six tests were performed to guide the guidewire out of the right groin using the tulip sheath, by catching the catheter first in 18 tests and just by catching the guidewire in the other 18. As a control, six tests were performed using a conventional sheath. We performed one clinical arterial application., Results: There was prompt capture of the wire in 35 of 36 tests using a self-expanding sheath. Five of six tests using a conventional sheath failed. The clinical application of the tulip principle was successful., Conclusion: Using the self-expanding tulip sheath to facilitate wire capture during pull-through maneuvers, even in difficult situations, is promising.

The common therapy of a persistent bronchocutaneous fistula is the operative endoscopic repair of the leak, the parietal pleurectomy or the endoscopic pleurodesis with different agents. Therefore the thoracotomy with all the risks for the patient can be avoid. Complications seen in the thoracoscopic treatment are low and often the result of techniqual problems. However there must be an alternative therapy for patients with a high operational risk. In our case we treated a bronchocutaneous persistent fistula by the instillation of iodized talc effectively. Although talc and others agents are used in the therapy of malignant pleural effusions, the talc poudrage in the therapy of bronchocutaneous fistulas is a good alternative treatment for patients in a bad condition.