Search

An expanded role for cardiac implantable electronic devices (CIEDs) in recent decades reflects an aging population and broader indications for devices, including both primary prevention and management of dysrhythmias. CIED infection is one of the most important device-related complications and has a major impact on mortality, quality of life, healthcare utilization, and cost. Unfortunately, the investigation and management of CIED infection remain complex, often necessitating complete and timely removal of the device and leads in order to eradicate the infection. In addition, the translation of knowledge from an extensive literature to a disparate group of medical practitioners has often been inadequate. This review of CIED infection management highlights the significant advances made during the past decade, including diagnostic criteria, advanced imaging, and next-generation sequencing for culture-negative cases or those in which uncertainty remains. We also outline the role and indication for powered lead extraction, the process of antibiotic choice and treatment duration, considerations related to the timing and location for reimplantation, and preimplantation risk stratification and associated interventions to reduce the risk of CIED infection.L’élargissement du rôle des dispositifs électroniques cardiaques implantables (DECI) au cours des dernières décennies reflète le vieillissement de la population et les indications plus vastes des dispositifs, notamment dans la prévention primaire et la prise en charge des dysrythmies. Les infections liées aux DECI sont l’une des plus importantes complications liées aux dispositifs et ont des conséquences majeures sur la mortalité, la qualité de vie, l’utilisation et les coûts des soins de santé. Malheureusement, le dépistage et la prise en charge des infections liées aux DECI demeurent complexes et nécessitent souvent le retrait complet et rapide du dispositif et des sondes en vue d’éradiquer l’infection. De plus, l’application des connaissances issues d’une vaste littérature à un groupe disparate de médecins praticiens a souvent été inadéquate. La présente revue sur la prise en charge des infections liées aux DECI illustre les avancées importantes réalisées au cours de la dernière décennie, notamment les critères diagnostiques, l’imagerie avancée et le séquençage de prochaine génération des cas à culture négative ou de ceux pour lesquels des incertitudes demeurent. Nous avons aussi décrit le rôle et les indications d’extraction des sondes fonctionnelles, le processus du choix des antibiotiques et de la durée du traitement, les considérations relatives au moment et au lieu de la réimplantation, et la stratification du risque en préimplantation et les interventions associées afin de réduire le risque d’infections liées aux DECI.

Background The coronavirus disease 2019 (COVID‐19) pandemic has had an unprecedented impact on health care and cardiac surgery. We report cardiac surgeons' concerns, perceptions, and responses during the COVID‐19 pandemic. Methods A detailed survey was sent to recruit participating adult cardiac surgery centers in North America. Data regarding cardiac surgeons' perceptions and changes in practice were analyzed. Results Our study comprises 67 institutions with diverse geographic distribution across North America. Nurses were most likely to be redeployed (88%), followed by advanced care practitioners (69%), trainees (28%), and surgeons (25%). Examining surgeon concerns in regard to COVID‐19, they were most worried with exposing their family to COVID‐19 (81%), followed by contracting COVID‐19 (68%), running out of personal protective equipment (PPE) (28%), and hospital resources (28%). In terms of PPE conservation strategies among users of N95 respirators, nearly half were recycling via decontamination with ultraviolet light (49%), followed by sterilization with heat (13%) and at home or with other modalities (13%). Reuse of N95 respirators for 1 day (22%), 1 week (21%) or 1 month (6%) was reported. There were differences in adoption of methods to conserve N95 respirators based on institutional pandemic phase and COVID‐19 burden, with higher COVID‐19 burden institutions more likely to resort to PPE conservation strategies. Conclusions The present study demonstrates the impact of COVID‐19 on North American cardiac surgeons. Our study should stimulate further discussions to identify optimal solutions to improve workforce preparedness for subsequent surges, as well as facilitate the navigation of future healthcare crises.

Введение. Одна из главнейших проблем современной трансплантологии – иммунологическая дисфункция трансплантата, частота развития которой достигает 40%. Пункционная биопсия в 2,2% случаев сопряжена с развитием осложнений и может привести к летальному исходу. Цель исследования – разработка методики неинвазивной диагностики отторжения трансплантата печени в отдаленном периоде после операции с использованием терминально-дифференцированных эффекторных CD8+Т-лимфоцитов. Материал и методы. Проведено пилотное одноцентровое обсервационное ретроспективное случай-контроль исследование, включающее 45 реципиентов после ортотопической трансплантации печени. По клиническому течению послеоперационного периода пациенты стратифицировались на 2 группы в зависимости от наличия эпизодов отторжения в трансплантате. Все пациенты после трансплантации получали иммуносупрессивную терапию. Иммунофенотипы реципиентов определялись методом проточной цитофлоуметрии. Всем пациентам была выполнена пункционная биопсия трансплантата. Результаты. Результаты исследования биоптатов трансплантатов печени показали, что 14 пациентов (31%) из 45 имели морфологические признаки отторжения. У пациентов с отторжением был достоверно более высокий уровень абсолютного количества СD8+ Тemra-клеток, что составило 0,23 (0,14; 0,38) ×109/л по сравнению с пациентами без отторжения – 0,09 (0,034; 0,16)×109/л (р=0,034). Результаты ROC- анализа показали, что наиболее оптимальный порог отсечения уровня СD8+ Тemra-лимфоцитов при диагностике иммунологической дисфункции трансплантата печени в отдаленном периоде составил 0,1882×109/л, чувствительность и специфичность при данном пороге отсечения составила 73,33 (95% ДИ: 44,9-92,0) и 96,55 (95% ДИ: 82,2-99,4,) соответственно. Выводы. Увеличение абсолютной численности терминально-дифференцированных эффекторных CD8+ Т-лимфоцитов является диагностическим критерием у пациентов с иммунологической дисфункцией трансплантата в позднем посттрансплантационном периоде. Высокая чувствительность и специфичность порога отсечения абсолютного количества CD8+ Тemra-лимфоцитов у пациентов после трансплантации печени и достоверная разница между количеством клеток у пациентов с нормальным послеоперационным течением, имеющих иммунологическую дисфункцию трансплантата, позволяет рассматривать субпопуляцию Т-лимфоцитов как прогностический биомаркер отторжения в позднем посттрансплантационном периоде. Корреляция этого показателя с результатами морфологического исследования делает его альтернативным и, главное, безопасным неинвазивным способом ранней диагностики отторжения.

Objectives The PROSE trial purpose is to investigate whether the incidence of thromboembolic—related complications is reduced with a current generation mechanical prosthesis (On-X Life Technologies/CryoLife Inc.—On-X) compared with a previous generation mechanical prosthesis (St Jude Medical—SJM). The primary purpose of the initial report is to document the preoperative demographics, and the preoperative and operative risk factors by individual prosthesis and by Western and Developing populations. Methods The PROSE study was conducted in 28 worldwide centres and incorporated 855 subjects randomized between 2003 and 2016. The study enrollment was discontinued on August 31, 2016. The preoperative demographics incorporated age, gender, functional class, etiology, prosthetic degeneration, primary rhythm, primary valve lesion, weight, height, BSA and BMI. The preoperative and operative evaluation incorporated 24 risk factors. Results The total patient population (855) incorporated On-X population (462) and the St Jude Medical population (393). There was no significant difference of any of the preoperative demographics between the On-X and SJM groups. The preoperative and operative risk factors evaluation showed there was no significant difference between the On-X and St Jude Medical populations. The preoperative and operative risk factors by valve position (aortic and mitral) also documented no differentiation. The dominant preoperative demographics of the Western world population were older age, male gender, sinus rhythm, aortic stenosis, congenital aortic lesion, and mitral regurgitation. The dominant demographics of the Developing world population were rheumatic etiology, atrial fibrillation, aortic regurgitation, mixed aortic lesions, mitral stenosis and mixed mitral lesions. The Developing world group had only one significant risk factor, congestive heart failure. The majority of the preoperative and operative risk factors were significant in the Western world population. Conclusions The preoperative demographics do not differentiate the prostheses but do differentiate the Western and Developing world populations. The preoperative and operative risk factors do not differentiate the prostheses BUT do differentiate the Western and Developing world populations.

Background. Immune-mediated graft dysfunction with the prevalence of 40% is one of the main problems of modern transplantology. Although percutaneous liver graft biopsy is associated with the development of different complications occurring in 2,2% of cases and can also lead to fatal outcome Objective – to develop a noninvasive method of graft dysfunction diagnostics in the late post-transplant period using terminally differentiated effector CD8+ T-lymphocytes. Material and methods. There was carried out a single center observational retrospective case-control pilot study, including 45 recipients after orthotopic liver transplantation. According to the postoperative clinical course the patients were stratified into 2 groups depending on the presence of graft rejection episodes. All patients got immunosuppressive therapy after liver transplantation. Immunophenotypes of the recipients were determined by flow cytometry method. Percutaneous liver graft biopsy was performed in all patients, the results of histological examination were evaluated according to the international Banff schema for grading liver allograft rejection. Results. The results of liver biopsies showed that 14 (31%) out of 45 patients had morphological signs of rejection. The patients with rejection had a reliably higher level of CD8+ Temra cells absolute number (0,23 (0,14;0,38) x 109/l) in comparison to those without rejection (0,09 (0,034;0,16) x 109/l (p=0,034)). The results of ROC-analysis have shown that the most optimal cut-off threshold of CD8+ T-lymphocytes level in immune-mediated graft dysfunction diagnostics in the late post-transplant period is 0,1882x109/l; sensitivity and specificity in this case being 73,33 (95%; 44,9-92,0) and 96,55 (95%; 82,2-99,4) respectively. Conclusions. The increase of terminally differentiated effector CD8+ T-lymphocytes absolute number has diagnostic importance in patients with immune-mediated graft dysfunction in the late post-transplant period. High sensitivity and specificity of cut-off threshold of CD8+ Temra lymphocytes absolute number in patients after liver transplantation as well as reliable difference between cell number in patients with normal postoperative period and in patients with immune-mediated graft dysfunction allow considering T-lymphocyte subpopulation as a rejection predictor in the late post-transplant period. The correlation between CD8+ T-lymphocyte absolute number and the results of histological examination makes the former an alternative and, what is more, safe noninvasive method in early diagnostics of liver graft rejection.

Transvenous lead extraction can have serious adverse events, such as cardiac or vascular perforation. Risk factors have not been well characterized.The purpose of this study was to identify factors associated with perforation and death, and to characterize lead extraction in a large contemporary population.We performed a retrospective multicenter study examining patients undergoing lead extraction at 8 Canadian institutions from 1996 through 2016. Demographic and clinical data were used to identify variables associated with perforation and mortality using logistic regression modeling.A total of 2325 consecutive patients (age 61.9 ±16.5 years) underwent extraction of 4527 leads. Perforation rate was 2.7% (63/2325) and 30-day mortality was 1.6% (38/2325), with mortality of 0.4% due to perforation (10/2325). Variables associated with perforation included no previous cardiac surgery (odds ratio [OR] 3.33; 95% confidence interval [CI] 1.54-7.19; P = .002), female sex (OR 3.27; 95% CI 1.91-5.60; P.001); left ventricular ejection fraction ≥40% (OR 2.81; 95% CI 1.28-6.14; P = .010); lead age8 years (OR 2.64; 95% CI 1.52-4.60; P.001); ≥2 leads extracted (OR 2.49; 95% CI 1.23-5.04; P = .011); and diabetes (OR 2.12; 95% CI 1.16-3.86; P = .014). Variables associated with death included infection as indication for extraction (OR 3.85; 95% CI 1.38-10.73; P = .010); anemia (OR 3.14; 95% CI 1.38-6.61; P = .003), and patient age (OR 1.04; 95% CI 1.01-1.07; P = .012).Risk factors associated with perforation in lead extraction include no history of cardiac surgery, female sex, preserved left ventricular ejection fraction, lead age8 years, ≥2 leads extracted, and diabetes.

ObjectivesThe PROSE trial purpose is to investigate whether the incidence of thromboembolic – related complications is reduced with a current generation mechanical prosthesis (On-X Life Technologies/CryoLife Inc. – On-X) compared with a previous generation mechanical prosthesis (St Jude Medical – SJM). The primary purpose of the initial report is to document the preoperative demographics, and the preoperative and operative risk factors by individual prosthesis and by Western and Developing populations. MethodsThe PROSE study was conducted in 29 worldwide centres and incorporated 854 subjects randomized between 2003 and 2016. The study enrollment was discontinued on August 31, 2016. The preoperative demographics incorporated age, gender, functional class, etiology, prosthetic degeneration, primary rhythm, primary valve lesion, weight, height, BSA and BMI. The preoperative and operative evaluation incorporated 24 risk factors.ResultsThe total patient population (854) incorporated On-X population (461) and the St Jude Medical population (393). There was no significant difference of any of the preoperative demographics between the On-X and SJM groups. The preoperative and operative risk factors evaluation showed there was no significant difference between the On-X and St Jude Medical populations. The preoperative and operative risk factors by valve position (aortic & mitral) also documented no differentiation. The dominant preoperative demographics of the Western world population were older age, male gender, sinus rhythm, aortic stenosis, congenital aortic lesion, and mitral regurgitation. The dominant demographics of the Developing world population were rheumatic etiology, atrial fibrillation, aortic regurgitation, mixed aortic lesions, mitral stenosis and mixed mitral lesions. The Developing world group had only one significant risk factor, congestive heart failure. The majority of the preoperative and operative risk factors were significant in the Western world population. ConclusionsThe preoperative demographics do not differentiate the prostheses but do differentiate the Western and Developing world populations. The preoperative and operative risk factors do not differentiate the prostheses BUT do differentiate the Western and Developing world populations.

Aim. To analyze the effectiveness of percutaneous minimally invasive technology of pancreatroсystgastrostomy formation on the stent. Material and Methods. The study group consisted of 37 patients with symptomatic single pancreatic pseudocysts type 2 (according to the D'Egidio classification) more than 5 cm in diameter. Modified minimally invasive technique (percutaneous transgastric pancreatoсystogastrostomy followed by stenting of anastomosis under ultrasound and endoscopic guidance) was applied. The control group consisted of 55 patients who underwent traditional surgical methods (pancreatoсystogastrostomy, pancreatoсystojejunostomy). Duration of surgery, postoperative hospital-stay and incidence of complications were analyzed. Follow-up examinations were performed at 6, 12 and 24 months. Results. The use of modified technique reduced duration of surgery from 135 minutes (110; 170) in the control group to 15 minutes (12; 22) in the study group (p < 0.0001), postoperative hospital stay to 4 (3, 5) days (vs. 14 days (11; 18) in the control group, p < 0.0001). Postoperative complications occurred in 2 (5.4%) and 12 (21.8%) patients of main and control groups respectively (p = 0.048). Recurrence of pseudocyst was detected in 7 (12.7%) patients in the control group while in the study group recurrence was absent (p = 0.039). There were no deaths in both groups. Conclusion. Percutaneous transgastric pancreatoсystogastrostomy is an effective treatment for patients with pancreatic pseudocysts type 2 according to D'Egidio classification

Objective The coronavirus disease 2019 (COVID-19) pandemic has resulted in an increase in hospital resource utilization and the need to defer nonurgent cardiac surgery procedures. The present study aims to report the regional variations of North American adult cardiac surgical case volume and case mix through the first wave of the COVID-19 pandemic. Methods A survey was sent to recruit participating adult cardiac surgery centers in North America. Data in regard to changes in institutional and regional cardiac surgical case volume and mix were analyzed. Results Our study comprises 67 adult cardiac surgery institutions with diverse geographic distribution across North America, representing annualized case volumes of 60,452 in 2019. Nonurgent surgery was stopped during the month of March 2020 in the majority of centers (96%), resulting in a decline to 45% of baseline with significant regional variation. Hospitals with a high burden of hospitalized patients with COVID-19 demonstrated similar trends of decline in total volume as centers in low burden areas. As a proportion of total surgical volume, there was a relative increase of coronary artery bypass grafting surgery (high +7.2% vs low +4.2%, P = .550), extracorporeal membrane oxygenation (high +2.5% vs low 0.4%, P = .328), and heart transplantation (high +2.7% vs low 0.4%, P = .090), and decline in valvular cases (high –7.6% vs low –2.6%, P = .195). Conclusions The present study demonstrates the impact of COVID-19 on North American cardiac surgery institutions as well as helps associate region and COVID-19 burden with the impact on cardiac surgery volumes and case mix.

Background— Injuries to cardiac and venous structures during pacemaker and defibrillator lead extraction are serious complications that have been studied poorly. The incidence of these injuries is unknown but likely underestimated. No systematic multicenter review of these injuries or their management has been undertaken. Methods and Results— We interrogated our mandatory administrative database for all excimer laser extractions that sustained a cardiac or venous injury in the province of British Columbia. Injuries were classified according to presentation and compared with respect to nature of injury, type of repair, utilization of cardiopulmonary bypass, and outcome. Of 1082 excimer laser extractions over 19 years, 33 sustained an injury (3.0%). The majority of injuries occurred in women (21/33; 63.6%), and median age of oldest lead extracted was 10.8 (7.5, 12.2) years. A type 1 presentation, defined as circulatory collapse, was found in 12/33 patients (36.4%). A type 2 presentation, defined as progressive hypotension responsive to treatment, was found in 20/33 patients (60.6%). Over half the patients had a moderate or large injury, and cardiopulmonary bypass was required in 13 patients with extensive injury. Despite the presence of devastating injuries, the immediate availability of aggressive salvage measures resulted in a survival of 87.9% of patients at 30 days. Conclusions— The immediate availability of a cardiovascular surgeon, perfusionist, and cardiopulmonary bypass pump facilitates lifesaving repair of injuries sustained during laser lead extraction. The size and complexity of injury correlates closely with the presentation, blood loss, and need for cardiopulmonary bypass to facilitate repair.

On incidental dermal exposure to chemicals in water, a key exposure factor is the amount of water adhering to skin. Although soil adherence factors have been developed for risk assessment, measurements of water adherence on human skin have not been described. In the Environmental Protection Agency's (EPA's) dermal risk assessment guidance, dermal dose from environmental exposures is based upon the flux rate across the skin, which assumes that an unlimited amount of chemical is available for absorption. This assumption is applicable to certain exposure scenarios such as swimming and bathing. However, exposures to contaminated water frequently involve scenarios where the available chemical is limited by the amount of water adhering to the skin, for example, during accidental splashes. We conducted studies in human volunteers to investigate water adherence per unit area of skin after brief contact with water. In two sets of experiments, either water was applied with a micropipette to 10-cm2 areas of the lower leg, foot, and hand, or the foot and hand were briefly immersed in water. In males, using a micropipette, water adherence ranged from 1.93 (foot) to 7.13 μL/cm2 (lower leg). In females, it ranged from 1.10 (lower leg) to 4.83 μL/cm2 (hand). Hand and foot immersion resulted in relatively higher values of 6.89 and 5.17 μL/cm2, respectively, in males, and 5.40 and 6.39 μL/cm2 in females. Water adherence was affected by amount of body hair and type of exposure. Water adherence factors can be used to calculate the applied dose per unit area for exposures involving intermittent water contact.

Mitral valve replacement is more frequently performed and perceived to be equivalent to repair in elderly patients, despite the superiority of repair in younger patients. Our objective was to compare mitral repair to replacement in elderly patients age 75 years or older. Patients younger than 75 years undergoing mitral valve surgery served as a reference population.Consecutive elderly patients undergoing operation for mitral regurgitation at our institution from 1998 to 2006 were reviewed. Elderly patients (mean age, 78.0 +/- 2.8 years) who underwent mitral repair (n = 70) or replacement (n = 47) were compared with cohorts of young patients (mean age, 58.9 +/- 9.3 years) who underwent repair (n = 100) or replacement (n = 98) during the same period. Patient details and outcomes were compared using univariate, multivariate, and Kaplan-Meier analyses.Mitral replacement in elderly patients had higher mortality than repair (23.4%, 11 of 47 versus 7.1%, 5 of 70; p = 0.01) or as compared with either operation in the reference group (p0.0001). Postoperative stroke was higher in elderly replacement patients compared with repair (12.8%, 6 of 47 versus 0%; p = 0.003) or compared with either young cohort (p = 0.02). Compared with elderly repair patients, elderly replacement patients had more cerebrovascular disease (21.3%, 10 of 47 versus 4.3%, 3 of 70; p = 0.005) and rheumatic mitral valves (21.3%, 10 of 47 versus 0%; p = 0.0001). In the young group, overall complication and mortality were no different between replacement and repair. Long-term survival favored repair over replacement in elderly patients (p = 0.04). One elderly repair patient experienced late recurrence of persistent mitral regurgitation.In patients age 75 years or older, mitral repair is associated with a lower risk of mortality, postoperative stroke, and prolonged intensive care unit and hospital stay compared with mitral replacement. Mitral repair can be performed in preference over replacement even in patients older than the age of 75.

Data on some novel kinds of refractory articles and materials developed and produced by the Berezhnoy Ukrainian Research Institute for Refractories (Berezhnoy UkrNIIO) are presented. Corundum articles with Sialon binder and unshaped materials of various kinds (ramming mixtures, dry mixtures, traditional and low-cement refractory concretes) containing normal electrocorundum or refractory scrap instead of the costly white electrocorundum are described.

Although the benefits of mitral valve repair for degenerative disease are well established, many consider surgery for functional ischemic mitral regurgitation (MR) less amenable to operative treatment. We hypothesized that mitral valve repair for ischemic MR results in outcomes similar to those for mitral valve repair for degenerative MR.Retrospective review of nonemergent mitral valve repairs for an 8-year period revealed 105 patients with functional ischemic MR, of whom 39 were treated for severe tethering (ischemic group), and 245 patients with degenerative MR (degenerative group).Patients in the ischemic group had more comorbidities (p0.01) and worse preoperative left ventricular dysfunction (ejection fractionor = 0.29) compared with patients in the degenerative group; (ischemic, 37.1% [39 of 105] versus degenerative, 2.0% [5 of 245]; p0.01). Immediate postrepair transesophageal echocardiogram revealed a 0 to 1+ MR in all patients in both groups (not significant). The hospital mortality rate was 1.9% (2 of 105) in the ischemic group and 1.2% (3 of 245) in the degenerative group (p = 1.00). The 5-year survival rate was 83.9% in the ischemic group and 94.3% in the degenerative group (p0.01). Five-year freedom from reoperation for recurrent MR was 100% and 97.5% in the ischemic and degenerative groups, respectively (p = 0.14). Postoperative renal failure and stroke rates were similar between both groups (not significant). The incidence of moderate or greater MR after more than 1 year of follow-up was similar between groups (not significant).Despite the multiple comorbidities that afflict patients with ischemic MR, mitral valve repair for ischemic and degenerative disease produces comparable and satisfactory outcomes. An aggressive approach to repair of functional ischemic MR, including treatment of tethering, leads to durable results.

Objective Anomalous origin of the right coronary artery from the opposite sinus of Valsalva can be a lethal congenital anomaly. Right internal thoracic artery grafting to the right coronary artery is prone to fail in this circumstance. We sought to describe alternative surgical techniques. Methods Retrospective analysis identified 5 adult and pediatric patients in our database. We reviewed the surgical techniques used to repair this anomaly. On the basis of our experience, we describe our management technique. Results There were no operative deaths, and postoperative computed tomographic scans demonstrated widely patent repairs in all patients. Two patients with previous right internal thoracic artery to right coronary artery grafts presented with occlusion of the right internal thoracic artery. Short-term follow-up demonstrated continued patency. Conclusion Right internal thoracic artery grafting fails in this circumstance, and alternative surgical options provide a good outcome.

Silicon carbide refractory materials and specimens of silicon nitride and silicon oxynitride are tested under high-temperature attack from reducing (H2 and CO) and oxidizing gases (O2, air) and from molten slag, alkalis, and iron. It is shown that nitride-based refractory materials are prone to change their properties, structure, and resistance when exposed to molten slag, iron, and alkalis. Silicon oxynitride and silicon nitride resist attack from carbon monoxide and alkali and provide protection to silicon carbide used as the refractory lining for blast furnaces.

The optimum compositions of oxygen-free mixtures for manufacture of nitride-based refractory bonds are reported. A technology for manufacturing chamotte refractory materials with a compound nitride-based bond is developed. The newly designed materials exhibit improved physicomechanical properties and enhanced durability against attack by alkalis and molten slag.

We present a case report of spontaneous hemothorax associated with neurofibromatosis. On review of the literature, a significant mortality rate of 36% is revealed in addition to a surgical mortality of 33%. Treatment options are reviewed and potential management strategies are discussed.

Properties of aluminosilicate, silicon carbide, and carbon refractories and mixtures used for lining blast furnaces and recommended for the future are presented. Recommendations are given for changing the design of some lining zones with the aim of increasing their endurance and reliability in service.

Extra-anatomic bypass grafts have been used to treat complex and recurrent forms of coarctation of the aorta. Here we describe the use of an extra-anatomic bypass graft from the ascending to supraceliac aorta to treat an unusual complication of compression of mediastinal structures caused by a bucket handle graft.

Silicon carbide refractories with binders of silicon nitride and silicon oxynitride are compared with dense aluminum silicate refractories. It is shown that silicon carbide refractories possess high stability in aluminum melts and vapors of aluminum chloride, whereas aluminosilicate refractories are severely damaged under these conditions. Silicon carbide refractories with a binder of silicon nitride possess the highest resistance to the effect of the tested aggressive factors and are recommended for operation in aluminum melts and gaseous aluminum chloride media.

Investigations of the technology of mullite-corundum refractories containing silicon carbide and used for linings of transportable mixers are described. It is shown that an addition (10%) of silicon carbide to a mullite-corundum mixture ensures a high slag resistance. Mixers lined with mullite-corundum refractories with silicon carbide have shown high service properties, namely, 720 pourings of cast iron with 5 hot repairs.

Formation of a combined nitride-containing binder for mullite-alumina refractories is studied. An optimal combination is found to consist of 80% crystalline silicon, 10% silicon carbide, and 10% aluminum, magnium, or zirconium oxide. Mullite-alumina refractories with selected binders showed high resistance to the effects of slag, alkali, and iron.

On incidental dermal exposure to chemicals in water, a key exposure factor is the amount of water adhering to skin. Although soil adherence factors have been developed for risk assessment, measurements of water adherence on human skin have not been described. In the Environmental Protection Agency's (EPA's) dermal risk assessment guidance, dermal dose from environmental exposures is based upon the flux rate across the skin, which assumes that an unlimited amount of chemical is available for absorption. This assumption is applicable to certain exposure scenarios such as swimming and bathing. However, exposures to contaminated water frequently involve scenarios where the available chemical is limited by the amount of water adhering to the skin, for example, during accidental splashes.

Investigation have been made on development of the production parameters for silicon carbide refractories from SiC, C, and Si. It has been shown that high quality parts are obtained with firing and cooling of the refractories in two gaseous media providing synthesis of a combined binder and high properties. The parts produced are used for protection of blast furnace tuyere noses.

Investigations of refractories made from Polozhe and Novoselits kaolins and fired in oxidizing and reducing conditions showed that development of the properties and phase composition occurs during heating to a certain temperature, in the process of soaking and cooling to 1200°C. The properties of kaolin refractories and their phase composition depend on the atmosphere, the firing temperature, soaking, and cooling rate. These factors are the main means of regulating the properties of refractories.

Compositions of silicon carbide-containing concrete with use of which steel combines have introduced a new method of lining blast furnace shafts have been developed. The physicomechanical and thermophysical properties of the concretes have been investigated and the results indicate their high quality confirmed by reliable operation in service.

Compositions of thermal-insulation concrete mixtures from which various elements of the lining of a furnace for pyrolysis of dichlorethane were produced have been developed. Burner blocks for the gas burners of the furnace were produced by vibrocasting. The refractories developed have provided reliable operation of the furnace, and for three years they have been in good condition.

A study of the formation of sialon in a charge based on the Ovruchsk quartzite and fine aluminum powder established that the density of the products increases with increasing content of the aluminum fines in the body (from 40 up to 60%). The material fired at 1450°C in nitrogen atmosphere consists ofβ-sialon, corundum, and a small quantity of aluminum nitride and silicon oxynitride as impurities.

A composition of mullite-corundum ramming compound has been developed with production of an experimental lot at Semiluki Refractory Plant. This compound was used to line the tuyere assemblies of No. 2 Blast Furnace of Kosogorsk Metallurgical Plant, which are operating successfully and provide a saving as the result of an increase in life and a decrease in heat losses.

The beneficial effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG Co-A) reductase inhibitors (statins) in patients undergoing coronary artery bypass grafting have been recognized. Reduced mortality rates and clinical events have been demonstrated. These outcomes were examined in patients taking statins who underwent cardiac valve operations.This retrospective study included 447 consecutive patients undergoing valve operations between July 2004 and February 2006; 203 patients (45.6%) received statins preoperatively and postoperatively vs 244 who did not. Preoperative risk factors and outcome data for both cohorts were compared. Primary outcomes included 30-day mortality, renal failure, and postoperative stroke.The statin group had more comorbidities. Although they had increased risk factors, including previous stroke (30 of 203 vs 16 of 244, p = 0.004), diabetes (66 of 203 vs 32 of 244, p0.0001), cerebrovascular disease (45 of 203 vs 24 of 244, p = 0.003), and dyslipidemia (191 of 203 vs 63 of 244, p0.0001), they had better outcomes. The unadjusted odds ratio (OR) for the composite end point of death/stroke/renal failure was 1.90 (95% confidence interval [CI], 0.95 to 3.76; p = 0.068) favoring the statin group. By univariate analysis, the adjusted OR for the composite end point demonstrated a benefit with statin therapy: diabetes, 2.29 (95% CI, 1.16 to 4.71; p = 0.024); stroke, 2.15 (95% CI, 1.06 to 4.35; p = 0.034); and renal dysfunction, 2.05 (95% CI, 1.02 to 4.13; p = 0.045).Statin therapy in this population undergoing cardiac valve procedures was associated with decreased postoperative morbidity and death. The mechanism may be independent of statins' lipid-lowering effects. A prospective, randomized-control trial of statin therapy in this population is warranted.

Screening kindergarten students to predict first-grade achievement is characterized by rather gross errors of both over identification and underidentification. This lack of predictive validity may be the consequence of overly simplistic conceptualizations that fail to take into account differences in first-grade teachers. This study attempted to evaluate the extent to which first-grade teachers differ in their preferences, requirements, and expectancies of students. Twenty-one teachers ranked 86 student descriptors on a continuum ranging from “absolutely contributes to student success” to “absolutely contributes to student failure.” Results suggest that teachers vary considerably in the way they rank student descriptors and that these variations may be a factor in the predictive inaccuracy of kindergarten screening.

Inferior vena cava filters are considered the therapeutic modality for treatment of deep venous thrombosis in patients who are not candidates for anticoagulation therapy. Filter migration to the heart is a rare but serious complication. In this report we present two cases of Inferior vena cava filters that migrated to the heart and how they were managed.

Background Only 40% of patients with mitral valve (MV) regurgitation undergo operative repair rather than replacement. Quadrangular resection combined with ring annuloplasty has been the most common method of repair for degenerative posterior leaflet disease. Techniques such as sliding annuloplasty and artificial chord usage have increased the complexity of repair. These techniques have been perceived to be difficult and have possibly reduced the incidence of MV repair. We present our experience with a simplified approach to MV repair utilizing a triangular resection and larger rings. Methods Retrospective review of all MV repairs over a 7-year period (1999 to 2006) revealed 154 patients who underwent triangular resection for degenerative disease. Patients who underwent ring annuloplasty without leaflet resection and patients who had artificial chords or quadrangular resections were excluded. Results Of 154 patients who underwent triangular resection, isolated posterior leaflet resection was performed on 130 patients. Isolated anterior and combined anterior and posterior leaflet triangular resections were performed on 16 and 8 patients, respectively. Thirty-day postoperative mortality was 0%. Five-year freedom from reoperation for recurrent mitral regurgitation was 99.0%. No patients who had intended leaflet resection were converted to MV replacement. Intraoperative transesophageal echocardiogram revealed trace to 1+ mitral regurgitation. Mild systolic anterior motion was noted in 7.1% of cases initially, but resolved with volume loading in all. Conclusions Triangular leaflet resection of the mitral valve produces durable results and can be safely and efficiently performed with minimal morbidity and mortality. This technique should allow increased utilization of MV repair for degenerative disease.

Ischemic cardiomyopathy accounts for as many as 70% of cases of heart failure with no clear algorithm for the treatment. We assessed the operative risks and mortality of various surgical options: coronary artery bypass grafting (CABG), CABG and mitral valve repair (CABG/MVR), and left ventricular remodeling (LVR) with or without CABG. We hypothesized that additional procedures increased the operative risk. We determined whether preoperative variables (eg, urgency of operation) impacted the surgical outcome.A retrospective analysis of University of Virginia patients from January 2000 until September 2006 was undertaken. Patients with CABG and an ejection fraction less than 35%, ischemic mitral regurgitation by operative characterization, and patients with LVR were identified. The Society of Thoracic Surgeons database risks, complications, and outcomes as well as degree of revascularization, quality of targets, and type of additional procedures were analyzed. Incomplete revascularization was defined as a planned bypass not performed. Poor targets were defined as per the operative note.In all, 382 patients were identified (220 CABG, 97 CABG/MVR, and 65 LVR). The overall operative mortality was 7.9%. Mortality was 9.1% for CABG, 8.2% for CABG/MVR, and 3.1% for LVR. Preoperative risk factors for mortality included diabetes mellitus (p = 0.05), previous cerebrovascular disease (p = 0.05), and chronic renal dysfunction (p = 0.03). Patients with emergency operations had a significantly increased mortality (p0.001) as did patients with intra-aortic balloon pumps (p = 0.015).Additional procedures such as MVR or LVR did not add to the operative risk of CABG for ischemic cardiomyopathy. Only preoperative comorbidities and emergency operations increased operative mortality.

This report describes an unusual cause of low cardiac output after coronary artery bypass grafting and left ventricular remodeling. It details left ventricular remodeling techniques and discusses the most recent advances and outcomes. As well, significant attention is paid to the issues surrounding failure to separate from cardiopulmonary bypass.

The ideal strategy for cerebral protection during aortic arch (AA) reconstructive surgery remains undefined. Antegrade cerebral perfusion (ACP) during systemic circulatory arrest (SCA) may provide superior results; however, optimal systemic temperature is undetermined. Our objective was to determine whether "deep" hypothermia is necessary during ACP with SCA, and whether the degree of hypothermia is associated with neurologic outcomes postoperatively.Retrospective series of 72 consecutive patients (aged 65.9 +/- 3.2 years) who underwent AA reconstructive surgery at Vancouver General Hospital using a cerebral protection strategy of ACP with SCA between December 1995 and December 2002. Patients were divided into two groups according to lowest systemic temperature:22 degrees C (n = 52) andor =22 degrees C (n = 20).ACP was via right axillary or innominate artery, +/- left common carotid cannulation. Median SCA time with ACP was not different between groups. There were four hospital deaths (5.6%) (three from the22 degrees C group). Eight patients (11.2%) had major neurologic injuries (seven from the22 degrees C group): 4 (5.6%) permanent (1 fatal) and 4 (5.6%) temporary. There was a trend toward a significantly higher incidence of delirium in the22 degrees C group than theor =22 degrees C group (30.8 vs 10.0%, respectively, p = 0.07).In our experience, SCA with ACP was a safe technique for AA reconstructive surgery. The observation of a larger number of major neurologic injuries, and a trend toward a higher incidence of delirium in the22 degrees C group, suggests that systemic temperatures below 22 degrees C may not be necessary and may be associated with a higher incidence of neurologic injury when using ACP during SCA.