Development of the Low-Pressure Die Casting Process for an Aluminium Alloy Part.

The low-pressure die casting (LPDC) process was experimentally and numerically studied to produce AlSi7Mg0.3 components such as steering knuckles. Steering knuckles are important safety components in the context of a vehicle's suspension system, serving as the mechanical interface that facilitates the articulation of the steering to control the front wheel's orientation, while simultaneously bearing the vertical load imposed by the vehicle's weight. This work focuses on the development of a numerical model in ProCAST®, replicating the production of the aforementioned part. The model analyses parameters such as the filling dynamics, solidification process, and presence of shrinkage porosities. For the purpose of evaluating the quality of the castings, six parts were produced and characterised, both mechanically (tensile and hardness tests) and microstructurally (porosity and optical microscopy analysis). When correlating simulation results with the available experimental data, it is possible to conclude that the usage of the LPDC process is a viable alternative to the use of steels and other metals for the production of very high-quality castings while using lighter alloys such as aluminium and magnesium in more demanding applications.

Primary coronary angioplasty in a nonagenarian.

A woman aged 98 years entered the tertiary hospital service with a picture of acute myocardial infarction of the extensive anterior wall, which began 4 hours earlier. Due to the large myocardial risk area suggested by the electrocardiogram, the patient was taken to the hemodynamics laboratory for the performance of emergency coronary arteriography, which revealed occlusion in the proximal third of the anterior descending artery. Primary angioplasty followed by stent grafting was successfully performed. The patient had a satisfactory evolution (Killip I) and was discharged from the hospital on the seventh postinfarction day. We discuss here aspects of thrombolysis and coronary percutaneous interventions in the aged.

Early ambulation and variability in anticoagulation during elective coronary stenting with a single intravenous bolus of low-dose, low-molecular weight heparin enoxaparin.

BACKGROUND: The best anticoagulation strategy for patients undergoing percutaneous coronary intervention (PCI) remains controversial. The primary objective of this study was to assess the feasibility of immediate sheath removal post-PCI in patients given a single low-dose intravenous (IV) bolus of enoxaparin as the sole anticoagulant. METHODS: In 53 patients with stable coronary disease undergoing elective PCI, a single IV bolus of 0.5 mg per kg enoxaparin was administered 10 minutes before PCI. Patients were pretreated with aspirin 100 mg and clopidogrel 300 mg. The femoral access sheaths were removed immediately after PCI by manual compression. Major and minor bleeding and coronary thrombosis were recorded. Anti-Xa levels were measured before, during and after PCI. RESULTS: One patient had an intracoronary thrombus 60 minutes after enoxaparin administration, and there was 1 ischemic stroke. Fifty-one of the 53 patients had their sheaths successfully pulled immediately post-PCI. One patient had a pseudoaneurysm requiring surgical repair, and 1 patient had a minor bleed. Postprocedural elevation of CK-MB > 3 times the upper limit of normal occurred in 7 patients (13.2%). Anti-Xa activity was 0.56 +/- 0.16 at 10 minutes post-IV injection, and then progressively decreased to 0.14 +/- 0.09 IU/ml at 6 hours after injection. Ten minutes after IV enoxaparin, 12 patients (23.5%) had anti-Xa levels < 0.5 IU/ml. CONCLUSIONS: Immediate removal of femoral sheaths, after a single low-dose of IV enoxaparin for elective stenting appears feasible. However, a sizeable proportion of patients achieved anti-Xa levels below the widely agreed upon "therapeutic" level after injection.

Human myocardium preconditioning during successive balloon inflations: irrelevant influence of both collateral recruitment and clinical pre-intervention interference.

AIMS: We hypothesised that ischaemic preconditioning (IP) results from complex cellular mechanisms without significant collateral recruitment or clinical pre-intervention interference. METHODS AND RESULTS: A total of 58 patients underwent three 2-min balloon inflations separated by 5-min reperfusions. Anginal symptoms were graded according to this scale: 0 = absent, 1 = mild, 2 = moderate and 3 = severe. ST-segment shift and QT dispersion (QTd) were measured from 12 lead ECGs. Ejection fraction (EF) was assessed by 2D echo and collateral flow recruitment by collateral flow index (CFI). Anginal scores were 2.4+/-0.6, 1.7+/-0.5 and 1.2+/-0.6 (p<0.05); ST-segment shifts were 6.0+/-2.1, 3.8+/-1.8, and 1.9+/-1.2 mm (p<0.05); QTd increased from a baseline value of 39+/-24 to 96+/-27 (p<0.05) and decreased to 66+/-23 and 45+/-16 ms, at the end of the first, second and third inflation, respectively. EF decreased from a baseline value of 63+/-3% to 33+/-2%, 34+/-3%, and 36+/-5% in the three inflations. The CFI was approximately 0.15 in all ischaemic periods. CONCLUSION: These results suggest that IP does occur during repeated brief coronary artery occlusion in patients with a low likelihood of both collateral recruitment and clinical pre-intervention interference.

Desfechos tardios da intervenção coronária percutânea com stent farmacológico em pontes de veia safena: dados do Registro InCor / Late percutaneous coronary intervention outcomes with drug-eluting stent in saphenous vein grafts: data from the InCor Registry

Introdução: A segurança e a eficácia do uso de stent farmacológico para o tratamento de lesões em ponte de veia safena (PVS) ainda é motivo de controvérsia. Este estudo avaliou a evolução tardia de pacientes com lesões em PVS tratados com stent farmacológico. Métodos: Registro unicêntrico que incluiu todos os pacientes submetidos a intervenção em PVS com stent farmacológico (n = 82), sem restrições clínicas ou angiográficas, no período de 2003 a 2009. Foram avaliadas as taxas de eventos cardíacos adversos maiores (ECAM), óbito, infarto agudo do miocárdio (IAM), revascularização do vaso-alvo (RVA) e trombose de stent. Resultados: A média de idade foi de 67,8 + 10,2 anos, a maioria era do sexo masculino (85,4%), 40,2% eram diabéticos e 52,4% eram portadores de angina estável. Foi utilizado 1,45 + 0,5 stent por paciente, empregando-se ostent CypherTM na maioria (61%) dos casos. O diâmetro dos stents foi de 3,22 + 0,39 mm e o comprimento, de 20,1 +7,3 mm. A taxa de sucesso angiográfico foi de 96,3%. No seguimento de 4,1 anos, a taxa de ECAM foi de 28%, com 6% de óbito, 19,5% de IAM e 18,2% de RVA. Nesse período ocorreram dois casos de trombose de stent definitiva ou provável (2,4%). Conclusões: Os resultados demonstraram, em seguimento muito tardio, altas taxas de ECAM em pacientes com lesões de PVS tratados com stent farmacológico, provavelmente pelo aspecto mais agressivo da doença vascular em enxertos venosos.

Background: The safety and efficacy of drug-eluting stents in the treatment of saphenous vein graft (SVG) lesions remains controversial. This study assessed the late follow-up of patients with SVG lesions treated with drug-eluting stents. Methods: Single center registry including patients undergoingSVG interventions using drug-eluting stents (n = 82), without clinical or angiographic exclusion criteria, from 2003 to 2009. The rates of major adverse cardiac events (MACE), death, acute myocardial infarction (AMI), target vessel revascularization (TVR) and stent thrombosis were evaluated. Results: Mean age was 67.8 + 10.2 years, most of them were male (85.4%), 40.2% were diabetic and 52.4% had stable angina. An average of 1.45 + 0.5 stents per patient were implanted and CypherTM was the stent used in most ofthe cases (61%). Stent diameter was 3.22 + 0.39 mm and stent length was 20.1 + 7.3 mm. Angiographic success rate was 96.3%. In the 4.1-year follow-up, the rate of MACE was 28%, death 6%, AMI 19.5% and TVR 18.2%. Therewere two cases of definitive or probable stent thrombosis (2.4%) within the follow-up period. Conclusions: Longtermfollow-up showed high MACE rates in patients with SVG lesions treated with drug-eluting stents, probably due tothe accelerated atherosclerosis that develops within the grafted vein conduits.

Evolução clínica de pacientes de alto risco cirúrgico submetidos a intervenção coronária percutânea em tronco da coronária esquerda não-protegido / Clinical outcome in high-surgical-risk patients undergoing percutaneous coronary intervention for unprotected left main coronary artery disease

INTRODUÇÃO: Recentemente, a intervenção coronária percutânea (ICP) em tronco de coronária esquerda (TCE) não-protegido tem se mostrado uma alternativa real à cirurgia de revascularização miocárdica. Os resultados clínicos tardios da ICP nesses pacientes são escassos na literatura, especialmente em nosso meio. Método: Registro de um centro terciário de atenção em cardiologia, que avaliou o seguimento clínico de pacientes com contraindicação à revascularização miocárdica cirúrgica submetidos A ICP em TCE, no período de 2002 a 2009. Nosso objetivo foi avaliar a mortalidade ao final de um ano. Resultados: No total, foram incluídos 77 indivíduos nesta análise, com média de idade de 65,4 +- 13,7 anos, dos quais 59,2 por cento eram do sexo masculino, 25 por cento eram diabéticos e 3,9 por cento eram portadores de insuficiência renal crônica dialítica. Com relação às características angiográficas, 79,6 por cento das lesões eram do tipo B2/C, com envolvimento do óstio em 47,4 por cento e da bifurcação distal em 62,3 por cento. Na maioria dos casos, a indicação de ICP foi emergencial (85,5 por cento) e os stents farmacológicos foram utilizados em 17,5 por cento dos pacientes. Suporte hemodinâmico por meio de balão intra-aórtico foi utilizado em 28,2 por cento da população. Ao final de um ano a probabilidade de sobrevivência...

BACKGROUND: Percutaneous coronary intervention (PCI) in unprotected left main coronary artery (LMCA) disease has proven to be an alternative to coronary artery bypass graft surgery (CABG). However, late clinical results of PCI in these patients are scarce in the literature, especially in our country. METHOD: Data from a tertiary cardiology center registry, which included patients with contraindications to CABG undergoing LMCA PCI, from 2002 to 2009, were analyzed. Our objective was to evaluate the 1-year mortality. RESULTS: A total of 77 subjects were included in this analysis, mean age was 65.4 ± 13.7 years, 59.2% were male, 25% were diabetic, and 3.9% had renal failure requiring dialysis. Regarding the angiographic characteristics, 79.6% of lesions were type B2/C, with involvement of the ostium in 47.4% and distal bifurcation in 62.3%. In most cases PCI was performed as an emergency procedure (85.5%) and drug eluting stents were used in 17.5% of the patients. Hemodynamic support using an intraaortic balloon pump was used in 28.2% of the population. At the end of 1 year the probability of overall survival was 69.7% and almost all of the deaths occurred in the first month of follow-up. CONCLUSION: In this highly selected population with unprotected LMCA disease, including high-surgi

Stenting vs. balloon angioplasty with provisional stenting for the treatment of vessels with small reference diameter.

A consecutive series of interventions in vessels with reference diameter < or = 2.75 mm was retrospectively analyzed according to preprocedure strategy: balloon angioplasty with provisional stenting (PTCA group, 73 patients) and primary stenting (PS group, 122 patients). In the PS group, there were more patients with single-vessel disease (54.1% vs. 37.0%; P = 0.021), less patients with three-vessel disease (9.0% vs. 24.7%; P = 0.003), more LAD interventions (54.9% vs. 31.5; P = 0.002), and less left circumflex interventions (22.1% vs. 45.2%; P < 0.001). Reference diameter was larger in the PS group (2.28 +/- 0.35 mm vs. 2.11 +/- 0.36 mm; P = 0.001). Provisional stenting was performed in 39.7% of PTCA group. At long-term outcome, the incidence of composite major events was similar between the PTCA and the PS groups (20.5% vs. 17.2%, respectively; P = NS). Treatment of small vessels with balloon dilatation and provisional stenting or with primary stenting yielded similar late outcomes. Operators' choice of treatment strategy was based on particular angiographic characteristics.

Angioplastia coronariana primária em nonagenária / Primary coronary angioplasty in a nonagenarian

A woman aged 98 years entered the tertiary hospital service with a picture of acute myocardial infarction of the extensive anterior wall, which began 4 hours earlier. Due to the large myocardial risk area suggested by the electrocardiogram, the patient was taken to the hemodynamics laboratory for the performance of emergency coronary arteriography, which revealed occlusion in the proximal third of the anterior descending artery. Primary angioplasty followed by stent grafting was successfully performed. The patient had a satisfactory evolution (Killip I) and was discharged from the hospital on the seventh postinfarction day. We discuss here aspects of thrombolysis and coronary percutaneous interventions in the aged

Eventos neurológicos na endocardite infecciosa / Neurologicol Events in Infective Endocorditis

PURPOSE--The study of frequency, modalities and course of neurological complications of infective endocarditis (IE), as well as the current indication and value of supplementary examinations. METHODS--Sixty-three patients with IE, 39 with native valve and 24 with valvar prosthesis, were prospectively studied; the mean age was 42 years and 45 (71.4 per cent ) were males. Two groups were formed: A) 41 patients without neurological events and B) 22 patients who presented 28 neurological events before or during hospitalization: ischemic cerebrovascular accident 20, hemorrhagic cerebrovascular accident 2, meningeal hemorrhage 2, meningitis 2, brain abscess 1 and seizure 1. All patients were submitted to neurological clinical examination; 57 computerized tomographies of the cranium, 28 arteriographies and 32 cerebrospinal fluid analysis were performed. RESULTS--The incidence of neurological events corresponded to 34.92 per cent of IE patients, with a clear predominance (85.71 per cent ) of vascular as compared to infectious manifestations. Mortality was 2.32 times higher in group B patients (22.73 per cent x 9.76 per cent ), albeit p = 0.256, and was not related to staphylococcal etiology. The neurological events were not related to sex, age and presence of valvar prosthesis. The presence of neurological complications was greater (p = 0.047) in patients with simultaneous infections in two valves (mitral and aortic) and also (p = 0.00884) in those with IE in prosthesis implanted for less than three months. All supplementary neurological examinations in group A were normal. CONCLUSION--1) Occurrence of neurological events is a factor which influences the prognosis of IE; 2) supplementary neurological examinations did not reveal subclinical neurological complications; 3) neurological complications were significantly more frequent in patients with simultaneous mitral and aortic valve IE; 4) IE in prosthesis implanted for less than 3 months has a greater probability to develop a neurological picture as compared to IE in prosthesis implanted for more than 3 months

Purpose - The study of frequency, modalities and course of neurological complications of infective endocartitis (IE), as well as the current indication and value of suplementary examinations. Methods - Sixty-three patients with IE, 39 with native valve and 24 with valvar prosthesis, were prospectively studied; the mean age was 42 years and 45 (71,4%) were males. Two groups were formed: A) 41 patients without neurological events and B) 22 patients who presented 28 neurological events before or during hospitalization: ischemic cerebrovascular accident 20, hemorrhagic cerebrovascular accident 2, meningeal hemorrhage 2, meningitis 2, brain abscess 1 and seizure 1. All patients were submitted to neurological clinical examination; 57 computerized tomographies of the cranium, 28 arteriographies and 32 cerebrospinal fluid analysis were performed. Results - The incidence of neurological events corresponded to 34.92% of IE patients, with a clear predominance (85.71%) of vascular as compared to infectious manifestations. Mortality was 2.32 times higher in group B patients (22.73% x 9.76%), albeit p=0.256, and was not related to staphilococcal etiology. The neurological events were not related to sex, age and presence of valvar prosthesis. The presence of neurological complications was greater (p=0.047) in patients with simultaneous infections in two valves (mitral and aortic) and also (p=0.00884) in those with IE in prosthesis implanted for less than three months. All supplementary neurological examinations in group A were normal. Conclusion - 1) Occurrence of neurological events is a factor which influences the prognosis of IE; 2) supplementary neurological examinations did not reveal subclinical neurological complications; 3) neurological complications were signifcantly more frequent in patients with simultaneous mitral and aortic valve IE; 4) IE in prosthesis implanted for less than 3 months has a greater probability to develop a neurological picture as compared to IE in prosthesis implanted for more than 3 months

Angioplastia percutânea e revascularizaçäo cirúrgica em hipertensäo renovascular: experiência no tratamento e seguimento de longo prazo em 124 pacientes / Percutaneous Angioplasty and Surgical Revascularization in Renovascular Hypertension. Experience on Long-Term Follow-up and Treatment in 124 Patients

PURPOSE--To report the experience in the treatment and long-term follow-up of patients with renovascular hypertension submitted to angioplasty and/or surgical revascularization, and to compare blood pressure and renal function responses to both treatment. METHODS--One hundred and twenty-four patients diagnosed with renovascular hypertension, divided, according to the etiology, as atherosclerosis (76 patients), fibromuscular dysplasia (32) and arteritis (16), were submitted to isolated or associated treatment of renal revascularization by percutaneous transluminal angioplasty (71 patients) or surgery (84). The patients were followed-up during 2.5 +/- 1.5 years and we evaluate blood pressure response and renal function preservation. In relation to blood pressure control, the patients were considered as cured when normotensives without antihypertensives, improved when normotensives with fewer drugs than previously, and unchanged, when out of these criteria. RESULTS--From 124 patients, 20 per cent were considered cured, 54 per cent improved and 26 per cent unchanged, after a mean follow-up of 2.5 +/- 1.5 years. Patients with atherosclerosis and fibromuscular dysplasia presented a higher rate of care and improvement after surgery. The blood pressure and the number of antihypertensive drugs decreased significantly during the follow-up among patients that cured or improved arterial hypertension, either after angioplasty (190 +/- 26/115 +/- 14 mmHg vs 130 +/- 34/85 +/- 7 mmHg. 2.70 vs 1.60 drugs) or after surgery (194 +/- 17/115 +/- 16 mmHg vs 143 +/- 18 mmHg vs 88 +/- 8 mmHg, 1.88 vs 1.51 drugs). It was also observed a significant decrease of serum creatinine among these patients. CONCLUSION--Renal revascularization in patients with renovascular hypertension, either by angioplasty or surgery, is beneficial to control blood pressure and to preserve renal function in the majority of patients