Ricardo Lima

Revascularização miocárdica em pacientes octogenários: estudo retrospectivo e comparativo entre pacientes operados com e sem circulação extracorpórea

OBJECTIVE: The purpose of the present study is to compare and analyze the benefits of this operation with and without cardiopulmonary bypass in octogenarian patients. METHOD: Retrospective data of the patients aged eighty years or more from December 1995 to December 2003 were analyzed. During this period 73 patients were submitted to coronary artery bypass grafting (CABG), 26 (35.6%) on-pump and 47 (64.4%) off-pump. A comparison was made of the demographic data, preoperative risks, concurrent morbid conditions, types of angina, postoperative complications and surgical outcomes between the on-pump and off-pump groups. The Student t-test was used to compare the groups and the level of significance was set at p-value < 0.05. RESULTS: Both groups showed a high preoperative risk, although the off-pump group presented less surgical mortality (11.5% vs 2.1%, p < 0.05). No strokes were observed in the patients operated on off-pump (11.5% vs 0.0%, p < 0.005). Atrial fibrillation (AF) in the immediate postoperative period was present less often in the off-pump group (30.8% vs 12.8%, p < 0.005). The postoperative mechanical ventilation time and the presence of respiratory failure were less in the off-pump group (p < 0.005). The presence of acute renal insufficiency (ARI) was 19.2% in the on-pump group and 0% in the off-pump group (p < 0.05). There was less need for transfusion of blood or blood derivatives in the off-pump group (69.2% vs 31.9%, p < 0.005). The mean sojourn in the intensive care unit (ICU) was shorter in the off-pump group (p < 0.05). The percentage of patients with no postoperative complications was higher in the off-pump group than in the on-pump group (89.4% vs 61.5%, p <0.001). CONCLUSIONS: The present study suggests that patients aged eighty years and over benefit when submitted to off-pump CABG and that this procedure is associated with low rates of postoperative complications such as stroke, AF, ARI and respiratory insufficiency, and with less time in the ICU, a shorter hospital sojourn, less use of blood derivatives and lower mortality. In octogenarian patients off-pump CABG surgery is a safe and effective technique, and may be the operation of choice when correctly indicated.

Prophylactic intra-aortic balloon pump in high-risk patients undergoing coronary artery bypass surgery: a meta-analysis of randomized controlled trials.

ObjectivesThe aim of this study was to assess the efficacy of a prophylactic intra-aortic balloon pump (IABP) in high-risk patients undergoing coronary artery bypass graft surgery. MethodsMEDLINE, EMBASE, CENTRAL/CCTR, SciELO, LILACS, Google Scholar, and reference lists of relevant articles were searched. We included only randomized controlled trials. Assessments for eligibility, relevance, and study validity and data extraction were performed in duplicate using prespecified criteria. Meta-analysis was carried out using fixed-effect and random-effect models. ResultsSeven publications fulfilled our eligibility criteria. There was no important statistical heterogeneity or publication bias among included studies. In total, 177 patients received prophylactic IABP and 168 did not. Overall relative risk (RR) for hospital mortality in patients treated with prophylactic IABP was 0.255 [95% confidence interval (CI), 0.122–0.533; P<0.001; same results for both effect models]. Pooled RR for postoperative low cardiac output syndrome was 0.206 (95% CI, 0.109–0.389; P<0.001) for the fixed-effect model and 0.219 (95% CI, 0.095–0.504; P<0.001) for the random-effect model. Patients treated with prophylactic IABP presented an overall difference in means for length of intensive care unit stay and hospital stay, which was lower than that in the control group (P<0.001 for both effect models). Only 7.4% (13/177) of patients who received prophylactic IABP developed complications at an insertion site, with no IABP-related death. ConclusionThis meta-analysis supports the use of prophylactic IABP in high-risk patients to reduce hospital mortality.

Endomyocardial Fibrosis: Report of 6 Patients and Review of the Surgical Literature

Six patients with endomyocardial fibrosis were treated by endocardium decortication and atrioventricular valve replacement. There were 5 female patients and 1 male patient ranging from 14 to 48 years old (mean, 30 years). Four patients had involvement of the right ventricle, 1 patient had involvement of the left ventricle, and 1 patient had biventricular disease. There was 1 operative death due to low cardiac output state (the patient with biventricular endomyocardial fibrosis), and there was 1 late noncardiac death. The surgical literature, which describes 19 previously reported cases, was reviewed. On the basis of the results of this series and those of the reported cases, it is concluded that surgical treatment of endomyocardial fibrosis is feasible and provides good clinical improvement.

Análise da eficiência do mercado futuro brasileiro de boi gordo usando co-integração

The hypothesis that future prices are unbiased predictors of spot prices is a joint hypothesis that markets are efficient and risk premium are absent. However, the unbiasedness hypothesis may be rejected in the presence of a risk premium, even when the market is efficient. The objective of this article is to test market efficiency for the Brazilian live cattle while permitting the presence of risk premium, using cointegration techniques. Results show that the future markets for live cattle are efficient and unbiasedness in the long run, and does not depend of the presence of a risk premium.

Myocardial revascularization without cardiopulmonary bypass: historical background and thirty-year experience

Myocardial revascularization without cardiopulmonary bypass (CPB) was introduced into surgical practice years after conventional coronary artery bypass surgery utilizing CPB. The initial series of consecutive patients revascularized without CPB were reported by a few groups, showing the possibility of achieving similar results via a less invasive approach. The technique, however, did not gain immediate widespread acceptance due to difficulties in performing coronary artery anastomoses on a beating heart. Two decades later, controversy still remains regarding case selection, advantages and pitfalls of the technique. The historical background of the development of off pump coronary surgery is herein presented, as well as points of view regarding training, longterm results, and applicability. Historically, among several indirect myocardial revascularization procedures, only the Vineberg operation developed at McGill University in Montreal, Canada by Dr. Arthur Vineberg, showed promising results. At that time he performed the procedure without knowledge of coronary artery anatomy [1]. Direct myocardial revascularization was later made possible with the introduction of coronary angiography by Mason Jones at the Cleveland Clinic in the early sixties [2]. Rene Favaloro, in the same Institution, pioneered direct coronary artery revascularization with the use of reverse saphenous vein, utilizing CPB and cardiac arrest. His initial reports focused on selection of patients and technical challenges with the operation. It is to be noted that Garret et al, in November 1964, performed a coronary bypass grafting with a segment of saphenous vein, instead of endarterectomy, without knowledge of the coronary anatomy, thereby antedating Rene Favaloro. A successful seven-year follow up of this patient was later published [4]. The familiarity of surgeons with CPB circuits and the development of myocardial protective strategies led surgeons to perform myocardial revascularization procedures on CPB, despite the fact that the coronary arteries are located on the surface of the heart. Also, the operation was performed on an arrested, rather than beating, heart. The idea of constructing a coronary artery bypass anastomosis on a beating heart was conceived, and performed long before saphenous vein grafting under CPB and cardiac arrest. In 1953, Demikhov [5], in Russia, and Murray et al. [6], in Canada, simultaneously performed left internal mammary artery anastomoses to the left anterior descending coronary artery in a beating heart. Goetz et al. [7], in 1961, continued experimental direct myocardial revascularization with the mammary artery and mechanical suture with tantalum ring. Kolesov & Potashov [8,9] reported in the Russian literature in 1965, and later in the United States in 1967, the first clinical experience with mammary artery coronary bypass to the left anterior descending coronary artery in a beating heart via left thoracotomy. Mechanical suture was utilized in a few cases. All these operations were performed without the benefit of angiography, which had not been developed at that time. Years later, Trapp & Bisarya [10] in Canada and, in the same year, Ankeny [11] in Western Reserve – Cleveland, independently reported acceptable results using this technique. Technical difficulties and the fear that occlusion of a coronary artery could lead to ischemia and myocardial infarction, hampered the acceptance of this procedure. Complex perfusion devices were considered necessary, as illustrated in a paper published by Trapp & Bisarya, outlining some of the obstacles for construction of the distal coronary artery anastomoses under these conditions [10]. Years later, Buffolo et al. [12] and independently, Benetti [13] reported consecutive series of patients undergoing saphenous vein or mammary artery bypass grafting to left

Previsão de preços futuros de Commodities agrícolas com diferenciações inteira e fracionária, e erros heteroscedásticos

This paper intends to model time series with the aim of per-form forecast using integer and fractional differencing for agricultural commodities future’s price. Time series models of the ARMA/ARIMA type (integer differencing) will be estimated and compared to ARFIMA type models (fractional differencing). In both cases errors are modeled assuming the occurrence of volatility. The forecast power of each model will be compared using the criterion of the mean squared error (MSE). The estimation of fractional term (d) will be also used to examine the long run dependency properties of the series. The results showed that, for all series, returns are stationary. The sugar series, however, showed anti-persistency, while all other series showed to be long memory. The ARFIMA models showed, in general, a better forecasting performance.

Mitral valve replacement combined with coronary artery bypass graft surgery in patients with moderate-to-severe ischemic mitral regurgitation

INTRODUCTION Ischemic mitral regurgitation (IMR) is associated with increased mortality. Even after coronary artery bypass grafting (CABG), IMR reduces survival. Several studies have shown increased perioperative mortality for mitral valve replacement (MVR) in this situation, but the subject remains controversial. OBJECTIVE To investigate the impact of MVR on immediate outcomes in patients with moderate-to-severe IMR undergoing concomitant CABG compared with those undergoing CABG only. METHODS We performed a retrospective study of 42 patients undergoing CABG+MVR (n=16) or CABG only (n=26) at the Division of Cardiovascular Surgery of PROCAPE, between May 2007 and April 2010. Preoperative clinical characteristics, procedural characteristics, major and minor complications after surgery, preoperative and postoperative left ventricular ejection fraction (LVEF) by echocardiography, and outcome (survivor or death) were assessed. RESULTS Mean patient age was 63.4 ± 8.5 years, and 64.8% (n=23) were male. The CABG+MVR group showed lower rates of postoperative low cardiac output (6.3% vs. 42.3%, p=0.014) and atrial fibrillation (6.3% vs. 38.5%, p=0.021). Both groups had higher mean LVEF in the postoperative compared with the preoperative period, but the average gain in LVEF in the CABG+MVR group was higher than in the CABG-only group (8.88 ± 2.39 vs. 4.31 ± 1.23, p<0.001). There was no significant difference in operative mortality (6.3% vs. 7.7%, p=0.679). CONCLUSIONS CABG+MVR can be performed safely in patients with moderate-to-severe IMR. CABG+MVR resulted in lower rates of complications than CABG only. Both surgical approaches resulted in significant improvement of postoperative LVEF. However, there was greater improvement in the CABG+MVR group.

An annotation-based approach for JCSP concurrent programming: a quantitative study

The construction of large scale parallel and concurrent applications is one of the greatest challenges faced by software engineers nowadays. Modern programming models for concurrency including libraries implementing high level abstractions such as JCSP lead to tangled and scattered concurrency code. As such, this paper outlines our initial effort on the separate of concurrent (JCSP code) concern from the sequential Java processes. We explore metadata annotations to implement this separation of concerns. A compiler generates AspectJ code used to instrument the JCSP features under the hood. We also present a case study that assesses the benefits of the proposed approach through a metrics suite

Análise da relação entre importações e produtividade: evidência empírica para a indústria de transformação do Brasil

A decada de 1990 foi marcada por mudancas na economia brasileira, dentre elas a abertura comercial e a retomada do crescimento da produtividade. Muitas teorias e trabalhos empiricos apontam os impactos do comercio externo sobre a produtividade e o crescimento economico, mas ainda nao ha consenso sobre essas questoes. Este trabalho tem por objetivo examinar a relacao entre o volume das importacoes e a produtividade do trabalho da industria de transformacao do Brasil. Para tanto, foram utilizados dados trimestrais das variaveis e a tecnica dos vetores autorregressivos. Os resultados indicaram que o crescimento das importacoes influencia positivamente a produtividade.

An adaptable framework for distributed and parallel applications

Complex applications need powerful computers to achieve results in a valid time. However, such machines are very expensive and not always available. An alternative is the adoption of several simple, less powerful, and less expensive computers, which triggers the need for an adaptable framework that would support parallel and distributed execution in several environments and with different communication protocols. By executing in a heterogeneous environment, the user benefits from a higher number of machines. The framework we propose allows switching from a heterogeneous to a more specialized executing environment, if or when it is available. It supports both newcomers who can use existing default implementations to more quickly create applications of their own, and experienced programmers who, besides using existing framework abstractions and implementations, can also implement some parts to increase performance. In fact, the main objective is supporting researches, being acceptable to loose some performance when compared to a tailored, and harder to implement solution, still having a better performance when compared to a nonparallel approach.