Marcos Aurélio Barboza de Oliveira

Acute kidney injury after on-pump coronary artery bypass graft surgery.

FUNDAMENTO: Lesion renal aguda (LRA) es una compleja enfermedad, la que, actualmente, no tiene definicion patron acepta. AKIN (Acute Kidney Injury Network) representa una tentativa de estandardizacion de criterios para el diagnostico y estadiamiento de LRA basado en los criterios RIFLE (risk, injury, failure, loss, y end-stage kidney disease) publicados recientemente. OBJETIVO: Evaluar la incidencia y mortalidad asociada a LRA en pacientes sometidos a revascularizacion del miocardio (RM) con circulacion extracorporea (CEC). METODOS: El total de 817 pacientes fueron divididos en dos grupos: LRA negativa (-), con 421 pacientes (51,5%), y LRA positiva (+), con 396 pacientes (48,5%). LRA fue considerada la elevacion de creatinina en 0,3 mg/dl el aumento en 50% de creatinina en relacion a su valor basal. RESULTADOS: La mortalidad dentro de 30 dias de los pacientes con y sin LRA ha sido de 12,3 y 1,4%, respectivamente (p 14 dias), 14 versus 2%; p<0,0001. CONCLUSION: En la poblacion estudiada, mismo una discreta alteracion de la funcion renal basada en los criterios AKIN ha sido predictora independiente de obito, en 30 dias tras RM con CEC. (Registro ClinicalTrials.gov - NCT00780845).BACKGROUND The acute kidney injury (AKI) is a complex disease for which there is no accepted standard definition nowadays. The Acute Kidney Injury Network (AKIN) represents an attempt to standardize the criteria for diagnosis and staging of acute renal dysfunction based on recently published RIFLE criteria, that means, (Risk, Injury, Failure, Loss, and End-stage kidney disease). OBJECTIVES To evaluate the incidence and associated mortality of AKI in patients submitted to on-pump coronary artery bypass graft surgery (on-pump CABG). METHODS A total of 817 patients were divided into two groups: negative AKI (-), with 421 patients (51.5%), and positive AKI (+), with 396 patients (48.5%). Increase of 0.3 mg/dL in creatinine or of 50% in creatinines basal value was considered as AKI. RESULTS The rate of patients mortality with or without AKI within 30 days after cardiac surgery was 12.6% and 1.4%, respectively (p<0.0001). In a multivariate logistic regression model, AKI after on-pump CABG was an independent predictor of death within 30 days (OR=6.7; p=0.0002). This group of patients presented a longer period of permanency in intensive care unit (ICU) [median 2 days (2 to 3) versus 3 days (2 to 5); p=0.0001] and a bigger proportion of patients with prolonged permanence in intensive care (>14 days) (14 versus 2%; p=0.0001). CONCLUSION In the studied population, even a discrete alteration in renal function, based on AKIN criteria, was an independent predictor of death in 30 days after on-pump CABG.

Concepts of basic physics that every cardiovascular surgeon should know: part I - mechanics of fluids

The professional activity that the cardiovascular surgeon performs is much more than a simple gesture to mechanically operate the patients heart. There is in every act of intraoperative most notions of physiology and physics than we generally realize. This paper discusses, in the light of mathematics, on the dynamics of fluids, ie blood, focused on invasive measurements of blood pressure, the effect of vessel size on its internal resistance and the flow passing through it in conversion of various units of measurements of pressure and resistance, blood viscosity and its relationship to the vessel, hemodilution, differences in laminar and turbulent flow, velocity and blood pressure and wall tension after a stenosis and the origin of poststenotic aneurysm. This study is not to enable the reader to the knowledge of all physics, but to show it as a useful tool in explaining phenomena known in the routine of cardiovascular surgery.

Modes of induced cardiac arrest: hyperkalemia and hypocalcemia--literature review.

The entry of sodium and calcium play a key effect on myocyte subjected to cardiac arrest by hyperkalemia. They cause cell swelling, acidosis, consumption of adenosine triphosphate and trigger programmed cell death. Cardiac arrest caused by hypocalcemia maintains intracellular adenosine triphosphate levels, improves diastolic performance and reduces oxygen consumption, which can be translated into better protection to myocyte injury induced by cardiac arrest.

The importance of troponin I in the diagnosis of myocardial infarction in the postoperative of coronary artery bypass graft surgery

OBJECTIVE The aim of this study is to establish a cut-off value for troponin I by correlating it to occurrence of postoperative myocardial infarction. METHODS 180 consecutive patients with coronary disease referred for surgery were included. The mean age of the patients were 60.6 (+/-9.3) years, with 119 (66.1%) males and 61 (33.9%) females. The patients were divided into two groups: group without myocardial infarction (A)--170 patients--and with myocardial infarction (B)--10 patients.The troponin I was collected from each patient at the beginning of anesthesia and on the second postoperative day by correlating it to presence or not of postoperative myocardial infarction. StatsDirect 1.6.0 for Windows was used for statistical analysis. RESULTS Preoperative troponin I was 1.0 (+/-6) ng/ml as mean. Univariate logistic regression showed correlation of troponin I of the second postoperative day with myocardial infarction (P=0.0005). ROC curve was used to define the cutoff value, and 6.1 ng/ml (sensitivity=90.0%, specificity=82.1%, OR=49.8 with CI=95% 6.1- 410.4, P<0.0001) were found. CONCLUSION The chance of a patient with postoperative myocardial infarction to present troponin I equal to or higher than 6.1 ng/ml is 49.8-fold higher than the chance of a patient without infarction to present troponin I higher than this value.

Lesão renal aguda após revascularização do miocárdio com circulação extracorpórea

FUNDAMENTO: Lesion renal aguda (LRA) es una compleja enfermedad, la que, actualmente, no tiene definicion patron acepta. AKIN (Acute Kidney Injury Network) representa una tentativa de estandardizacion de criterios para el diagnostico y estadiamiento de LRA basado en los criterios RIFLE (risk, injury, failure, loss, y end-stage kidney disease) publicados recientemente. OBJETIVO: Evaluar la incidencia y mortalidad asociada a LRA en pacientes sometidos a revascularizacion del miocardio (RM) con circulacion extracorporea (CEC). METODOS: El total de 817 pacientes fueron divididos en dos grupos: LRA negativa (-), con 421 pacientes (51,5%), y LRA positiva (+), con 396 pacientes (48,5%). LRA fue considerada la elevacion de creatinina en 0,3 mg/dl el aumento en 50% de creatinina en relacion a su valor basal. RESULTADOS: La mortalidad dentro de 30 dias de los pacientes con y sin LRA ha sido de 12,3 y 1,4%, respectivamente (p 14 dias), 14 versus 2%; p<0,0001. CONCLUSION: En la poblacion estudiada, mismo una discreta alteracion de la funcion renal basada en los criterios AKIN ha sido predictora independiente de obito, en 30 dias tras RM con CEC. (Registro ClinicalTrials.gov - NCT00780845).BACKGROUND The acute kidney injury (AKI) is a complex disease for which there is no accepted standard definition nowadays. The Acute Kidney Injury Network (AKIN) represents an attempt to standardize the criteria for diagnosis and staging of acute renal dysfunction based on recently published RIFLE criteria, that means, (Risk, Injury, Failure, Loss, and End-stage kidney disease). OBJECTIVES To evaluate the incidence and associated mortality of AKI in patients submitted to on-pump coronary artery bypass graft surgery (on-pump CABG). METHODS A total of 817 patients were divided into two groups: negative AKI (-), with 421 patients (51.5%), and positive AKI (+), with 396 patients (48.5%). Increase of 0.3 mg/dL in creatinine or of 50% in creatinines basal value was considered as AKI. RESULTS The rate of patients mortality with or without AKI within 30 days after cardiac surgery was 12.6% and 1.4%, respectively (p<0.0001). In a multivariate logistic regression model, AKI after on-pump CABG was an independent predictor of death within 30 days (OR=6.7; p=0.0002). This group of patients presented a longer period of permanency in intensive care unit (ICU) [median 2 days (2 to 3) versus 3 days (2 to 5); p=0.0001] and a bigger proportion of patients with prolonged permanence in intensive care (>14 days) (14 versus 2%; p=0.0001). CONCLUSION In the studied population, even a discrete alteration in renal function, based on AKIN criteria, was an independent predictor of death in 30 days after on-pump CABG.

Forma inusitada de Pericardite Crônica Constritiva Idiopática

A 55-year-old male patient presented in our service with progressive dyspnea and ascitis beginning 1 year and 8 months previously. He weighed 160 kg (normal weight 95 kg), with ascitis and orthopnea. On admission he presented normal echocardiograms. An electrocardiogram showed diffuse inverted T waves. An endomyocardial biopsy was not elucidative. A new echocardiogram confirmed a very thick pericardium. Surgical pericardial resection was indicated. The postoperative period was uneventful with complete remission of symptoms. The anatomopathological analysis was normal. The pericarditis was classified as idiopathic. This case is a warning for the need of much suspicion in patients with apparent causeless voluminous ascitis.

Risk factors for mortality of patients undergoing coronary artery bypass graft surgery

Introduction Coronary artery bypass grafting is a safe procedure performed worldwide with low rates of mortality and morbidity in general population. Objective To investigate risk factors for mortality of patients undergoing coronary artery bypass grafting coronary artery bypass grafting surgery. Methods A total of 1,628 consecutive patients undergoing on-pump coronary artery bypass grafting were retrospectively studied from December 1999 to February 2012. Data analysis involved paired Student t test, Mann-Whitney test and Fisher’s exact test for the categorical data. Logistic regression, Odds Ratio and 95%CI were used for definition of risk factors for mortality. Results Of a total of 1,628 patients undergoing on-pump coronary artery bypass grafting, 141 (8.7%) died. The following risk factors for mortality were identified after logistic regression: dialysis (OR=7.61; 95%CI 3.58-16.20), neurologic dysfunction type I (OR=4.42; 95%CI 2.48-7.81), use of IABP (OR=3.38; 95%CI 1.98-5.79), cardiopulmonary bypass time (OR=3.09; 95%CI 2.04-4.68), serum creatinine on admission and peak values > 0.4mg/dL (OR=2.67; 95%CI 1.79-4.00), age > 65 years (OR=2.31; 95%CI 1.55-3.44), and time between hospital admission and and surgical procedure (OR=1.53; 95%CI 1.03-2.27). Conclusion Dialysis, type I neurologic dysfunction, use of IABP, cardiopulmonary bypass time (> 115 minutes), serum creatinine on admission and peak values>0.4mg/dL, age > 65 years and time between hospital admission and surgical procedure were considered as risk factors for mortality in patients undergoing on-pump coronary artery bypass grafting surgery.

The calcium paradox - What should we have to fear?

The calcium paradox was first mentioned in 1966 by Zimmerman et al. Thereafter gained great interest from the scientific community due to the fact of the absence of calcium ions in heart muscle cells produce damage similar to ischemia-reperfusion. Although not all known mechanisms involved in cellular injury in the calcium paradox intercellular connection maintained only by nexus seems to have a key role in cellular fragmentation. The addition of small concentrations of calcium, calcium channel blockers, and hyponatraemia hypothermia are important to prevent any cellular damage during reperfusion solutions with physiological concentration of calcium.

Comparison of fractal dimension and Shannon entropy in myocytes from rats treated with histidine-tryptophan-glutamate and histidine-tryptophan cetoglutarate

Introduction Solutions that cause elective cardiac arrest are constantly evolving, but the ideal compound has not yet been found. The authors compare a new cardioplegic solution with histidine-tryptophan-glutamate (Group 2) and other one with histidine-tryptophan-cetoglutarate (Group 1) in a model of isolated rat heart. Objective To quantify the fractal dimension and Shannon entropy in rat myocytes subjected to cardioplegia solution using histidine-tryptophan with glutamate in an experimental model, considering the caspase markers, IL-8 and KI-67. Methods Twenty male Wistar rats were anesthetized and heparinized. The chest was opened, the heart was withdrawn and 40 ml/kg of cardioplegia (with histidine-tryptophan-cetoglutarate or histidine-tryptophan-glutamate solution) was infused. The hearts were kept for 2 hours at 4ºC in the same solution, and thereafter placed in the Langendorff apparatus for 30 min with Ringer-Locke solution. Analyzes were performed for immunohistochemical caspase, IL-8 and KI-67. Results The fractal dimension and Shannon entropy were not different between groups histidine-tryptophan-glutamate and histidine-tryptophan-acetoglutarate. Conclusion The amount of information measured by Shannon entropy and the distribution thereof (given by fractal dimension) of the slices treated with histidine-tryptophan-cetoglutarate and histidine-tryptophan-glutamate were not different, showing that the histidine-tryptophan-glutamate solution is as good as histidine-tryptophan-acetoglutarate to preserve myocytes in isolated rat heart.

Evaluation of infant membrane oxygenator in sheep

OBJECTIVE To analyze the security and efficacy of a new membrane oxygenator, the so-called OXM - 1500. METHODS From May 2005 to September 2006, six sheep of Santa Inês breed (five male and one female, respectively) were studied. The average body weight was 14.1 (+/-5) kg, body surface 0.6 (+/-0.2) m(2) and a mean age 3.8 (+/-1.5) months. All of them were submitted to extracorporeal circulation (CEC) with evaluation at 10, 30, 60, 120, 180 and 240 minutes. The following values were obtained: values of oxygen transference (TTO2) and carbon dioxide transference (TTCO2), haemoglobin (HBS) and free haemoglobin (HBL), the score of platelets and of leucocytes, and heat transference rate. RESULTS TTO2 and TTCO2 were adequate. Lesion of the majority formed blood elements was insignificant; there no modifications in HBS, HBL levels; platelets and leucocytes decreased over time. Heat exchange was effective (p < 0.05). CONCLUSIONS The membrane OXM--1500 infant oxygenator, tested in sheep, showed adequate oxygenation capacity, CO2 removal capacity, and small alteration of haemoglobin and platelets without significant decrease of leucocytes, as expected. Heat exchanger connected to the oxygenator was efficient in temperature changes.