Accelerated progression of arterial stiffness in dialysis patients compared with the general population

BACKGROUND/AIMS: The aim of this study was to compare the progression of aortic stiffness in chronic hemodialysis patients (CHP) with that of general population patients (GPP) over a 36-month period and to evaluate the determinants of this progression. METHODS: The study group included 80 patients undergoing hemodialysis (aged 59.3 +/- 11.8 years; duration of dialysis 5.47 +/- 5.16 years). The control group consisted of 60 patients (aged 57.5 +/- 10.9 years) with a glomerular filtration rate of > 60 mL/min/1.73 m2. Pulse wave velocity (PWV) was determined from time diversity propagation of the common carotid artery and femoral artery by Doppler ultrasound. Clinical and biochemical parameters were determined in serum using standard laboratory procedures. RESULTS: The mean PWV values at baseline and 36 months were 11.18 +/- 2.29 and 11.82 +/- 2.34 m/sec in the CHP group, and 9.02 +/- 1.89 and 9.29 +/- 1.93 m/sec in the GPP group, respectively. The average PWV progressions were 63.95 +/- 18.373 cm/sec in CHP and 27.28 +/- 28.519 cm/sec in GPP. By multiple regression analysis, hemoglobin (standardized coefficient beta [betast] = -0.405, p = 0.004; betast = -0.364, p = 0.011), albumin (betast = -0.349, p = 0.042; betast = -0.303, p = 0.034), CRP (betast = 0.458, p = 0.002; betast = 0.187, p = 0.008), and total cholesterol (betast = 0.236, p = 0.038; betast = 0.171, p = 0.078) were independently associated with PWV in the CHP and GPP groups, respectively. CONCLUSIONS: Accelerated arterial stiffness was more pronounced in the CHP group than in the GPP group. The independent determinants of this progression in both groups include traditional risk factors and blood levels of hemoglobin, albumin and CRP. Cholesterol and uremia-related factors are determinants only in CHP.

Técnica de cuantificación de la agregación eritrocitaria por análisis digital de imágenes / Erythrocyte aggregation quantification technique using digital image analysis / Técnica de quantificagáo do agregado eritrocitário por análise digital de imagens

La caracterización de agregados eritrocitarios es importante para analizar las posibles alteraciones en la microcirculación observadas en ciertas patologías vasculares como la hipertensión y la diabetes. El objetivo de este trabajo fue estandarizar una técnica que pueda ser utilizada por cualquier operador con un equipamiento similar. Para ello se prepararon distintas suspensiones de glóbulos rojos de dadores sanos en plasma autólogo, que fueron observadas con un microscopio óptico invertido. Se registraron para su análisis las imágenes de los agregados con una cámara digital. Se realizaron los recuentos de células individuales, agregados de 2 a 4 células, agregados de 5 ó más células y amas (redes de agregados de gran tamaño). Se midió el perímetro y el área, obteniéndose un parámetro de forma (ASP) de cada agregado de 5 ó más células. Los resultados obtenidos permitieron estandarizar el protocolo de trabajo concluyendo que la dilución óptima de glóbulos rojos en plasma autólogo para esta técnica es 0,5%.

Characterization of erythrocyte aggregates is important in the analysis of the possible alterations observed in the microcirculation of certain vascular pathologies such as hypertension and diabetes. The objective of this work was to standardize a technique that can be used by any operator having similar equipment. For that purpose, different suspensions of red blood cells from healthy donors were prepared in autologous plasma and then observed with an inverted light microscope. The images of the aggregates were recorded with a digital camera in order to be later analyzed. Individual cell count was carried out, as well as 2 to 4 cell- aggregates, 5 or more cell- aggregate and amas (big aggregate networks). Measurement of perimeter and area of each of the aggregates made up of 5 or more cells was performed, getting a shape parameter (ASP). Due to the results obtained, this working protocol has been standardized and it can be concluded that the optimal dilution of red blood cells in autologous plasma is 0.5% for this particular technique.

A caracterizagáo de agregados eritrocitários é importante para analisar as possíveis alteragóes na microcirculagáo observadas em certas patologias vasculares como a hipertensáo e a diabetes. O objetivo deste trabalho foi padronizar uma técnica que possa ser utilizada por qualquer operador com um equipamento similar. Para isso foram preparadas diversas suspensóes de glóbulos vermelhos de doadores saudáveis em plasma autólogo, que foram observadas com um microscópio óptico invertido. Foram registradas para a sua análise as imagens dos agregados com uma camera digital. Realizaramse as recontagens de células individuais, agregados de 2 a 4 células, agregados de 5 ou mais células e amas (redes de agregados de grande tamanho). Foi medido o perímetro e a área, obtendo um parametro de forma (ASP) de cada agregado de 5 ou mais células. Os resultados obtidos permitiram padronizar o protocolo de trabalho concluindo que a diluigáo ótima de glóbulos vermelhos em plasma autólogo para esta técnica é de 0,5%.

Plasma N-Terminal Pro-B-Type Natriuretic Peptide Is Predictive of Perioperative Cardiac Events in Patients Undergoing Vascular Surgery

BACKGROUND/AIMS: Identification of patients at high risk for perioperative cardiac events (POCE) is clinically important. This study aimed to determine whether preoperative measurement of plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) could predict POCE, and compared its predictive value with that of conventional cardiac risk factors and stress thallium scans in patients undergoing vascular surgery. METHODS: Patients scheduled for non-cardiac vascular surgery were prospectively enrolled. Clinical risk factors were identified, and NT-proBNP levels and stress thallium scans were obtained. POCE was the composite of acute myocardial infarction, congestive heart failure including acute pulmonary edema, and primary cardiac death within 5 days after surgery. A modified Revised Cardiac Risk Index (RCRI) was proposed and compared with NT-proBNP; a positive result for ischemia and a significant perfusion defect (> or = 3 walls, moderate to severely decreased, reversible perfusion defect) on the thallium scan were added to the RCRI. RESULTS: A total of 365 patients (91% males) with a mean age of 67 years had a median NT-proBNP level of 105.1 pg/mL (range of quartile, 50.9 to 301.9). POCE occurred in 49 (13.4%) patients. After adjustment for confounders, an NT-proBNP level of > 302 pg/mL (odds ratio [OR], 5.7; 95% confidence interval [CI], 3.1 to 10.3; p < 0.001) and a high risk by the modified RCRI (OR, 3.9; 95% CI, 1.6 to 9.3; p = 0.002) were independent predictors for POCE. Comparison of the area under the curves for predicting POCE showed no statistical differences between NT-proBNP and RCRI. CONCLUSIONS: Preoperative measurement of NT-proBNP provides information useful for prediction of POCE as a single parameter in high-risk patients undergoing noncardiac vascular surgery.

Relation between hypercholesterolaemia and vascular endothelial microinflammation

We investigated the correlation between hypercholesterolaemia and oxidative stress and P-selectin and interleukin-6 [IL-6] as markers for endothelial status. We studied 40 Egyptian adults with asymptomatic hypercholesterolaemia and 20 age- and sex-matched controls. Lipid peroxidation was significantly higher [P < 0.001] in the study group and positively correlated with cholesterol [P < 0.001] and low-density lipoprotein [LDL] [P < 0.002]. Glutathione peroxidase activity was also significantly higher [P < 0.001] with positive correlation with cholesterol [P < 0.001] and LDL [P < 0.001]. Markers for endothelial cell function were significantly higher in the study group [P < 0.001] with a positive correlation with cholesterol [P < 0.001] and LDL [P < 0.001]. Hypercholesterolaemia causes endothelial microinflammation, and P-selectin and IL-6 may also be risk factors for cardiovascular disease

Fibrinógeno y vasculopatía diabética / Fibrinogen and diabetic vasculopathy

La enfermedad vascular se presenta con mayor frecuencia en los diabéticos. En su patología están involucrados fenómenos aterogénicos y trombóticos. Se ha demostrado en diabéticos y no diabéticos que el fibrinógeno >300mg/dl sería un factor de riesgo coronario. Los métodos para su cuantificación son poco confiables; se ha desarrollado uno más preciso, que por oscilación magnética mide el tiempo de formación del coágulo. En diabéticos los niveles elevados de fibrinógeno están asociados a las complicaciones micro y macroangiopáticas; la hiperglicemia crónica produce un fibrinógeno glicosilado más resistente a la fibrinólisis. Los diabéticos microalbuminúricos tienen concentraciones de fibrinógeno superiores a los normoalbuminúricos y existe una correlación positiva entre los dos parámetros bioquímicos. Se deben tomar estrategias terapeúticas para disminuir el fibrinógeno; la reducción de peso, el control de la glicemia, de los lípidos y de la presión arterial son medidas efectivas. Entre los fármacos el bezafibrato sería el de mayor utilidad

Consideraçöes sobre lipoproteínas, risco cardiovascular e conotaçäo com o ciclo gravídico-puerperal / Lipoproteins, cardiovascular risk and connotation with the gravidic puerperal cycle

Neste estudo atualiza-se aspectos relevantes sobre a elevaçäo do colesterol total plasmático e particularmente enfatiza a sua distribuiçäo nas classes de lipoproteínas LDL (lipoproteína de baixa densidade) e HDL (lipoproteína de alta densidade), como preditores de risco para a coronariopatia, acidente vascular cerebral e/ou obstruçäo arterial periférica. O trabalho correlaciona esses aspectos com a chamada "hiperlipemia da gravidez"

A study of the effects of venous occlusion on haemostatic variables in males and females.

The response of the coagulation-fibrinolysis system to venous occlusion was studied in 20 healthy subjects of both sexes. All of them showed increased fibrinolytic activity, the increase being greater in females. Fibrinogen content also increased in both sexes. The other parameters of coagulation studied showed varied responses.