Perfil de risco cardiovascular nos pais de crianças dos 3 aos 6 anos

A doença cardiovascular constitui a causa de morte mais relevante em toda a Europa, incluindo Portugal, e é atualmente considerada como uma junção de doença arterial coronária nas suas diversas apresentações clínicas, eventos cerebrovasculares, doença arterial periférica e insuficiência cardíaca. De modo a contribuir para o estudo da importância de uma intervenção baseada numa estratégia populacional integrada na promoção de estilos de vida saudáveis, a principal finalidade deste estudo consistiu em definir o perfil de risco cardiovascular tendo por base os dados de prevalência de alguns fatores de risco, numa amostra de adultos (792 de ambos os sexos), em várias regiões de Portugal Continental. Para tal foram: caraterizados os hábitos alimentares, o contexto sociodemográfico dos adultos; analisadas as correlações entre o peso, perímetro da cintura, índice de massa corporal e a pressão arterial para ambos os sexos. Os resultados revelaram uma prevalência do excesso de peso, de obesidade e das respetivas caraterísticas, como o aumento do perímetro abdominal, e do IMC, sugerindo um contínuo de risco de doença cardiovascular. Verificou-se também uma elevada prevalência de hipertensão nos sujeitos com excesso de peso, sugerindo a existência de um risco cardiovascular acrescido. Os resultados obtidos neste estudo sustentam a necessidade de serem desenvolvidos planos de intervenção que contribuam para a redução do risco cardiovascular nos adultos. Palavras-chave: Estilos de vida; Hipertensão arterial; Índice de Massa Corporal; Obesidade; Risco Cardiovascular.

Advances in vascular tissue engineering

Coronary and peripheral artery bypass grafting is commonly used to relieve the symptoms of vascular deficiencies, but the Supply Of autologous artery or vein may not be sufficient or suitable for multiple bypass or repeat procedures, necessitating the use of other materials. Synthetic materials are suitable for large bore arteries but often thrombose when used in smaller arteries. Suitable replacement grafts must have appropriate characteristics, including resistance to infection, low immunogenicity and good biocompatability and thromboresistance, with appropriate mechanical and physiological properties and cheap and fast manufacture. Current avenues of graft development include coating synthetic grafts with either biological chemicals or cells with anticoagulatory properties. Matrix templates or acellular tubes of extracellular matrix (such as collagen) may be coated or infiltrated with cultured cells. Once placed into the artery, these grafts may become colonised by host cells and gain many of the properties of normal artery. Tissue-engineered blood vessels may also be formed from layers of human vascular cells grown in culture. These engineered vessels have many of the characteristics of arteries formed in vivo. Artificial arteries may be also be derived from peritoneal granulation tissue in body bioreactors by adapting the body's natural wound healing response to produce a hollow tube. (C) 2003 Elsevier Inc. All rights reserved.

Alpha-lipoic acid does not acutely affect resistance and conduit artery function or oxidative stress in healthy men

Aims Alpha-lipoic acid (ALA) is a thiol compound with antioxidant properties used in the treatment of diabetic polyneuropathy. ALA may also improve arterial function, but there have been scant human trials examining this notion. This project aimed to investigate the effects of oral and intra-arterial ALA on changes in systemic and regional haemodynamics, respectively. Methods In study 1, 16 healthy older men aged 58 +/- 7 years (mean +/- SD) received 600 mg of ALA or placebo, on two occasions 1 week apart, in a randomized cross-over design. Repeated measures of peripheral and central haemodynamics were then obtained for 90 min. Central blood pressure and indices of arterial stiffness [augmentation index (AIx) and estimated aortic pulse wave velocity] were recorded non-invasively using pulse wave analysis. Blood samples obtained pre- and post-treatments were analysed for erythrocyte antioxidant enzyme activity, plasma nitrite and malondialdehyde. In study 2 the effects of incremental cumulative doses (0.5, 1.0, 1.5 and 2.0 mg ml(-1) min(-1)) of intra-arterial ALA on forearm blood flow (FBF) were assessed in eight healthy subjects (aged 31 +/- 5 years) by conventional venous occlusion plethysmography. Results There were no significant changes on any of the central or peripheral haemodynamic measures after either oral or direct arterial administration of ALA. Plasma ALA was detected after oral supplementation (95% confidence intervals 463, 761 ng ml(-1)), but did not alter cellular or plasma measures of oxidative stress. Conclusions Neither oral nor intra-arterial ALA had any effect on regional and systemic haemodynamics or measures of oxidative stress in healthy men.

Effect of aldosterone antagonism on myocardial dysfunction in hypertensive patients with diastolic heart failure

Background - Specific treatments targeting the pathophysiology of hypertensive heart disease are lacking. As aldosterone has been implicated in the genesis of myocardial fibrosis, hypertrophy, and dysfunction, we sought to determine the effects of aldosterone antagonism on myocardial function in hypertensive patients with suspected diastolic heart failure by using sensitive quantitative echocardiographic techniques in a randomized, double-blinded, placebo-controlled study. Methods and Results - Thirty medically treated ambulatory hypertensive patients (19 women, age 62 +/- 6 years) with exertional dyspnea, ejection fraction >50%, and diastolic dysfunction (E/A 250m/sec) and without ischemia were randomized to spironolactone 25 mg/d or placebo for 6 months. Patients were overweight (31 +/- 5 kg/m(2)) with reduced treadmill exercise capacity (6.7 +/- 2.1 METS). Long-axis strain rate (SR), peak systolic strain, and cyclic variation of integrated backscatter (CVIB) were averaged from 6 walls in 3 standard apical views. Mean 24-hour ambulatory blood pressure at baseline (133 +/- 17/80 +/- 7mm Hg) did not change in either group. Values for SR, peak systolic strain, and CVIB were similar between groups at baseline and remained unchanged with placebo. Spironolactone therapy was associated with increases in SR (baseline: -1.57 +/- 0.46 s(-1) versus 6-months: -1.91 +/- 0.36 s(-1), P < 0.01), peak systolic strain (-20.3 &PLUSMN; 5.0% versus -26.9 &PLUSMN; 4.3%, P < 0.001), and CVIB (7.4 +/- 1.7dB versus 8.6 +/- 1.7 dB, P = 0.08). Each parameter was significantly greater in the spironolactone group compared with placebo at 6 months (P = 0.05, P = 0.02, and P = 0.02, respectively), and the increases remained significant after adjusting for baseline differences. The increase in strain was independent of changes in blood pressure with intervention. The spironolactone group also exhibited reduction in posterior wall thickness (P = 0.04) and a trend to reduced left atrial area (P = 0.09). Conclusions - Aldosterone antagonism improves myocardial function in hypertensive heart disease.

Noninvasive tests for arterial structure, function, and compliance: Do they identify risk or diagnose disease?

Background: Brachial artery reactivity (BAR), carotid intima-media thickness (IMT), and applanation tonometry for evaluation of total arterial compliance may provide information about preclinical vascular disease. We sought to determine whether these tests could be used to identify patients with coronary artery disease (CAD) without being influenced by their ability to identify those at risk ford CAD developing. Methods: We studied 100 patients and compared 3 groups: 35 patients with known CAD; 34 patients with symptoms and risk factors but no CAD identified by stress echocardiography (risk group); and 31 control subjects. BAR and IMT were measured using standard methods, and total arterial compliance was calculated by the pulse-pressure method from simultaneous radial applanation tonometry and pulsed wave Doppler of the left ventricular outflow. Ischemia was identified as a new or worsening wall-motion abnormality induced by stress. Results: In a comparison between the control subjects and patients either at risk for developing CAD or with CAD, the predictors of risk for CAD were: age (P = .01); smoking history (P = .002); hypercholesterolemia (P = .002); and hypertension (P = .004) (model R = 0.82; P = .0001). The independent predictors of CAD were: IMT (P = .001); BAR (P = .04); sex (P = .005); and hypertension (P = .005) (model R = 0.80; P = .0001). Conclusion: IMT, BAR, and traditional cardiovascular risk factors appear to identify patients at risk for CAD developing. However, only IMT was significantly different between patients at risk for developing CAD and those with overt CAD.

Dog peritoneal and pleural cavities as bioreactors to grow autologous vascular grafts

Objective: The purpose of this study was to grow artificial blood vessels for autologous transplantation as arterial interposition grafts in a large animal model (dog). Method and results: Tubing up to 250 mm long, either bare or wrapped in biodegradable polyglycolic acid (Dexon) or nonbiodegradable polypropylene (Prolene) mesh, was inserted in the peritoneal or pleural cavity of dogs, using minimally invasive techniques, and tethered at one end to the wall with a loose suture. After 3 weeks the tubes and their tissue capsules were harvested, and the inert tubing was discarded. The wall of living tissue was uniformly 1-1.5 mm thick throughout its length, and consisted of multiple layers of myofibroblasts and matrix overlaid with a single layer of mesothelium. The myofibroblasts stained for a-smooth muscle actin, vimentin, and desmin. The bursting strength of tissue tubes with no biodegradable mesh scaffolds was in excess of 2500 mm Hg, and the suture holding strength was 11.5 N, both similar to that in dog carotid and femoral arteries. Eleven tissue tubes were transplanted as interposition grafts into the femoral artery of the same dog in which they were grown, and were harvested after 3 to 6.5 months. Eight remained patent during this time. At harvest, their lumens were lined with endothelium-like cells, and wall cells stained for alpha-actin, smooth muscle myosin, desmin and smoothelin; there was also a thick adventitia containing vasa vasorum. Conclusion: Peritoneal and pleural cavities of large animals can function as bioreactors to grow myofibroblast tubes for use as autologous vascular grafts.

Characterization of heat shock protein-specific T cells in atherosclerosis

A role for infection and inflammation in atherogenesis is widely accepted. Arterial endothelium has been shown to express heat shock protein 60 (HSP60) and, since human (hHSP60) and bacterial (GroEL) HSP60s are highly conserved, the immune response to bacteria may result in cross-reactivity, leading to endothelial damage and thus contribute to the pathogenesis of atherosclerosis. In this study, GroEL-specific T-cell lines from peripheral blood and GroEL-, hHSP60-, and Porphyromonas gingivalis-specific T-cell lines from atherosclerotic plaques were established and characterized in terms of their cross-reactive proliferative responses, cytokine and chemokine profiles, and T-cell receptor (TCR) V beta expression by flow cytometry. The cross-reactivity of several lines was demonstrated. The cytokine profiles of the artery T-cell lines specific for GroEL, hHSP60, and P. gingivalis demonstrated Th2 phenotype predominance in the CD4 subset and Tc0 phenotype predominance in the CD8 subset. A higher proportion of CD4 cells were positive for interferon-inducible protein 10 and RANTES, with low percentages of cells positive for monocyte chemoattractant protein 1 and macrophage inflammatory protein la, whereas a high percentage of CD8 cells expressed all four chemokines. Finally, there was overexpression of the TCR V beta 5.2 family in all lines. These cytokine, chemokine, and V beta profiles are similar to those demonstrated previously for P. gingivalis-specific lines established from periodontal disease patients. These results support the hypothesis that in some patients cross-reactivity of the immune response to bacterial HSPs, including those of periodontal pathogens, with arterial endothelial cells expressing hHSP60 may explain the apparent association between atherosclerosis and periodontal infection.

Urinary albumin levels in the normal range determine arterial wall thickness in adults with Type 2 diabetes: a FIELD substudy

Aim Cardiovascular disease (CVD) rates are substantially higher among patients with Type 2 diabetes than in the general population. The objective of this study was to identify the determinants of carotid intima media thickness (IMT) in patients with Type 2 diabetes. Methods We measured the thickness of the intima media layer of the carotid artery, a strong predictor of the risk of future vascular events, in 397 Type 2 diabetic patients drawn from the Fenofibrate Intervention and Event Lowering in Diabetes study, prior to treatment allocation. Results The mean IMT was 0.78 mm [interquartile range (IQR) 0.23 mm], and the maximum IMT was 1.17 mm (IQR 0.36 mm). By multivariate analysis, age, sex, duration of diabetes, triglycerides, and total cholesterol were independently correlated with IMT, as was urine albumin-creatinine ratio (ACR) (P < 0.001). The effect of ACR on IMT was further examined by tertile. Clinically significant differences in IMT were associated with ACR > 0.65 mg/mmol, approximately one-fifth the standard clinical threshold for microalbuminuria (P < 0.01). Long-term diabetes, independent of other parameters, was associated with a 50% increase in age-related thickening. Conclusions IMT in people with Type 2 diabetes is independently and continuously related to urine albumin levels and to the duration of diabetes. These results support previous data linking urine albumin measurements within the normal range with increased ischaemic cardiac mortality in the setting of Type 2 diabetes, and strongly suggest that urine albumin levels within this range should trigger a formal evaluation for CVD.

Comparison of contamination rates of catheter-drawn and peripheral blood cultures

The aim of this study was to assess the sensitivity and specificity of catheter-drawn and peripheral blood cultures. Paired blood culture samples collected over a 44-month period from a 280 bed Brisbane metropolitan hospital were analysed, using standard clinical and microbiological criteria, to determine whether blood culture isolates represented true bacteraemias or contamination. Catheter-collected cultures had a specificity of 85% compared with 97% for peripheral cultures. In only two instances (0.2%) was the diagnosis of clinically significant bacteraemia made on the basis of catheter culture alone. This study concluded that catheter-collected samples are not a good test for true bacteraemia, and that peripheral. cultures are more reliable when the results of the paired cultures are discordant. (c) 2004 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.

The effect of exercise on large artery haemodynamics in healthy young men

Background Brachial blood pressure predicts cardiovascular outcome at rest and during exercise. However, because of pulse pressure amplification, there is a marked difference between brachial pressure and central (aortic) pressure. Although central pressure is likely to have greater clinical importance, very little data exist regarding the central haemodynamic response to exercise. The aim of the present study was to determine the central and peripheral haemodynamic response to incremental aerobic exercise. Materials and methods Twelve healthy men aged 31 +/- 1 years (mean +/- SEM) exercised at 50%, 60%, 70% and 80% of their maximal heart rate (HRmax) on a bicycle ergometer. Central blood pressure and estimated aortic pulse wave velocity, assessed by timing of the reflected wave (T-R), were obtained noninvasively using pulse wave analysis. Pulse pressure amplification was defined as the ratio of peripheral to central pulse pressure and, to assess the influence of wave reflection on amplification, the ratio of peripheral pulse pressure to nonaugmented central pulse pressure (PPP : CDBP-P-1) was also calculated. Results During exercise, there was a significant, intensity-related, increase in mean arterial pressure and heart rate (P < 0.001). There was also a significant increase in pulse pressure amplification and in PPP : CDBP-P-1 (P < 0.001), but both were independent of exercise intensity. Estimated aortic pulse wave velocity increased during exercise (P < 0.001), indicating increased aortic stiffness. There was also a positive association between aortic pulse wave velocity and mean arterial pressure (r = 0.54; P < 0.001). Conclusions Exercise significantly increases pulse pressure amplification and estimated aortic stiffness.

Influence of arterial compliance on presence and extent of ischaemia during stress echocardiography

Objective: To seek an association between total arterial compliance (TAC) and the extent of ischaemia at stress echocardiography. Design: Cohort study. Setting: Regional cardiac centre. Methods: 255 consecutive patients (147 men; mean (SD) age 58 (8)) presenting for stress echocardiography for clinical indications were studied. Wall motion score index (WMSI) was calculated and ischaemia was defined by an inducible or worsening wall motion abnormality. Peak WMSI was used to reflect the extent of dysfunction (ischaemia or scar), and Delta WMSI was indicative of extent of ischaemia. TAC was assessed at rest by simultaneous radial applanation tonometry and pulsed wave Doppler in all patients. Results: Ischaemia was identified by stress echocardiography in 65 patients (25%). TAC was similar in the groups with negative and positive echocardiograms (1.08 (0.41) v 1.17 (0.51) ml/ mm Hg, not significant). However, the extent of dysfunction was associated with TAC independently of age, blood pressure, risk factors, and use of a beta blocker. Moreover, the extent of ischaemia was determined by TAC, risk factors, and use of a b blocker. Conclusion: While traditional cardiovascular risk factors are strong predictors of ischaemia on stress echocardiography, TAC is an independent predictor of the extent of ischaemia.

Validation of a generalized transfer function to noninvasively derive central blood pressure during exercise

Exercise brachial blood pressure ( BP) predicts mortality, but because of wave reflection, central ( ascending aortic) pressure differs from brachial pressure. Exercise central BP may be clinically important, and a noninvasive means to derive it would be useful. The purpose of this study was to test the validity of a noninvasive technique to derive exercise central BP. Ascending aortic pressure waveforms were recorded using a micromanometer-tipped 6F Millar catheter in 30 patients (56 +/- 9 years; 21 men) undergoing diagnostic coronary angiography. Simultaneous recordings of the derived central pressure waveform were acquired using servocontrolled radial tonometry at rest and during supine cycling. Pulse wave analysis of the direct and derived pressure signals was performed offline (SphygmoCor 7.01). From rest to exercise, mean arterial pressure and heart rate were increased by 20 +/- 10 mm Hg and 15 +/- 7 bpm, respectively, and central systolic BP ranged from 77 to 229 mm Hg. There was good agreement and high correlation between invasive and noninvasive techniques with a mean difference (+/- SD) for central systolic BP of -1.3 +/- 3.2 mm Hg at rest and -4.7 +/- 3.3 mm Hg at peak exercise ( for both r=0.995; P < 0.001). Conversely, systolic BP was significantly higher peripherally than centrally at rest (155 +/- 33 versus 138 +/- 32mm Hg; mean difference, -16.3 +/- 9.4mm Hg) and during exercise (180 +/- 34 versus 164 +/- 33 mm Hg; mean difference, -15.5 +/- 10.4 mm Hg; for both P < 0.001). True myocardial afterload is not reliably estimated by peripheral systolic BP. Radial tonometry and pulse wave analysis is an accurate technique for the noninvasive determination of central BP at rest and during exercise.