106 resultados para Cardiovascular Systems

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo


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Abuse of cocaine and androgenic-anabolic steroids has become a serious public health problem. Despite reports of an increase in the incidence of simultaneous illicit use of these substances, potential toxic interactions between cocaine and androgenic-anabolic steroids in the cardiovascular system are unknown. In the present study, we investigated the effect of single or combined administration of testosterone and cocaine for 1 or 10 consecutive days on basal cardiovascular parameters, baroreflex activity, and hemodynamic responses to vasoactive agents in unanesthetized rats. Ten-day combined administration of testosterone and cocaine increased baseline arterial pressure. Changes in arterial pressure were associated with altered baroreflex activity and impairment of both hypotensive response to intravenous sodium nitroprusside and pressor effect of intravenous phenylephrine. Chronic single administration of either testosterone or cocaine did not affect baseline arterial pressure. However, testosterone-treated animals presented rest bradycardia, cardiac hypertrophy, alterations in baroreflex activity, and enhanced response to sodium nitroprusside. Repeated administration of cocaine affected baroreflex activity and impaired vascular responsiveness to both sodium nitroprusside and phenylephrine. One-day single or combined administration of the drugs did not affect any parameter investigated. In conclusion, the present results suggest a potential interaction between toxic effects of cocaine and testosterone on the cardiovascular activity. Changes in baseline arterial pressure after combined administration of these 2 drugs may result from alterations in baroreflex activity and impairment of vascular responsiveness to vasoactive agents.

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Background: Cigarette exposure increases brain oxidative stress. The literature showed that increased brain oxidative stress affects cardiovascular regulation. However, no previous study investigated the involvement of brain oxidative stress in animals exposed to cigarette and its relationship with cardiovascular regulation. We aimed to evaluate the effects of central catalase inhibition on baroreflex and cardiovascular responses in rats exposed to sidestream cigarette smoke (SSCS). Methods: We evaluated males Wistar rats (320-370 g), which were implanted with a stainless steel guide cannula into the fourth cerebral ventricle (4th V). Femoral artery and vein were cannulated for mean arterial pressure (MAP) and heart rate (HR) measurement and drug infusion, respectively. Rats were exposed to SSCS during three weeks, 180 minutes, 5 days/week (CO: 100-300 ppm). Baroreflex was tested with a pressor dose of phenylephrine (PHE, 8 mu g/kg, bolus) to induce bradycardic reflex and a depressor dose of sodium nitroprusside (SNP, 50 mu g/kg, bolus) to induce tachycardic reflex. Cardiovascular responses were evaluated before, 5, 15, 30 and 60 minutes after 3-amino-1,2,4-triazole (ATZ, catalase inhibitor, 0.001 g/100 mu L) injection into the 4th V. Results: Central catalase inhibition increased basal HR in the control group during the first 5 minutes. SSCS exposure increased basal HR and attenuated bradycardic peak during the first 15 minutes. Conclusion: We suggest that SSCS exposure affects cardiovascular regulation through its influence on catalase activity.

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Background-The clinical significance of the interaction between clopidogrel and proton pump inhibitors (PPIs) remains unclear. Methods and Results-We examined the relationship between PPI use and 1-year cardiovascular events (cardiovascular death, myocardial infarction, or stroke) in patients with acute coronary syndrome randomized to clopidogrel or ticagrelor in a prespecified, nonrandomized subgroup analysis of the Platelet Inhibition and Patient Outcomes (PLATO) trial. The primary end point rates were higher for individuals on a PPI (n = 6539) compared with those not on a PPI (n = 12 060) at randomization in both the clopidogrel (13.0% versus 10.9%; adjusted hazard ratio [HR], 1.20; 95% confidence interval [CI], 1.04 -1.38) and ticagrelor (11.0% versus 9.2%; HR, 1.24; 95% CI, 1.07-1.45) groups. Patients on non-PPI gastrointestinal drugs had similar primary end point rates compared with those on a PPI (PPI versus non-PPI gastrointestinal treatment: clopidogrel, HR, 0.98; 95% CI, 0.79-1.23; ticagrelor, HR, 0.89; 95% CI, 0.73-1.10). In contrast, patients on no gastric therapy had a significantly lower primary end point rate (PPI versus no gastrointestinal treatment: clopidogrel, HR, 1.29; 95% CI, 1.12-1.49; ticagrelor, HR, 1.30; 95% CI, 1.14-1.49). Conclusions-The use of a PPI was independently associated with a higher rate of cardiovascular events in patients with acute coronary syndrome receiving clopidogrel. However, a similar association was observed between cardiovascular events and PPI use during ticagrelor treatment and with other non-PPI gastrointestinal treatment. Therefore, in the PLATO trial, the association between PPI use and adverse events may be due to confounding, with PPI use more of a marker for, than a cause of, higher rates of cardiovascular events.

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Background-It remains uncertain whether acetylcysteine prevents contrast-induced acute kidney injury. Methods and Results-We randomly assigned 2308 patients undergoing an intravascular angiographic procedure with at least 1 risk factor for contrast-induced acute kidney injury (age >70 years, renal failure, diabetes mellitus, heart failure, or hypotension) to acetylcysteine 1200 mg or placebo. The study drugs were administered orally twice daily for 2 doses before and 2 doses after the procedure. The allocation was concealed (central Web-based randomization). All analysis followed the intention-to-treat principle. The incidence of contrast-induced acute kidney injury (primary end point) was 12.7% in the acetylcysteine group and 12.7% in the control group (relative risk, 1.00; 95% confidence interval, 0.81 to 1.25; P = 0.97). A combined end point of mortality or need for dialysis at 30 days was also similar in both groups (2.2% and 2.3%, respectively; hazard ratio, 0.97; 95% confidence interval, 0.56 to 1.69; P = 0.92). Consistent effects were observed in all subgroups analyzed, including those with renal impairment. Conclusions-In this large randomized trial, we found that acetylcysteine does not reduce the risk of contrast-induced acute kidney injury or other clinically relevant outcomes in at-risk patients undergoing coronary and peripheral vascular angiography.

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Delayed lipoprotein clearance is associated with atherosclerosis. This study examined whether chronic intermittent hypoxia (CIH), a hallmark of obstructive sleep apnoea (OSA), can lead to hyperlipidaemia by inhibiting clearance of triglyceride rich lipoproteins (TRLP). Male C57BL/6J mice on high-cholesterol diet were exposed to 4 weeks of CIH or chronic intermittent air (control). FIO2 was decreased to 6.5 once per minute during the 12 h light phase in the CIH group. After the exposure, we measured fasting lipid profile. TRLP clearance was assessed by oral gavage of retinyl palmitate followed by serum retinyl esters (REs) measurements at 0, 1, 2, 4, 10, and 24 h. Activity of lipoprotein lipase (LpL), a key enzyme of lipoprotein clearance, and levels of angiopoietin-like protein 4 (Angptl4), a potent inhibitor of the LpL activity, were determined in the epididymal fat pads, skeletal muscles, and heart. Chronic intermittent hypoxia induced significant increases in levels of total cholesterol and triglycerides, which occurred in TRLP and LDL fractions (P 0.05 for each comparison). Compared with control mice, animals exposed to CIH showed increases in REs throughout first 10 h after oral gavage of retinyl palmitate (P 0.05), indicating that CIH inhibited TRLP clearance. CIH induced a 5-fold decrease in LpL activity (P 0.01) and an 80 increase in Angptl4 mRNA and protein levels in the epididymal fat, but not in the skeletal muscle or heart. CIH decreases TRLP clearance and inhibits LpL activity in adipose tissue, which may contribute to atherogenesis observed in OSA.

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Background: Highly active antiretroviral therapy for AIDS is known to increase cardiovascular risk, but the effects of potent antiretroviral agents according to gender are unknown. Objective: The present study evaluated the impact of HIV infection treatment on aortic stiffness according to gender. Methods: From university-affiliated hospitals, we recruited 28 AIDS patients undergoing highly active antiretroviral treatment (HAART), 28 treatment-naive HIV-infected patients, 44 patients with type 2 diabetes, and 30 controls. Aortic stiffness was determined by measuring pulse wave velocity (PWV) using a validated and non-invasive automatic device. Results: The crude mean PWV values and 95% confidence intervals (95% CI) for HAART, diabetics, and controls were 9.77 m/s (95% CI 9.17-10.36),, 9.00 m/s (95% CI 8.37-9.63), 9.90 m/s (95% CI 9.32-10.49), and 9.28 m/s (95% CI 8.61-9.95), respectively, for men (P-value for trend = 0.14), and 9.61 m/s (95% CI 8.56-10.66), 8.45 m/s (95% CI 7.51-9.39), 9.83 (95% CI 9.21-10.44), and 7.79 m/s (95% CI 6.99-8.58), respectively, for women (P-value for trend <0.001). Post-hoc analysis revealed a significant difference between the mean PWV values in the HAART group and controls in women (P-value <0.01). After adjusting for other potential covariates, including systolic blood pressure and diabetes, these results did not change. The findings indicate that the impact of HAART treatment on aortic stiffness was amplified in women with hypertension, dyslipidemia, and metabolic syndrome. Conclusion: Potent anti-retroviral agents used in the treatment of HIV infection increases aortic stiffness, mainly among women with higher cardiovascular risk. (Arq Bras Cardiol 2012;99(6):1100-1107)

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FUNDAMENTO: A redução da frequência cardíaca (FC) na angiografia por tomografia das artérias coronarianas (ATCCor) é fundamental para a qualidade de imagem. A eficácia dos bloqueadores de cálcio como alternativas para pacientes com contraindicações aos betabloqueadores não foi definida. OBJETIVOS: Comparar a eficácia na redução da FC e variabilidade RR do metoprolol e diltiazem na ATCCor. MÉTODOS: Estudo prospectivo, randomizado, aberto, incluiu pacientes com indicação clínica de ATCCor, em ritmo sinusal, com FC>70bpm e sem uso de agentes que interferissem com a FC. Cinquenta pacientes foram randomizados para grupos: metoprolol IV 5-15 mg ou até FC≤60 bpm(M), e diltiazem IV 0,25-0,60mg/kg ou até FC≤60 bpm (D). Pressão arterial (PA) e FC foram aferidas na condição basal, 1min, 3min e 5min após agentes, na aquisição e após ATCCor. RESULTADOS: A redução da FC em valores absolutos foi maior no grupo M que no grupo D (1, 3, 5min, aquisição e pós-exame). A redução percentual da FC foi significativamente maior no grupo M apenas no 1 min e 3 min após início dos agentes. Não houve diferença no 5 min, durante a aquisição e após exame. A variabilidade RR percentual do grupo D foi estatisticamente menor do que a do grupo M durante a aquisição (variabilidade RR/ FC média da aquisição). Um único caso de BAV, 2:1 Mobitz I, revertido espontaneamente ocorreu (grupo D). CONCLUSÃO: Concluímos que o diltiazem é uma alternativa eficaz e segura aos betabloqueadores na redução da FC na realização de angiografia por tomografia computadorizada das artérias coronarianas. (Arq Bras Cardiol. 2012; [online].ahead print, PP.0-0)

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Background: Inadequate life habits are known to favor hypertension, and Adventists recommend healthy life habits. Objective: To assess the prevalence of hypertension among Seventh-Day Adventists from the inner Sao Paulo state and Sao Paulo state capital. Methods: This study assessed 264 Adventists (mean age, 41.17 +/- 15.27 years; women, 59.8%) with a high religiosity level assessed by use of the Duke University Religion Index. Blood pressure was measured with a validated automatic device. The significance level adopted was p < 0.05. Results: The total prevalence of hypertension was 22.7% (27.4% in the inner state and 15% in the capital). The Adventists from the capital differed from those of inner state as follows (p < 0.05), respectively: higher education (62% vs 36.6%); employed by a third party (44%) vs self-employed (40.9%); family income (8.39 +/- 6.20 vs 4.59 +/- 4.75 minimum wages); individual income (4.54 +/- 5.34 vs 6.35 +/- 48; couple responsible for family income (35% vs 39.6%); vegetarianism (11% vs 3%); blood pressure (115.38 +/- 16.52/68.74 +/- 8.94 vs 123.66 +/- 19.62/74.88 +/- 11.85 mmHg); white ethnicity (65% vs 81.1%); married (53% vs 68.9%); lower tangible support in the social aspect (15.7 +/- 5.41 vs 16.9 +/- 4.32); and recalling the last time one's blood pressure was measured (65% vs 48.8%). On multivariate analysis, hypertension associated with the following: 1) vegetarianism (OR 0.051; 95% CI: 0.004-0.681); 2) educational level (OR 5.317; 95% CI: 1.674-16.893); 3) recalling the last time one's blood pressure was measured (OR 2.725; 95% CI: 1.275-5.821); 4) being retired (OR 8.846; 95% CI: 1.406-55.668); and 5) being responsible for family income (OR 0.422; 95% CI: 0.189-0.942). Conclusion: The prevalence of hypertension among Adventists was lower as compared with that reported in Brazilian studies, and it was lower in the Sao Paulo state capital as compared with that in the inner Sao Paulo state, possibly because of the better socioeconomic conditions and life habits of the former. (Arq Bras Cardiol 2012; 98(4): 329-337)

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Background: Metabolic syndrome is characterized by insulin resistance, which is closely related to GLUT4 content in insulin-sensitive tissues. Thus, we evaluated the GLUT4 expression, insulin resistance and inflammation, characteristics of the metabolic syndrome, in an experimental model. Methods: Spontaneously hypertensive neonate rats (18/group) were treated with monosodium glutamate (MetS) during 9 days, and compared with Wistar-Kyoto (C) and saline-treated SHR (H). Blood pressure (BP) and lipid levels, C-reactive protein (CRP), interleukin 6 (IL-6), TNF-alpha and adiponectin were evaluated. GLUT4 protein was analysed in the heart, white adipose tissue and gastrocnemius. Studies were performed at 3 (3-mo), 6 (6-mo) and 9 (9-mo) months of age. Results: MetS rats were more insulin resistant (p<0.001, all ages) and had higher BP (3-mo: p<0.001, 6-mo: p = 0.001, 9-mo: p = 0.015) as compared to C. At 6 months, CRP, IL-6 and TNF-alpha were higher (p<0.001, all comparisons) in MetS rats vs H, but adiponectin was lower in MetS at 9 months (MetS: 32 +/- 2, H: 42 +/- 2, C: 45 +/- 2 pg/mL; p<0.001). GLUT4 protein was reduced in MetS as compared to C rats at 3, 6 and 9-mo, respectively (Heart: 54%, 50% and 57%; Gastrocnemius: 37%, 56% and 50%; Adipose tissue: 69%, 61% and 69%). Conclusions: MSG-treated SHR presented all metabolic syndrome characteristics, as well as reduced GLUT4 content, which must play a key role in the impaired glycemic homeostasis of the metabolic syndrome.

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Background: Admission hyperglycaemia is associated with mortality in patients with acute coronary syndrome (ACS), but controversy exists whether hyperglycaemia uniformly affects both genders. We evaluated coronary risk factors, gender, hyperglycaemia and their effect on hospital mortality. Methods: 959 ACS patients (363 women and 596 men) were grouped based on glycaemia >= or < 200 mg/dL and gender: men with glucose < 200 mg/dL (menG-); women with glucose < 200 mg/dL (womenG-); men with glucose >= 200 mg/dL (menG+); and women with glucose >= 200 mg/dL (womenG+). A logistic regression analysis compared the relation between gender and glycaemia groups and death, adjusted for coronary risk factors and laboratory data. Results group: menG- had lower mortality than menG+ (OR = 0.172, IC95% 0.062-0.478), and womenG+ (OR = 0.275, IC95% 0.090-0.841); womenG- mortality was lower than menG+ (OR = 0.230, IC95% 0.074-0.717). No difference was found between menG+ vs womenG+ (p = 0.461), or womenG- vs womenG+ (p = 0.110). Age (OR = 1.067, IC95% 1.031-1.104), EF (OR = 0.942, IC95% 0.915-0.968), and serum creatinine (OR = 1.329, IC95% 1.128-1.566) were other independent factors related to in-hospital death. Conclusions: Death was greater in hyperglycemic men compared to lower blood glucose men and women groups, but there was no differences between women groups in respect to glycaemia after adjustment for coronary risk factors.

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Objective: To ascertain incidence and predictors of new permanent pacemaker (PPM) following transcatheter aortic valve implantation (TAVI) with the self-expanding aortic bioprosthesis. Background: TAVI with the Medtronic Corevalve (MCV) Revalving System (Medtronic, Minneapolis, MN) has been associated with important post-procedural conduction abnormalities and frequent need for PPM. Methods: Overall, 73 consecutive patients with severe symptomatic AS underwent TAVI with the MCV at two institutions; 10 patients with previous pacemaker and 3 patients with previous aortic valve replacement were excluded for this analysis. Clinical, echocardiographic, and procedural data were collected prospectively in a dedicated database. A standard 12-lead ECG was recorded in all patients at baseline, after the procedure and predischarge. Decision to implant PPM was taken according to current guidelines. Logistic multivariable modeling was applied to identify independent predictors of PPM at discharge. Results: Patients exhibited high-risk features as evidenced by advanced age (mean = 82.1 +/- 6.2 years) and high surgical scores (logistic EuroSCORE 23.0 +/- 12.8%, STS score 9.4 +/- 6.9%). The incidence of new PPM was 28.3%. Interventricular septum thickness and logistic Euroscore were the baseline independent predictors of PPM. When procedural variables were included, the independent predictors of PPM were interventricular septum thickness (OR 0.52; 95% CI 0.320.85) and the distance between noncoronary cusp and the distal edge of the prosthesis (OR 1.37; 95% CI 1.031.83). Conclusions: Conduction abnormalities are frequently observed after TAVI with self-expandable bioprosthesis and definitive pacing is required in about a third of the patients, with a clear association with depth of implant and small interventricular septum thickness. (c) 2011 Wiley Periodicals, Inc.

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Angiotensin-converting enzyme inhibitors (ACEi) may downregulate matrix metalloproteinases (MMPs). We examined whether enalapril affects MMP-2, MMP-8, and MMP-9 levels and activity, and their endogenous inhibitors (tissue inhibitors of MMPs, TIMP-1 and TIMP-2) levels in hypertensive patients. Moreover, we assessed the effects of enalaprilat on MMP-9 and TIMP-1 secretion by human endothelial cells (HUVECs). Thirty-eight hypertensive patients received enalapril for 8 weeks and were compared with thirty-eight normotensive controls. Blood samples were collected at baseline and after treatment. Plasma ACE activity was determined by a fluorimetric assay. Plasma MMP-2, MMP-8, MMP-9, TIMP-1, and TIMP-2 were measured by ELISA and gelatin zymography. A fluorogenic peptide cleavage assay was used to measure MMP activity. HUVECs cells were stimulated by phorbol-12-myristate-13-acetate (PMA) and the effects of enalaprilat (10(-10) to 10(-6) M) on MMP-9 and TIMP-1 levels were determined. Enalapril decreased blood pressure and ACE activity in hypertensive patients (P < 0.05), but had no effects on plasma MMP-2, MMP-8, MMP-9, TIMP-1, and TIMP-2 levels, or MMP activity. Enalaprilat had no effects on PMA-induced increases in MMP-9 and TIMP-1 secretion by HUVECs or on MMP activity. We show consistent evidence, both in vivo and in vitro, that enalapril does not affect MMPs and TIMPs levels in hypertensive patients.

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FUNDAMENTO: Penicilina G benzatina a cada 3 semanas é o protocolo padrão para a profilaxia secundária para febre reumática recorrente. OBJETIVO: Avaliar o efeito da penicilina G benzatina em Streptococcus sanguinis e Streptococcus oralis em pacientes com doença valvular cardíaca, devido à febre reumática com recebimento de profilaxia secundária. MÉTODOS: Estreptococos orais foram avaliados antes (momento basal) e após 7 dias (7º dia) iniciando-se com penicilina G benzatina em 100 pacientes que receberam profilaxia secundária da febre reumática. Amostras de saliva foram avaliadas para verificar a contagem de colônias e presença de S. sanguinis e S. oralis. Amostras de saliva estimulada pela mastigação foram serialmente diluídas e semeadas em placas sobre agar-sangue de ovelhas seletivo e não seletivo a 5% contendo penicilina G. A identificação da espécie foi realizada com testes bioquímicos convencionais. Concentrações inibitórias mínimas foram determinadas com o Etest. RESULTADOS: Não foram encontradas diferenças estatísticas da presença de S. sanguinis comparando-se o momento basal e o 7º dia (p = 0,62). No entanto, o número existente de culturas positivas de S. oralis no 7º dia após a Penicilina G benzatina apresentou um aumento significativo em relação ao valor basal (p = 0,04). Não houve diferença estatística existente entre o momento basal e o 7º dia sobre o número de S. sanguinis ou S. oralis UFC/mL e concentrações inibitórias medianas. CONCLUSÃO: O presente estudo mostrou que a Penicilina G benzatina a cada 3 semanas não alterou a colonização por S. sanguinis, mas aumentou a colonização de S. oralis no 7º dia de administração. Portanto, a susceptibilidade do Streptococcus sanguinis e Streptococcus oralis à penicilina G não foi modificada durante a rotina de profilaxia secundária da febre reumática utilizando a penicilina G.

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Background: Arterial hypertension is an important risk factor for Lower-Limb Occlusive Arterial Disease (LLOAD). However, the correlation between blood pressure and pulse pressure (PP) with LLOAD severity and functional impairment resulting from this disease is not well established in the Brazilian population. Objective: To verify whether there is a correlation between blood pressure, PP, LLOAD severity and functional capacity in patients with symptomatic LLOAD. Methods: A total of 65 patients (62.2 + 8.1 years, 56.9% males) were evaluated. They were divided into two groups: normal (A) and high (B) blood pressure. LLOAD severity was assessed using the ankle-brachial index (ABI) and functional capacity by the total and pain-free walking distance at the 6-minute walking test (6MWT). Results: Group A consisted of 17 (26.1%) patients. The systolic (SBP), diastolic blood pressure (DBP), and PP were, respectively, 125.4 +/- 11.7, 74.5 +/- 9.1 and 50.9 +/- 10.0 mmHg in group A and 160.7 +/- 19.6, 90.0 +/- 12.2 and 70.7 +/- 20.2 mmHg in group B. The ABI was significantly lower in group B (0.66 +/- 0.12 vs. 0.57 +/- 0.13, p < 0.05). SBP and PP correlated with LLOAD severity and the distances walked at the 6MWT. Patients with PP > 40 mmHg walked shorter distances. Conclusion: SBP and PP significantly correlated with the distances walked in the 6MWT, suggesting they are clinical markers of functional capacity impairment in patients with symptomatic LLOAD. (Arq Bras Cardiol 2012; 98(2): 161-166)