Cardiovascular autonomic dysfunction in sickle cell anemia

Sickle cell anemia (SCA) is associated to increased cardiac output, normal heart rate (HR), abnormal QT dispersion and lower diastolic blood pressure (DBP). The mechanisms are still unknown. The objective of this study was to test the hypothesis that there is cardiovascular autonomic dysfunction (CAD) in SCA. The secondary objectives were to distinguish the roles of chronic anemia and hemoglobinopathy and to evaluate the predominance of the sympathetic or parasympathetic systems in the pathogenesis of CAD. Sixteen subjects with SCA, 13 with sickle cell trait (SCT), 13 with iron deficiency anemia (IDA), and 13 healthy volunteers (HV) were evaluated. All subjects were submitted to 24 h-electrocardiogram (24 h-ECG), plasma norepinephrine (NE) measurement before and after isometric exercise (IE), and also Valsalva maneuver (VM), diving maneuver (DV), and tilt test (TT). Baroreflex sensitivity (BRS) was also evaluated. The minimum, average and maximum HR as well as the percentage of bradycardia and tachycardia at 24-h ECG were similar in all groups. NE at baseline and after IE did not differ between groups. The SCA group showed less bradycardia at phase IV of VM, less bradycardia during DV, and also less tachycardia and lower DBP during TT. BRS for bradycardia and tachycardia reflex was decreased in the SCA and SCT groups. In conclusion, 1) there is CAD in SCA, and it is characterized by the reduction of BRS and the limitation of HR modulation mediated by the parasympathetic system; 2) cardiovascular sympathetic activity is preserved in SCA; and 3) hemoglobinopathy is the preponderant ethiopathogenic factor. (C) 2011 Elsevier B.V. All rights reserved.

Burnt sugarcane harvesting: cardiovascular effects on a group of healthy workers, Brazil

Background: Brazil is the world's largest producer of sugarcane. Harvest is predominantly manual, exposing workers to health risks: intense physical exertion, heat, pollutants from sugarcane burning. Design: Panel study to evaluate the effects of burnt sugarcane harvesting on blood markers and on cardiovascular system. Methods: Twenty-eight healthy male workers, living in the countryside of Brazil were submitted to blood markers, blood pressure, heart rate variability, cardiopulmonary exercise testing, sympathetic nerve activity evaluation and forearm blood flow measures (venous occlusion plethysmography) during burnt sugarcane harvesting and four months later while they performed other activities in sugar cane culture. Results: Mean participant age was 31 +/- 6.3 years, and had worked for 9.8 +/- 8.4 years on sugarcane work. Work during the harvest period was associated with higher serum levels of Creatine Kinase - 136.5 U/L (IQR: 108.5-216.0) vs. 104.5 U/L (IQR: 77.5-170.5), (p = 0.001); plasma Malondialdehyde-7.5 +/- 1.4 mu M/dl vs. 6.9 +/- 1.0 mu M/dl, (p = 0.058); Glutathione Peroxidase - 55.1 +/- 11.8 Ug/Hb vs. 39.5 +/- 9.5 Ug/Hb, (p < 0.001); Glutathione Transferase- 3.4 +/- 1.3 Ug/Hb vs. 3.0 +/- 1.3 Ug/Hb, (p = 0.001); and 24-hour systolic blood pressure - 120.1 +/- 10.3 mmHg vs. 117.0 +/- 10.0 mmHg, (p = 0.034). In cardiopulmonary exercise testing, rest-to-peak diastolic blood pressure increased by 11.12 mmHg and 5.13 mmHg in the harvest and non-harvest period, respectively. A 10 miliseconds reduction in rMSSD and a 10 burst/min increase in sympathetic nerve activity were associated to 2.2 and 1.8 mmHg rises in systolic arterial pressure, respectively. Conclusion: Work in burnt sugarcane harvesting was associated with changes in blood markers and higher blood pressure, which may be related to autonomic imbalance.

No effect of creatine supplementation on oxidative stress and cardiovascular parameters in spontaneously hypertensive rats

Background: Exacerbated oxidative stress is thought to be a mediator of arterial hypertension. It has been postulated that creatine (Cr) could act as an antioxidant agent preventing increased oxidative stress. The aim of this study was to investigate the effects of nine weeks of Cr or placebo supplementation on oxidative stress and cardiovascular parameters in spontaneously hypertensive rats (SHR). Findings: Lipid hydroperoxidation, one important oxidative stress marker, remained unchanged in the coronary artery (Cr: 12.6 +/- 1.5 vs. Pl: 12.2 +/- 1.7 nmol.mg(-1); p = 0.87), heart (Cr: 11.5 +/- 1.8 vs. Pl: 14.6 +/- 1.1 nmol.mg(-1); p = 0.15), plasma (Cr: 67.7 +/- 9.1 vs. Pl: 56.0 +/- 3.2 nmol.mg(-1); p = 0.19), plantaris (Cr: 10.0 +/- 0.8 vs. Pl: 9.0 +/- 0.8 nmol.mg(-1); p = 0.40), and EDL muscle (Cr: 14.9 +/- 1.4 vs. Pl: 17.2 +/- 1.5 nmol.mg(-1); p = 0.30). Additionally, Cr supplementation affected neither arterial blood pressure nor heart structure in SHR (p > 0.05). Conclusions: Using a well-known experimental model of systemic arterial hypertension, this study did not confirm the possible therapeutic effects of Cr supplementation on oxidative stress and cardiovascular dysfunction associated with arterial hypertension.

Association between UCP2 A55V polymorphism and risk of cardiovascular events in patients with multi-vessel coronary arterial disease

Background UCP2 (uncoupling protein 2) plays an important role in cardiovascular diseases and recent studies have suggested that the A55V polymorphism can cause UCP2 dysfunction. The main aim was to investigate the association of A55V polymorphism with cardiovascular events in a group of 611 patients enrolled in the Medical, Angioplasty or Surgery Study II (MASS II), a randomized trial comparing treatments for patients with coronary artery disease and preserved left ventricular function. Methods The participants of the MASS II were genotyped for the A55V polymorphism using allele-specific PCR assay. Survival curves were calculated with the Kaplan–Meier method and evaluated with the log-rank statistic. The relationship between baseline variables and the composite end-point of cardiac death, acute myocardial infarction (AMI), refractory angina requiring revascularization and cerebrovascular accident were assessed using a Cox proportional hazards survival model. Results There were no significant differences for baseline variables according genotypes. After 2 years of follow-up, dysglycemic patients harboring the VV genotype had higher occurrence of AMI (p=0.026), Death+AMI (p=0.033), new revascularization intervention (p=0.009) and combined events (p=0.037) as compared with patients carrying other genotypes. This association was not evident in normoglycemic patients. Conclusions These findings support the hypothesis that A55V polymorphism is associated with UCP2 functional alterations that increase the risk of cardiovascular events in patients with previous coronary artery disease and dysglycemia.

Chest associated to motor physiotherapy improves cardiovascular variables in newborns with respiratory distress syndrome

Background We aimed to evaluate the effects of chest and motor physiotherapy treatment on hemodynamic variables in preterm newborns with respiratory distress syndrome. Methods We evaluated heart rate (HR), respiratory rate (RR), systolic (SAP), mean (MAP) and diastolic arterial pressure (DAP), temperature and oxygen saturation (SO2%) in 44 newborns with respiratory distress syndrome. We compared all variables between before physiotherapy treatment vs. after the last physiotherapy treatment. Newborns were treated during 11 days. Variables were measured 2 minutes before and 5 minutes after each physiotherapy treatment. We applied paired Student t test to compare variables between the two periods. Results HR (148.5 ± 8.5 bpm vs. 137.1 ± 6.8 bpm - p < 0.001), SAP (72.3 ± 11.3 mmHg vs. 63.6 ± 6.7 mmHg - p = 0.001) and MAP (57.5 ± 12 mmHg vs. 47.7 ± 5.8 mmHg - p = 0.001) were significantly reduced after 11 days of physiotherapy treatment compared to before the first session. There were no significant changes regarding RR, temperature, DAP and SO2%. Conclusions Chest and motor physiotherapy improved cardiovascular parameters in respiratory distress syndrome newborns.

Involvement of the atrial natriuretic peptide in cardiovascular pathophysiology and its relationship with exercise

In this minireview we describe the involvement of the atrial natriuretic peptide (ANP) in cardiovascular pathophysiology and exercise. The ANP has a broad homeostatic role and exerts complex effects on the cardio-circulatory hemodynamics, it is produced by the left atrium and has a key role in regulating sodium and water balance in mammals and humans. The dominant stimulus for its release is atrial wall tension, commonly caused by exercise. The ANP is involved in the process of lipolysis through a cGMP signaling pathway and, as a consequence, reducing blood pressure by decreasing the sensitivity of vascular smooth muscle to the action of vasoconstrictors and regulate fluid balance. The increase of this hormone is associated with better survival in patients with chronic heart failure (CHF). This minireview provides new evidence based on recent studies related to the beneficial effects of exercise in patients with cardiovascular disease, focusing on the ANP.

Management of diabetes mellitus and associated cardiovascular risk factors in Brazil – the Brazilian study on the practice of diabetes care

Abstract Background The Brazilian Study on the Practice of Diabetes Care main objective was to provide an epidemiological profile of individuals with type 1 and 2 diabetes mellitus (DM) in Brazil, concerning therapy and adherence to international guidelines in the medical practice. Methods This observational, cross-sectional, multicenter study collected and analyzed data from individuals with type 1 and 2 DM attending public or private clinics in Brazil. Each investigator included the first 10 patients with type 2 DM who visited his/her office, and the first 5 patients with type 1 DM. Results A total of 1,358 patients were analyzed; 375 (27.6%) had type 1 and 983 (72.4%) had type 2 DM. Most individuals were women, Caucasian, and private health care users. High prevalence rates of hypertension, dyslipidemia and central obesity were observed, particularly in type 2 DM. Only 7.3% and 5.1% of the individuals with types 1 and 2 DM, respectively, had optimal control of blood pressure, plasma glucose and lipids. The absence of hypertension and female sex were associated with better control of type 1 DM and other cardiovascular risk factors. In type 2 DM, older age was also associated with better control. Conclusions Female sex, older age, and absence of hypertension were associated with better metabolic control. An optimal control of plasma glucose and other cardiovascular risk factors are obtained only in a minority of individuals with diabetes. Local numbers, compared to those from other countries are worse.

Cardiovascular risk in Japanese-Brazilian subjects

OBJECTIVE: To evaluate the prevalence of risk factors for cardiovascular disease in Japanese-Brazilian subjects. SUBJECTS AND METHODS: One hundred thirty-one residents of the Mombuca community were studied. Statistical analysis was based on the X² test, Fisher's Exact test, Student's t test, and ANOVA, at a 5% significance level. RESULTS: The average age was 56.7 years-old; 76.3% had dyslipidemia, 24.4% pre-diabetes (PDM), 10.7% type 2 diabetes mellitus (T2DM), 46.6% hypertension, 52.7% abdominal obesity, and 35.8% metabolic syndrome (MS). There were significant correlations between HOMA-IR and MS diagnosis and obesity, while HOMA-β levels were decreased in T2DM and PDM. The ankle-brachial index was positive for peripheral artery disease in 22.3% of the individuals. Electrocardiograms did not show increased evidence of myocardial ischemia. CONCLUSION: Subjects of this community are exposed to major cardiovascular risk factors, namely high prevalence of MS diagnoses and increased HOMA-IR. Arq Bras Endocrinol Metab. 2012;56(9):608-13

Escore de cálcio e angiotomografia coronariana na estratificação do risco cardiovascular

A doença cardiovascular representa a principal causa de mortalidade no mundo. A capacidade de identificar, dentre os indivíduos assintomáticos, o subgrupo que apresenta maior risco de desenvolver eventos cardiovasculares no futuro representa uma etapa fundamental em qualquer estratégia voltada para a diminuição da taxas de eventos cardiovasculares. O primeiro passo na estratificação do risco cardiovascular é a utilização dos "escores de risco global", dentre os quais o mais frequentemente utilizado é o escore de Framingham. Entretanto, estudos prévios demonstraram que embora muito úteis, os escores clínicos, quando utilizados isoladamente, apresentam capacidade limitada de estratificação do risco cardiovascular em uma parcela significativa da população. É nesse contexto que o escore de cálcio (EC) coronariano e a angiotomografia das artérias coronárias podem desempenhar papel importante como ferramentas complementares na estratificação de risco dos pacientes assintomáticos. O EC coronariano proporciona importantes informações prognósticas que são incrementais aos escores clínicos baseados nos fatores de risco tradicionais e a outras modalidades diagnósticas, como a dosagem da proteína C reativa, por exemplo. Além disso, o EC também tem o potencial de alterar a conduta e auxiliar no manejo clínico dos pacientes. Já a angiotomografia coronariana proporciona avaliação detalhada da anatomia das artérias coronárias, permitindo visualizar não apenas o lúmen, mas também as paredes arteriais coronarianas. Comparada à coronariografia invasiva convencional, a angiotomografia apresenta excelente acurácia para identificar e, principalmente, excluir a presença de lesões obstrutivas significativas. Adicionalmente, demonstrou-se capaz de proporcionar informações prognósticas incrementais aos fatores de risco tradicionais e ao EC coronariano.

Risco cardiovascular em profissionais de saúde de serviços de atendimento pré-hospitalar

Avaliar os fatores de risco cardiovascular, com ênfase na hipertensão, e estratificá-los de acordo com o Escore de Risco de Framingham (ERF). Estudo com 154 profissionais que atuavam em aten-dimento pré-hospitalar na cidade de São Paulo e rodovia Br-116. Foi considerado significante o valor de p<0,05. A prevalência de hipertensão foi de 33%, sendo que 20,1% eram tabagistas, 47% ingeriam bebidas alcoólicas, 64% eram sedentários, 66% apresentaram obesidade/sobrepeso e 70% cintura abdominal alterada, glicemia>110mg/dL- 11%, colesterol total>200mg/dL- 36%, LDL-c>130mg/dL- 33%, HDL-c<60mg/dL- 89%, triglicérides>150mg/dL- 30% e proteína C reativa>0,5mg/dL- 16%. O ERF foi médio em 10,3% e alto em 1,3%. Na análise de regressão logística verificou-se que a hipertensão associou-se com as variáveis: HDL-c (odds ratio: 0,257) e ERF (odds ratio: 23,159). Houve forte associação entre ERF e hipertensão. Os dados chamam a atenção, por se tratar principalmente de profissionais da área da saúde relativamente jovens.