Systemic arterial hypertension and cognition in adults: effects on executive functioning / Hipertensão arterial sistêmica e cognição em adultos: efeitos no funcionamento executivo

ABSTRACT Background: Central nervous system changes associated to systemic arterial hypertension (SAH) are progressive and may cause negative effects on cognitive performance. The objective of this study was to investigate the relation between SAH and the components of executive functions (EF), inhibitory control (IC), updating and shifting, comparing a control group (without SAH) to patients with SAH, in two levels of severity. Methods: The protocol included the following tests to evaluate EF components: T.O.V.A. Test (IC), Backward Digit Span from Wechsler Adults Intelligence Scale (WAIS-III), Phonemic and Semantic Verbal Fluency (updating), and Trail Making Test Part B (shifting). Results: A total of 204 participants was included: 56 from the Control Group (CG), 87 SAH stage 1, and 61 SAH stage 2. The groups were not different for age (52.37±12.29) and education (10.98±4.06). As to controlled blood pressure (BP), duration of hypertension treatment and number of drugs, the SAH 2 group had a worse BP control, longer duration of hypertension treatment and use of more drugs when compared to the SAH 1. The findings revealed that patients with more severe hypertension presented worse performance in updating (Backward Digit Span, phonemic and semantics VF) and shifting (Trail Making Test Part B). Conclusion: The results suggest that patients with SAH have a significant impairment in EF, more specifically in updating and shifting. Besides that, such damage may be directly proportional to the severity of SAH. It is suggested that future studies include neuroimaging exams to exclude possible cerebrovascular diseases.

RESUMO Introdução: As alterações do sistema nervoso central associadas à hipertensão arterial sistêmica (HAS) são progressivas e podem ocasionar efeitos negativos no desempenho cognitivo. O objetivo deste estudo foi investigar a relação entre a HAS e os componentes das funções executivas (FE), controle inibitório (CI), atualização e alternância, comparando um grupo controle (sem HAS) a pacientes com HAS, em dois níveis de gravidade. Métodos: O protocolo incluiu os seguintes testes para avaliar os componentes das FE: T.O.V.A. Test (CI), Dígitos Ordem Indireta da Escala de Inteligência Wechsler para Adultos (Wechsler Adults Intelligence Scale - WAIS-III), Fluência Verbal fonêmica e semântica (atualização) e Teste de Trilhas parte B (alternância). Resultados: Foram incluídos 204 participantes, sendo 56 do Grupo Controle (GC), 87 HAS estágio 1 (HAS 1) e 61 de HAS estágio 2 (HAS 2). Os grupos não foram diferentes em relação à idade (52,37±12,29) e escolaridade (10,98±4,06). Em relação à pressão arterial (PA) controlada, tempo de tratamento da HAS e número de medicações, o grupo HAS 2 apresentou pior controle de PA, mais tempo de tratamento da HAS e uso de maior número de medicações quando comparado ao grupo HAS 1. Os achados revelaram que os pacientes com HAS em estágio mais grave apresentaram pior desempenho nos testes de alternância (Teste de Trilhas parte B) e atualização (Dígitos Ordem Indireta, FV fonêmica e semântica). Conclusão: Esses resultados sugerem que pacientes com a HAS possuem prejuízo significativo em FE, especificamente em alternância e atualização, e que esse prejuízo pode ser diretamente proporcional à gravidade da HAS. Sugere-se que, em estudos futuros, incluam-se exames de neuroimagem com o objetivo de excluir possíveis doenças cerebrovasculares.

Applicability of the Test of Variables of Attention - T.O.V.A. in Brazilian adults / Aplicabilidade do teste de variáveis de atenção - T.O.V.A. em adultos brasileiros

ABSTRACT: The functioning of attention is complex, a primordial function in several cognitive processes and of great interest to neuropsychology. The Test of Variables of Attention (T.O.V.A) is a continuous computerized performance test that evaluates some attention components such as response time to a stimulus and errors due to inattention and impulsivity. Objective: 1) To evaluate the applicability of T.O.V.A in Brazilian adults; 2) To analyze the differences in performance between genders, age ranges, and levels of education; 3) To examine the association between T.O.V.A variables and other attention and cognitive screening tests. Methods: The T.O.V.A was applied to 63 healthy adults (24 to 78 years of age) who also underwent the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Digit Span and Digit Symbol (Wechsler Intelligence Scale for Adults ­ WAIS-III) and the Trail Making Test. Results: The T.O.V.A was little influenced by age or education, but was influenced by gender. The correlations between some T.O.V.A variables and the Digit Symbol and Trail Making test were weak (r-values between 0.2 and 0.4), but significant (p<0.05). There was no correlation with the Digit Span test. Conclusion: The T.O.V.A showed good applicability and proved adequate for evaluating attentional processes in adults.

RESUMO: O funcionamento da atenção é complexo, função primordial em diversos processos cognitivos e de grande interesse para a neuropsicologia. O Teste de Variáveis de Atenção (T.O.V.A) é um teste computadorizado de desempenho contínuo que avalia alguns componentes de atenção, como tempo de resposta a um estímulo e erros por desatenção e impulsividade. Objetivo: 1) Avaliar a aplicabilidade do T.O.V.A em adultos brasileiros; 2) Analisar as diferenças de desempenho entre os gêneros, faixas etárias e níveis de escolaridade; 3) Examinar a associação entre as variáveis T.O.V.A e outros testes de atenção e triagem cognitiva. Métodos: O TOVA foi aplicado a 63 adultos saudáveis (24 a 78 anos) submetidos ao Mini-Exame do Estado Mental (MEEM), Montreal Cognitive Assessment (MoCA), Digit Span e Digit Symbol (Wechsler Intelligence Scale for Adults ­ WAIS-III) e o Trail Making Test. Resultados: T.O.V.A teve pouca influência da idade e escolaridade, mas foi influenciado pelo gênero. As correlações entre algumas variáveis T.O.V.A e o símbolo Digit e o teste Trail Making foram fracas (valores de r entre 0,2 e 0,4), mas significativas (p <0,05). Não houve correlação com o teste Digit Span. Conclusão: T.O.V.A apresentou boa aplicabilidade e foi adequado para avaliar os processos de atenção em adultos.

Resting spontaneous baroreflex sensitivity and cardiac autonomic control in anabolic androgenic steroid users

OBJECTIVES: Misuse of anabolic androgenic steroids in athletes is a strategy used to enhance strength and skeletal muscle hypertrophy. However, its abuse leads to an imbalance in muscle sympathetic nerve activity, increased vascular resistance, and increased blood pressure. However, the mechanisms underlying these alterations are still unknown. Therefore, we tested whether anabolic androgenic steroids could impair resting baroreflex sensitivity and cardiac sympathovagal control. In addition, we evaluate pulse wave velocity to ascertain the arterial stiffness of large vessels. METHODS: Fourteen male anabolic androgenic steroid users and 12 nonusers were studied. Heart rate, blood pressure, and respiratory rate were recorded. Baroreflex sensitivity was estimated by the sequence method, and cardiac autonomic control by analysis of the R-R interval. Pulse wave velocity was measured using a noninvasive automatic device. RESULTS: Mean spontaneous baroreflex sensitivity, baroreflex sensitivity to activation of the baroreceptors, and baroreflex sensitivity to deactivation of the baroreceptors were significantly lower in users than in nonusers. In the spectral analysis of heart rate variability, high frequency activity was lower, while low frequency activity was higher in users than in nonusers. Moreover, the sympathovagal balance was higher in users. Users showed higher pulse wave velocity than nonusers showing arterial stiffness of large vessels. Single linear regression analysis showed significant correlations between mean blood pressure and baroreflex sensitivity and pulse wave velocity. CONCLUSIONS: Our results provide evidence for lower baroreflex sensitivity and sympathovagal imbalance in anabolic androgenic steroid users. Moreover, anabolic androgenic steroid users showed arterial stiffness. Together, these alterations might be the mechanisms triggering the increased blood pressure in this population.

Impact of hypertension severity on arterial stiffness, cerebral vasoreactivity, and cognitive performance / Impacto da gravidade da hipertensão na rigidez arterial, vasorreatividade cerebral e desempenho cognitivo

ABSTRACT. Aging, hypertension (HTN), and other cardiovascular risk factors contribute to structural and functional changes of the arterial wall. Objective: To evaluate whether arterial stiffness (AS) is related to cerebral blood flow changes and its association with cognitive function in patients with hypertension. Methods: 211 patients (69 normotensive and 142 hypertensive) were included. Patients with hypertension were divided into 2 stages: HTN stage-1 and HTN stage-2. The mini-mental state examination (MMSE), Montreal Cognitive Assessment (MoCA) and a battery of neuropsychological (NPE) tests were used to determine cognitive function. Pulse wave velocity was measured using the Complior®. Carotid properties were assessed by radiofrequency ultrasound. Central arterial pressure and augmentation index were obtained using applanation tonometry. Middle cerebral artery flow velocity was measured by transcranial Doppler ultrasonography. Results: Both arterial stiffness parameters and cerebral vasoreactivity worsened in line with HTN severity. There was a negative correlation between breath holding index (BHI) and arterial stiffness parameters. Cognitive performance worsened in line with HTN severity, with statistical difference occurring mainly between the HTN-2 and normotension groups on both the MMSE and MoCA. The same tendency was observed on the NPE tests. Conclusion: Hypertension severity was associated with higher AS, worse BHI, and lower cognitive performance.

RESUMO. A idade, hipertensão arterial (HA), e outros fatores de risco cardiovascular contribuem para as alterações estruturais e funcionais da parede arterial. Objetivo: Avaliar o quanto a rigidez arterial está relacionada com as alterações do fluxo sanguíneo cerebral e sua associação com a função cognitiva em pacientes com hipertensão. Métodos: Foram incluídos 211 pacientes (69 normotensos e 142 hipertensos). Os pacientes com hipertensão foram divididos em dois estágios: HA-1 e HA-2. O mini exame do estado mental (MEEM), Montreal Cognitive Assessment (MoCA) e uma bateria de testes neuropsicológicos foram usados para avaliar a função cognitiva. A velocidade da onda de pulso foi medida usando o Complior®. As propriedades da artéria carótida foram avaliadas usando o ultrassom de radiofrequência. A pressão arterial central e o índice de incremento foram obtidos usando a tonometria de aplanação. A velocidade de fluxo sanguíneo da arterial cerebral média foi medida pelo ultrassom com Doppler Transcraniano. Resultados: Tanto os parâmetros da rigidez arterial quanto a vasorreatividade cerebral foram piores com a gravidade da hipertensão. Houve uma correlação negativa entre o índice de apnéia e os parâmetros da rigidez arterial. O desempenho cognitivo foi pior com a gravidade de hipertensão arterial com diferença estatística ocorrendo principalmente entre os grupos HA-2 e normotensão tanto no MEEM quanto no MoCA. A mesma tendência foi observada em relação aos testes neuropsicológicos. Conclusão: A gravidade de hipertensão arterial foi associada com maior rigidez arterial, pior índice de apneia, e menor desempenho cognitivo.

Intermittent claudication and severe renal artery stenosis are independently associated in hypertensive patients referred for renal arteriography

OBJECTIVE: The purpose of this study was to evaluate the association between the presence of clinical symptoms of peripheral artery disease and severe renal artery stenosis in patients referred for renal angiography. METHOD: We included 82 patients with clinical suspicion of renovascular hypertension and performed an imaging investigation (renal Doppler ultrasound and/or renal scintigraphy) for possible renal artery stenosis. All patients underwent renal arteriography and were examined for peripheral artery disease based on the presence of intermittent claudication and ankle-brachial index test results. Severe renal artery stenosis was defined as a lesion causing 70% obstruction. RESULTS: Severe renal artery stenosis was present in 32 of 82 (39%) patients. Patients with severe renal artery stenosis were older (63±12 vs 56±12 years, p=0.006), had more intermittent claudication (55 vs 45%, p=0.027), and had a greater prevalence of an ankle-brachial index <0.9 (44% vs 20%, p=0.021) than patients without severe renal artery stenosis. Multivariate logistic regression analysis showed that the presence of intermittent claudication was independently associated with renal artery stenosis ≥70% (OR: 3.33; 95% CI 1.03-10.82, p=0.04), unlike the ankle-brachial index, which showed no association (OR: 1.44; 95% CI 0.37-5.66, p=0.60). CONCLUSION: Intermittent claudication is independently associated with severe renal artery stenosis (≥70%) in patients clinically suspected of having renovascular hypertension.

Factors associated with subendocardial ischemia risk in patients on hemodialysis / Fatores associados ao risco de isquemia subendocárdica em pacientes em hemodiálise

Abstract Introduction: Bone metabolism disorder (BMD) and vascular dysfunction contribute to excess cardiovascular mortality observed in hemodialysis patients. Vascular dysfunction, a new marker of atherosclerosis, can play a role in this risk. Even though associated with higher mortality in the general population, such vascular evaluation in patients on hemodialysis has not been extensively studied. Methods: In this cross-sectional study, hemodialysis patients were submitted to flow-mediated dilation, subendocardial viability ratio (SEVR) and ejection duration index assessment, in order to estimate the impact of BMD markers on vascular dysfunction. Results: A matched cohort of patients with (n = 16) and without (n = 11) severe secondary hyperparathyroidism (SHPT) was studied. Additionally, time spent under severe SHPT was also evaluated. Patients with severe SHPT had lower SEVR and higher ejection duration index, indicating higher cardiovascular risk. Lower SEVR was also associated to diastolic blood pressure (r = 0.435, p = 0.049), serum 25-Vitamin-D levels (r = 0.479, p = 0.028) and to more time spent under severe secondary hyperparathyroidism (SHPT), defined as time from PTH > 500pg/ml until parathyroidectomy surgery or end of the study (r = -0.642, p = 0.027). In stepwise multiple regression analysis between SEVR and independent variables, lower SEVR was independently associated to lower serum 25-Vitamin-D levels (p = 0.005), female sex (p = 0.012) and more time spent under severe SHPT (p = 0.001) in a model adjusted for age, serum cholesterol, and blood pressure (adjusted r² = 0.545, p = 0.001). Conclusion: Subendocardial perfusion was lower in patients with BMD, reflecting higher cardiovascular risk in this population. Whether early parathyroidectomy in the course of kidney disease could modify such results still deserves further investigation.

Resumo Introdução: Distúrbios do metabolismo ósseo (DMO) e alterações da função vascular contribuem para a elevada mortalidade de pacientes em hemodiálise. A disfunção vascular, um novo marcador de aterosclerose, pode contribuir para este risco. Apesar de associada a aumento de mortalidade na população geral, a avaliação de tal disfunção ainda não foi realizada de modo amplo em pacientes em hemodiálise. Métodos: Neste estudo transversal, pacientes em hemodiálise foram submetidos à avaliação da vasodilatação mediada por fluxo, razão de viabilidade subendocárdica (RVSE) e índice de duração de ejeção, como estimativas de avaliação dos marcadores de DMO sobre disfunção vascular. Resultados: Uma coorte pareada com (n = 16) e sem (n = 11) hiperparatireoidismo secundário (HPTS) grave foi estudada. Adicionalmente, o tempo transcorrido do diagnóstico de HPTS grave também foi avaliado. Pacientes com HPTS grave apresentaram menores valores de RVSE e maiores valores de índice de duração de ejeção, apontando maior risco cardiovascular. Baixa RVSE também foi associada à pressão arterial diastólica (r = 0,435, p = 0,049), níveis séricos de 25-Vitamina D (r = 0,479, p = 0,028) e maior tempo transcorrido desde diagnóstico de HPTS grave, definido como tempo em que o paciente permaneceu com valores de paratormônio superiores a 500 pg/ml até realização de cirurgia de paratireoidectomia ou término do estudo (r = -0,642, p = 0,027). Em regressão logística stepwise entre RVSE e variáveis independentes, menor RVSE foi independentemente associado a menores valores de 25-Vitamina D (p = 0,005), sexo feminino (p = 0,012) e maior tempo transcorrido desde diagnóstico de HPTS grave (p = 0,001) em um modelo ajustado para idade, colesterol sérico e pressão arterial (r2 ajustado = 0,545, p = 0,001). Conclusão: A perfusão subendocárdica foi menor em pacientes com DMO, refletindo o maior risco cardiovascular nesta população. Investigações adicionais são necessárias para definir se a paratireoidectomia precoce no curso da doença renal crônica poderia interferir neste risco.

Determinants of Functional and Structural Properties of Large Arteries in Healthy Individuals / Determinantes das Propriedades Funcionais e Estruturais de Grandes Artérias em Indivíduos Saudáveis

Background: Changes in the properties of large arteries correlate with higher cardiovascular risk. Recent guidelines have included the assessment of those properties to detect subclinical disease. Establishing reference values for the assessment methods as well as determinants of the arterial parameters and their correlations in healthy individuals is important to stratify patients. Objective: To assess, in healthy adults, the distribution of the values of pulse wave velocity, diameter, intima-media thickness and relative distensibility of the carotid artery, in addition to assessing the demographic and clinical determinants of those parameters and their correlations. Methods: This study evaluated 210 individuals (54% women; mean age, 44 ± 13 years) with no evidence of cardiovascular disease. The carotid-femoral pulse wave velocity was measured with a Complior® device. The functional and structural properties of the carotid artery were assessed by using radiofrequency ultrasound. Results: The means of the following parameters were: pulse wave velocity, 8.7 ± 1.5 m/s; diameter, 6,707.9 ± 861.6 μm; intima-media thickness, 601 ± 131 μm; relative distensibility, 5.3 ± 2.1%. No significant difference related to sex or ethnicity was observed. On multiple linear logistic regression, the factors independently related to the vascular parameters were: pulse wave velocity, to age (p < 0.01) and triglycerides (p = 0.02); intima-media thickness, to age (p < 0.01); diameter, to creatinine (p = 0.03) and age (p = 0.02); relative distensibility, to age (p < 0.01) and systolic and diastolic blood pressures (p = 0.02 and p = 0.01, respectively). Pulse wave velocity showed a positive correlation with intima media thickness (p < 0.01) and with relative distensibility (p < 0.01), while diameter showed a positive correlation with distensibility (p = 0.03). Conclusion: In healthy individuals, ...

Fundamento: Alterações das propriedades de grandes artérias são correlacionadas a maior risco cardiovascular. Recentes diretrizes incluem a avaliação dessas propriedades para detecção de doença subclínica. O estabelecimento de valores de referência dos métodos para essa avaliação e de determinantes dos parâmetros arteriais e suas correlações em indivíduos saudáveis é importante para a estratificação dos pacientes. Objetivo: Avaliar, em adultos saudáveis, a distribuição dos valores de velocidade de onda de pulso e de diâmetro, espessura íntima-média e distensão relativa da artéria carótida, além de avaliar os determinantes demográficos e clínicos desses parâmetros e suas correlações. Métodos: Foram avaliados 210 indivíduos (54% mulheres; idade média, 44 ± 13 anos) sem evidência de doença cardiovascular. A velocidade de onda de pulso carótida-femoral foi medida com o aparelho Complior®. Propriedades funcionais e estruturais da carótida foram avaliadas por ultrassom de radiofrequência. Resultados: As seguintes médias foram obtidas: velocidade de onda de pulso, 8,7 ± 1,5 m/s; diâmetro, 6.707,9 ± 861,6 µm; espessura íntima-média, 601 ± 131 µm; distensão relativa, 5,3 ± 2,1%. Não houve diferenças significativas conforme sexo ou raça. Na análise de regressão logística linear múltipla, os fatores independentemente relacionados aos parâmetros vasculares foram: velocidade de onda de pulso, com idade (p < 0,01) e triglicérides (p = 0,02); espessura íntima-média, com idade (p < 0,01); diâmetro, com creatinina (p = 0,03) e idade (p = 0,02); distensão relativa, com idade (p < 0,01) e ...

The impact of metabolic syndrome on metabolic, pro-inflammatory and prothrombotic markers according to the presence of high blood pressure criterion

OBJECTIVES: We explored whether high blood pressure is associated with metabolic, inflammatory and prothrombotic dysregulation in patients with metabolic syndrome. METHODS: We evaluated 135 consecutive overweight/obese patients. From this group, we selected 75 patients who were not under the regular use of medications for metabolic syndrome as defined by the current Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults criteria. The patients were divided into metabolic syndrome with and without high blood pressure criteria (≥130/≥85 mmHg). RESULTS: Compared to the 45 metabolic syndrome patients without high blood pressure, the 30 patients with metabolic syndrome and high blood pressure had significantly higher glucose, insulin, homeostasis model assessment insulin resistance index, total cholesterol, low-density lipoprotein-cholesterol, triglycerides, uric acid and creatinine values; in contrast, these patients had significantly lower high-density lipoprotein-cholesterol values. Metabolic syndrome patients with high blood pressure also had significantly higher levels of retinol-binding protein 4, plasminogen activator inhibitor 1, interleukin 6 and monocyte chemoattractant protein 1 and lower levels of adiponectin. Moreover, patients with metabolic syndrome and high blood pressure had increased surrogate markers of sympathetic activity and decreased baroreflex sensitivity. Logistic regression analysis showed that high-density lipoprotein, retinol-binding protein 4 and plasminogen activator inhibitor-1 levels were independently associated with metabolic syndrome patients with high blood pressure. There is a strong trend for an independent association between metabolic syndrome patients with high blood pressure and glucose levels. CONCLUSIONS: High blood pressure, which may be related to the autonomic dysfunction, is associated with metabolic, inflammatory and prothrombotic dysregulation ...

Estresse oxidativo e disfunção endotelial na doença renal crônica / Oxidative stress and endothelial dysfunction in chronic kidney disease / Estrés oxidativo y disfunción endotelial en la enfermedad renal crónica

Fundamento: A doença renal crônica (DRC) caracteriza-se pela alta prevalência de aterosclerose. Uma vez que o estresse oxidativo e a disfunção endotelial são promotores da aterosclerose, é interessante verificar se as duas condições estão associadas em pacientes com DRC, ainda sem doença cardiovascular (DCV) clínica.Objetivo: Avaliar as relações entre o estresse oxidativo e a função endotelial em pacientes com DRC estágio 5, sem DCV. Métodos: Foram estudados 22 pacientes com DRC, não-diabéticos, não-fumantes, sem DCV e tratados por hemodiálise; além de 22 indivíduos normais. Em todos os indivíduos foram avaliados a reatividade vascular, dependente e independente de endotélio (ultra-som de alta resolução da artéria braquial), e o estresse oxidativo (níveis plasmáticos de substâncias reativas ao ácido tiobarbitúrico - TBARS). Resultados: A reatividade vascular dependente de endotélio (6,0 ± 4,25% vs. 11,3 ± 4,46%, p <0,001) e a reatividade independente de endotélio (11,9 ± 7,68% vs. 19,1 ± 6,43%, p <0,001) foram reduzidas na DRC, enquanto o estresse oxidativo (2,63 ± 0,51 vs. 1,49 ± 0,43, p <0,001) foi aumentado. Os níveis de TBARS, quando utilizado na totalidade de indivíduos do estudo (pacientes e controles), correlacionaram-se com a reatividade vascular dependente de endotélio (r = -0,56, p<0,001) e com a pressão arterial sistólica (r = 0,48, p = 0,002). Conclusão: O estresse oxidativo é associado à disfunção endotelial. Pacientes com DRC apresentam aumento do estresse oxidativo e comprometimento da reatividade vascular. Os resultados sugerem ainda que o estresse oxidativo e a disfunção endotelial podem estar envolvidos na susceptibilidade exagerada da DRC às complicações cardiovasculares.

Background: Chronic kidney disease (CKD) is characterized by the high prevalence of atherosclerosis. Considering that endothelial dysfunction and oxidative stress are promoters of atherosclerosis, it is of interest to verify whether the two conditions are associated in CKD patients still free of clinical cardiovascular disease (CVD).Objective: To evaluate the association between oxidative stress and endothelial function in end-stage CKD patients without clinically evident CVD.Methods: We studied 22 nondiabetic, nonsmoker CKD patients without clinical CVD treated by maintenance hemodialysis and 22 healthy controls. Endothelium- dependent and independent vascular reactivity and oxidative stress, as determined by the plasma levels of thiobarbituric acid-reactive substances – TBARS, were evaluated in all subjects. Results: Endothelium-dependent (6.0 ± 4.25 vs. 11.3 ± 4.46 %, p< 0.001) and endothelium-independent (11.9 ± 7.68 vs. 19.1 % ± 6.43 %, p< 0.001) vascular reactivity were reduced, while TBARS (2.63 ± 0.51 vs. 1.49 ± 0.42 nmols/mL) was increased in CKD patients when compared to controls. TBARS levels were significantly related to endothelium-dependent vascular reactivity (r= - 0.56, p< 0.001) and to systolic blood pressure (r= - 0.48, p= 0.002). Conclusion: Oxidative stress is increased in CKD patients free of CVD and is associated with endothelial dysfunction in patients and controls. The results suggest that oxidative stress and endothelial dysfunction may be involved in the increased susceptibility of CKD patients to CVD and cardiovascular complications.

Fundamento: La enfermedad renal crónica (ERC) se caracteriza por la alta prevalencia de aterosclerosis Siendo el estrés oxidativo y la disfunción endotelial promotores de la aterosclerosis, es interesante verificar si las dos condiciones están asociadas en pacientes con ERC, aun sin enfermedad cardiovascular (ECV) clínica. Objetivo: Evaluar las relaciones entre el estrés oxidativo y la función endotelial en pacientes con ERC estado 5, sin ECV. Métodos: Se estudiaron 22 pacientes con ERC, no diabéticos, no fumadores, sin ECV y tratados por hemodiálisis; además de 22 individuos normales. En todos los individuos se evaluaron la reactividad vascular, dependiente e independiente de endotelio (ecografía de alta resolución de la arteria braquial), y el estrés oxidativo (niveles plasmáticos de sustancias reactivas al ácido tiobarbitúrico – TBARS). Resultados: La reactividad vascular dependiente de endotelio (6,0 ± 4,25% vs. 11,3 ± 4,46%, p <0,001) y la reactividad independiente de endotelio (11,9 ± 7,68% vs. 19,1 ± 6,43%, p <0,001) se redujeron en la ERC, mientras el estrés oxidativo (2,63 ± 0,51 vs. 1,49 ± 0,43, p <0,001) se vio aumentado. Los niveles de TBARS, cuando se utiliza en la totalidad de individuos del estudio (pacientes y controles), se correlacionaron con la reactividad vascular dependiente de endotelio (r = -0,56, p<0,001) y con la presión arterial sistólica (r = 0,48, p = 0,002). Conclusión: El estrés oxidativo está asociado a la disfunción endotelial. Pacientes con ERC presentan aumento del estrés oxidativo y compromiso de la reactividad vascular. Los resultados sugieren además que el estrés oxidativo y la disfunción endotelial pueden estar involucrados en la susceptibilidad exagerada de la ERC a las complicaciones cardiovasculares.