Effect of sodium intake on blood pressure, serum levels and renal excretion of sodium and potassium in normotensives with and without familial predisposition to hypertension

1. Seventeen normal volunteers aged 19 to 22 were randomly subjected, in a trial of crossover design, to three distinct regimens of sodium chloride intake : high (16 to 20 g), normal (8 to 12 g) and low (0 .5 to 1 g). Each regimen lasted nine days, with determination of blood pressure and heart rate (in the supine position and after sudden rising), body weight, and urinary output of creatinine, sodium and potassium on the third, sixth and ninth days. 1n addition, plasma levels of creatinine, sodium and potassium were determined on the ninth day so that sodium and potassium clearance and fractional excretion could be calculated. 2. Eleven of the volunteers had a family history of hypertension. Compared to the' six without such a history, these subjects showed : 1) higher supirie systolic blood pressure on the third day of sodium overload (124 .7 ± 3.0 vs 112.3 ± 2.9 mmHg, P <o;02); 2) higher supine diastolic blood pressure on ·the third day of sodium overload (76 .5 ·± 2.8 vs 64.5 ± 4.3 mmHg; P < 0.05); 3) higher supine diastolic blood pressure on the sixth day of sodium overload (73 .7 ± 2.3 vs 63 .8 ± 3.2 mmHg, P < 0 .05); 4) lower supine heart rate on the ninth day of sodium overload (6 LO ± 3.1 vs 72.7 ± 4.6: P< 0.05), and 5) lower plasma potassium on the ninth day of sodium overload (4.10 ±0.05 vs 4-28 ± 0.06 mEq/1, P <0.05). 3. These results suggest that normal individuals whose familial history places them at risk for the development of hypertension differ from those not at risk during their adaptation to sodium load by suffering a transient elevation of blood pressure within a few days of the increase in load. The low levels of plasma potassium observed in these volunteers after a period of sodium load may be due to the operation of different renal mechanisms of sodium excretion in this group, leading to increased kaliuresis, and may explain the high vascular reactivity of such individuals

HIPERTENSÃO ARTERIAL SISTÊMICA: PREVALÊNCIA E MECANISMOS FISIOPATOGÊNICOS

A prevalência de hipertensão arterial, agravo de saúde com distribuição internacional, também é alta em Porto Alegre. Seus fatores de risco – obesidade, predisposição familiar, consumo abusivo de bebidas alcoólicas – foram encontrados em estudos epidemiológicos conduzidos pela unidade de Hipertensão Arterial, ao lado do risco independente propiciado por baixo nível socioeconômico, um aspecto que merece investigações específicas. A interação entre história familiar de hipertensão arterial e consumo aumentado de cloreto de sódio é um mecanismo fisiopatogênico da doença identificado em modelo experimental e em indivíduos jovens vivendo na comunidade. O consumo abusivo de bebidas alcoólicas pode aumentar a pressão arterial nas fases de depuração do etanol, como se demonstrou, sob condições experimentais, em jovens voluntários normotensos e em indivíduos vivendo em comunidades. Exposições ambientais ao excesso de sal, calorias e álcool explicam grande parte dos casos de hipertensão arterial.Unitermos: Hipertensão arterial, prevalência, mecanismos fisiopatogênicos, álcool, sal, predisposição familia

Hypertension : prevalence and pathophysiologic mechanisms

A prevalência de hipertensão arterial, agravo de saúde com distribuição internacional, também é alta em Porto Alegre. Seus fatores de risco – obesidade, predisposição familiar, consumo abusivo de bebidas alcoólicas – foram encontrados em estudos epidemiológicos conduzidos pela unidade de Hipertensão Arterial, ao lado do risco independente propiciado por baixo nível socioeconômico, um aspecto que merece investigações específicas. A interação entre história familiar de hipertensão arterial e consumo aumentado de cloreto de sódio é um mecanismo fisiopatogênico da doença identificado em modelo experimental e em indivíduos jovens vivendo na comunidade. O consumo abusivo de bebidas alcoólicas pode aumentar a pressão arterial nas fases de depuração do etanol, como se demonstrou, sob condições experimentais, em jovens voluntários normotensos e em indivíduos vivendo em comunidades. Exposições ambientais ao excesso de sal, calorias e álcool explicam grande parte dos casos de hipertensão arterial.Arterial hypertension, which is a cardiovascular risk factor with a worldwide distribution, is highly prevalent in Porto Alegre, Brazil. Risk factors for hypertension – obesity, familial predisposition, abusive intake of alcoholic beverages – were identified in epidemiological studies carried out by the hypertension unit at Hospital de Clínicas de Porto Alegre. The independent risk for hypertension resulting from low socioeconomic level requires further investigation. An interaction between familial predisposition to arterial hypertension and higher salt intake is a pathophysiologic mechanism of the disease, identified in experimental models and in free-living individuals. Abusive consumption of alcoholic beverages may increase blood pressure during the vanishing period, a mechanism demonstrated, under experimental conditions, in young normotensive volunteers, and in free living-individuals. Excessive consumption of calories, salt and alcohol explains the incidence of most cases of arterial hypertension

Incidência de hipertensão arterial em uma coorte de adultos da região urbana de Porto Alegre, RS

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Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).

Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362