Diurnal variation of vascular diameter and reactivity in healthy young men

The higher incidence of cardiovascular events in the morning is accompanied by an increased vascular tone. However, there are few published studies designed to evaluate the diurnal variation of vascular and endothelial parameters in healthy subjects. In the present investigation, we evaluated the diurnal variation in brachial artery diameter (BAD), flow-mediated dilation (FMD) and endothelium-independent dilation (NFMD) in a homogeneous sample of healthy non-smoker young men. Fifty subjects aged 20.8 ± 0.3 years (range: 18 to 25 years) were investigated by brachial artery ultrasound. Exclusion criteria were female gender and evidence of clinically significant health problems, including obesity. Volunteers were asked to rest and avoid fat meals as well as alcoholic beverages 48 h before and until completion of the evaluations. BAD, FMD and NFMD were measured at 7 am, 5 pm, and 10 pm and tested by repeated measures ANOVA. BAD was smaller at 7 am (mean ± SEM, 3.8 ± 0.1 mm) in comparison with 5 pm (3.9 ± 0.1) and 10 pm (4.0 ± 0.1 mm; P < 0.001). FMD values did not change significantly during the day, while NFMD increased more at 7 am (18.5 ± 1.1 percent), when compared to 15.5 ± 0.9 percent at 10 pm and 15.5 ± 0.9 percent at 5 pm (P = 0.04). The physiological state of vasoconstriction after awakening, with preserved capability to dilate in the morning, should be considered to be part of the healthy cardiovascular adaptation before considering later life risk factors and endothelial dysfunction.

Diurnal variation of vascular diameter and reactivity in healthy young men.

The higher incidence of cardiovascular events in the morning is accompanied by an increased vascular tone. However, there are few published studies designed to evaluate the diurnal variation of vascular and endothelial parameters in healthy subjects. In the present investigation, we evaluated the diurnal variation in brachial artery diameter (BAD), flow-mediated dilation (FMD) and endothelium-independent dilation (NFMD) in a homogeneous sample of healthy non-smoker young men. Fifty subjects aged 20.8 +/- 0.3 years (range: 18 to 25 years) were investigated by brachial artery ultrasound. Exclusion criteria were female gender and evidence of clinically significant health problems, including obesity. Volunteers were asked to rest and avoid fat meals as well as alcoholic beverages 48 h before and until completion of the evaluations. BAD, FMD and NFMD were measured at 7 am, 5 pm, and 10 pm and tested by repeated measures ANOVA. BAD was smaller at 7 am (mean +/- SEM, 3.8 +/- 0.1 mm) in comparison with 5 pm (3.9 +/- 0.1) and 10 pm (4.0 +/- 0.1 mm; P < 0.001). FMD values did not change significantly during the day, while NFMD increased more at 7 am (18.5 +/- 1.1%), when compared to 15.5 +/- 0.9% at 10 pm and 15.5 +/- 0.9% at 5 pm (P = 0.04). The physiological state of vasoconstriction after awakening, with preserved capability to dilate in the morning, should be considered to be part of the healthy cardiovascular adaptation before considering later life risk factors and endothelial dysfunction.

[Single daily dose of verapamil (COER-24 180/24 mg) in mild and moderate hypertension evaluated by ambulatory blood pressure monitoring]. / Verapamil COER-24 180/240 mg na hipertensão arterial leve a moderada em dose única diária avaliado pela monitorização ambulatorial da pressão arterial.

OBJECTIVE: To evaluate the anti-hypertensive effect of verapamil COER-24 180/240 mg in a single dose at bedtime as single therapy in mild to moderate hypertensives. METHODS: A multicentric, open, placebo controlled study of 81 hypertensive patients older than 20 years-old followed to 8 weeks. Blood pressure was measured in doctor's office and by 24 h ambulatory monitoring (ABPM). RESULTS: We observed a decreased in systolic and diastolic blood pressure in doctor's office at 4th and 8th weeks. ABPM showed that both systolic, diastolic and mean blood pressure, heart rate and the mean 24-hour blood pressure load decreased after the 8-week treatment. In addition, there was a reduction of the double-product, especially in the morning and 68% of the patients didn't have any adverse events. CONCLUSION: The therapy verapamil COER-24 180/240 mg in a single dose is useful for mild and moderate hypertensive patients, with significant pressure decrease in both office blood pressure measurements and in the ABPM/24 hours, as well as showing good tolerability.

Dose-dependent biphasic effect of ethanol on 24-h blood pressure in normotensive subjects.

The vasodilation that follows acute alcohol intake is hard to conciliate with the high prevalence of hypertension detected in those persons who consume regular amounts of alcohol. In this experiment we examined early and late hemodynamic effects of acute administration of water and of 15 g, 30 g, and 60 g of alcohol in 40 normal men, aged 19 to 30 years, using 24-h ambulatory blood pressure monitoring (ABPM). Mean systolic and diastolic blood pressures were each approximately 4 mm Hg lower during the period immediately after ingestion of 60 g (v 0 g) of ethanol, and were 7 and 4 mm Hg higher, respectively, at night. The day minus night differences displayed a dose-response curve both for systolic (P < .001) and diastolic blood pressure (P = .045). Three subjects in the 60-g group had more than 50% of nightly blood pressure loads in the hypertensive range against none in the remaining groups (P < .01). In conclusion, our findings suggest that acute alcohol intake elicits a biphasic hemodynamic response, causing, first, vasodilatation and, later, a pressor effect. The higher prevalence of hypertension in alcohol abusers seen in epidemiological surveys may be, in part, a result of measurements done in the period of transiently increased blood pressure during ethanol washout.

Diagnóstico de hipertensäo arterial sistêmica: evidências de que os critérios contemporâneos devem ser revistos / Diagnosis of systemic hypertension: evidences that current criteria should be revised

Diversos comitês normativos em hipertensäo arterial recomendam considerar a média de várias aferiçöes da pressäo arterial com esfigmomanômetro para diagnosticar hipertensäo. Näo há consenso sobre o número de medidas a serem consideradas. OBJETIVO. Descrever o comportamento da pressäo arterial obtida em três dias diferentes, utilizando-se a média de seis aferiçöes para o diagnóstico de hipertensäo. MÉTODOS. No ambulatório de hipertensäo da Unidade de Farmacologia Clínica do Hospital de Clínicas de Porto Alegre, emprega-se a média de seis determinaçöes, obtidas em três dias diferentes, para diagnosticar e classificar a hipertensäo, exceto nos pacientes com valores muito baixos ou elevados nas duas primeiras aferiçöes. Cinqüenta e oito pacientes foram submetidos a essa rotina. RESULTADOS. As médias das pressöes sistólica (PS) e diastólica (PD) decresceram da primeira à sexta determinaçäo (ANOVA para medidas repetidas: F = 4,45, p = 0,001 para PS e F = 5,54, p < 0,001 para PD). Os pacientes foram divididos em grupos com PS e PD obtidas na primeira aferiçäo superiores e inferiores à média de todo grupo. A diminuiçäo de ambas as pressöes ao longo das seis aferiçöes ficou restrita aos grupos com valores da primeira determinaçäo superiores à média de todo o grupo (ANOVA: F = 8.03; p < 0,0001 para PS e F = 6,33, p < 0,0001 para PD). A regressäo à média e uma reaçäo de alerta inicial säo explicaçöes aventadas para esse fenômeno. CONCLUSÄO. Esses dados demonstram que o diagnóstico de hipertensäo arterial näo deve ser feito com base em uma única aferiçäo e sugerem que a recomendaçäo de diagnosticar hipertensäo severa baseando-se em altos valores das duas primeiras medidas pode classificar erroneamente alguns pacientes.

Blood pressure effects of antihypertensive drugs and changes in lifestyle in a Brazilian hypertensive cohort.

BACKGROUND: The antihypertensive efficacy of drug therapy and of some nonpharmacologic recommendations has been demonstrated in controlled clinical trials, but not in a clinical setting. OBJECTIVE: To assess the antihypertensive effectiveness of drug therapy and of three nonpharmacologic recommendations (loss of weight, salt-intake restriction, and physical exercise). DESIGN: A prospectively planned cohort study. SETTING: A hospital-based hypertensive outpatient clinic. PATIENTS: We studied 637 patients (65.5% women) with systolic blood pressures above 140 mmHg or diastolic blood pressures above 90 mmHg, corresponding to 76% of 839 patients who were administered a prescription for hypertension and who returned for the first follow-up visit 3.5 months later on average. METHODS: The nonpharmacologic prescription consisted of salt-intake restriction for all, weight reduction for overweight patients, and practice of aerobic physical exercise for those for whom it was not contraindicated; 60% of the patients were treated with drugs according to standard recommendations. Patients treated with drugs were compared with untreated subjects; for the nonpharmacologic interventions, the groups were compared according to their reported compliances with the recommendations (at least some compliance versus none). The main outcome measures were variations in systolic and diastolic blood pressures between the baseline evaluation and the first follow-up visit and an improvement in prognosis, represented by a favorable change in the classification of the blood pressure (according to Joint National Committee V criteria). RESULTS: The cohort constituted predominantly low-income, middle-aged, overweight white women, with low-to-moderate hypertension of long duration. The group treated with drugs exhibited the greatest reduction in blood pressure, with clinical significance even discounting the losses in follow-up; the group of patients who reported compliance with the low-energy-intake diet also showed a consistent antihypertensive effect, which was still detectable on the occasion of the third follow-up visit 9 months after the first prescription; reported compliance with a low-sodium diet and practice of physical exercise were not associated with a reduction in blood pressure; among a subset of the patients, reported compliance with the salt-intake-restricted diet did not reduce the amount of sodium to the theoretical antihypertensive threshold. It was not possible to determine whether the lack of an antihypertensive effect of physical exercise for this cohort was secondary to a misreport of the extent of compliance or to an absence of effect of the intensity of training prescribed. The effects of drug therapy and compliance with a low-energy-intake diet were shown to be independent of other interventions or confounders. CONCLUSION: The antihypertensive effect of drugs demonstrated in well-controlled clinical trials is achievable in clinical practice. The recommendation to lose weight was the only nonpharmacologic intervention with a detectable antihypertensive effect in this cohort. The absence of effect of a low-sodium diet is probably secondary to the insufficient reduction in the amount of salt consumed. The lack of an antihypertensive effect of physical exercise could reflect either a misreported compliance or an absence of effect of the intensity of training recommended in this study.

[Diagnosis of systemic hypertension: evidences that current criteria should be revised]. / Diagnóstico de hipertensão arterial sistêmica: evidências de que os critérios contemporâneos devem ser revistos.

UNLABELLED: It has been recommended to take the average of several blood pressure (BP) determinations with a sphygmomanometer to diagnose hypertension, but there is no agreement on the reading numbers. PURPOSE: Describing the behavior of BP readings taken in three different days to establish the classificatory BP in an outpatient hypertension clinic. METHOD: In the outpatient hypertension clinic of the Clinical Pharmacology Division of the Hospital de Clínicas de Porto Alegre, we use the mean of six readings taken in three different days to establish the classificatory blood pressure, except for those with very high or low values in the first day. In this report we describe the behavior of BP in 58 patients submitted to this routine. RESULTS: The mean of systolic (SBP) and diastolic (DBP) blood pressures decreased from the first to the 6th reading (ANOVA for repeated measurements: F = 4.45, P = 0.001 for SBP and F = 5.54, P < 0.001 for DBP). Afterward, the patients were classified into two groups according their first SBP and DBP reading. The decreasing in both SBP and DBP was confined to those with the first measurement in the upper half of the entire group (ANOVA: F = 8.03; P < 0.0001 for SBP and F = 6.33, P < 0.0001 for DBP). Regression to the mean and some reactiveness in the first day are possible explanations for this. CONCLUSION: These data corroborate that the hypertension diagnosis should not be based in an single blood pressure determination and suggest that the recommendation to diagnose severe hypertension based on high values in the first two readings could misclassify some patients.

Effect of sustained-release Verapamil on the morning systemic arterial pressure surge during daily activity in patients with systemic hypertension.

In a placebo-controlled study of 13 subjects with systemic hypertension, sustained-release verapamil reduced the morning surge in systolic pressure by 10.2 mm Hg (p = 0.04), diastolic pressure by 11.1 mm Hg (p = 0.008), and heart rate by 3.3 beats/min (p = 0.17). Blunting of the morning hemodynamic surge may be a mechanism by which verapamil could reduce the risk of plaque disruption and acute coronary events in the morning.

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. In 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 supine systolic blood pressure on the third day of sodium overload (124.7 +/- 3.0 vs 112.3 +/- 2.9 mmHg, P less than 0.02); 2) higher supine diastolic blood pressure on the third day of sodium overload (76.5 +/- 2.8 vs 64.5 +/- 4.3 mmHg; P less than 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 less than 0.05); 4) lower supine heart rate on the ninth day of sodium overload (61.0 +/- 3.1 vs 72.7 +/- 4.6, P less than 0.05), and 5) lower plasma potassium on the ninth day of sodium overload (4.10 +/- 0.05 vs 4.28 +/- 0.06 mEq/l, P less than 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.