Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 39
Filtrar
1.
Am J Hypertens ; 20(5): 587-97, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17485026

RESUMO

A review of six clinical trials of aliskiren involving >5,000 patients with mild to moderate hypertension indicated that this first of a new class of orally active antihypertensive drugs is no more effective than angiotensin-converting enzyme inhibitors (CEIs), angiotensin receptor blockers (ARBs), or diuretics for lowering blood pressure. The starting dose is 150 mg; 300 mg is usually more effective, but 600 mg is no better than 300 mg. Aliskiren in combination with a diuretic appeared to lower blood pressure more than an aliskiren-ARB combination, but still failed to control blood pressure (<140/90) in 50% of the patients. Although aliskiren suppresses plasma renin activity, it causes much greater reactive rises in plasma renin concentration than does any other antihypertensive class tested. Because aliskiren, like CEIs and ARBs, only blocks 90% to 95% of plasma renin, the pressor consequences of its greater reactive increases in plasma renin concentration appear to offset its net ability to lower blood pressure, especially with higher doses. Patients with hyperreactive renin systems (renovascular, advanced, and malignant hypertension) were excluded from all of the trials. Until the possibility is eliminated of inducing increases in blood pressure with aliskiren in patients with highly reactive renin levels, it seems safe and simple to stick to the less expensive, equally effective and widely available generic CEI drugs for treating the renin factor in hypertension.


Assuntos
Amidas/farmacologia , Anti-Hipertensivos/farmacologia , Fumaratos/farmacologia , Hipertensão/tratamento farmacológico , Renina/antagonistas & inibidores , Renina/metabolismo , Amidas/efeitos adversos , Amidas/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Anti-Hipertensivos/efeitos adversos , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Ensaios Clínicos como Assunto , Quimioterapia Combinada , Feminino , Fumaratos/efeitos adversos , Fumaratos/uso terapêutico , Humanos , Masculino , Renina/sangue
2.
Am J Hypertens ; 20(8): 907-16, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17679042

RESUMO

BACKGROUND: Plasma renin activity (PRA), measured under controlled conditions, is a marker of the degree and persistence of renin-angiotensin system blockade. METHODS: Two similarly designed five-way crossover studies evaluated angiotensin II type 1 (AT1) receptor blockade-induced changes in PRA in quietly seated, ambulatory volunteers who were ingesting uncontrolled diets. At weekly intervals, PRA was measured during the 24 h after administration of placebo, olmesartan medoxomil (20 or 40 mg), or valsartan (80 or 160 mg) (Study CS866-445), or placebo, olmesartan medoxomil (40 mg), valsartan (160 or 320 mg), or irbesartan (300 mg) (Study CS866-448). The primary end point was change in PRA relative to placebo from predose to 24 h postdose (DeltaPRA24). RESULTS: In the 20 subjects who completed each study, there was a direct relationship between baseline PRA and DeltaPRA24 for all doses. Subjects with low PRA (<0.65 ng/mL/h) exhibited very low absolute increases in PRA. The DeltaPRA(24) increased significantly with olmesartan medoxomil 20 mg (P<.01) and 40 mg (P<.001) and valsartan 160 mg (P<.05) but not with valsartan 80 mg. In the second study (in which baseline PRA was lower), DeltaPRA24 increased with olmesartan medoxomil 40 mg (P<.0001), valsartan 320 mg (P<.01), and irbesartan 300 mg (P<.01) but not with valsartan 160 mg. The DeltaPRA24 was greatest with olmesartan medoxomil 40 mg and was dose-related for olmesartan medoxomil but not for valsartan. CONCLUSIONS: The greater DeltaPRA24 with olmesartan medoxomil 40 mg indicates a more prolonged AT1 receptor blockade than with valsartan 80, 160, or 320 mg or irbesartan 300 mg. A routine, clinic ambulatory PRA level can be used as a biochemical marker of the persistence and degree of AT1 receptor blockade in subjects without suppressed PRA levels.


Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II/administração & dosagem , Ritmo Circadiano/fisiologia , Sistema Renina-Angiotensina/efeitos dos fármacos , Renina/sangue , Cloreto de Sódio na Dieta/administração & dosagem , Adolescente , Adulto , Idoso , Aldosterona/urina , Angiotensina II , Biomarcadores/sangue , Biomarcadores/urina , Compostos de Bifenilo/administração & dosagem , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Ritmo Circadiano/efeitos dos fármacos , Estudos Cross-Over , Relação Dose-Resposta a Droga , Feminino , Seguimentos , Humanos , Imidazóis/administração & dosagem , Irbesartana , Masculino , Pessoa de Meia-Idade , Olmesartana Medoxomila , Prognóstico , Radioimunoensaio , Valores de Referência , Renina/efeitos dos fármacos , Sistema Renina-Angiotensina/fisiologia , Método Simples-Cego , Tetrazóis/administração & dosagem , Valina/administração & dosagem , Valina/análogos & derivados , Valsartana
4.
J Hypertens ; 24(11): 2163-8, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17053536

RESUMO

BACKGROUND: In the Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial the primary outcome (cardiac morbidity and mortality) did not differ between valsartan and amlodipine-based treatment groups, although systolic blood pressure (SBP) and diastolic blood pressure reductions were significantly more pronounced with amlodipine. Stroke incidence was non-significantly, and myocardial infarction was significantly lower in the amlodipine-based regimen, whereas cardiac failure was non-significantly lower on valsartan. OBJECTIVES: The study protocol specified additional analyses of the primary endpoint according to: sex; age; race; geographical region; smoking status; type 2 diabetes; total cholesterol; left ventricular hypertrophy; proteinuria; serum creatinine; a history of coronary heart disease; a history of stroke or transient ischemic attack; and a history of peripheral artery disease. Additional subgroups were isolated systolic hypertension and classes of antihypertensive agents used immediately before randomization. METHODS: The 15,245 hypertensive patients participating in VALUE were divided into subgroups according to baseline characteristics. Treatment by subgroup interaction analyses were carried out by a Cox proportional hazard model. Within each subgroup, treatment effects were assessed by hazard ratios and 95% confidence intervals. RESULTS: For cardiac mortality and morbidity, the only significant subgroup by treatment interaction was of sex (P = 0.016), with the hazard ratio indicating a relative excess of cardiac events with valsartan treatment in women but not in men, but SBP differences in favour of amlodipine were distinctly greater in women. No other subgroup showed a significant difference in the composite cardiac outcome between valsartan and amlodipine-based treatments. For secondary endpoints, a sex-related significant interaction was found for heart failure (P < 0.0001), with men but not women having a lower incidence of heart failure with valsartan. CONCLUSION: As in the whole VALUE cohort, in no subgroup of patients were there differences in the incidence of the composite cardiac endpoint with valsartan and amlodipine-based treatments, despite a greater blood pressure decrease in the amlodipine group. The only exception was sex, in which the amlodipine-based regimen was more effective than valsartan in women, but not in men, whereas the valsartan regimen was more effective in preventing cardiac failure in men than in women.


Assuntos
Anlodipino/uso terapêutico , Bloqueadores do Receptor Tipo 1 de Angiotensina II/uso terapêutico , Bloqueadores dos Canais de Cálcio/uso terapêutico , Parada Cardíaca/prevenção & controle , Insuficiência Cardíaca/prevenção & controle , Hipertensão/tratamento farmacológico , Tetrazóis/uso terapêutico , Valina/análogos & derivados , Idoso , Feminino , Parada Cardíaca/mortalidade , Insuficiência Cardíaca/mortalidade , Humanos , Hipertensão/complicações , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Fatores Sexuais , Resultado do Tratamento , Valina/uso terapêutico , Valsartana
6.
Trends Endocrinol Metab ; 16(3): 108-13, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15808808

RESUMO

Some causes of low renin hypertension are familial with known genetic bases. One of them, primary aldosteronism, is specifically treatable by mineralocorticoid receptor blockers or by surgery, and has at least two different familial varieties. These have provided insights into its natural history, with long normotensive and normokalemic phases, and variable expression within the same family. Primary aldosteronism was considered rare, but recent work beginning in 1992 suggests that it might be the most common curable cause of hypertension, worth screening for in every hypertensive. Evidence is now compelling that inappropriate aldosterone for salt status can cause not only hypertension, but vascular inflammation and end-organ damage, preventable by mineralocorticoid receptor blockade.


Assuntos
Hipertensão/sangue , Renina/sangue , Cardiologia/tendências , Cardiotônicos/uso terapêutico , Endocrinologia/tendências , Humanos , Hiperaldosteronismo/complicações , Hiperaldosteronismo/genética , Hipertensão/etiologia , Hipertensão/genética , Antagonistas de Receptores de Mineralocorticoides
7.
Lancet ; 363(9426): 2022-31, 2004 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-15207952

RESUMO

BACKGROUND: The Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial was designed to test the hypothesis that for the same blood-pressure control, valsartan would reduce cardiac morbidity and mortality more than amlodipine in hypertensive patients at high cardiovascular risk. METHODS: 15?245 patients, aged 50 years or older with treated or untreated hypertension and high risk of cardiac events participated in a randomised, double-blind, parallel-group comparison of therapy based on valsartan or amlodipine. Duration of treatment was event-driven and the trial lasted until at least 1450 patients had reached a primary endpoint, defined as a composite of cardiac mortality and morbidity. Patients from 31 countries were followed up for a mean of 4.2 years. FINDINGS: Blood pressure was reduced by both treatments, but the effects of the amlodipine-based regimen were more pronounced, especially in the early period (blood pressure 4.0/2.1 mm Hg lower in amlodipine than valsartan group after 1 month; 1.5/1.3 mm Hg after 1 year; p<0.001 between groups). The primary composite endpoint occurred in 810 patients in the valsartan group (10.6%, 25.5 per 1000 patient-years) and 789 in the amlodipine group (10.4%, 24.7 per 1000 patient-years; hazard ratio 1.04, 95% CI 0.94-1.15, p=0.49). INTERPRETATION: The main outcome of cardiac disease did not differ between the treatment groups. Unequal reductions in blood pressure might account for differences between the groups in cause-specific outcomes. The findings emphasise the importance of prompt blood-pressure control in hypertensive patients at high cardiovascular risk.


Assuntos
Anlodipino/uso terapêutico , Bloqueadores do Receptor Tipo 1 de Angiotensina II , Anti-Hipertensivos/uso terapêutico , Bloqueadores dos Canais de Cálcio/uso terapêutico , Hipertensão/tratamento farmacológico , Tetrazóis/uso terapêutico , Valina/uso terapêutico , Idoso , Anlodipino/efeitos adversos , Anti-Hipertensivos/efeitos adversos , Pressão Sanguínea/efeitos dos fármacos , Bloqueadores dos Canais de Cálcio/efeitos adversos , Doenças Cardiovasculares/prevenção & controle , Diuréticos , Método Duplo-Cego , Determinação de Ponto Final , Feminino , Humanos , Hidroclorotiazida/uso terapêutico , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Fatores de Risco , Inibidores de Simportadores de Cloreto de Sódio/uso terapêutico , Tetrazóis/efeitos adversos , Resultado do Tratamento , Valina/efeitos adversos , Valina/análogos & derivados , Valsartana
8.
Lancet ; 363(9426): 2049-51, 2004 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-15207957

RESUMO

The Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial was designed to test whether, for the same achieved blood pressures, regimens based on valsartan or amlodipine would have differing effects on cardiovascular endpoints in high risk hypertension. But inequalities in blood pressure, favouring amlodipine, throughout the multiyear trial precluded comparison of outcomes. A technique of serial median matching, applied at 6 months when treatment adjustments intended to achieve control of blood pressure were complete, created 5006 valsartan-amlodipine patient pairs matched exactly for systolic blood pressure, age, sex, and the presence or absence of previous coronary disease, stroke, or diabetes. Subsequent combined cardiac events, myocardial infarction, stroke, and mortality were almost identical in the two cohorts, but admission to hospital for heart failure was significantly lower with valsartan. Reaching blood pressure control (systolic <140 mm Hg) by 6 months, independent of drug type, was associated with significant benefits for subsequent major outcomes; the blood pressure response after just 1 month of treatment predicted events and survival.


Assuntos
Bloqueadores do Receptor Tipo 1 de Angiotensina II , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Hipertensão/tratamento farmacológico , Tetrazóis/uso terapêutico , Valina/uso terapêutico , Anlodipino/uso terapêutico , Bloqueadores dos Canais de Cálcio/uso terapêutico , Doenças Cardiovasculares/prevenção & controle , Humanos , Hipertensão/fisiopatologia , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do Tratamento , Valina/análogos & derivados , Valsartana
9.
Am Heart J ; 143(3): 546-51, 2002 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-11868064

RESUMO

BACKGROUND: It has been hypothesized that the level of end-systolic wall stress (sigma(m)) is a feedback signal that regulates the level of hypertrophy. Thus, low levels of sigma(m) may signify inappropriate hypertrophy. METHODS: To characterize left ventricular (LV) structure and systolic function in hypertensive subjects with low levels of sigma(m), we studied 763 patients. LV function was studied by midwall stress-shortening analysis. Partition values for sigma(m) were derived from a separate group of normal subjects, and the study population was divided into low stress (group I, n = 136), high stress (group III, n = 157), and intermediate stress group II (n = 470). LV chamber and myocardial function were characterized by relating shortening at the endocardium and at the midwall, respectively, to stress. RESULTS: As expected, group III patients had the highest values for systolic blood pressure and LV cavity size but the lowest values for wall thickness and relative wall thickness. Surprisingly, however, there were no significant differences among stress groups with regard to age or body mass index. Contrary to the hypothesis that low levels of stress are indicative of excessive hypertrophy, there were no significant differences among the 3 groups with regard to LV mass or any form of LV mass index. Furthermore, despite lower mean values for afterload, group I patients had significantly lower values for midwall shortening, and this finding was indicative of reduced myocardial function; stress-shortening plots demonstrated that 28% of group I patients fell below 95% CI compared with 10% of group II and only 5% of group III patients. CONCLUSIONS: Hypertensive subjects with low values for sigma(m) have more concentric LV geometry (higher relative wall thickness) and, on average, reduced myocardial function.


Assuntos
Hipertensão/patologia , Hipertensão/fisiopatologia , Hipertrofia Ventricular Esquerda/fisiopatologia , Contração Miocárdica/fisiologia , Disfunção Ventricular Esquerda/patologia , Disfunção Ventricular Esquerda/fisiopatologia , Algoritmos , Análise de Variância , Pressão Sanguínea/fisiologia , Ecocardiografia , Eletrocardiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Sístole , Função Ventricular Esquerda
10.
Am J Hypertens ; 17(3): 203-8, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15001191

RESUMO

The extent to which the clinical effects of angiotensin receptor blockers (ARB) are related to ambient renin system activity remains poorly defined. Therefore, we measured blood pressure (BP), large (C1) and small (C2) arterial compliance, systemic vascular resistance (SVR), plasma renin activity (PRA), and the 24-h urinary excretion of sodium (UNaV) and aldosterone before and 1, 2, 4, and 24 h after administration of single doses of placebo, and 5, 20, and 40 mg of the ARB olmesartan medoximil to 12 unmedicated normotensive subjects. In the basal state, SVR was inversely related to UNaV (r = -0.3, P =.04); the greater the UNaV, the more vasodilated the subject. Indices of arterial compliance, both C1 (r = -0.32, P =.03) and C2 (r = -0.35, P =.02) were inversely related to the basal PRA. Renin also predicted olmesartan-induced changes in C1 (r = 0.43, P =.004) and C2 (r = 0.33, P =.04). The greater the basal PRA, the less the arterial compliance, and the more compliance improved after olmesartan. Both systolic (P =.003) and diastolic (P <.0001) BP fell significantly on olmesartan compared with placebo (MANOVA with time), and relations were observed between the basal PRA and olmesartan-induced changes in pressure (systolic BP: r = -0.414, P =.012; diastolic BP: r = -0.561 P <.0001)-the greater the initial PRA, the more olmesartan lowered BP. Furthermore, the more pressure fell, the more PRA rose reciprocally (r = -0.44, P =.007). Finally, aldosterone excretion fell (sig = 0.05) on each dose of olmesartan compared with placebo. We conclude that 1) the inverse relation of UNaV and SVR illustrates the reciprocal role of volume versus constrictor factors in maintaining normal BP; and 2) PRA is a physiologic determinant of arterial compliance in normal individuals and of the response to the ARB olmesartan. Measurement of PRA may help to predict clinical ARB responses in individual subjects.


Assuntos
Antagonistas de Receptores de Angiotensina , Anti-Hipertensivos/administração & dosagem , Imidazóis/administração & dosagem , Receptores de Angiotensina/administração & dosagem , Tetrazóis/administração & dosagem , Resistência Vascular/efeitos dos fármacos , Adulto , Aldosterona/urina , Biomarcadores/sangue , Pressão Sanguínea/efeitos dos fármacos , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Humanos , Masculino , Natriurese/efeitos dos fármacos , New York , Olmesartana Medoxomila , Valor Preditivo dos Testes , Valores de Referência , Renina/sangue , Renina/efeitos dos fármacos , Sistema Renina-Angiotensina/efeitos dos fármacos , Estatística como Assunto , Fatores de Tempo , Resultado do Tratamento , Vasoconstrição/efeitos dos fármacos
11.
Am J Hypertens ; 17(1): 1-7, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14700504

RESUMO

BACKGROUND: The renin-angiotensin system (RAS) maintains hemodynamic integrity by modulating both volume and vasoconstriction through a cybernetic feedback control mechanism. In addition, angiotensin II, the active component of the RAS, can be vasculotoxic and, in hypertensive individuals, is associated with increased cardiovascular morbidity and mortality. The objective of this study was to determine the distribution and determinants of plasma renin activity (PRA) in a representative sample of hypertensive persons. METHODS: We systematically measured PRA in 4170 untreated participants in a systematic work site-based, hypertension treatment program. RESULTS: In this multiethnic employed population, patients were classified as follows: low renin, <0.65 ng/mL/h (30% of the sample); medium renin, 0.66 to 4.5 mg/mL/h (60%); or high renin, >4.5 ng/mL/h (10%). Low renin patients were more likely to be African American, female, and slightly older. However, the majority of women and African American individuals were not low renin. The 469 diabetic subjects distributed across renin categories, as did the group as a whole. CONCLUSIONS: This systematic study of PRA in a large community sample of hypertensive patients reveals a wide distribution of activity level, with identifiable differences according to ethnicity, age, and sex but not diabetic status. However, these demographic differences were more quantitative than qualitative and do not provide a useful basis for estimation of the activity of the RAS. Instead, in hypertensive subjects, direct measurement of PRA is necessary, both for prognosis and for guiding hypertensive therapy.


Assuntos
Creatinina/urina , Hipertensão/sangue , Renina/sangue , Fatores Etários , Diabetes Mellitus/sangue , Diabetes Mellitus/fisiopatologia , Diabetes Mellitus/urina , Etnicidade , Feminino , Humanos , Hipertensão/fisiopatologia , Hipertensão/urina , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Potássio/sangue , Sistema Renina-Angiotensina/fisiologia , Fatores de Risco , Fatores Sexuais
12.
Am J Hypertens ; 15(12): 1021-8, 2002 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-12460696

RESUMO

BACKGROUND: It is uncertain whether reduction of left ventricular (LV) mass during antihypertensive treatment predicts reduces cardiovascular complications of hypertension. METHODS: A total of 172 prospectively identified patients with essential hypertension without complications of hypertension at baseline and follow-up echocardiograms 5.5 +/- 3.0 years apart, were followed an additional 4.8 +/- 2.9 years. Antihypertensive treatment was determined by primary physicians. RESULTS: After the second echocardiograms, cardiovascular events occurred in 24 patients (14%). Fewer of the 91 patients with unchanged or decreased LV mass experienced cardiovascular events than of the 81 patients whose LV mass increased during follow-up (8.8% [95% confidence interval (CI): 3.9%-13.7%] v 19.8% [95% CI 12.6%-27.0%]; P =.04) despite greater baseline LV mass in the former group (118 g/m(2) [95% CI 111-125] v 95 g/m(2) [95% CI 88-102]; P <.0001). Absence or presence of LV hypertrophy on the follow-up echocardiogram was the strongest predictor of relatively low (9.2% [95% CI 5%-13.4%]) v high (28.6% [95% CI 17.1%-40.1%]; P =.004) rates of subsequent morbid events. In multivariate analyses, only LV mass index at follow-up consistently predicted adverse outcomes. CONCLUSIONS: The LV mass reduction during antihypertensive treatment is associated with reduced rate of complications of essential hypertension. Our data further suggest that development or regression of LV hypertrophy during antihypertensive treatment may be more closely linked to prognosis than are changes in clinic blood pressure.


Assuntos
Hipertensão/tratamento farmacológico , Hipertrofia Ventricular Esquerda/tratamento farmacológico , Adulto , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/fisiologia , Progressão da Doença , Intervalo Livre de Doença , Ecocardiografia , Feminino , Humanos , Hipertensão/complicações , Hipertensão/fisiopatologia , Hipertrofia Ventricular Esquerda/complicações , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do Tratamento
13.
Am J Hypertens ; 15(10 Pt 1): 917-23, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12372681

RESUMO

Cardiovascular disease prevention depends on reduction of risk factors, including hypertension. Guidelines designed to improve management of hypertension are widely available. Their purpose is to assemble the available data from basic biomedical science, epidemiology, and clinical science in an accessible form with which physicians and patients can make reasoned decisions for individual cases. However, guidelines have been neither widely accepted, nor effectively implemented. We recommend a strategy for guideline preparation designed to yield a product more user friendly, accessible, and effective. Guideline recommendations and the evidence used to make them should be based on an explicit grading system. Relevant clinical as well as nonclinical factors must be considered. Moreover, because the goal of antihypertensive therapy is to prevent cardiovascular events, and the likelihood of such events is determined by multifactor or absolute risk assessment, risk, rather than level of blood pressure (BP), should determine the need for therapy. Similarly, the benefit of therapy must be assessed by reduction in cardiovascular disease morbidity and mortality.


Assuntos
Hipertensão/prevenção & controle , Hipertensão/terapia , Guias de Prática Clínica como Assunto/normas , Humanos , Hipertensão/epidemiologia , Fatores de Risco
14.
Am J Hypertens ; 17(5 Pt 1): 395-403, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15110897

RESUMO

Because nitric oxide may attenuate both the pressor and cytotoxic effects of angiotensin II (Ang II), we investigated whether nitric oxide synthase (NOS) inhibition might accelerate the slow pressor effect of Ang II, and augment target organ damage. Using conscious, chronically catheterized rats, we previously observed that low-dose Ang II (10 ng/kg/min) rapidly increased mean arterial pressure (MAP) by approximately 25 mm Hg. The MAP then remained at this level for 2 to 4 days, and then increased again during the next 5 days by a further 25 mm Hg to a second plateau. In the present study, 7 days of N(omega)-nitro-l-arginine methyl ester (L-NAME; 10 microg/kg/min) alone increased MAP by 16 mm Hg. When Ang II was added to L-NAME, MAP increased as much as with Ang II alone, but then continued to increase until day 4, reaching a plateau as high as that reached only on day 9 of Ang II alone. In approximately half the rats infused with L-NAME + Ang II, plasma renin escaped from Ang II-induced suppression after day 4 of Ang II, and continued to increase for the duration of the study. On the first day that Ang II was added to L-NAME, urinary protein excretion and plasma cardiac troponin T increased, indicating early target organ damage. By the end of the study, all rats treated with L-NAME + Ang II developed tubulointerstitial and glomerular injuries, fibrosis of the renal and cardiac arteries, and cardiac interstitial fibrosis. Target organ damage was greater in rats that developed renin escape than in those in which plasma renin remained suppressed, but was minimal in rats infused with Ang II or L-NAME alone. Taken together, these findings suggest that endogenous NO normally attenuates the pressor response to low-dose Ang II for several days, and protects from Ang II-induced target organ damage. Under conditions of reduced NO bioavailability, which may result from endothelial insufficiency, relatively small changes in circulating Ang II levels may damage target organs. Moreover, renal damage leading to renin escape may initiate a vicious cycle of elevated Ang II production, leading to higher blood pressure and greater target organ damage.


Assuntos
Angiotensina II/administração & dosagem , Inibidores Enzimáticos/administração & dosagem , Rim/patologia , Miocárdio/patologia , Óxido Nítrico Sintase/administração & dosagem , Óxido Nítrico Sintase/antagonistas & inibidores , Renina/sangue , Renina/efeitos dos fármacos , Vasoconstritores/administração & dosagem , Animais , Biomarcadores/sangue , Pressão Sanguínea/efeitos dos fármacos , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Fibrose , Infusões Intravenosas , Rim/efeitos dos fármacos , Rim/metabolismo , Modelos Cardiovasculares , Miocárdio/metabolismo , NG-Nitroarginina Metil Éster/administração & dosagem , Proteinúria/induzido quimicamente , Proteinúria/metabolismo , Proteinúria/fisiopatologia , Ratos , Ratos Sprague-Dawley , Fatores de Tempo , Troponina T/sangue , Troponina T/efeitos dos fármacos
15.
Am J Hypertens ; 17(11 Pt 1): 1068-74, 2004 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-15533736

RESUMO

BACKGROUND: Most current clinical guidelines focus primarily on the management of individual cardiovascular risk factors, such as high blood pressure (BP), hypercholesterolemia, or diabetes. A more appropriate clinical approach to reducing cardiovascular disease risk would be based on a comprehensive evaluation of risk profile, and accurate stratification of global (absolute) risk in individual patients. We propose that global risk should be used as the main determinant of whom to treat, how to treat, and how much to treat. METHODS: In this article we use a series of case studies to demonstrate the implications of replacing the traditional "single risk factor-based" approach to managing hypertension by one based on global risk assessment. In some situations patients with mildly elevated BP levels would not be recommended for antihypertensive drug treatment whereas others with lower BP would be treated, depending upon the entire risk profile. CONCLUSION: We propose to replace the single risk factor-based approach with the assessment of global cardiovascular risk, both in the clinical management of individual patients and in guidelines.


Assuntos
Doenças Cardiovasculares/prevenção & controle , Seleção de Pacientes , Idoso , Anti-Hipertensivos/uso terapêutico , Doenças Cardiovasculares/etiologia , Estudos de Casos e Controles , Feminino , Comportamentos Relacionados com a Saúde , Humanos , Hipertensão/complicações , Hipertensão/tratamento farmacológico , Hipertensão/mortalidade , Masculino , Pessoa de Meia-Idade , Guias de Prática Clínica como Assunto , Medição de Risco , Fatores de Risco
16.
Am J Hypertens ; 16(7): 544-8, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12850387

RESUMO

BACKGROUND: The Valsartan Antihypertensive Long-term Use Evaluation (VALUE) study compares cardiovascular outcomes in 15,314 eligible patients from 31 countries randomized to valsartan or amlodipine-based treatment. METHODS: The blood pressure (BP) trends are analyzed in 13,449 of VALUE study patients who had baseline BP and 24 months BP and treatment data. RESULTS: In a cohort of 12,570 patients, baseline 24 and 30 months BP, but not 30 months treatment data, were available. Of 13,449 patients, 92% (N = 12,398) received antihypertensive therapy at baseline. The baseline BP was 153.5/86.9 mm Hg in treated compared to 168.1.8/95.3 mm Hg in 1051 untreated patients. After 6 months both groups had indistinguishable BP values. At 12 months the BP decreased to 141.2/82.9 mm Hg (P <.0001 for systolic BP and diastolic BP versus baseline), at 24 months to 139.1/80 mm Hg (P <.0001 v 12 months), and to 138/79 mm Hg at 30 months (P <.0001 v 24 months). The systolic BP control (<140 mm Hg) at 30 months increased from 21.9% at baseline to 62.2%, the diastolic BP (< 90 mm Hg) from 54.2% to 90.2% and the combined control (<140 and <90 mm Hg) from 18.9% to 60.5%. At 24 months 85.8% of patients were on protocol drugs: monotherapy = 39.7%, added hydrochlorothiazide = 26.6%, add-on drugs = 15.1%, and protocol drugs in nonstandard doses = 4.3%. CONCLUSIONS: The achieved BP control exceeds values reported in most published large-scale trials. The VALUE study is executed in regular clinical settings and 92% of the patients received antihypertensive drugs at baseline. When an explicit BP goal is set, and a treatment algorithm is provided, the physicians can achieve better control rates than in their regular practice.


Assuntos
Pressão Sanguínea/efeitos dos fármacos , Doenças Cardiovasculares/tratamento farmacológico , Hipertensão/tratamento farmacológico , Valina/análogos & derivados , Algoritmos , Anlodipino/farmacologia , Anlodipino/uso terapêutico , Anti-Hipertensivos/farmacologia , Anti-Hipertensivos/uso terapêutico , Pressão Sanguínea/fisiologia , Estudos de Coortes , Método Duplo-Cego , Uso de Medicamentos/estatística & dados numéricos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Risco , Tetrazóis/farmacologia , Tetrazóis/uso terapêutico , Valina/farmacologia , Valina/uso terapêutico , Valsartana
17.
Am J Hum Biol ; 6(3): 283-291, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-28548446

RESUMO

This study examined the effect of large changes in dietary sodium on the average ambulatory blood pressure and its variability in 19 patients with uncomplicated borderline hypertension. Each patient participated in a 16-week protocol that consisted of four 4-week periods of different sodium intake (medium (120-160 mEq/day) during periods 1 and 3 and low (< 40 mEq/day) or high (> 225 mEq/day) during either period 2 or 4. The 24-hour urine sodium during the low and high periods averaged 18 and 327 mEq/day, respectively. Ambulatory blood pressure monitoring was done at the end of the fourth week of the low and high diet periods. During monitoring, pressures were recorded every 15 minutes while awake; in addition, patients kept diaries noting activities, posture, and situation at each measurement. The results show that there was a decline of 16/7 mmHg in the average ambulatory awake systolic and diastolic pressures from the high sodium to low sodium diets. Corresponding casual pressures decreased an average of 15 and 8 mmHg, respectively. In examining the factors associated with ambulatory pressure variability, systolic pressure showed greater variation by activity on a low sodium diet than on the high. The findings suggest that sodium restriction has a variable, but in some cases marked, effect on lowering the ambulatory blood pressure in borderline mildly hypertensive patients and that sodium balance may be important to consider when examining ambulatory blood pressure variability. © 1994 Wiley-Liss, Inc.

18.
Am J Hypertens ; 26(6): 727-38, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23548411

RESUMO

BACKGROUND: Four recent reports revealed differences in survival rates among treated cardiovascular patients taking renin-angiotensin system-blocking drugs. Patients with higher on-treatment plasma renin activity (PRA) levels died sooner of cardiovascular mortality than those with lower levels. We investigated whether excessive sodium depletion might have induced the higher PRA levels and contributed to the greater morbidity and mortality. METHODS: Using published data, ranges of PRA, blood pressures, drug usage, and biochemical parameters were compared among various groups of cardiovascular patients. RESULTS: We showed (i) that PRA levels are usually medium to low in treated cardiovascular patients, but are sometimes abnormally high, (ii) that excessive sodium depletion can induce such high PRA levels, (iii) that the higher PRA patients exhibited evidence of sodium depletion: lower blood pressures, more frequent natriuretic drug usage, lower N-terminal pro b-type natriuretic peptide (NT-proBNP), and higher blood urea nitrogen and uric acid levels, with similar usage of renin-angiotensin blocking drugs. CONCLUSIONS: We hypothesize that patients with high on-treatment PRA levels die sooner of cardiovascular events because they are excessively sodium-volume depleted. Moreover, renin-angiotensin system-blocking drugs may be harmful in such patients because they can functionally interfere with the effects of reactive rises in PRA that are triggered to prevent potentially dangerous falls in blood pressure, increases in plasma potassium, and falls in glomerular filtration rate. Careful liberalization of salt intake and subtraction of natriuretic drugs, sufficient to reduce reactive hyperreninemia without inducing unacceptable increases in blood pressure, might benefit such patients and decrease risk of adverse effects from drugs that block the renin-angiotensin system.


Assuntos
Doenças Cardiovasculares/tratamento farmacológico , Sistema Renina-Angiotensina/efeitos dos fármacos , Renina/sangue , Sódio/sangue , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/mortalidade , Saúde Global , Humanos , Sistema Renina-Angiotensina/fisiologia , Fatores de Risco , Taxa de Sobrevida/tendências
19.
Am J Hypertens ; 25(3): 379-88, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22158065

RESUMO

BACKGROUND: Although hypertension guidelines have utility in treating uncomplicated hypertension, they often overlook the pathophysiologic basis and heterogeneity of hypertension. This may explain the relatively poor hypertension control rates. A proposed approach is to guide addition and subtraction of medications using ambulatory plasma renin activity (PRA) values. To evaluate the heterogeneity of hypertension and the medication burden associated with it, we investigated medication usage in relation to PRA among hypertensive patients within a large ethnically diverse organization. METHODS: A cross sectional data analysis was performed of hypertensive subjects with PRA measurements in the Kaiser Permanente Southern California database between 1 January 1998 and 31 October 2009. RESULTS: Among 7,887 such patients 0, 1, 2, ≥3 medication usage was 16%, 20%, 24%, 40% respectively. PRA levels ranged 1000-fold. Across PRA quartiles (Q1 to Q4) ≥3 meds were prescribed to 50%, 40%, 34%, 37%. From low to high PRA quartiles there was no usage trend for angiotensin converting enzyme inhibitors (ACEIs)/ angiotensin receptor blockers (ARBs) (71%), but diuretics increased (52%, 53%, 57%, 68%), calcium channel blocker's (CCB) fell (56%, 53%, 51%, 42%), and ß-blockers fell (77%, 61%, 49%, 41%). Moreover, systolic BP fell (146, 142, 140, 135 mm Hg), blood urea nitrogen (BUN) rose (16, 17, 18, 20 mg/dl), serum uric acid rose (6.1, 6.3, 6.5, 6.9 mg/dl), and chronic kidney disease rose (22%, 22%, 23%, 27%). CONCLUSIONS: Polytherapy was the norm for treating hypertension. Lower PRAs were associated with higher blood pressures and more medications. Higher PRAs were associated with lower pressures and fewer medications. The results indicate that opportunities exist to simplify antihypertensive therapy by using current ambulatory PRA levels to guide drug selections and subtractions.


Assuntos
Anti-Hipertensivos/uso terapêutico , Hipertensão/tratamento farmacológico , Padrões de Prática Médica/estatística & dados numéricos , Renina/efeitos dos fármacos , Adolescente , Antagonistas Adrenérgicos beta/farmacologia , Antagonistas Adrenérgicos beta/uso terapêutico , Adulto , Idoso , Antagonistas de Receptores de Angiotensina/farmacologia , Antagonistas de Receptores de Angiotensina/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Anti-Hipertensivos/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Nitrogênio da Ureia Sanguínea , Bloqueadores dos Canais de Cálcio/farmacologia , Bloqueadores dos Canais de Cálcio/uso terapêutico , California , Estudos Transversais , Diuréticos/farmacologia , Diuréticos/uso terapêutico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Polimedicação , Renina/sangue , Sistema Renina-Angiotensina/efeitos dos fármacos , Estudos Retrospectivos , Ácido Úrico/sangue
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA