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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Diurnal variation has been demonstrated for blood pressure and heart function. Several hormones influence these hemodynamic parameters. This study investigates the diurnal variation in plasma prorenin in relation to renin, atrial natriuretic peptide (ANP), norepinephrine, and hemodynamic changes. Circulating plasma prorenin may be able to serve as a marker for the activity of the local renin-angiotensin system. In 12 healthy male volunteers who were allowed to carry out quiet activity, hemodynamic factors and the plasma levels of hormones were monitored at 2-h intervals for 26 h. Blood pressure was measured every hour. In accordance with the literature, during the night blood pressure (4%), cardiac index (19%), stroke index (10%), and heart rate (10%) decreased in a classic day-night pattern. Systemic vascular resistance increased during the night (23%). No classic day-night pattern was found for ANP, although it increased (15%) at night and showed a peak early in the night. This peak seemed to be influenced by posture. A classic day-night pattern was demonstrated for norepinephrine and prorenin. Norepinephrine was lower (18%) at night and increased as soon as the subjects awoke, while they were still in bed. Therefore, plasma norepinephrine levels seemed to be related to awakening. Plasma prorenin decreased at night (6%). Renin fluctuated throughout the day, but showed no clear day-night pattern. In conclusion, renin fluctuated throughout the day and did not show a classic day-night pattern. In contrast, prorenin fluctuated less and showed 6% higher levels during the day compared to the night. The origin and clinical significance of this small diurnal variation in prorenin is not clear yet.
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PMID:Diurnal variation in prorenin in relation to other humoral factors and hemodynamics. 798 63

Hemodynamics (by aortic Doppler), autonomic factors (power spectrum analysis of heart rate and blood pressure variabilities and baroreceptor sensitivity), and plasma renin activity during the hypotension after maximal exercise were studied in 10 normal subjects on two separate days: a nonexercise (control) day (30 min of upright rest followed by 60 min of supine rest) and an exercise day (maximal upright bicycle exercise followed by 60 min supine) in random order. After exercise, diastolic pressure was reduced for the entire hour, cardiac output increased (+33.8%, P < 0.05), stroke volume was unchanged, and systemic vascular resistance fell (-28.6%, P < 0.01). Indexes of vagal activity were reduced for 60 min, whereas the sympathetic indexes were elevated. Baroreflex sensitivity was also reduced for the first 10 min after exercise. Renin activity increased threefold after exercise. The postexercise hypotension results from a persisting peripheral vasodilation despite an increase in renin activity: the persistent sympathetic activity and reduced vagal tone are probably reflex responses to this vasodilatation.
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PMID:Persistent peripheral vasodilation and sympathetic activity in hypotension after maximal exercise. 828 35

Concomitant arterial hypertension and metabolic disorders is a frequent finding raising the risk of micro- and macrovascular complications. While prevalence of stroke and myocardial infarction is going down in hypertensives, end-stage renal disease (ESRD) becomes a bigger problem especially in diabetic hypertensives. The metabolic abnormalities are linked to the hypertension by the sympathoadrenal system mediated by insulin resistance (IR); subjects with hyperinsulinemia and increased sympathetic activity tend to have higher blood pressure, typical dyslipidemia, reduced fibrinolytic activity and other risk factors (RF) called metabolic syndrome of IR. Albuminuria (AUR) is considered as an important RF for the development of nephropathy, ESRD, cardiovascular diseases. AUR is a marker of cardiovascular and total mortality in diabetic and/or non-diabetic hypertensives. AUR reflects the endothelial dysfunction not only in glomerulus but also in the other arteries. Tissue Renin-Angiotensin System plays a significant role in the pathogenesis of hypertension and metabolic disorders; it affects the arterial wall, kidneys and heart longitudinally. Life style is very essential in the treatment of hypertension and metabolic disorders: rational diet with reduced amount of salt and animal proteins, non-smoking and sufficient physical activity. Antihypertensive drugs without any metabolic side effects and with the renal protection are necessary for the patients with hypertension and metabolic disturbances. ACE-inhibitors and/or some of the Ca-antagonists seems to be valuable especially as combined therapy.
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PMID:[New approaches in the treatment of hypertension in metabolic diseases]. 972 74

Treatment of patients with severe heart failure by ACE inhibition is often limited by worsening of renal function. To evaluate whether trandolapril, a potent lipophilic ACE inhibitor, affects renal function in severe heart failure, we studied 12 patients with severe heart failure treated with only diuretics and digoxin. Patients received increasing oral dosages of trandolapril (0, 1, and 2 mg) on 3 consecutive days (A). Patients were then discharged on 2 mg trandolapril bid and re-evaluated 8 weeks later (B). Mean arterial and pulmonary wedge pressures decreased by maximal 14% and 43%, and stroke volume and work indexes increased by 24% and 20% at A and similarly at B (11, 45, and 25 ns and 33%, respectively). In contrast, heart rate, systemic resistance, pulmonary artery pressure, and cardiac index decreased by 6%, 23%, 29%, and 17%, respectively, at only A. Renal blood flow improved by approximately 40% both at A and B. In contrast, the glomerular filtration rate decreased by 25% at only B, whereas serum creatinine, creatinine clearance, and urine osmolality were unaffected during the study. Norepinephrine, angiotensin II, and aldosterone levels decreased by approximately 30%, 60%, and 65%, respectively, at both A and B. Renin levels increased by 136% at A and remained elevated at B. Thus, whereas the initial systemic vasodilating and inotropic effects did not persist, long-term trandolapril results in sustained neurohormonal modulation, reduced preload, and improved organ perfusion, indicated by a persistent increase in renal blood flow and preservation of renal function in severe heart failure.
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PMID:Renal hemodynamic effects in patients with moderate to severe heart failure during chronic treatment with trandolapril. 982 86

Recent investigations have furnished a complete analysis of the hemodynamic events accompanying whole-body immersion. About 700 ml of blood are translocated into the intrathoracic circulation, and heart volume increases by 180 +/- 62 ml. These changes are followed by an increase in stroke volume and cardiac output of over 30%. At the same time a reflex reduction of total peripheral resistance and venous tone occurs. Renin and aldosterone activity are reduced while the 17-hydroxycorticosteroid is not affected. Treatment of the subject with DOCA attenuates but does not extinguish the excess sodium excretion of immersion. This finding strengthens the arguments in favor of an unknown factor enhancing sodium excretion. Finally, the relative activation of the three factors that serve volume control, the excretory function of the kidney, capillary filtration pressure, and the thirst mechanism, is discussed.
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PMID:Recent advances in the physiology of whole body immersion. 1184 Oct 92

Activation of the RAAS has been linked with an increased risk of myocardial infarction and stroke,(1,2,37,38) and recently these beneficial effects have, in part, been attributed to the effects of the RAAS on the fibrinolytic system. Indeed, ACE seems to occupy a central position in modulating the fibrinolytic balance, where an angiotensin II-mediated increase of PAI-1 plays a major role. By contrast, the effect on bradykinin stimulated t-PA release may be of lesser importance, although the data are conflicting. Importantly, the impact of the RAAS on the fibrinolytic balance may also contribute to the favourable effects of ACE inhibition and AT1-receptor antagonists on cardiovascular events, particularly when considering the activation of the RAAS in hypertension and heart failure. More work is clearly required in this area to elucidate potential therapeutic targets.
J Renin Angiotensin Aldosterone Syst 2000 Sep
PMID:The renin-angiotensin-aldosterone system and fibrinolysis. 1188 Oct 31

The Heart Outcomes Prevention Evaluation (HOPE) study was designed to test the hypotheses that two preventive intervention strategies, namely angiotensin-converting enzyme (ACE) inhibition or vitamin E, would improve morbidity and mortality in patients at high risk of cardiovascular events compared with placebo. This review addresses the ACE inhibitor (ACE-I) (ramipril) arm of the study, both on the trial population as a whole, and on the large diabetic subgroup. Patients were included in the study who were considered to be at high risk of future fatal or non-fatal cardiovascular events, by virtue of their age (>55 years), existing or previous cardiovascular disease, or diabetes. Diabetics had at least one other risk factor, either known vascular disease or other factors such as cigarette smoking, high cholesterol or hypertension. Ramipril or placebo was added to concomitant medication, which included, in a substantial proportion of patients, antihypertensive drugs (excluding ACE-I), lipid-lowering agents or aspirin. As a result, despite a history of hypertension in nearly 50% of patients, blood pressure (BP) at baseline was normal and the reduction in BP attributable to ramipril modest (a fall of 3-4 mmHg systolic BP and 1-2 mmHg diastolic). The trial was stopped early on the advice of the Data Monitoring Committee because of convincing evidence of the benefit of ramipril treatment on the combined primary endpoint of cardiovascular death, non-fatal myocardial infarct (MI) and non-fatal stroke (14% vs. 17.8% on ramipril and placebo, respectively; relative risk reduction 22%, p<0.001). This comprised a risk reduction of 32% for stroke, 20% for MI, 26% for cardiovascular death and 16% for all-cause mortality, as well as a reduction in the risk of several other endpoints including heart failure and revascularisation procedures. The results among the 3577 diabetic subjects were even more striking, with a reduction of 25% in the combined primary endpoint. This reduction in the combined endpoint and in particular the reduction in MI far exceeded that which would be expected from the modest fall in BP. Furthermore, a multiple regression analysis of the diabetic subgroup showed similar relative risk reductions even after allowing for the effects of the fall in BP. Possible explanations for the non BP-mediated benefits of ramipril include reduction of angiotensin II-induced intimal and vascular smooth muscle proliferation and possible plaque stabilisation. The HOPE study results show that it is both safe and beneficial to lower BP that is already within the 'normal' range, particularly in patients with known vascular risk factors. This should greatly extend the use of ACE-I to a wider group of patients - not only those with left ventricular dysfunction, hypertension or diabetic microalbuminuria, but to the sort of high-risk patients who are currently given prophylactic treatment with aspirin.
J Renin Angiotensin Aldosterone Syst 2000 Mar
PMID:The HOPE Study (Heart Outcomes Prevention Evaluation). 1196 89

The Study on Cognition and Prognosis in the Elderly (SCOPE) was designed to provide outcome data on cardiovascular endpoints and cognitive function in 4500 elderly hypertensive patients randomised to the angiotensin receptor blocker, candesartan, or to placebo and followed up for 4.5 years. The primary endpoint of combined cardiovascular mortality, non-fatal myocardial infarction and non-fatal stroke was not significantly reduced by active treatment (relative risk reduction 11%, p=0.19). There was also no significant difference in the decline of cognitive function between the two treatment arms. Active treatment of the placebo group (mainly hydrochlorothiazide) reduced the blood pressure differences between the treatment arms to only 3.2/1.6 mmHg, thus markedly reducing the overall power of the study. In a number of non-prespecified subgroup analyses, advantages of candesartan over placebo were reported.
J Renin Angiotensin Aldosterone Syst 2002 Jun
PMID:The SCOPE trial. Study on Cognition and Prognosis in the Elderly. 1222 43

Treatment of high blood pressure (BP) reduces the risk of death and morbidity from stroke and coronary heart disease. There is accumulating evidence from large outcome studies that support a move towards lower treatment targets in hypertensives, particularly for those with concomitant risk factors or evidence of established target organ damage. At present, the achieved rates for BP control in the UK are very poor. Amongst the many possible reasons for poor BP control is the under utilisation of effective drug combinations. This article addresses the rationale for two and three drug combination therapy in hypertension and reviews the trial evidence for efficacy of combinations.
J Renin Angiotensin Aldosterone Syst 2002 Jun
PMID:The frequent need for three or more drugs to treat essential hypertension. What evidence for optimal combinations? 1222 50

Renin-angiotensin-aldosterone system blockade has been shown to protect against renal damage in salt-supplemented, stroke-prone spontaneously hypertensive rats (SHRsp). Based on intermittent tail-cuff blood pressure (BP) measurements, it has been claimed that such protection is BP-independent and mediated by a blockade of the direct tissue-damaging effects of angiotensin and/or aldosterone. BP radiotelemetry was performed for 8 weeks in approximately 10-week-old male SHRsp who received a standard diet and either tap water (n=10) or 1% NaCl to drink. Saline-drinking SHRsp were either left untreated (n=12), received enalapril (50 mg/L) in drinking fluid (n=9), or had subcutaneous implantation of time-release 200-mg pellets of aldactone (n=10). The average systolic BP (mean+/-SEM) during the final 3 weeks was significantly higher (P<0.05) in untreated saline-drinking (215+/-6 mm Hg) SHRsp but not aldactone-treated (198+/-4 mm Hg) or enalapril-treated treated SHRsp (173+/-1 mm Hg), as compared with tap water-drinking SHRsp (197+/-3 mm Hg). Histological renal damage scores at 8 weeks paralleled the BP in all groups, with an excellent correlation (r=0.8, P<0.001, n=41). Moreover, a renal damage score of >5 was only observed in SHRsp whose average systolic BP during the final 3 weeks exceeded 200 mm Hg, indicating a threshold relation with BP. These data show that protection by renin-angiotensin-aldosterone system blockade in this model is BP-dependent and mediated by preventing the severe increases in BP seen in untreated salt-supplemented SHRsp and further underscore the limitations of interpretations based on conventional tail-cuff BP measurements.
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PMID:Renoprotection by ACE inhibition or aldosterone blockade is blood pressure-dependent. 1257 79


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