ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The presence, and in many cases the regulated synthesis, of components of the renin-angiotensin system have been demonstrated in multiple tissues, indicating the existence of tissue angiotensin-generating systems. These vary with respect to which renin-angiotensin system components are synthesized locally and which are taken up from plasma. Enzymes unrelated to the classical renin-angiotensin system may also contribute to tissue angiotensin synthesis. However, based on the available data, the prevailing opinion that kidney-derived renin is in all cases the only physiologically relevant renin in tissues must be revised. Also there is evidence indicating a role for tissue angiotensin systems in the pathogenesis of cardiovascular disease and in cardiovascular structural remodeling. The angiotensin-regulated synthesis of aldosterone in cardiac tissue has been described, suggesting the possibility that a renin-angiotensin-aldosterone system exists in the heart. In addition, intracellular (intracrine) sites of angiotensin action have been reported. Some of these findings have implications for therapeutics and, in particular, for the use of angiotensin converting-enzyme inhibitors and angiotensin receptor blockers. Finally, tissue angiotensin systems outside the cardiovascular system also appear to be physiologically relevant.

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Myocardial fibrosis is one of the histologic constituents of myocardial remodeling present in hypertensive patients with hypertensive heart disease. In fact, an exaggerated interstitial and perivascular accumulation of fibrillar collagens type I and type III has been found in the myocardium of patients with arterial hypertension and left ventricular hypertrophy. Hypertensive myocardial fibrosis has been shown to facilitate abnormalities of cardiac function, coronary reserve, and electrical activity that adversely affect the clinical outcome of hypertensive patients. Therefore, development of noninvasive tools for the monitoring of myocardial fibrosis and pharmacological strategies aimed to promote the regression of fibrosis could be of particular relevance in the clinical treatment of patients with hypertensive heart disease.

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Hypertension and aging adversely affect cardiovascular system and the heart is invariably involved. Manifestations of hypertensive heart disease and of the aging heart appear similar; ventricular hypertrophy, myocardial fibrosis, and impairments in ventricular function and coronary hemodynamics characterize both conditions. However, a great deal of evidence suggests that different underlying pathophysiological mechanisms may be involved. This report discusses most recent clinical and experimental findings and focuses on the alterations in nonmyocytic elements that are a part of heart involvement. Particular attention was given to factors that are responsible for exaggerated myocardial deposition of collagen that, by itself, may be responsible for ventricular dysfunction and impaired coronary hemodynamics in hypertensive and aging hearts. Newly developed therapeutical strategies, based on the most recent experimental and clinical studies, are also discussed.

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The Syst-Eur trial investigated whether active treatment starting with the dihydropyridine calcium channel blocker (CCB) nitrendipine, could reduce the cardiovascular complications of isolated systolic hypertension (ISH) in the elderly. The intention-to-treat analysis showed that active treatment improved outcome. The per-protocol analysis largely confirmed these results. The effect of treatment on total and cardiovascular mortality might be attenuated in very old patients. Further analysis also suggested benefit in those patients who remained on nitrendipine monotherapy. Active treatment was more beneficial in patients with diabetes as compared with those without diabetes at entry and reduced the incidence of dementia by 50%. Analyses of data from the Ambulatory Blood Pressure Monitoring (ABPM) Side Project suggested that most of the benefit of treatment was seen in patients with a daytime systolic BP ≥ 160 mm Hg. Finally, a meta-analysis partly based on Syst-Eur data showed that in older hypertensive patients pulse pressure and not mean pressure is the major determinant of cardiovascular risk.

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Calcium antagonists effective in lowering blood pressure are a heterogeneous group including three main classes: phenylalkylamines, benzothiazepines and dihydropyridines. Dihydropyridines have a dual mode of action upon the endothelium contributing to their beneficial antihypertensive effects: (1) direct relaxation by inhibition of smooth muscle L-type calcium current, and (2) indirect relaxation through release of nitric oxide from the vascular endothelium. Calcium antagonists may affect many calcium-dependent events in the formation of atherosclerosis such as the localized accumulation of collagen, elastin, and calcium together with monocyte infiltration and smooth muscle proliferation and migration. In the INSIGHT calcification study, the overall treatment effect of nifedipine demonstrated significant inhibition of coronary calcium progression over a three-year period. Calcium antagonists improve symptoms and reduce ischemia in hypertensive patients with ischemic heart disease. Although in placebo-controlled trials calcium antagonists demonstrated a significant reduction in cardiovascular morbidity and mortality, they may be less effective than other types of antihypertensive drugs in preventing ischemic heart disease.

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Epidemiologic studies have consistently revealed inverse associations between physical activity (or fitness) and hypertension. There are hypotensive benefits to exercise training found across a number of aerobic and progressive resistance training modalities. Optimal exercise prescriptions remain unclear, but hypotensive benefits have been noted for mild to vigorous ranges of exercise intensity, for as few as three exercise sessions per week and durations as short as 20 minutes. Hypertensive subjects appear to experience greater reductions than normotensive subjects. Exercise interventions may be safely and effectively used with mild to moderate as well as severe levels of hypertension. The incorporation of physical activity with other lifestyle interventions provides multiple benefits to hypertensive patients that extend beyond a reduction in blood pressure.

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The primary pathophysiologic mechanism underlying all non-ST-segment elevation acute coronary syndromes (NSTE ACS) is the formation of platelet-rich coronary thrombi in response to spontaneous or intervention-induced endothelial damage with exposure of subendothelial substrates. Antagonists of the glycoprotein (GP) IIb/IIIa receptor ameliorate this process by blocking the final common pathway for platelet aggregation. Based upon collective data in over 24,000 patients, clinical trials have demonstrated that treatment of NSTE ACS patients with GP IIb/IIIa agents results in an approximate 12% relative risk reduction in the incidence of death or myocardial infarction at 30 days. The magnitude of this clinical benefit is increased in patients who are troponin-positive and who are referred for early percutaneous intervention. Potential benefits of GP IIb/IIIa inhibitor use must be weighed against an increased risk of bleeding. Ongoing controversies exist concerning the relative efficacy of different GP IIb/IIIa antagonists, the accurate use of platelet function tests to define safe and efficacious drug dosing, the adjunctive use of additional anti-thrombotic agents, and the optimal timing of upstream therapy before diagnostic cardiac catheterization and revascularization.

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID