Journal of hypertension. Supplement : official journal of the International Society of Hypertension最新文献

Experimental and clinical studies have established a link between end-organ damage in hypertensive patients and the severe impairment of tissue perfusion and microcirculation structure and function. Microvascular rarefaction is constantly observed in hypertension, and probably contributes to higher systemic resistance and lower tissue perfusion. Endothelial dysfunction leading to impaired arteriolar reactivity is also characteristic of the microvascular dysfunction in hypertensive patients. The effective lowering of blood pressure while maintaining optimal tissue perfusion is therefore one of the major goals of antihypertensive therapy, in order to improve the cardiovascular prognosis of hypertensive patients.

Objective and rationale: ADVANCE (Action in Diabetes and Vascular disease: preterAx and diamicroN-MR Controlled Evaluation) is a large-scale trial designed to investigate the benefits of blood pressure lowering and intensive glucose control in patients with type 2 diabetes, and to address a number of unresolved issues: whether blood pressure-lowering therapy and intensive glucose control therapy will reduce the risk of major vascular disease regardless of initial blood pressure or glucose concentration; whether more intensive glucose control targeting a haemoglobin A1c (HbA1c) level of 6.5% or less will confer greater protection against microvascular disease; and whether the benefits of the two interventions are additive.

Design and methods: ADVANCE is a 2 x 2 factorial randomized clinical trial evaluating the risks and benefits of the low-dose fixed combination of perindopril and indapamide versus placebo to lower blood pressure and of an intensive gliclazide-MR-based glucose control regimen, targeting an HbA1c of 6.5% or less versus standard guidelines based therapy for glucose control. There are two primary outcomes: a composite macrovascular endpoint and a composite microvascular endpoint.

Results: A total of 12 878 participants from 215 centres in 20 countries entered a 6-week run-in phase between June 2001 and January 2003, and 11 140 patients were randomly assigned by March 2003. The average (SD) systolic and diastolic blood pressure fell from 145 (22)/81 (11) to 137 (20)/78 (10) mmHg during the 6-week run-in phase, during which participants received one tablet of open-labelled perindopril 2 mg/indapamide 0.625 mg. Of the 12 878 patients who entered the run-in, only 3.6% withdrew because of suspected intolerance to perindopril/indapamide. The study is half way through follow-up and both the study medications (perindopril 2 mg/indapamide 0.625 mg and gliclazide-MR) continue to be well tolerated. Completion is expected in 2007.

Conclusion: Safe and effective blood pressure lowering with the fixed low-dose combination of perindopril and indapamide was confirmed during the run-in phase in 11 140 patients with type 2 diabetes, who were subsequently randomly assigned. Post-randomization study treatments have been well tolerated, and the completion of follow-up is scheduled in 2007.

Structural alterations in the microcirculation form a major link between hypertension and target organ damage. More than 60% of the overall peripheral resistance of the circulatory system arises at the level of the microcirculation. The primary function of the microcirculation is to supply oxygen and nutrients to tissues. In hypertension, remodelling of the microvascular vessels occurs, leading to an early, functional then anatomical reduction in the number of arterioles or capillaries in a given vascular bed. Such changes have been seen in the structure and density of the microvasculature of different target organs such as the myocardium and the kidneys. In hypertension, capillary rarefaction induces an increase in blood pressure, a relative decrease in tissue perfusion and an increased cardiovascular risk. Recent in-vivo non-invasive techniques for exploring the human microcirculation have allowed the detection of myocardial and renal microvascular impairment in hypertensive patients. In comparative therapeutic studies, antihypertensive drugs have been shown to have different capacities for preventing or reversing changes to the microvasculature of affected organs.

Inflammation plays a role in all stages of atherosclerosis from the formation to the rupture of the plaque. Guided by inflammatory mediators, monocytes bind to an endothelium damaged by cardiovascular risk factors, and then migrate towards the intima where, after incorporating oxidized low-density lipoprotein particles, they are transformed into foam cells. The lipid streak forms and develops as an atherosclerotic plaque, which is susceptible to erosion and rupture. Inflammation fed by excess adipose tissue decreases insulin sensitivity, which is the central feature of the metabolic syndrome. Inflammation therefore appears to be a common factor of atherosclerosis and the metabolic syndrome. The factors triggering this inflammation have yet to be determined. One line of thought would appear to point to diet.

Peripheral pulse pressure (PP) is a marker of aging-associated arterial stiffening after the fifth decade. In addition, PP has emerged as a strong predictor of cardiovascular morbidity and mortality. A study of the relationship between renal function and aging of the arterial system using reliable methods of estimating renal haemodynamics (effective renal plasma flow) and function (glomerular filtration rate; GFR) was thus undertaken in a large number of never-treated individuals with essential hypertension. In 212 patients with isolated systolic hypertension, there was an inverse correlation between GFR and PP, but the correlation did not persist after adjustment for age. In fact, the deleterious effect of PP on GFR was observed, independent of age and mean arterial pressure, only in patients aged 60 years and over. In contrast, no clear influence of PP on GFR was detected in patients aged 40 years and over but less than 60 years and in those younger than 40 years. It is thus proposed that PP may have a detrimental influence on the age-related decline in GFR. Prospective studies on the influence of antihypertensive agents with possible effects on peripheral and central PP on the progressive decline of GFR are required.

Brachial pulse pressure (PP) is now a well-established cardiovascular risk factor. Central rather than peripheral PP should be measured to determine the 'true' haemodynamic effects of antihypertensive agents on target organs. Peripheral PP, measured at the brachial artery, does not reflect central PP (either carotid or ascending aorta), because their determinants are different and pathophysiological conditions and drugs may change central PP without changing peripheral PP. Central PP (i.e. carotid artery or ascending aorta) has shown an independent predictive value for all-cause mortality in patients with end-stage renal disease and in the hypertensive patients of the CAFE study. Antihypertensive treatment has repeatedly demonstrated its ability to prevent cardiovascular events. Whether the effect on cardiovascular events in clinical trials comparing two pharmacological classes or two therapeutic strategies is, at least partly, the result of differential effects on PP remains to be demonstrated. It is therefore of major importance to determine which therapeutic strategies may differentially lower central PP, and in turn reduce cardiovascular events. In clinical practice, lowering PP is often a difficult task, particularly in diabetic hypertensive individuals. In the PARADIS study, we aimed to determine, in a population of hypertensive patients with both type 2 diabetes and PP greater than 60 mmHg, which clinical characteristics predict the fall in PP on treatment and a reduction in cardiovascular events. The reinforcement of therapeutic measures, including a fixed low-dose perindopril/indapamide combination, made possible the effective lowering of PP and cardiovascular events in type 2 diabetic hypertensive patients, under conditions of usual care by general practitioners and specialists.

Pharmacological treatment of hypertension represents a cost-effective way of preventing cardiovascular and renal complications. To benefit maximally from antihypertensive treatment, blood pressure should be brought to below 140/90 mmHg in every hypertensive patient, and even lower (< 130/80 mmHg) if diabetes or renal disease co-exists. Such targets cannot usually be reached using monotherapies. This is especially true in patients who present with a high cardiovascular risk. The co-administration of two agents acting by different mechanisms considerably increases the blood pressure control rate. Such combinations are not only efficacious, but are also well tolerated, and some fixed low-dose combinations even have a placebo-like tolerability. This is the case for the preparation containing the angiotensin-converting enzyme inhibitor perindopril (2 mg) and the diuretic indapamide (0.625 mg), a fixed low-dose combination that has been shown in controlled trials to be more effective than monotherapies in reducing albuminuria, regressing cardiac hypertrophy and improving the stiffness of large arteries. Using this combination to initiate antihypertensive therapy has been shown in a double-blind trial (Strategies of Treatment in Hypertension: Evaluation; STRATHE) to normalize blood pressure (< 140/90 mmHg) in significantly more patients (62%) than a sequential monotherapy approach based on atenolol, losartan and amlodipine (49%) and a stepped-care strategy based on valsartan and hydrochlorothiazide (47%), with no difference between the three arm groups in terms of tolerability. An ongoing randomized trial (Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation; ADVANCE) is a study with a 2 x 2 factorial design assessing the effects of the fixed-dose perindopril-indapamide combination and of the intensive gliclazide modified release-based glucose control regimen in type 2 diabetic patients, with or without hypertension. A total of 11 140 patients were randomly selected. Within the first 6 weeks of treatment (run-in phase), the perindopril-indapamide combination lowered blood pressure from 145/81 +/- 22/11 mmHg (mean +/- SD) to 137/78 +/- 20/10 mmHg. Fixed-dose combinations are becoming more and more popular for the management of hypertension, and are even proposed by hypertension guidelines as a first-line option to treat hypertensive patients.

Type 2 diabetes mellitus (T2DM) is often accompanied by high blood pressure (BP) and the clustering of several cardiovascular risk factors, and is the most frequent cause of end-stage renal disease. The stages of development of overt nephropathy in T2DM patients range from an initial alteration in renal function with an increased GFR, followed by the development of microalbuminuria and macroalbuminuria or proteinuria, featuring an established diabetic nephropathy, which eventually progresses to end-stage renal disease. Early intervention is needed to prevent the development of diabetic nephropathy and requires effective control of the different risk factors, and in particular high BP. In the initial stages of the disease, strict BP control is crucial to prevent the development of initial renal and vascular damage. Adequate BP control is particularly difficult in T2DM patients and in most cases requires the use of combination therapy. Preterax, a fixed-dose combination of perindopril 2 mg and indapamide 0.625 mg, allows BP to be significantly reduced compared with conventional strategies; this combination can be uptitrated to BiPreterax when further BP control is needed. In the PREMIER study performed in T2DM over 12 months, the perindopril/indapamide combination brought about, in addition to excellent BP control, a significant reduction in urinary albumin excretion, compared with monotherapy with enalapril. In more advanced degrees of renal damage, higher doses of the fixed combination have to be considered. The pharmacological basis of the renoprotective effect of perindopril/indapamide is the demonstration that this combination prevented nephropathy as well as proteinuria in obese Zucker rats, independently of BP control. Strict BP control from the initial stages of nephropathy together with inhibition of the renin-angiotensin system is mandatory to prevent albuminuria. The fixed combination of perindopril/indapamide can greatly help clinicians in achieving the above goals, using Preterax in the early and BiPreterax in the late stages of nephropathy.

Endothelial dysfunction, characterized by impaired nitric oxide activity, constitutes an early step in the pathogenesis of atherosclerotic disease. Prospective studies have shown that impaired endothelium-dependent vasorelaxation and the vasodilatory response of coronary arteries to acetylcholine predict cardiovascular events. Microalbuminuria and estimated glomerular filtration rate, which are both deeply influenced by renal nitric oxide activity, are predictors of cardiovascular outcome and total mortality but develop at a later stage of renal impairment. Endothelial dysfunction reflects early stage renal involvement in the atherosclerotic processes. The Telmisartan versus Ramipril in renal ENdothelium DYsfunction (TRENDY) trial examined endothelial function of the renal vasculature as a therapeutic target in patients with hypertension and type 2 diabetes, but without albuminuria. The rationale was that blockade of the renin-angiotensin system (RAS) is cardio- and renoprotective at later stages of the disease, but the impact of blockade of the RAS at earlier stages of disease is unknown. The results of TRENDY indicate that the endothelial function, as assessed by basal nitric oxide activity, can be improved after RAS blockade. These data complement the results of the Diabetics Exposed to Telmisartan And enalaprIL (DETAIL) trial, which demonstrated that telmisartan and enalapril similarly decelerate the progression of overt diabetic nephropathy. The results of TRENDY are in accordance with the observed changes in peripheral circulation. Endothelium-dependent vasorelaxation could be improved with angiotensin II receptor blockers, but not with diuretics or beta-blockers, in hypertensive patients. Intervention at the beginning of the renal and cardiovascular continuum offers the opportunity to prevent the fatal development towards renal and cardiac failure.