Effect of inhibitors of the renin-angiotensin system and other antihypertensive drugs on renal outcomes: systematic review and meta-analysis

'Beyond blood pressure' means multiple risk factor intervention, not pleiotropic antihypertensive drugs

PURPOSE OF REVIEW

We examined the role of blood pressure-lowering compared with class-specific properties of antihypertensive drugs in cardiovascular prevention.

RECENT FINDINGS

We reviewed recently published trials and meta-regression analyses.

SUMMARY

From 150,000 to 180,000 randomized patients followed up from 3 to 5 years were required to demonstrate a 10-15% benefit 'beyond blood pressure lowering' of newer antihypertensive drugs, such as calcium channel blockers or angiotensin-converting enzyme inhibitors in the prevention of cause-specific cardiovascular complications. Assuming an absolute risk of new-onset diabetes mellitus on older drugs of approximately 10% over 5 years and a relative benefit on the newer drugs of approximately 30%, about 100 patients would have to be treated for 5 years with the newer agents to avert approximately three iatrogenic cases of diabetes. Whether or not new-onset diabetes is associated with increased risk is uncertain. In most patients, optimization of treatment at acceptable tolerance requires rotation through and combination of several drug classes. Combination of different classes of antihypertensive drugs not only enhances the blood pressure-lowering efficacy, but likely decreases the risk of metabolic adverse effects as well. True benefit beyond blood pressure lowering in hypertensive patients comes from multiple risk factor intervention.

Do beta-blockers combined with RAS inhibitors make sense after all to protect against renal injury?

In chronic kidney disease (CKD) sympathetic overactivity is stimulated by signals from the diseased kidney activating hypothalamic centers. In addition, breakdown of circulating catecholamines is decreased. Indications for beta-blockers are cardio- and renoprotection. Cardioprotection is important because cardiovascular (CV) death is two- to 20-fold more likely in CKD than end-stage kidney disease; consequently, beta-blockers, with their adverse effect on CV risk profile, should be avoided. Controlled prospective evidence for renoprotection by beta-blockers in nondiabetic CKD with hard end points is lacking, but renoprotection by antihypertensive agents was first documented by administering beta-blockers in patients with diabetic nephropathy. Renoprotection by beta-blockers was seen experimentally. Furthermore, controlled studies documented a beneficial effect on albuminuria as a surrogate marker for renoprotection in diabetic and nondiabetic patients. Renin-angiotensin system blockade is the undoubted first-line treatment in CKD. Several points argue for ancillary treatment with beta-blockers: in CKD often four or more different antihypertensive drugs are required and cardiac indications are frequent.

Telmisartan improves endothelial function in patients with essential hypertension

BACKGROUND

: Hypertension is a cardiovascular risk factor commonly associated with endothelial dysfunction and increased renal vascular resistance. Angiotensin receptor blockers (ARBs) may beneficially affect these parameters via antagonism of angiotensin type 1 (AT1) receptor-mediated vasoconstriction and vascular superoxide production. We therefore investigated whether the new ARB telmisartan improves endothelial function and renal vascular resistance in patients with essential hypertension.

METHODS

: Thirty-seven patients with essential hypertension were randomized to receive telmisartan, the calcium channel blocker nisoldipine, or their combination for 6 weeks in a prospective, parallel group study. Brachial artery flow-mediated (endothelium-dependent) dilation (FMD) and renal vascular resistance index (RVRI) were evaluated using high-resolution ultrasound before, at 3 weeks (low dose), and at 6 weeks (high dose) after initiation of treatment.

RESULTS

: At baseline, FMD and RVRI did not significantly differ between treatment groups. After 3 weeks of treatment neither treatment significantly changed FMD or RVRI. After 6 weeks of treatment, patients randomized to receive telmisartan alone or the combination, but not those treated with nisoldipine alone, displayed a significantly improved FMD, whereas RVRI values again were not significantly different as compared to those at baseline.

CONCLUSION

: In our study cohort of patients with essential hypertension, treatment with telmisartan improved FMD but did not change RVRI. Future studies will demonstrate whether this telmisartan-induced effect may contribute to a blood pressure-independent reduction in cardiovascular morbidity.

The management of hypertension in ischaemic heart disease

PURPOSE OF REVIEW

Patients with hypertension and coronary artery disease are often inadequately treated. Blood pressure levels remain unacceptably high in about half of such patients. A significant shortfall exists between guidelines and practice in implementing evidence-based drug therapy.

RECENT FINDINGS

Recent trials underscore the importance of blood pressure reduction. The purported superiority of specific drug classes, notably angiotensin-converting enzyme inhibitors and beta-blockers, is increasingly debated. Conversely, the benefits of calcium channel blockers are increasingly recognized. Irrespective of differences, all three agents are frequently required to achieve blood pressure targets. Beyond blood pressure reduction, statin therapy is undoubtedly the single most important risk factor intervention. New studies suggest that intensive lipid lowering and greater reductions in low-density lipoprotein cholesterol will further reduce major cardiovascular events. Finally, the impact of smoking cessation, exercise, and diet is often underestimated.

SUMMARY

The prognosis for patients is critically dependent on reducing global cardiovascular risk by addressing all modifiable risk factors. The cornerstone of treatment remains blood pressure reduction, using agents with both antihypertensive and antianginal properties.

Primer on systematic review and meta-analysis

A systematic review uses an explicitly defined process to comprehensively identify all studies pertaining to a specific focused question, appraise the methods of the studies, summarize the results, identify reasons for different findings across studies, and cite limitations of current knowledge. Meta-analyses usually combine aggregate-level data reported in each primary study, which may provide a more precise estimate of the "true effect" than any individual study. However, the conclusions may be limited by between-trial heterogeneity, publication bias, or deficits in the conduct or reporting of individual primary studies.

Rationale for combination angiotensin receptor blocker and angiotensin-converting enzyme inhibitor treatment and end-organ protection in patients with chronic kidney disease

Chronic kidney disease (CKD) is a major public health problem that has received increasing attention because of the high rate of associated cardiovascular morbidity and mortality. Mounting evidence indicates that angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), drugs that inhibit the renin-angiotensin-aldosterone system (RAAS) safely slow down progression of CKD. There is also growing evidence supporting combination treatment of nephropathies with an ACE inhibitor plus an ARB to more completely block the RAAS and provide greater renoprotection than either an ACE inhibitor-based or ARB-based regimen. The National Kidney Foundation suggests that ACE inhibitors and ARBs may be used in combination to reduce proteinuria in patients with kidney disease; however, larger outcomes trials are needed.

European guidelines on cardiovascular disease prevention in clinical practice: executive summary. Fourth Joint Task Force of the European Society of Cardiology and other societies on cardiovascular disease prevention in clinical practice (constituted by representatives of nine societies and by invited experts)

Other experts who contributed to parts of the guidelines: Edmond Walma, Schoonhoven (The Netherlands), Tony Fitzgerald, Dublin (Ireland), Marie Therese Cooney, Dublin (Ireland), Alexandra Dudina, Dublin (Ireland) European Society of Cardiology (ESC) Committee for Practice Guidelines (CPG):, Alec Vahanian (Chairperson) (France), John Camm (UK), Raffaele De Caterina (Italy), Veronica Dean (France), Kenneth Dickstein (Norway), Christian Funck-Brentano (France), Gerasimos Filippatos (Greece), Irene Hellemans (The Netherlands), Steen Dalby Kristensen (Denmark), Keith McGregor (France), Udo Sechtem (Germany), Sigmund Silber (Germany), Michal Tendera (Poland), Petr Widimsky (Czech Republic), José Luis Zamorano (Spain)

Document reviewers: Irene Hellemans (CPG Review Coordinator) (The Netherlands), Attila Altiner (Germany), Enzo Bonora (Italy), Paul N. Durrington (UK), Robert Fagard (Belgium), Simona Giampaoli(Italy), Harry Hemingway (UK), Jan Hakansson (Sweden), Sverre Erik Kjeldsen (Norway), Mogens Lytken Larsen (Denmark), Giuseppe Mancia (Italy), Athanasios J. Manolis (Greece), Kristina Orth-Gomer (Sweden), Terje Pedersen (Norway), Mike Rayner (UK), Lars Ryden (Sweden), Mario Sammut (Malta), Neil Schneiderman (USA), Anton F. Stalenhoef (The Netherlands), Lale Tokgözoglu (Turkey), Olov Wiklund (Sweden), Antonis Zampelas (Greece)

In vivo effect of enalapril on lysosomal compartment isolated from kidney and liver of rats

INTRODUCTION

Angiotensin II (Ang II) inhibitory agents such as angiotensin-converting enyzme (ACE) inhibitors have been used as antihypertensive and anti-proteinuric drugs, attenuating the progression and inducing regression of glomerulosclerosis. The mechanisms related to the renoprotective effects of the ACE-inhibitors, although partly related to the blockade of the renin-angiotensin system (RAS), are not completely understood. Their effects on many cellular functions and intracellular components have not been directly studied. The aim of the present studies was to investigate the effect of enalapril on lysosomal activity.

MATERIAL AND METHODS

Two groups of Wistar rats were studied. The experimental group received enalapril, 50 mg/L, in the drinking water; the control group was submitted to the same conditions except for enalapril. After two weeks of treatment, each animal was sacrificed and samples of liver and kidney were individually collected, homogenised and subjected to differential centrifugation. The supernatant was utilised for evaluation of ortophosphoric-monoester phosphohydrolase as a marker of lysosome stability and the results expressed as specific units of phosphatase activity.

RESULTS

The mean specific activities of the lysosomal compartment isolated from kidneys of enalapril-treated rats showed a mean specific activity that was 17.6% higher than the control group; no: difference was found in the liver.

CONCLUSION

The present studies suggests that the beneficial effect of enalapril is not related to effects on lysosomal membrane.

Chronic kidney disease, cardiovascular events, and the effects of perindopril-based blood pressure lowering: data from the PROGRESS study

Chronic kidney disease (CKD) is associated with a high risk of cardiovascular disease, but evidence regarding the effectiveness of interventions to reduce that risk is lacking. The Perindopril Protection against Recurrent Stroke Study (PROGRESS) study enrolled 6105 participants with cerebrovascular disease and randomly allocated them to perindopril-based blood pressure-lowering therapy or placebo. Individuals with CKD were at approximately 1.5-fold greater risk of major vascular events, stroke, and coronary heart disease, and were more than twice as likely to die (all P< or =0.002). Perindopril-based treatment reduced the risk of major vascular events by 30% and stroke by 35% among subjects with CKD, and the absolute effects of treatment were 1.7-fold greater for those with CKD than for those without. Considering patients with CKD and a history of cerebrovascular disease, perindopril prevented one stroke or other cardiovascular event among every 11 patients treated over five years. In conclusion, kidney function should be considered when determining the need for blood pressure lowering therapy in patients with cerebrovascular disease.

Cilnidipine and Telmisartan Similarly Improves Vascular Damage in Hypertensive Patients

This study was designed to compare the effects of 12-month blood pressure (BP) control using cilnidipine and telmisartan on vascular damage in untreated hypertensive patients. One hundred patients were randomly assigned to either a cilnidipine group or a telmisartan group. The extent of vascular damage was assessed before and after treatment by measuring urinary albumin excretion (UAE), pulse wave velocity (PWV), and intima-media thickness (IMT) of the carotid arteries in each patient. Both drugs similarly decreased BP without altering plasma markers for oxidative stress or inflammation. Both UAE and PWV were significantly improved in both groups, but IMT was significantly reduced only in the cilnidipine group. Multiple regression analyses suggested that the UAE may have decreased as a result of a reduction in intraglomerular pressure caused by telmisartan or by efferent arteriolar dilation caused by cilnidipine. In addition, the PWV may have decreased as a result of the improvement in lipid metabolism caused by telmisartan or the reduction in plasma levels of aldosterone caused by cilnidipine. However, the analyses could not identify any definitive causal relationships or suggest the mechanism responsible for the improvement in IMT caused by cilnidipine. Thus, telmisartan and cilnidipine have unique properties for inhibiting vascular complications.

Are differences in calcium antagonists relevant across all stages of nephropathy or only proteinuric nephropathy?

PURPOSE OF REVIEW

The main effects of classic calcium antagonists are mediated by the inhibition of L-type calcium channels broadly distributed within the renal vascular bed. Calcium antagonists act predominantly on the afferent arterioles, and dihydropyridines can favour the increase in glomerular hypertension and progression of kidney diseases, in particular when systemic blood pressure remains uncontrolled.

RECENT FINDINGS

Calcium antagonists have been widely used in clinical practice because of their antihypertensive capacity. The prevention of renal damage is a very important aim of antihypertensive therapy. This is particularly so taking into account the high prevalence of chronic kidney disease in the general population. Non-dihydropyridines such as verapamil have been shown to possess an antiproteinuric effect that could be particularly relevant.

SUMMARY

Recent data from clinical trials have confirmed that, in hypertensive patients with preserved renal function or with chronic kidney disease, calcium antagonists are effective antihypertensive drugs to be considered alone or in combination with an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. In those patients presenting with proteinuric kidney disease, non-dihydropyridines could reduce proteinuria to a greater degree than dihydropyridines.

Discordant Effects of β-Blockade on Central Aortic Systolic and Brachial Systolic Blood Pressure: Considerations Beyond the Cuff

The role of beta-blockers in uncomplicated hypertension has been challenged recently. Compared with other antihypertensives, beta-blockers are less effective for preventing cardiovascular events in patients with uncomplicated hypertension. Moreover, a recent meta-analysis of placebo-controlled clinical trials concluded that atenolol is not more efficacious than placebo for preventing cardiovascular events in patients with hypertension. Although these agents lower blood pressure measured conventionally over the brachial artery with a blood pressure cuff, they do not exert a commensurate effect on blood pressure in the central aorta. Central aortic blood pressure and aortic augmentation index are strong predictors of left ventricular hypertrophy, an independent risk factor for cardiovascular events. Emerging data are illuminating the antihypertensive paradox whereby antihypertensive agents may elicit discordant effects on central and peripheral blood pressure and hemodynamics. Vasodilatory antihypertensives, such as renin-angiotensin-aldosterone system inhibitors and calcium channel blockers, elicit reductions in central aortic blood pressure equal to or greater than that in the brachial artery. Conversely, beta-blockers lower central aortic blood pressure to a lesser degree even when blood pressure measured by sphygmomanometry is reduced substantially. Given the strong relationship between central aortic blood pressure and target organ damage, the effectiveness of beta-blockers may be overestimated in practice on the basis of conventional blood pressure measurements alone. Differences in central and peripheral blood pressure may account for the lack of cardiovascular protection afforded by beta-blockers in clinical trials and could account for a portion of the apparent "benefit beyond blood pressure" reduction with other classes of antihypertensive agents. Future studies should aim to better clarify the role of central aortic blood pressure in the treatment of hypertension. In the meantime, the effects of antihypertensive drugs on blood pressure "beyond the brachial blood pressure cuff" should be considered when prescribing antihypertensive agents for a patient.

Blood pressure reduction and cardiovascular outcomes: past, present, and future

Hypertension has not always been recognized as a harbinger of cardiovascular complications and premature death. Only 70 years ago, hypertension was considered the body's adaptation to sclerotic blood vessel disease and essential to maintain organ perfusion; thus, treatment was regarded as undesirable. Epidemiologic studies have since established a strong linear relation between blood pressure and cardiovascular disease (CVD), and randomized trials have documented that blood pressure reductions by antihypertensive drugs confer cardiovascular protection, making the hypertension-related risk a reversible risk. There is now a consensus that blood pressure should be reduced to <140/90 mm Hg in all patients and that a more aggressive blood pressure target (<130/80 mm Hg) should be pursued in those in whom the cardiovascular risk is high. Despite this, blood pressure control remains elusive in most individuals in the hypertensive population, which makes improvement of blood pressure control in this population a priority goal. This goal may meet with new challenges, however. Optimal blood pressure control may have to include the measurement of blood pressure every day, given the fluctuations of blood pressure and their prognostic importance independent of and in addition to that of classically measured blood pressure values.

The kidney and cardiovascular risk--implications for management: a consensus statement from the European Society of Hypertension

Cardiovascular and renal diseases share many of the same risk factors. In fact, renal failure is usually accompanied by an increased global cardiovascular risk. Thus, preservation of kidney function might simultaneously protect the heart and the brain and, conversely, addressing cardiovascular risk factors might safeguard the kidney. This review considers the evidence supporting this approach, focusing on the protective effect of blood-pressure lowering and the ancillary actions of antihypertensive agents on renal protection. We review recent evidence on renal protection in individuals with and without diabetes, and the importance of offering a high standard of care also to those with the metabolic syndrome or prediabetes in order to prevent initial forms of renal, and as a consequence, cardiovascular damage. Intervention may be appropriate even in individuals with high-normal blood pressure, if they already have early renal and/or cardiovascular risk markers. As a consequence of these insights, thresholds for starting antihypertensive therapy are gradually falling, whereas awareness of the need for an early intervention in patients at high risk of developing renal damage and simultaneously cardiovascular disease is growing.

Nonallergic angioedema: role of bradykinin

Angioedema is an underestimated clinical problem. Many cases are nonallergic reactions, e.g. bradykinin-induced angioedema caused by genetic defects and angiotensin-converting enzyme (ACE) inhibitors. This difference is crucial for successful therapy, in particular when complete emergency care is not available. Five important forms of nonallergic angioedema can be distinguished: hereditary (HAE), acquired (AAE), renin-angiotensin-aldosterone system (RAAS)-blocker-induced (RAE), pseudoallergic angioedema (PAE) and idiopathic angioedema (IAE). Some angioedema are present in the larynx and may cause death. A vast majority of nonallergic angioedema are RAE, particularly those caused by ACE inhibitors. It appears important to emphasize that in patients with complete intolerance to RAAS-blockers, cessation of RAAS-blockers is likely to be associated with increased cardiovascular risk. Currently, there is no published algorithm for diagnosis and treatment. Angioedema is usually treated by a conservative clinical approach using artificial ventilation, glucocorticoids and antihistamines. Today, a plasma pool C1-esterase inhibitor (C1-INH) concentrate is the therapy of choice in HAE. The current pharmacotherapy of nonallergic angioedema is not satisfactory, thus requiring the identification of effective agents in clinical trials. Recently, several new drugs were developed: a recombinant C1-INH, a kallikrein inhibitor (ecallantide) and a specific bradykinin-B2-receptor antagonist (icatibant). According to currently available reports, these drugs may improve the treatment of kinin-induced angioedema.

[Strategies to slow the progression of chronic kidney disease]

High blood pressure and proteinuria are the major factors that drive progression of chronic kidney disease. Target levels for preserving renal function are blood pressure less than 130/80 mmHg and proteinuria less than 0.5 g/day. Angiotensin II converting enzyme inhibitors and sartans should be used as first-line therapy to reach these targets. Their use requires close monitoring of renal function and serum potassium levels. Moderate sodium restriction, possibly combined with diuretic therapy, helps to maximize the effect of renin-angiotensin inhibitors. Patients with chronic kidney disease have a high risk of acute kidney failure, especially due to drugs. All prescriptions must take into account the existence and extent of kidney disease. Patient adhesion and collaboration between health professionals are required if these measures are to be effective in the long term.

Effects of monotherapy of temocapril or candesartan with dose increments or combination therapy with both drugs on the suppression of diabetic nephropathy

We examined the effects of increasing the recommended initial doses of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs), or of switching to combination therapy with both drugs, on diabetic nephropathy. Hypertensive type 2 diabetic patients with urinary albumin excretion (ACR) between 100 and 300 mg/g creatinine (Cre) were assigned to the following five groups in which an antihypertensive drug was administered at a recommended initial dose for 48 weeks, and then either the dose was doubled or an additional drugs was added to regimen for the following 48 weeks: N, nifedipine-CR (N) 20 mg/day (initial dose); T, ACEI temocapril (T) 2 mg/day; C, ARB candesartan (C) 4 mg/day; T+C, T first and then addition of C; C+T, C first and then addition of C. ACR decreased in the T (n=34), C (n=40), T+C (n=37) and C+T (n=35) groups, but not in the N group (n=18). However, the anti-proteinuric effect was less in the T than in the C, T+C or C+T groups, while no differences existed among the latter three. In each group, there were significant linear relationships between attained BP and ACR; however, the regression lines were shifted toward lower ACR level in the renin-angiotensin system-inhibition groups compared with the N group. These results indicate that an ACEI and/or ARB is superior to a CCB in retarding diabetic nephropathy, while the combination of low doses of ACEI and ARB has effects similar to those of high-dose ARB. Even among patients treated with an ACEI and/or ARB, lowering BP is important.

Will generic hypertension guidelines reduce the proliferation of directives?

“…practitioners should realise that recommendations can never replace sound clinical judgment or take precedence over the personal interaction between patient and doctor”

Treatment of hypertension in patients with diabetes mellitus

Antihypertensive treatment in diabetes mellitus, especially in diabetics known to have cardiac autonomic neuropathy, may have to consider the status of the autonomic nervous system. In diabetic subjects with cardiac autonomic neuropathy, vagal activity during the night is often reduced. The reduction results in relative or absolute sympathetic activation, which could increase cardiovascular risk. Pathophysiological and clinical data suggests that antihypertensive treatment should reduce rather than induce sympathetic activity in this setting. Beta blocking agents, ACE inhibitors, calcium antagonists of verapamil or diltiazem type and selective imidazoline receptor agonists reduce sympathetic activity and, therefore, may have a beneficial effect in diabetic patients with disturbed sympathovagal balance.

Is population-wide diuretic use directly associated with the incidence of end-stage renal disease in the United States?

In the quest for "evidence-based" medicine, an accepted hierarchy of evidence has been proposed. This hierarchy places in vitro studies and animal data at the base, and puts systematic reviews, meta-analyses, and randomized controlled trials at the pinnacle. However, when clinical medicine faces questions that have not yet been studied by the "gold standard" methods, how is one to proceed? Often, the best evidence at hand falls short of randomized controlled trials and meta-analyses. Using this framework, a review of the evidence supporting the hypothesis that population-wide diuretic use is directly associated with end-stage renal disease in the United States is presented. Publications pertaining to diuretic use in recent clinical trials are also discussed.

Systemic hypertension

Hypertension is a growing public health problem worldwide. Only 37% of American hypertensives currently have their blood pressures controlled. Hypertension is traditionally diagnosed in the medical office, but both home and ambulatory blood pressure monitoring can help. Lifestyle modifications are recommended for everyone who has higher than "normal" blood pressure (<120/80 mm Hg). Voluminous clinical trial data support beginning drug therapy with low-dose chlorthalidone, unless the patient has a specific indication for a different drug. Additional drugs (typically in the sequence, angiotensin converting-enzyme inhibitor or angiotensin receptor blocker, calcium antagonist, beta-blocker, alpha-blocker, aldosterone antagonist, direct vasodilator, and centrally acting alpha(2)-agonist) can be added to achieve the blood pressure goal (usually <140/90 mm Hg, but <130/80 mm Hg for diabetics and those with chronic kidney disease). Special circumstances exist for treatment of hypertension in pregnancy, in childhood, in the elderly, and in both extremes of blood pressure (pre-hypertension or hypertensive emergencies).

[Which optimal antihypertensive bitherapy for kidney patients?]

In this editorial review on the optimal antihypertensive treatment for chronic kidney disease (CKD) patients, we start with the controversy triggered by Casas et al., for proposing a bitherapy optimal not only for nephroprotection, but also for global cardiovascular protection. The incidence of cardiovascular complications are indeed much greater than the occurrence of end stage renal disease (ESRD) in these patients, so that their prevention has at least the same priority. We explain the huge amount of discordant papers, on the basis of methodology deficiencies in the studies aiming at evidencing the truth of 2 antinomic concepts underlying this controversy: 1) "The correction by antihypertensive drugs of the cardiovascular risk excess in hypertensive patients is exclusively related to their blood pressure lowering effect, the optimal blood pressure (BP) level being defined by epidemiologists at 115/75 mmHg"; 2) "Independently of BP lowering effect, antihypertensive drugs may have intrinsic, protective or deleterious, renal and cardiovascular effects which may be variable according to the target organ". We think that truth is conciliating and that both mechanisms should not be exclusive. However more rigorous studies are still needed to evidence it. Meanwhile we propose the optimal therapy by hypokaliemic diuretics (thiazides+/-loop diuretics according to glomerular filtration decline)+inhibitors of the angiotensin AT1-receptor (ACE inhibitors or AT1RB), in preference to the association of dihydropyridines with diuretics. This recommendation is strong however, only for CKD patients with macroproteinuria. The priority that we give to diuretic therapy is based on the evidence that this class confers good prevention against both heart failure and strokes, which is not the case for all AT1-inhibitors and dihydropyridines. Furthermore the diuretics are the drugs with the longest antihypertensive effect (many weeks) and their efficiency in CKD patients is proportional to the sodium depletion they initially induce and therefore to the dose (specially of the loop diuretics). Indeed volemia control is an incontrovertible factor for optimal BP control in renal insufficiency. As regards the use of betablockers, they should no more be considered as first drug for hypertension because they have the strongest diabetogenic effect. They should be used selectively for their specific cardiologic indications such as angina, heart failure, arythmia and as substitute for ACEI or AT1RB when general anesthesia is considered. Regarding the choice between ACEI and AT(1)RB, on the basis of indirect comparisons, we think that the latter may grant a comparable cardiac protection while giving a better cerebral protection. We shall have to wait the results of ONTARGET study to have or not the evidence for this preference. Finally, we want to stress the necessity to individualize the treatment by taking into account coexistence of cardiovascular complications and of other diseases, as well as the tolerance of the treatment (which may be influenced by seasons, in particular the canicula one), and the cost of the drugs.

Benazepril slows progression of renal dysfunction in patients with non-diabetic renal disease

AIM

The present study examined the effects of benazepril, an angiotensin-converting enzyme inhibitor, on the progression of renal insufficiency in patients with non-diabetic renal disease.

METHODS

Fifteen patients with non-diabetic renal disease whose serum creatinine (Cr) ranged from 1.5 to 3.0 mg/dL were given either benazepril (2.5-5 mg) or placebo once daily for 1 year in a random crossover manner. In both periods, antihypertensive medications were increased if blood pressure was greater than 130/85 mmHg. Blood sampling and urinalysis were performed bimonthly throughout the study period.

RESULTS

Blood pressure was similar when comparing the benazepril and the placebo periods (128+/-12/83+/-6 vs 129+/-10/83+/-7 mmHg). Serum Cr significantly increased from 1.62+/-0.18 to 1.72+/-0.30 mg/dL (P=0.036) during the placebo period, while there was no statistically significant increase in serum Cr during the benazepril period (from 1.67+/-0.17 to 1.71+/-0.27 mg/dL). The slope of decrease of the reciprocal of serum Cr was steeper in the placebo period than in the benazepril period (-0.073+/-0.067 vs-0.025+/-0.096/year, P=0.014). Urinary protein excretion was lower during the benazepril period than during the placebo period (0.57+/-0.60 vs 1.00+/-0.85 g/gCr, P=0.006). Serum K was significantly higher in the benazepril period than in the placebo period (4.4+/-0.5 vs 4.2+/-0.5 mEq/L, P<0.001), but no patient discontinued benazepril therapy as a result of hyperkalemia.

CONCLUSION

Long-term benazepril treatment decreased the progression of renal dysfunction in patients with non-diabetic renal disease by a mechanism that is independent of blood pressure reduction.

Treating hypertension in the patient with overt diabetic nephropathy

Arterial blood pressure is a major determinant of renal and cardiovascular outcomes in diabetic nephropathy. There is a proportional relationship between the systolic blood pressure and renal and mortality outcomes. Decreasing the diastolic pressure does not significantly decrease these outcomes. Irrespective of the magnitude of pretreatment systolic hypertension in the patient with type 2 diabetic nephropathy, the systolic pressure achieved with antihypertensive therapy is the important determinant of renal and cardiovascular risk. Achieving a lower systolic pressure down to 120 mm Hg is associated with substantial risk reduction. Although the data are limited, systolic blood pressure less than 120 mm Hg may be associated with increased all-cause mortality in this patient population, increasing the possibility of a J-curve response. A marked decrease in diastolic pressure, which is a danger when undertaking aggressive therapy with the goal of decreasing the systolic pressure to 130 mm Hg, can be associated with an increased risk of cardiac events. The renoprotective and proteinuria-decreasing effects of angiotensin-converting enzyme inhibitors and angiotensin-receptor blockers recommend these agents as the standard of care in type 2 diabetic nephropathy. In addition to angiotensin-converting enzyme inhibitor and angiotensin-receptor blocker therapy, controlling the systolic blood pressure in this difficult to control patient population may require the use of 3 or more antihypertensive agents.

Complications of hypertension and the role of angiotensin receptor blockers in hypertension trials

Hypertension is a high-prevalence disease that may affect several organs. In recent years, data have accumulated indicating that angiotensin II receptor blockers (ARBs) may have a supplementary effect beyond lowering blood pressure. The aim of this review is to evaluate the impact of ARBs on the most important complications of hypertension--heart, cerebrovascular and renal diseases, and metabolic complications--based on the findings from large clinical hypertension trials. The results may indicate that ARBs have a superior effect compared with placebo or other antihypertensive drugs in order to prevent left ventricular hypertrophy, atrial fibrillation, stroke, renal disease and diabetes mellitus, while there appears to be no blood pressure-independent superior effect of ARBs regarding prevention of myocardial infarction or heart failure.

Current dilemmas in inhibiting the renin-angiotensin system: do not forget real life

For a long time, the inhibition of the renin-angiotensin-aldosterone (RAA) axis has been considered a must in almost all patients with progressive chronic kidney disease (CKD), with the aim of reducing the rate of progression to end-stage renal disease (ESRD). However, recent data from a meta-analysis, including the ALLHAT study, and a study in Canadian diabetic patients questioned the usefulness of angiotensin converting enzyme (ACE) inhibition in delaying the onset of dialysis. Publication of these data led to an intensive recent debate among reputed nephrologists, with numerous pros and cons regarding the pharmacological influence of CKD progression. The authors of the present review critically discuss the arguments and counterarguments of this challenging debate. Finally, a cautious view for the practicing nephrologist is expressed, highlighting the difference between study patients and real-life patients, and the possible overlooked aspects of recent renal protection studies (the importance of central blood pressure, of ambulatory blood pressure monitoring and possible, the impact of angiotensin converting inhibitors on stroke), are presented.

Hypertension and kidney protection in the elderly: what is the evidence in 2007?

Hypertension and diabetes mellitus are the two most widely recognized risk factors for cardiovascular disease (CVD), chronic kidney disease (CKD), and end-stage renal disease (ESRD) requiring dialysis/transplantation; both become increasingly important as one ages. Common pathways and mechanisms are involved in the development of renal vascular lesions in both conditions, and effective treatments for each are now available to reduce morbidity, mortality and progression of organ damage. Although this review will focus primarily on the ability to protect the kidney and vasculature elsewhere by lowering blood pressure in the elderly, other approaches, specifically dietary restriction of protein, strict control of diabetes mellitus, and the management of the different dyslipidemias, must be used in conjunction with the antihypertensive agents to obtain optimum protection.

Renin: friend or foe?

Renin maintains blood pressure through vasoconstriction when there is inadequate salt to maintain volume. In populations where blood pressure is more often high than low, and vascular death more common than haemorrhage or dehydration, therapeutic reductions in renin secretion or response are valuable. Whether long-term benefits are due entirely to blood pressure reduction remains unproved. The pathway can be blocked at its rate-limiting step (beta blockade or direct renin inhibition), the synthesis of the active product, angiotensin II, or at the receptor for angiotensin. Because renin and sodium are the two main factors in blood pressure control, and renin levels vary inversely with sodium load, blood pressure control requires a combination of natriuresis and blocking the consequential increase in renin activity. Being a large and stable molecule, renin is among the easiest and cheapest of hormone measurements. Understanding the simple biochemistry and physiology of renin permits optimal use of the drugs acting to raise or suppress this hormone.

Progression risk, urinary protein excretion, and treatment effects of angiotensin-converting enzyme inhibitors in nondiabetic kidney disease

It is unclear whether patients with nondiabetic kidney disease benefit from angiotensin-converting enzyme inhibitor (ACEI) therapy when they are at low risk for disease progression or when they have low urinary protein excretion. With the use of a combined database from 11 randomized, clinical trials (n = 1860), a Cox proportional hazards model, based on known predictors of risk and the composite outcome kidney failure or creatinine doubling, was developed and used to stratify patients into equal-sized quartiles of risk. Outcome risk and treatment effect were examined across various risk strata. Use of this risk model for targeting ACEI therapy was also compared with a strategy based on urinary protein excretion alone. Control patients in the highest quartile of predicted risk had an annualized outcome rate of 28.7%, whereas control patients in the lowest quartile of predicted risk had an annualized outcome rate of 0.4%. Despite the extreme variation in risk, there was no variation in the degree of benefit of ACEI therapy (P = 0.93 for the treatment x risk interaction). Significant interaction was detected between baseline urine protein and ACEI therapy (P = 0.003). When patients were stratified according to their baseline urinary protein excretion, among the subgroup of patients with proteinuria > or =500 mg/d, significant treatment effect was seen across all patients with a measurable outcome risk, including those at relatively low risk (1.7% annualized risk for progression). However, there was no benefit of ACEI therapy among patients with proteinuria <500 mg/d, even among higher risk patients (control outcome rate 19.7%). Patients with nondiabetic kidney disease vary considerably in their risk for disease progression, but the treatment effect of ACEI does not vary across risk strata. Patients with proteinuria <500 mg/d do not seem to benefit, even when at relatively high risk for progression.

Combination therapy with an ACE inhibitor and an angiotensin receptor blocker for diabetic nephropathy: a meta-analysis

AIMS

Angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) prevent the progression of diabetic nephropathy (DN). Studies suggest that combination renin-angiotensin-aldosterone system (RAAS)-inhibiting therapy provides additive benefit in DN. However, these studies are small in size. We performed a meta-analysis of studies investigating combination therapy for DN.

METHODS

Studies were identified through a search of medline, embase, cinahl and the Cochrane Database. All trials involving combined ACEI and ARB for slowing progression of DN were included. The primary end point was 24-h urinary protein excretion. Blood pressure, serum potassium and glomerular filtration rate (GFR) were secondary end points.

RESULTS

In the 10 included trials, 156 patients received ACEI + ARB and 159 received ACEI only. Most studies were 8-12 weeks in duration. Proteinuria was reduced with ACEI + ARB (P = 0.01). This was associated with significant statistical heterogeneity (P = 0.005). ACEI + ARB was associated with a reduction in GFR [3.87 ml/min (7.32-0.42); P = 0.03] and a trend towards an increase in serum creatinine (6.86 micromol/l 95% CI -0.76-13.73; P = 0.09). Potassium was increased by 0.2 (0.08-0.32) mmol/l (P < 0.01) with ACEI + ARB. Systolic and diastolic blood pressure were reduced by 5.2 (2.1-8.4) mmHg (P < 0.01) and 5.3 (2.2-8.4) mmHg (P < 0.01), respectively.

CONCLUSIONS

This meta-analysis suggests that ACEI + ARB reduces 24-h proteinuria to a greater extent than ACEI alone. This benefit is associated with small effects on GFR, serum creatinine, potassium and blood pressure. These results should be interpreted cautiously as most of the included studies were of short duration and the few long-term studies (12 months) have not demonstrated benefit.

Albuminuria is a target for renoprotective therapy independent from blood pressure in patients with type 2 diabetic nephropathy: post hoc analysis from the Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) trial

Albuminuria reduction could be renoprotective in hypertensive patients with diabetic nephropathy. However, the current use of renin-angiotensin-system intervention is targeted to BP only. Therefore, this study investigated the adequacy of this approach in 1428 patients with hypertension and diabetic nephropathy from the placebo-controlled Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL) study. Investigated were the extent of discordance in treatment effects on systolic BP (SBP) and albuminuria and its association with renal outcome in a multivariate Cox model. Among patients with a reduced SBP during treatment, a lack of albuminuria reduction was observed in 37, 26, and 51% (total, losartan, and placebo, respectively) at month 6. SBP or albuminuria reduction was associated with a lower risk for ESRD, whereas combined SBP and albuminuria reduction was associated with the lowest risk for events. Across all categories of SBP change, a progressively lower ESRD hazard ratio was observed with a larger albuminuria reduction. A lower residual level of albuminuria was also associated with lower ESRD risk. In conclusion, changes in albuminuria are not concordant in a substantial proportion of patients when titrated for BP. Meanwhile, the ESRD risk showed a clear dependence on albuminuria reduction. The ESRD risk also showed dependence on the residual level of albuminuria, even in patients who reached the current SBP target. Antihypertensive treatment that is aimed at improving renal outcomes in patients with diabetic nephropathy may therefore require a dual strategy, targeting both SBP and albuminuria reduction.