ACE inhibitors and appearance of renal events in hypertensive nephrosclerosis

Nefroangioesclerosis: actualización

Nephroangiosclerosis or kidney disease that accompanies chronic essential arterial hypertension has been known for more than a hundred years. The definitive diagnosis is established by renal biopsy, which is reserved for doubtful cases or atypical presentation, being in most cases a presumptive clinical diagnosis. The objective of this review is to analyse the main controversies that currently exist related to nephroangiosclerosis: inaccuracy in epidemiological aspects (prevalence and incidence unknown), diagnostic difficulties and lack of correlation studies between clinical data and histopathology, progression factors in Caucasians. Currently, with advances in genetic studies in hypertension, not using or redefining the term hypertensive kidney disease for another condition such as nephropathy related to the present genetic alteration is being considered.

Renal participation in cardiovascular risk inessential hypertension

The kidney plays a relevant role in the origin of essential hypertension in humans, and it suffers the consequences of sustained elevated blood pressure in the absence of therapy. Recently, a relevant prevalence of mild renal insufficiency both in general population than in hypertensive patients has been described. A direct relationship seems to exist between the level of cardiovascular risk and the prevalence of the renal disorder, whether this is detected as an elevation in serum creatinine or as a diminution of estimated creatinine clearance. This renal function impairment is a strong predictor of cardiovascular risk in patients with chronic heart failure and following myocardial infarction. Prevention of renal and cardiovascular damage in these patients will be one of the most relevant tasks in the future. The aim of this short review is to discuss the evidence in favor of a relevant prevalence of mild renal insufficiency in hypertensive patients, as well as the association of this disorder with a very significant increment in global cardiovascular risk.

[Vascular nephropathies: a fresh look at a systemic disease]

Hypertensive nephropathy represents the most prevalent cause of end-stage renal disease in France. Renal lesions are unspecific. Nephroangiosclerosis diagnosis is overestimated due to non standardized clinical criteria and available histological analysis. Other factors than hypertension contribute to vascular lesions.MYH9 and APOL1 polymorphisms are strongly associated with kidney diseases including hypertensive nephropathy. Elevated blood pressure levels are associated with CKD progression. Treatment includes angiotensin blockers which have a synergic effect on blood pressure reduction and lowering urinary protein excretion with sodium restriction and diuretics.

Hypertension in moderate-to-severe nondiabetic CKD patients

High blood pressure can be both a cause and a consequence of chronic kidney disease and will contribute to an unfavorable renal and cardiovascular (CV) prognosis. Both in the general population and in hypertensive patients, the presence of chronic kidney disease is associated with a high prevalence of CV disease. Elevated blood pressure and the amount of albumin present in urine are the 2 most relevant factors facilitating the progression of chronic kidney disease in hypertensive patients. Therapeutic attitudes that must be considered when chronic kidney disease is present include the simultaneous performance of CV and renal protection.

Renin-angiotensin-aldosterone system blockade effects on the kidney in the elderly: benefits and limitations

The proportion of the population that is elderly (age>or=65 years) is growing across the world. The increasing longevity of humans results in a higher number of elderly patients' presenting with multiple chronic diseases such as hypertension, diabetes, and chronic kidney disease (CKD). These problems increase morbidity and mortality in the elderly. Overactivity of the renin-angiotensin-aldosterone system (RAAS) is associated with the development of hypertension, cardiovascular events, and CKD, so targeting the RAAS is a logical therapeutic approach. Elderly patients present special concerns regarding the benefits versus risks of using RAAS blockers. Plasma renin activity declines with age, which has been attributed to the effect of age-associated nephrosclerosis. Plasma aldosterone is also reduced with age, resulting in a greater risk for hyperkalemia in older individuals, especially when coupled with the age-associated decline in GFR. Moreover, the elderly have a higher frequency of concurrent conditions and are on many medications, which may further increase the risk for adverse effects of RAAS blocking agents. Unfortunately, there is a paucity of literature that is specifically aimed at studying elderly using the RAAS blockers. We present in our in-depth review data regarding benefits and limitations of the use of the RAAS blockades on the various sites along the RAAS pathway for elderly patients. Specific attention was given to the role of combination RAAS blockade therapy and higher monotherapy dosing in the treatment of hypertension in the elderly.

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.

Prediction of cardiovascular outcome by estimated glomerular filtration rate and estimated creatinine clearance in the high-risk hypertension population of the VALUE trial

BACKGROUND

Reduced renal function is predictive of poor cardiovascular outcomes but the predictive value of different measures of renal function is uncertain.

METHODS

We compared the value of estimated creatinine clearance, using the Cockcroft-Gault formula, with that of estimated glomerular filtration rate (GFR), using the Modification of Diet in Renal Disease (MDRD) formula, as predictors of cardiovascular outcome in 15 245 high-risk hypertensive participants in the Valsartan Antihypertensive Long-term Use Evaluation (VALUE) trial. For the primary end-point, the three secondary end-points and for all-cause death, outcomes were compared for individuals with baseline estimated creatinine clearance and estimated GFR < 60 ml/min and > or = 60 ml/min using hazard ratios and 95% confidence intervals. Coronary heart disease, left ventricular hypertrophy, age, sex and treatment effects were included as covariates in the model.

RESULTS

For each end-point considered, the risk in individuals with poor renal function at baseline was greater than in those with better renal function. Estimated creatinine clearance (Cockcroft-Gault) was significantly predictive only of all-cause death [hazard ratio = 1.223, 95% confidence interval (CI) = 1.076-1.390; P = 0.0021] whereas estimated GFR was predictive of all outcomes except stroke. Hazard ratios (95% CIs) for estimated GFR were: primary cardiac end-point, 1.497 (1.332-1.682), P < 0.0001; myocardial infarction, 1.501 (1.254-1.796), P < 0.0001; congestive heart failure, 1.699 (1.435-2.013), P < 0.0001; stroke, 1.152 (0.952-1.394) P = 0.1452; and all-cause death, 1.231 (1.098-1.380), P = 0.0004.

CONCLUSION

These results indicate that estimated glomerular filtration rate calculated with the MDRD formula is more informative than estimated creatinine clearance (Cockcroft-Gault) in the prediction of cardiovascular outcomes.

Clinical trials in nephrology: success or failure

PURPOSE OF REVIEW

A large amount of clinical and epidemiologic evidence has been gathered supporting the importance of blood pressure control in reducing chronic kidney disease progression. Suppression of the rennin-angiotensin-aldosterone system should also be considered in any patient with chronic kidney disease, in particular if albuminuria is present.

RECENT FINDINGS

Analysis of renal outcome by estimating glomerular filtration rate in trials primarily devoted to cardiovascular protection in hypertensive patients, in particular the Antihypertensive and Lipid-Lowering treatment to prevent Heart Attack Trial trial, has come to question the effectiveness of suppressing the rennin-angiotensin-aldosterone system in controlling blood pressure and thus protecting the kidney in hypertensive patients. This subject is particularly interesting because the existence of an increased cardiovascular risk associated with renal function decline has been demonstrated in many different clinical conditions including arterial hypertension. The increase in global cardiovascular risk accompanying chronic kidney disease would necessitate the use of drugs suppressing the rennin-angiotensin-aldosterone system for cardiovascular protection irrespective of the influence on renal outcome.

SUMMARY

This review includes the most recent data evaluating renal endpoints in clinical trials primarily devoted to renal function as well as those dedicated to arterial hypertension and its cardiovascular consequences.

Rate of Decline of GFR and Progression of Vascular Disease in Type 2 Diabetic Patients with Diabetic or Vascular Nephropathy during the Last Three Years before Starting Dialysis Therapy

BACKGROUND

The progression of chronic renal insufficiency depends on the type of primary renal disease and blood pressure (BP) levels. We investigated the rate of decline of glomerular filtration rate (GFR) during 3 years prior to the start of dialysis therapy in type 2 diabetic patients with diabetic nephropathy (dNP) or vascular nephropathy (vNP). The aim of the study was to determine differences in the progression of renal insufficiency and the prevalence of vascular diseases in the two patient groups.

METHODS

In a retrospective study, we investigated type 2 diabetic patients with chronic renal insufficiency who were undergoing regular controls in our outpatient care unit for at least 3 years prior to the start of dialysis. We evaluated only patients who had already died under chronic dialysis therapy, and whose diagnosis of primary renal disease was histologically conformed at autopsy. A total of 40 type 2 diabetic patients were included in the study. Of these, 28 patients had dNP (age 62 +/- 8 years) and 12 had vNP (age 70 +/- 7 years). The following parameters were determined at 3- to 6-month intervals: body weight, BP, HbA1c, serum creatinine (Cr), Cr clearance (Cockroft formula), cholesterol and triglycerides. The prevalence of vascular disease in the two groups was also assessed.

RESULTS

The average decrease in Cr clearance was 7.7 +/- 2.4 ml/min/year in patients with dNP and 7.7 +/- 2.1 ml/min/year in those with vNP (NS). During the entire observation period, mean HbA1c values (7.0 +/- 0.8 vs. 6.8 +/- 0.6%), systolic BP (137 +/- 8 vs. 138 +/- 11 mm Hg) and diastolic BP (86 +/- 4 vs. 87 +/- 7 mm Hg), cholesterol and triglycerides did not differ significantly in the two groups. The prevalence of vascular disease 3 years prior to and at the start of dialysis therapy was similar in patients with dNP and vNP.

CONCLUSION

The progression of dNP and vNP is similar at least during 3 years before the start of dialysis therapy. Vascular risk factors and the prevalence of vascular diseases were not significantly different in the two patient groups. However, diabetic patients with ESRD secondary to dNP were significantly younger than those with vNP.

Systemic and glomerular hypertension and progression of chronic renal disease: the dilemma of nephrosclerosis

The link between the kidney and hypertension has been considered a villain-victim relationship. High blood pressure levels are a well-recognized feature in chronic renal disease, but the ability of mild-to-moderate hypertension to produce renal insufficiency has been questioned. Nephrosclerosis, benign nephrosclerosis, and hypertensive kidney disease are terms that clinicians use when renal damage is thought to be secondary to essential hypertension. Many cases of end-stage renal disease are ascribed to so-called benign nephrosclerosis. This entity could actually be a primary renal disease affecting the preglomerular microvasculature, perhaps genetically mediated and ethnically influenced, and showing a heterogeneous clinical expression. African Americans suffer from nephrosclerosis more frequently than Caucasians. Nephrosclerosis affecting Caucasians seems to show a less aggressive pattern and could represent early age-related renal sclerosis. The risk of end-stage renal disease is increased when atherosclerotic lesions in large renal arteries coexist. Age, systolic blood pressure, proteinuria, and concomitant cardiovascular disease are well-known promoters of renal failure. A multifactorial strategy, including antihypertensive and antiproteinuric drugs, and lipid-lowering and anti-platelet agents, could improve cardiovascular and renal outcomes in patients with nephrosclerosis.

Minor abnormalities of renal function: a situation requiring integrated management of cardiovascular risk

Changes in renal function related with essential hypertension are associated with an elevated cardiovascular morbidity and mortality. Indices of altered renal function (e.g. microalbuminuria, increased serum creatinine concentrations, decrease in estimated creatinine clearance or overt proteinuria) are independent predictors of cardiovascular morbidity and mortality. The Framingham Heart Study documented the relevance of proteinuria for cardiovascular prognosis in the community. The Intervention as a Goal in Hypertension Treatment (INSIGHT) Study assessed the role of proteinuria as a very powerful risk factor. It has also been shown that microalbuminuria along with primary hypertension poses a high risk for cardiovascular diseases. Recent data indicate that even minor derangements of renal function are associated with the clustering of cardiovascular risk factors observed in metabolic syndrome, that promote progression of atherosclerosis. All these parameters should be routinely evaluated in clinical practice, and considered in any stratification of cardiovascular risk in hypertensive patients. The high prevalence of chronic kidney disease in the general and in the hypertensive populations implies the need for an integrative therapeutic approach to fully protect renal and cardiovascular systems simultaneously.

Calcium channel blockers and renal protection: insights from the latest clinical trials

Calcium channel blockers have been widely used in clinical practice because of their antihypertensive capacity. 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 (CKD) in the general population. Recent data have shown that CKD is related to the absence of adequate BP control and also to the clustering of other cardiovascular risk factors seen in the metabolic syndrome. The knowledge of the capacities of the different antihypertensive drugs or their combinations to simultaneously control BP while protecting the kidney and avoiding the facilitation of metabolic alterations is warranted. Recent data from the Intervention as a Goal in Hypertension Treatment trial, Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial, and African American Study of Kidney Disease and Hypertension (AASK) allow the conclusion that in hypertensive patients with preserved renal function or with CKD, calcium channel blockers are effective antihypertensive drugs to be considered alone or in combination with an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker.

Effect of proteinuria and glomerular filtration rate on cardiovascular risk in essential hypertension

Changes in renal function related with essential hypertension are associated with an elevated cardiovascular morbidity and mortality. Indices of altered renal function (e.g., microalbuminuria, increased serum creatinine concentrations, decrease in estimated creatinine clearance or GFR, and overt proteinuria) are independent predictors of cardiovascular morbidity and mortality. The Framingham Heart Study documented the relevance of proteinuria for cardiovascular prognosis in the community. The INSIGHT Study assessed the role of proteinuria as a risk factor in essential hypertension. The presence of proteinuria at baseline turned out to be a very potent predictor for the development of cardiovascular events and death in patients with essential hypertension and one or more associated cardiovascular risk factors. Recent data indicate that minor derangements of renal function, including proteinuria, are associated, both in the community and in the hypertensive population, with the clustering of cardiovascular risk factors observed in metabolic syndrome that promote progression of atherosclerosis. Renal function has to be routinely evaluated in every hypertensive patient, and the presence of minor alterations considered in the stratification of cardiovascular risk in hypertensive patients.

Development of chronic kidney disease in essential hypertension during long-term therapy

PURPOSE OF REVIEW

This review examines the relevance of the development of chronic kidney disease in long-term hypertensive patients on the cardiovascular prognosis.

RECENT FINDINGS

Recently published guidelines recognize the relevance of the development of chronic kidney disease in the stratification of risk for the hypertensive patient. An adequate assessment of renal function, including an estimation of the glomerular filtration rate, is mandatory in order to ensure an adequate evaluation of the global cardiovascular risk in the hypertensive patient. The presence of subtle elevations in serum creatinine concentrations is a potent predictor of a poor cardiovascular prognosis. The clustering of associated risk factors seems to justify the elevated cardiovascular risk observed in patients with essential hypertension and mild renal function derangement.

SUMMARY

Chronic kidney disease is associated with a significant increase in cardiovascular risk attributable to the simultaneous existence of other risk factors related to the metabolic syndrome. The high prevalence of chronic kidney disease in the general and hypertensive populations forces the recognition of its relevance and the need for an integrated therapeutic approach simultaneously to protect the renal and cardiovascular systems fully.

Relevancia de la insuficiencia renal en el pronóstico cardiovascular de los pacientes con hipertensión arterial esencial

Recently published guidelines recognize the relevance of the finding of chronic kidney disease in the stratification of risk of the hypertensive patient. Determination of the presence of microalbuminuria and estimation of glomerular filtration rate are mandatory in order to ensure an adequate evaluation of global cardiovascular risks in the hypertensive patient. The presence of subtle elevations of serum creatinine concentrations and/or proteinuria are also potent predictors of a poor cardiovascular prognosis. Clustering of associated risk factors seems to justify the elevated cardiovascular risk observed in patients with essential hypertension and mild alterations of renal function.

Preventing renal dysfunction in patients with hypertension: clinical implications from the early AASK Trial results

Strategies to delay progression of established renal disease have primarily been directed at examining the class of antihypertensive therapy and/or the level of blood pressure control. In diabetic renal disease many trials have noted a protective role of ACE inhibitor-based therapy over non-ACE inhibitor-based therapy. This paper reviews recent clinical trials evaluating hypertension-related kidney disease including the interim results of the African-American Study of Kidney Diseases and Hypertension (AASK) Study, to date the largest prospective study of African-American patients with kidney disease due to hypertension. This trial reports a renoprotective effect of ACE inhibitor-based therapy over calcium-channel antagonist- based therapy. The renoprotective effect of ACE inhibitor-based therapy may, in part, be due to their antiproteinuric effect independent of blood pressure lowering.

Proteinuria: an underappreciated risk factor in cardiovascular disease

Changes in renal function produced by hypertension appear to be associated with higher cardiovascular morbidity and mortality. Indices of altered renal function (eg, microalbuminuria, increased serum creatinine concentrations, decrease in estimated creatinine clearance, or overt proteinuria) are independent predictors of cardiovascular morbidity and mortality. The Framingham Heart Study documented the relevance of proteinuria for cardiovascular prognosis in the community. The International Nifedipine GITS study: Intervention as a goal in Hypertension Treatment (INSIGHT) study assessed the role of proteinuria as a very powerful risk factor. Several studies demonstrated that microalbuminuria is a predictor of cardiovascular disease. It has been shown that the presence of microalbuminuria in primary hypertension carries an elevated cardiovascular risk. Furthermore, recent data indicate that even minor derangements of renal function are associated with an increase in cardiovascular risk factors, and promote progression of atherosclerosis. All these parameters should routinely be evaluated in clinical practice, and in the future must be considered in any stratification of cardiovascular risk in hypertensive patients.

The kidney as a sensor of cardiovascular risk in essential hypertension

Renal damage as a consequence of uncontrolled arterial hypertension is well recognized. Antihypertensive therapy has come to very significantly decrease the vascular damage in the kidneys of hypertensive patients. However, prevalence of mild renal insufficiency remains present in a significant proportion of the hypertensive population. This is accompanied by a marked increase in cardiovascular risk, as a consequence of the clustering of other cardiovascular risk factors and of insufficiently controlled BP. Prevention and protection of renal and cardiovascular damage in these patients will be one of the most relevant tasks in the future.

Renal dysfunction as a cardiovascular risk factor

Indices of altered renal function (eg, microalbuminuria, increased serum creatinine concentration, or decrease in estimated creatinine clearance, particularly overt proteinuria) are independent predictors of cardiovascular morbidity and mortality. These parameters should be routinely evaluated in the elderly and in high cardiovascular risk populations, particularly when hypertension is present. Hypertensive kidney damage should be prevented by early aggressive treatment of hypertensive patients with microalbuminuria. To avoid further aggravation of high cardiovascular risk, antihypertensive agents devoid of unwanted metabolic side effects should be used. Epidemiologic information suggests that renal and cardiovascular outcome run parallel in this segment of the population.

Renal protection by antihypertensive therapy

The attainment of adequate renal protection requires strict blood pressure control and a diminution of proteinuria or microalbuminuria to values as near from normalcy as possible. It has been considered that by getting the first, the second could be attained at the same price. Recent data have confirmed that renal protection in hypertensive patients, diabetics or not, requires combination therapy that has to include an angiotensin converting enzyme inhibitor or an angiotensin receptor blocker. A calcium channel blocker can be added to this without renal compromise. A diuretic will also be needed in most cases. Proteinuria will diminish with this combination in particular if up-titration of the drug blocking the effects of angiotensin II is performed. The control of other associated risk factors is also required, in particular smoking and lipids.

Are clinical endpoint benefits of angiotensin converting enzyme inhibitors independent of their blood pressure effects?

Both basic and experimental data indicate that the renin-angiotensin system through angiotensin II mediates its classic hemodynamic role, but also has a significant deleterious role in a number of cardiac, vascular, and renal disorders. Indeed, evidence indicates that angiotensin II negatively impacts endothelial function, cardiac remodeling, vessel wall hypertrophy, atherosclerosis, and progressive renal disease. Newer data point to a significant role for angiotensin II in inflammation and in inducing plasminogen activator inhibitor. This widespread negative effect can be countered by newer antihypertensive drugs, angiotensin converting enzyme inhibitors, and angiotensin receptor blockers. Both small and large clinical trials suggest a large benefit of such drugs on not only organ-specific endpoints such as renal disease or proteinuria, but on global cardiovascular events. It does appear that when blood pressure is significantly elevated, lowering blood pressure does indeed provide protection for larger endpoints such as stroke. However, at lower blood pressure levels, a hemodynamically independent effect is likely to be contributing to the positive effects. We should embrace these effects and champion them for our patients.

Renal function: the Cinderella of cardiovascular risk profile

The presence of an altered renal function in essential hypertension, advanced heart failure (HF) and after a myocardial infarction (MI) is associated with higher cardiovascular morbidity and mortality. Indices of altered renal function (e.g., microalbuminuria, increased serum creatinine concentrations, decrease in estimated creatinine clearance or overt proteinuria) are independent predictors of cardiovascular morbidity and mortality in any of the three clinical situations. These parameters should then be routinely evaluated in clinical practice. These facts have several therapeutic implications. First, although there is no evidence-based information on the level of blood pressure that confers optimal renal protection, levels substantially lower than past recommendations are advisable. Second, hypertensive kidney damage should be prevented by early treatment of hypertensive patients, particularly those with microalbuminuria. Finally, to avoid further aggravation of high cardiovascular risk, antihypertensive agents devoid of unwanted metabolic side effects should be used for the treatment of hypertensive vascular damage. In HF, the combination of an angiotensin-converting enzyme (ACE) inhibitor and a beta-blocker seem to be the most renoprotective. Renal outcome is also improved by ACE inhibition after an MI. Finally, renal and cardiovascular outcome seem to run in parallel in all these situations.