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

The effect of an L/N-type calcium channel blocker on intradialytic blood pressure in intradialytic hypertensive patients

BACKGROUND

Intradialytic hypertension (HTN), which is one of the poor prognostic markers in patients undergoing hemodialysis, may be associated with sympathetic overactivity. The L/N-type calcium channel blocker, cilnidipine, has been reported to suppress sympathetic nerves activity in vivo. Therefore, we hypothesized that cilnidipine could attenuate intradialytic systolic blood pressure (SBP) elevation.

METHODS

Fifty-one patients on chronic hemodialysis who had intradialytic-HTN (SBP elevation ≥10 mmHg during hemodialysis) and no fluid overload were prospectively randomized into two groups: control and cilnidipine groups. Cilnidipine group patients took cilnidipine (10 mg/day) for 12 weeks. The primary endpoint was the change in the intradialytic SBP elevation before and after the 12-week intervention.

RESULTS

Before the intervention, no differences were observed in age, sex or pre-dialytic SBP (148.5 ± 12.9 vs. 148.3 ± 19.3 mmHg) between the two groups. Intradialytic SBP elevation was unchanged in the control group. Cilnidipine significantly lowered the post-dialytic SBP with an attenuation of the intradialytic SBP elevation from 12.0 ± 15.4 mmHg to 4.8 ± 10.1 mmHg. However, the observed difference in the intradialytic SBP elevation by cilnidipine did not reach statistical significance (group×time interaction effect p = 0.25). Cathecolamine levels were unaffected by the intervention in both groups.

CONCLUSION

Cilnidipine lowers both the pre- and post-dialytic SBP and might attenuate intradialytic SBP elevation. Therefore, cilnidipine may be effective in lowering SBP during HD in patients with intradialytic-HTN.

Renal dopaminergic system: Pathophysiological implications and clinical perspectives

Fluid homeostasis, blood pressure and redox balance in the kidney are regulated by an intricate interaction between local and systemic anti-natriuretic and natriuretic systems. Intrarenal dopamine plays a central role on this interactive network. By activating specific receptors, dopamine promotes sodium excretion and stimulates anti-oxidant and anti-inflammatory pathways. Different pathological scenarios where renal sodium excretion is dysregulated, as in nephrotic syndrome, hypertension and renal inflammation, can be associated with impaired action of renal dopamine including alteration in biosynthesis, dopamine receptor expression and signal transduction. Given its properties on the regulation of renal blood flow and sodium excretion, exogenous dopamine has been postulated as a potential therapeutic strategy to prevent renal failure in critically ill patients. The aim of this review is to update and discuss on the most recent findings about renal dopaminergic system and its role in several diseases involving the kidneys and the potential use of dopamine as a nephroprotective agent.

Effects of aliskiren on blood pressure and humoral factors in hypertensive hemodialysis patients previously on angiotensin II receptor antagonists

BACKGROUND

A direct renin inhibitor (DRI), aliskiren, may be effective for blood pressure (BP) control in hemodialysis patients. However, it is unclear whether aliskiren has a greater beneficial effect on BP and humoral factors than angiotensin II receptor antagonists (ARBs) in hypertensive patients on hemodialysis.

METHODS

Eighteen hemodialysis patients (58 ± 14 years) on the recommended dose of an ARB were prospectively randomized into two groups: ARB and DRI groups. Patients in the ARB group continued taking their previous ARB, whereas those in the DRI group switched to aliskiren (150 mg/day) for 12 weeks. Baseline measurements of BP and humoral factors such as plasma renin activity (PRA), plasma aldosterone concentration (PAC) and brain natriuretic peptide (BNP) were performed. Measurements were repeated every 4 weeks.

RESULTS

At baseline, no differences were observed in age, gender or BP between the two groups. Systolic BP was unaffected by treatment in either groups (group effect, p = 0.26; time effect, p = 0.38; group × time effect, p = 0.24). PRA decreased in DRI (p ≤ 0.02, group effect, p = 0.65; time effect, p = 0.13; group × time effect, p = 0.048), but not in ARB (p ≥ 0.94). PAC increased only in DRI (p ≤ 0.03), whereas BNP was unaffected in either group.

CONCLUSION

Aliskiren at a dose of 150 mg/day had a similar effect on BP compared with ARBs, but significantly lowered PRA.

Prevention of microalbuminuria in patients with type 2 diabetes: what do we know?

Cardiovascular and chronic kidney disease are epidemic throughout industrialized societies. Diabetes leads to premature cardiovascular disease and is regarded by many as the most common etiological factor for chronic kidney disease. Because most studies of blood-pressure lowering agents in people with diabetes and hypertension have been conducted in individuals who already have some target organ damage, it is unclear whether earlier intervention could prevent or delay the onset of renal or systemic vascular disease. In early disease there is only a low possibility of observing cardiovascular or renal events; thus intervention trials in this population must rely on disease markers such as microalbuminuria. Accordingly, the authors review the evidence to support the use of microalbuminuria as a disease marker in diabetic patients based on its strong association with renal and cardiovascular events, and discuss recent trials that examine the impact of preventing or delaying the onset of microalbuminuria.

Recognition, pathogenesis, and treatment of different stages of nephropathy in patients with type 2 diabetes mellitus

Nephropathy is a common microvascular complication among patients with type 2 diabetes mellitus and a major cause of kidney failure. It is characterized by albuminuria (≥ 300 mg/d) and a reduced glomerular filtration rate and is often present at the time of diabetes diagnosis after the kidney has been exposed to chronic hyperglycemia during the prediabetic phase. A low glomerular filtration rate (<60 mL/min/1.73 m(2)) is also an independent risk factor for cardiovascular events and death. Detection of diabetic nephropathy during its initial stages provides the opportunity for early therapeutic interventions to prevent or delay the onset of complications and improve outcomes. An intensive and multifactorial management approach is needed that targets all risk determinants simultaneously. The strategy should comprise lifestyle modifications (smoking cessation, weight loss, increased physical activity, and dietary changes) coupled with therapeutic achievement of blood glucose, blood pressure, and lipid goals that are evidence-based. Prescribing decisions should take into account demographic factors, level of kidney impairment, adverse effects, risk of hypoglycemia, tolerability, and effects on other risk factors and comorbidities. Regular and comprehensive follow-up assessments with appropriate adjustment of the therapeutic regimen to maintain risk factor control is a vital component of care, including referral to specialists, when required.

Cardiovascular and Renal Links along the Cardiorenal Continuum

The cardiorenal syndrome includes the widely known relationship between kidney function and cardiovascular disease. A large number of patients have various degrees of heart and kidney dysfunction worldwide, both in developed and developing countries. Disorders affecting one of them mostly involve the other. Such interactions represent the pathogenesis for a clinical condition called cardiorenal syndrome. Renal and cardiovascular disease shares similar etiologic risk factors. The majority of vascular events are caused by accelerated atherosclerosis. Moreover, cardiovascular events rarely occur in patients without underlying disease; rather, they typically take place as the final stage of a pathophysiological process that results in progressive vascular damage, including vital organ damage, specifically the kidney and the heart if these factors are uncontrolled. Chronic kidney disease is a novel risk factor included at this stage that accelerates both vascular and cardiac damage.

Are there effects of renin-angiotensin system antagonists beyond blood pressure control?

Angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) are recognized to reduce cardiovascular and renal morbidity and mortality, which is primarily attributed to their antihypertensive effects. Activation of the renin-angiotensin system (RAS) may also play an important role in the pathogenesis of cardiovascular and renal disease through blood pressure-independent mechanisms mediated by angiotensin II. Thus, inhibiting the RAS with either an ARB or an ACE inhibitor may confer additional benefit in people with advanced nephropathy that cannot be explained totally by reductions in blood pressure. Preclinical evidence suggests that blood pressure lowering is not solely responsible for the organ and tissue protective effects of ACE inhibitors or ARBs. Furthermore, clinical studies evaluating effects on end organs and surrogate markers have shown that these agents have blood pressure-independent effects. There is also intriguing evidence that agents in the same class may differ in their effects on renal function despite similar blood pressure control. Support for blood pressure-independent effects comes from outcome studies. Agents evaluated in such studies and that appear to have effects independent of blood pressure lowering include irbesartan, losartan, ramipril, and telmisartan. Taken together, this body of evidence indicates that the clinical benefits of ARBs and ACE inhibitors in patients with advanced nephropathy extend beyond blood pressure reduction. Therefore, although antihypertensive efficacy is of primary importance in choosing a treatment to provide cardiovascular and renal protection, consideration should be given to the effects of an agent that extend beyond blood pressure.

Short-term treatment with a beta-blocker with vasodilative capacities improves intrarenal endothelial function in experimental renal failure

AIMS

In patients with renal disease the cardiovascular risk is greatly increased, and endothelial dysfunction is assumed to play a pivotal role in this process. Therefore we compared treatment effects of a beta-blocker with additional vasodilatory capacities (nebivolol) and a beta-blocker lacking these actions (metoprolol) on intrarenal and coronary vascular function in a rat model of renal failure with hypertension.

MAIN METHODS

Renal failure was induced by 5/6-nephrectomy (Nx) and analyzed after 4 weeks in Wistar rats. Untreated Nx, Nx/nebivolol 6 mg/d (Nx-Nebi); Nx/metoprolol 60 mg/d (Nx-Meto) and sham-operated (Sham) animals were studied. Isolated small renal and coronary arteries were investigated for endothelium-dependent relaxation to acetylcholine (ACh) and for the contribution of the endothelial mediators NO and endothelium-derived hyperpolarizing factor (EDHF).

KEY FINDINGS

Systolic blood pressure (SBP) was significantly increased in Nx, Nx-Nebi, and Nx-Meto (168+/-5, 153+/-3, and 162+/-6 mmHg) compared to Sham (138+/-3 mmHg, p<0.05, respectively). The increase in albuminuria of Nx (120-fold vs. Sham, p<0.0001) was almost (-85%) normalized by nebivolol compared to Sham (p<0.05), whereas metoprolol induced no significant effect. Renal arteries showed significantly increased Ach-relaxation in Nx and Nx-Nebi (Emax 86+/-4% and 76+/-7%, p<0.05) due to an increase in EDHF-mediated dilation (Emax_EDHF 78+/-7% and 73+/-6%) compared to Sham (Emax 54+/-4% and Emax_EDHF 44+/-6%) and Nx-Meto (Emax 42+/-12% and Emax_EDHF 18+/-5%). ACh-relaxation in coronary arteries was similar between groups but the contribution of NO (relative to EDHF) was strongly increased by nebivolol.

SIGNIFICANCE

The present findings offer an explanation of the nephroprotective effect of intrarenal endothelial function in renal failure.

Reactive oxygen species and dopamine receptor function in essential hypertension

Essential hypertension is a major risk factor for stroke, myocardial infarction, and heart and kidney failure. Dopamine plays an important role in the pathogenesis of hypertension by regulating epithelial sodium transport and by interacting with vasoactive hormones and humoral factors. However, the mechanisms leading to impaired dopamine receptor function in hypertension states are not clear. Compelling experimental evidence indicates a role of reactive oxygen species (ROS) in hypertension, and there are increasing pieces of evidence showing that in conditions associated with oxidative stress, which is present in hypertensive states, dopamine receptor effects, such as natriuresis, diuresis, and vasodilation, are impaired. The goal of this review is to present experimental evidence that has led to the conclusion that decreased dopamine receptor function increases ROS activity and vice versa. Decreased dopamine receptor function and increased ROS production, working in concert or independent of each other, contribute to the pathogenesis of essential hypertension.

ASH position paper: treatment of hypertension in patients with diabetes-an update

This report updates concepts on hypertension management in patients with diabetes. It focuses on clinical outcomes literature published within the last 3 years and incorporates these observations into modifications of established guidelines. While the fundamentals of treatment and goal blood pressures remain unchanged, approaches to specific patient-related issues has changed. This update focuses on questions such as what to do when a patient has an elevated potassium level when therapy is initiated and whether combinations of agents that block the renin-angiotensin system still be used. In addition, there are updates from trials, just published and in press, that focus on related management issues influencing cardiovascular outcomes in persons with diabetes. Last, an updated algorithm is provided that incorporates many of the new findings and is suggested as a starting point to achieve blood pressure goals.

New ADVANCEs in guidelines

BACKGROUND

Recently published Guidelines for the Management of Arterial Hypertension jointly written by the European Society of Hypertension and the European Society of Cardiology are of great relevance to the diabetic population as a result of the elevated cardiovascular and renal risk that accompanies the simultaneous presence of hypertension and diabetes. Guidelines also recognize the relevance of prediabetes, a situation characterized by the presence of the metabolic syndrome.

METHODS

Guidelines consider the need for integral protection of the cardiovascular and renal systems that includes a goal blood pressure (BP) lower than 130/80 mmHg, accompanied by strict metabolic and lipid control often accompanied by antiplatelet therapy. In order to attain the adequate BP and cardiorenal protection beyond the BP decrease, suppression of the renin-angiotensin system should be attempted, usually in association with other antihypertensive drugs.

RESULTS

A few months after the publication of the guidelines, the ADVANCE study was published. This study has shown that the addition of a fixed combination of perindopril and indapamide on top of the other medications in patients with diabetes with BP ranging from normal to elevated greatly helps diminish BP when required, while protecting the cardiovascular and renal systems from the deleterious effects of diabetes associated with high BP. This protection includes as the most relevant finding a significant decrease in all-cause death.

CONCLUSION

The combination of a diminution in BP with further suppression of the renin-angiotensin system obtained through the administration of a fixed combination of perindopril and indapamide explains the benefits observed in ADVANCE in terms of the cardiovascular and renal prognosis of patients with diabetes with BP ranging from normal to elevated.

Hypertension awareness, treatment, and control in chronic kidney disease

BACKGROUND

Hypertension prevalence, awareness, treatment, and blood pressure control rates in the population with chronic kidney disease are limited. The objective of this study was to determine the state of blood pressure control in patients with chronic kidney disease.

METHODS

This is a cross-sectional analysis of data of participants with chronic kidney disease from the Kidney Early Evaluation Program. The Kidney Early Evaluation Program is a national-based health screening program for individuals at high risk for kidney disease conducted in 49 states and the District of Columbia. Of 55,220 adults with kidney disease, 10,813 completed information for demographic and medical characteristics used in the analysis. Predictors of blood pressure control were assessed using multiple logistic regression analysis.

RESULTS

Hypertension prevalence, awareness, and treatment proportions in the screened cohort were high (86.2%, 80.2%, and 70.0%, respectively), but blood pressure control rates were low (13.2%). These proportions increased with advancing stage of kidney disease. Elevated systolic blood pressure accounted for the majority of inadequate control. Male gender (odds ratio [OR] 0.86; 95% confidence interval [CI], 0.75-0.99), non-Hispanic black race (OR 0.76; 95% CI, 0.65-0.89), and body mass index of 30 kg/m(2) or more (OR 0.83; 95% CI, 0.73-0.94) were inversely related with blood pressure control. Those with stage 3 kidney disease were more likely to have blood pressure at goal than those with stage 1 kidney disease (OR 2.08; 95% CI, 1.55-2.80).

CONCLUSION

We conclude that despite increased awareness and treatment of hypertension, control rates in these participants are poor. This poor control rate centers around elevated systolic pressure in people who are obese, non-Hispanic black, or male. These data suggest that those who are aware of their kidney disease are more likely to achieve blood pressure control.