Treatment of microalbuminuria in hypertensive subjects with elevated cardiovascular risk: Results of the IMPROVE trial

Long-term antiproteinuric effect of dual renin-angiotensin system blockade

We evaluated the long-term changes on overt proteinuria induced by dual blockade of the renin-angiotensin system (RAS). Dual blockade was produced by adding an angiotensin II receptor blocker (ARB) to treatment with maximal recommended doses of an angiotensin converting enzyme (ACE) inhibitor in proteinuric patients. A total of 28 patients (19 men and 9 women) with proteinuria higher than 1 g/24 h were enrolled in this trial of treatment with the ARB candesartan (from 4 up to 32 mg daily) added to existing treatment with an ACE inhibitor. At 6, 12, 24, and 36 months, we evaluated proteinuria in 24-h urinary collections, office blood pressure (BP), plasmatic creatinine (Cr), serum potassium (K), and 24 h urine collection creatinine clearance (CrC). During monoblockade of the RAS by ACE inhibitor treatment, albuminuria was 2.94 +/- 1.92 mg/24 h; BP was 137/76 mmHg; K+ was 4.8 +/- 0.5 mmol/l, Cr was 1.76 +/- 0.67 mg/dL, and CrC was 62 +/- 31.9 mL/min. After 6 months, dual blockade of the RAS albuminuria was 2.18 +/- 2.29 mg/24 h (P < 0.01 vs. baseline) and BP was 133/75 mmHg (not significant). At 36 months, albuminuria was 2.21 +/- 2.20 mg/24 h (P < 0.05 vs. baseline); BP was 133/73 mmHg (not significant). CrC was not changed along the follow up. A small increment of Cr was detected at 24 months (2.11 +/- 1.06 mg/mL, P < 0.05). The antiproteinuric effect of dual renin-angiotensin system blockade combining candesartan and ACE inhibitors remain after 36 months without losing its initial effect. Blood pressure changes seem not to explain this long-term antiproteinuric effect.

Inhibition of the renin-angiotensin system: is more better?

Inhibitors of the renin-angiotensin-aldosterone system (RAS) exert beneficial effects in diabetic nephropathy, but the possibility of regression of existing renal lesions remains to be investigated. Teles et al. tested the effects of the RAS inhibitor losartan in rats starting 10 months after induction of diabetes, when glomerular lesions were already present. They linked the reductions of proteinuria with regression of mesangial expansion. More advanced lesions were not affected. There were no dose-response renal effects of losartan.

Elevations in serum creatinine with RAAS blockade: why isn't it a sign of kidney injury?

PURPOSE OF REVIEW

The aim of this article is to review the pertinent physiology and pathophysiology of the renin-angiotensin-aldosterone system (RAAS), summarize the proven beneficial cardiovascular and renal effects of RAAS blockade, examine clinical situations in which RAAS blockade may induce reductions in glomerular filtration rate, and explore why increases in serum creatinine in the setting of angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) therapy do not necessarily signify the presence of clinically relevant kidney failure.

RECENT FINDINGS

RAAS inhibition appears to reduce the likelihood of atrial fibrillation. RAAS inhibition leads to improved insulin sensitivity and glycemic control, but does not appear to prevent diabetes. The beneficial effects of ACEi/ARB therapy extend to those with significant renal disease. Combination ACEi/ARB is safe, and reduces proteinuria more than either agent alone in patients with macroalbuminuric nephropathy. Acute deteriorations in renal function that result from RAAS inhibition are usually reversible.

SUMMARY

RAAS blockade exerts potent hemodynamic, antihypertensive, and antiinflammatory effects, and slows progression of kidney disease beyond that due to lowering of blood pressure. The benefit extends to those with advanced disease. In spite of established benefit, ACEi and ARB therapy remains underutilized, in part due to concerns about acute deteriorations in renal function that result from interruption of the RAAS.

Valsartan in combination with lisinopril versus the respective high dose monotherapies in hypertensive patients with microalbuminuria: the VALERIA trial

OBJECTIVES

Microalbuminuria is known as an independent predictor for stroke, myocardial infarction, and death. The purpose of the VALERIA trial was a comparison of the efficacy and safety of combination therapy of valsartan and lisinopril with valsartan and lisinopril high-dose monotherapy in patients with hypertension and microalbuminuria.

METHODS

This was a randomized, double-blind, interventional, parallel-group study. After a washout/placebo-run-in phase of 3 weeks, 133 patients were randomized to treatment (1: 1:1) with either lisinopril 40 mg, valsartan 320 mg, or a combination of valsartan/lisinopril 320/20 mg for 30 weeks.

RESULTS

At baseline, the urine albumin creatinine ratio was similar for the three treatment groups (geometric means, lisinopril 9.6 mg/mmol, valsartan 9.1 mg/mmol, and valsartan/lisinopril 9.5 mg/mmol). After 30 weeks of treatment, the geometric mean urine albumin creatinine ratio had decreased in all three groups by 41, 51, and 62% to 5.7 mg/mmol (lisinopril), 4.5 mg/mmol (valsartan), and 3.6 mg/mmol (valsartan/lisinopril). The decrease for valsartan/lisinopril was statistically significantly greater compared with lisinopril [adjusted ratio 60%, confidence interval (38-94%), P = 0.029]. Normalization of microalbuminuria was greatest with valsartan and valsartan/lisinopril (lisinopril 17%, valsartan 31%, and valsartan/lisinopril 38% of patients) and was statistically significant for lisinopril in contrast with valsartan/lisinopril (P = 0.034). Differences in blood pressure reduction between the groups were not statistically significant. All treatments were safe and well tolerated.

CONCLUSION

The combination of valsartan and lisinopril provided a significantly better reduction of urine albumin creatinine ratio and more than doubled the rate of patients with normalized urine albumin creatinine ratio compared with lisinopril alone. All treatments were safe and well tolerated.

Inhibition of the renin-angiotensin system and chronic kidney disease

Chronic kidney disease (CKD), a major worldwide public-health problem which affects about 10% of the population, has an increased annual incidence rate of about 5-8%. This increased incidence is mainly due to type 2 diabetes and hypertension and the increasing incidence of elderly patients with CKD. Although the progression to end-stage renal failure (ESRF) is mainly based upon the underlying disease, comorbid conditions such as an initial low renal function, severe proteinuria, and high levels of blood pressure also play important roles in the development of ESRF. Since experimental and clinical evidence suggest that angiotensin II plays a central role in the progression of CKD, pharmacological inhibition of the renin-angiotensin-aldosteron system (RAAS) with angiotensin converting enzyme inhibitors or angiotensin II receptor antagonists has been suggested as first-line treatment for hypertension and prevention of ESRF in these patients. Aliskiren, a novel renin inhibitor is also a promising medical intervention. However, independently of the category of the drugs used, low target blood pressure levels seem to be equally or more important for the delay or prevention of CKD. In this review the results of studies with pharmacological inhibition of the RAAS in patients with diabetic and nondiabetic nephropathy is discussed.

Implications of ethnicity for the treatment of hypertensive kidney disease, with an emphasis on African Americans

The recognition of chronic kidney disease (CKD) as an important public health issue has fostered an increasing number of strategies to increase CKD awareness and to reduce both the prevalence and the complications of CKD. Despite these advances, end-stage renal disease (ESRD) and cardiovascular events remain the major complications of CKD. Although the ESRD epidemic is attributed in greater part to the increasing rate of diabetes, hypertension remains the second most common reported cause of ESRD and is present in approximately 90% of cases of diabetes-related ESRD. The disproportionately high prevalence of hypertension in ethnic minorities, as well as the difficulty of achieving adequate blood-pressure control in these populations, contributes substantially to the high rate of CKD progression and complications in these groups. Although the role of hypertension as a primary cause of CKD is debated, hypertension is commonly recognized as the most important CKD progression factor. Important differences have been reported in the degree and likelihood of blood-pressure response to antihypertensive medications between ethnic groups, but ethnicity seems to be less important as a determinant of clinical outcomes. In this Review we examine key ethnic variations in hypertensive CKD in terms of pathophysiology, response to antihypertensive therapy, clinical outcomes, and evidence-based recommendations for blood-pressure control, with an emphasis on African Americans.

Aliskiren combined with losartan in type 2 diabetes and nephropathy

BACKGROUND

Diabetic nephropathy is the leading cause of end-stage renal disease in developed countries. We evaluated the renoprotective effects of dual blockade of the renin-angiotensin-aldosterone system by adding treatment with aliskiren, an oral direct renin inhibitor, to treatment with the maximal recommended dose of losartan (100 mg daily) and optimal antihypertensive therapy in patients who had hypertension and type 2 diabetes with nephropathy.

METHODS

We enrolled 599 patients in this multinational, randomized, double-blind study. After a 3-month, open-label, run-in period during which patients received 100 mg of losartan daily, patients were randomly assigned to receive 6 months of treatment with aliskiren (150 mg daily for 3 months, followed by an increase in dosage to 300 mg daily for another 3 months) or placebo, in addition to losartan. The primary outcome was a reduction in the ratio of albumin to creatinine, as measured in an early-morning urine sample, at 6 months.

RESULTS

The baseline characteristics of the two groups were similar. Treatment with 300 mg of aliskiren daily, as compared with placebo, reduced the mean urinary albumin-to-creatinine ratio by 20% (95% confidence interval, 9 to 30; P<0.001), with a reduction of 50% or more in 24.7% of the patients who received aliskiren as compared with 12.5% of those who received placebo (P<0.001). A small difference in blood pressure was seen between the treatment groups by the end of the study period (systolic, 2 mm Hg lower [P=0.07] and diastolic, 1 mm Hg lower [P=0.08] in the aliskiren group). The total numbers of adverse and serious adverse events were similar in the groups.

CONCLUSIONS

Aliskiren may have renoprotective effects that are independent of its blood-pressure-lowering effect in patients with hypertension, type 2 diabetes, and nephropathy who are receiving the recommended renoprotective treatment. (ClinicalTrials.gov number, NCT00097955 [ClinicalTrials.gov].).

Albuminuria reduction: The Holy Grail for Kidney Protection

Increased urinary excretion of albumin or total protein has become firmly established as a risk predictor for progression of chronic kidney disease. Observational analyses have raised a strong hypothesis that albuminuria reduction should be a clinical treatment target. Bakris et al. report further exploration of albuminuria-lowering capabilities of intensified renin-angiotensin system inhibition in a randomized clinical trial that included patients at high cardiovascular risk, most of whom appeared to have diabetic kidney disease.