Treatment of patients with essential hypertension and microalbuminuria

End-organ protection in patients with hypertension: focus on the role of angiotensin receptor blockers on renal function

The renin-angiotensin system (RAS) plays a key role in a number of pathophysiological mechanisms that are involved in the development and progression of cardiovascular and renal disease. For these reasons, pharmacological antagonism of this system, particularly the blockade of formation or the receptor antagonism of angiotensin II, has been demonstrated to be an effective and safe strategy to reduce the burden of cardiovascular disease. Among different drug classes, angiotensin II type 1 receptor antagonists (angiotensin receptor blockers [ARBs]) have provided an excellent alternative to ACE inhibitors, representing a more selective and a better tolerated pharmacological approach to interfere with the RAS. Results derived from large, international, randomized clinical trials have consistently indicated that ARB-based therapeutic strategies may effectively provide cardiovascular and renal disease prevention and protection in different clinical conditions across the entire cardiovascular continuum. This article reviews the pathophysiological rationale of RAS involvement in the pathogenesis of renal diseases, focusing on the beneficial effects provided by ARBs in terms of renal protection.

Clinical value of microalbuminuria in hypertension

Microalbuminuria (MA) is a well recognized marker of cardiovascular complications in hypertension, but whether MA can predict adverse outcome in this clinical condition is still a subject for debate. The fact that in hypertensive cohorts those patients who showed an increase in albumin excretion rate also manifested an increased incidence of morbid events indicates that the presence of MA in hypertension may carry an increased cardiovascular risk. However, the prognostic significance of MA remains controversial because no results of prospective studies performed in hypertensive subjects without diabetes mellitus are available. Several factors can affect the prevalence of MA in hypertension, including severity of the disease, selection procedures, concomitant risk factors, degree of obesity, age, and sex distribution. This accounts for the large differences in the prevalence of MA that can be found in the literature, with prevalence rates going from a low of 4.7% to a high of 40%. There is still conflict over whether MA in hypertension is due to increased intraglomerular pressure or to glomerular damage. The data from the literature suggest that in subjects with mild hypertension the main determinant of albumin excretion rate is the haemodynamic load. In subjects with more severe hypertension and hypertensive complications, the augmented urinary albumin leak is probably the consequence of a systemic microvascular disturbance which involves the glomeruli. In this respect, the insulin resistance state often associated to high blood pressure appears as one of the main pathogenetic factors. Whether management of hypertensive populations may be improved by monitoring of albumin excretion rate and whether antihypertensive drugs which are more effective in decreasing urinary albumin can be more beneficial in patients with MA remains to be determined.

Natural history of cardiovascular and renal disease in patients with type 2 diabetes: effect of therapeutic interventions and risk modification

Several observational studies document a considerably increased risk of advanced renal disease, cardiovascular disease, and early mortality in persons with diabetes. Both epidemiologic and observational studies indicate that progression of cardiovascular disease and renal disease is associated not only with high blood glucose levels, but also with hypertension and dyslipidemia. In persons with type 1 diabetes, hypoglycemic and antihypertensive therapy are important in the prevention of cardiovascular and renal disease. In those with type 2 diabetes, hypoglycemic therapy can help to prevent microvascular disease in the retina and in the kidney, and recent studies show that antihypertensive treatment is important in preventing cardiovascular disease. Thus, a multifactorial intervention program is key to preventing complications of hyperglycemia and, equally important, elevated blood pressure and dyslipidemia.