'Angiotensin receptor antagonists and cardiovascular disease in the elderly

The renin-angiotensin system is a biologic cascade of enzymes and their substrates leading to the final product, angiotensin II, (AII) which acts on specific receptors (AT-1, AT-2, AT-r). Recently, a new class of therapeutic agents which block the angiotensin II receptors AT-1 have been made available for medical use. Their blocking is different from that of the ACE-inhibitors. The ACE-inhibitors do not completely block the system and at the same time reduce the inactivation of a vasodilating substance like bradykinin. On the other hand, the angiotensin II receptor antagonists act at the end of the system, so completely blocking the action of AII, without interfering with the metabolism of bradykinin. The selective antagonism of AT-1 receptors completely blocks the main actions of AII, because vasoconstriction, water and sodium retention and cardiac output increase are AT-1 mediated. The clinical use of these agents, especially in the elderly, appears to be of particular interest both in essential hypertension and in congestive heart failure. The results of the ELITE study (Evaluation of Losartan in the Elderly Study) suggest a favourable effect of losartan in elderly patients affected by chronic heart failure. Moreover, angiotensin II receptor antagonists have shown an excellent tolerability, event in the elderly patient. The presence of side effects, particularly cough, is similar to the placebo group. The encouraging results in the use of this class of therapeutic agents have been, up to now, obtained in very few studies, based on a limited numbers of patients. The ability of the angiotensin II receptor antagonists to reduce morbidity and mortality in the elderly patient affected by hypertension and congestive heart failure will be definitely established by the large clinical trials that are presently being carried out.