Renin-angiotensin-aldosterone system in the elderly: rational use of aliskiren in managing hypertension

Karl Andersen

Department of Medicine, Division of Cardiology, Landspitali University Hospital, University of Iceland, Reykjavik, Iceland

Abstract: The overall purpose of hypertension treatment is 2-fold. First, patients often have symptoms that are related to their high blood pressure and although subtle in many instances may be improved dramatically by blood pressure control. The main reason for blood pressure treatment, however, is to reduce the burden of cardiovascular complications and end organ damage related to the condition. This may be considered the ultimate goal of blood pressure treatment. In this respect, actual blood pressure measurements may be seen as surrogate end points as the organ protective effects of two antihypertensive agents may differ significantly even though their blood pressure lowering effects are similar. Thus beta-blockers, once seen as first-line treatment of hypertension for most patients, now are considered as third- or fourth-line agents according to the latest NICE guidelines (National Institute for Health and Clinical Excellence, www.nice.org.uk/CG034). On the other hand, agents that inhibit the activity of the renin-angiotensin-aldosterone system (RAAS) are being established as safe, effective and end organ protective in numerous clinical trials, resulting in their general acceptance as first-line treatment in most patients with stage 2 hypertension. This shift in emphasis from beta-blockers and thiazide diuretics is supported by numerous clinical trials and has proven safe and well tolerated by patients. The impact of this paradigm shift will have to be established in future long-term randomized clinical trials. The optimal combination treatment with respect to end organ protection has yet to be determined. Most combinations will include either a RAAS active agent and calcium channel blocker or two separate RAAS active agents working at different levels of the cascade. In this respect direct renin inhibitors and angiotensin receptor blockers seem particularly promising but the concept awaits evaluation in upcoming randomized clinical trials. Although safety data from the randomized clinical trials to date have been promising, we still lack data on the long-term effect of aliskiren on mortality and there still are patient groups where the safety of aliskiren is unexplored.

Keywords: aliskiren, elderly, hypertension, renin-angiotensin-aldosterone system