Renin angiotensin aldosterone system in the cardiovascular continuum: An overview of the trial evidence and clinical practice

The renin angiotensin aldosterone system (RAAS) inhibitors represent an invaluable class of drugs in the management of various stages of the cardiovascular disease continuum. Both angiotensin converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) have unique pharmacodynamics properties. These enable them to block the RAAS system at multiple levels. The ARBs inhibit RAAS in a mechanistically distinct fashion when compared to the ACEIs. Whereas ACEIs decrease the synthesis of angiotensin II, ARBs selectively and competitively bind to the AT1 receptors hence preventing there activation by angiotensin II. The differential effects of these two groups of drugs, resulted in them playing different roles in primary and secondary cardiovascular protection. It is suggested that ACEIs tend to be more “cardioprotective” whereas ARBs may be more “cerebral-protective”. In this review article, we will attempt to enhance understanding of the role of RAAS blockers in most appropriate selection of ACEIs and ARBs according to their attributes and the needs of the clinical situation. We will initially described the role of RAAS activation in the pathophysiology of common cardiovascular disease processes. This will be followed by a review of the major clinical trials of different ACEIs and ARBs in the primary prevention and secondary prevention of cardiovascular diseases. In conclusion, the effects of ACEIs across a wide spectrum of cardiovascular diseases remain indisputable. However, ARBs showed a superior effect to ACEIs with regard to stroke, but their efficacy in certain major clinical end points seems limited.