Invited commentary

Abstract

This report represents a thorough analysis of the search for associations between plasma renin or aldosterone levels and excised carotid artery plaque characteristics and composition and includes evaluation of many important intraplaque inflammatory mediators. Because activation of the renin-angiotensin system has been previously described to be associated with an increase in coronary and cerebrovascular events, it seemed logical to assume that these levels should correlate with the atherosclerotic plaque. Failure to find such a relationship was unexpected, which implies that the mechanism for the clinical outcomes is unrelated to acceleration of plaque lesion growth or plaque destabilization. Interestingly, a higher incidence of the composite of subsequent major clinical cardiovascular events was noted to be associated with higher levels of renin and aldosterone, although a history of prior cardiac disease at baseline was also higher among these patients. Nonetheless, the association of subsequent cardiovascular events did reflect greater numbers of adverse cerebrovascular and peripheral vascular episodes in addition to cardiac events. In attempting to understand the findings presented, it must be noted that plasma samples were obtained at only one point during the lifetime of the atherosclerotic process. Were the mature plaques derived from arteries that may have long since become activated by the renin-angiotensin system and no longer were dependent on it for continued activity, with the effect of renin and aldosterone most critical in the early stages of lesion development? Alternatively, although exclusion of patients using angiotensin-converting enzyme inhibitors in this real-life population would have severely limited the sample set size available for analysis, such inhibition may still compromise the ability to interpret these results, even if use of this drug class did not appear to affect the results of preliminary Cox regression analysis. Certainly, use of these inhibitors has been associated with reductions in cardiovascular events.1Yusuf S. Sleight P. Pogue J. Bosch J. Davies R. Dagenais G. Heart Outcomes Prevention Evaluation Study InvestigatorsEffects of an angiotensin-converting-enzyme inhibitor, ramipril, on cardiovascular events in high-risk patients.N Engl J Med. 2000; 342: 145-153Crossref PubMed Scopus (8167) Google Scholar Could it be that elevated renin and aldosterone levels have, in fact, no causal role, but rather serve merely as markers of an as yet undiscovered mechanism of plaque destabilization? Whatever the case, atherosclerosis remains a complex process, resistant to complete explanation despite the laudable efforts of committed researchers such as Dr Hillaert and her colleagues. The opinions or views expressed in this commentary are those of the authors and do not necessarily reflect the opinions or recommendations of the Journal of Vascular Surgery or the Society for Vascular Surgery. Renin and aldosterone are not associated with vulnerable plaque characteristics in patients with carotid artery diseaseJournal of Vascular SurgeryVol. 68Issue 1PreviewThe renin-angiotensin-aldosterone system is increasingly being recognized to play an important role in the development and clinical course of cardiovascular diseases. Renin-angiotensin-aldosterone system activation is associated with clinical outcome in various populations of cardiovascular patients, such as patients with coronary artery, peripheral artery, and cerebrovascular disease. In this study, we investigated the associations between plasma renin and aldosterone concentrations and atherosclerotic plaque characteristics and secondary vascular events in patients undergoing carotid endarterectomy. Full-Text PDF Open Archive