Renin and aldosterone are not associated with vulnerable plaque characteristics in patients with carotid artery disease

Background: The 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. Methods and Results: Baseline plasma renin and aldosterone concentrations from 506 subjects undergoing carotid endarterectomy (mean age, 67 ± 9 years; 65% male) were correlated with histopathologic characteristics and inflammatory protein concentrations of the excised atherosclerotic plaque. Ordinal logistic regression (for ordinal outcome parameters) or linear regression (for linear outcome) analysis did not show a statistically significant relationship between plasma renin or aldosterone concentrations and plaque fat, thrombus, calcifications, collagen, smooth muscle cells, or macrophage content. Neither could any association be found with intraplaque inflammatory mediators. During a median follow-up of 3 years, 102 (20%) patients experienced a major secondary vascular event (composite of stroke, myocardial infarction, leg amputation, vascular death, or coronary revascularization or peripheral intervention). In multivariable Cox regression analysis, including both renin and aldosterone, baseline renin concentrations were associated with the occurrence of secondary events. Conclusions: In patients with established atherosclerotic disease undergoing carotid endarterectomy, plasma renin and aldosterone concentrations were not associated with atherosclerotic plaque characteristics. Plasma renin concentration was positively associated with the occurrence of major secondary vascular events.