Cardiovascular Interactions of Renin-Angiotensin-Aldosterone System Assessed by Cardiac Magnetic Resonance: The Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: The effects of the renin-angiotensin-aldosterone system in cardiovascular system have been described based on small studies. The aim of this study was to evaluate the relationship between aldosterone and plasma renin activity (PRA) and cardiovascular structure and function. METHODS: We studied a random sample of Multi-Ethnic Study of Atherosclerosis participants who had aldosterone and PRA blood assays at 2003-2005 and underwent cardiac magnetic resonance at 2010. Participants taking angiotensin-converting enzyme inhibitors or angiotensin receptor blockers were excluded. RESULTS: The aldosterone group was composed by 615 participants, mean age 61.6 ± 8.9 years, while the renin group was 580 participants, mean age 61.5 ± 8.8 years and both groups had roughly 50% females. In multivariable analysis, 1 SD increment of log-transformed aldosterone level was associated with 0.07 g/m2 higher left ventricle (LV) mass index (P = 0.04) and 0.11 ml/m2 higher left atrium (LA) minimal volume index (P < 0.01). Additionally, higher log-transformed aldosterone was associated with lower LA maximum strain and LA emptying fraction (P < 0.01). Aldosterone levels were not significantly associated with aortic measures. Log-transformed PRA was associated with lower LV end diastolic volume index (ß standardized = 0.08, P = 0.05). PRA levels were not significantly associated with LA and aortic structural or functional differences. CONCLUSIONS: Higher levels of aldosterone and PRA are associated with concentric LV remodeling changes. Moreover, aldosterone was related to deleterious LA remodeling changes.

Myocardial fibrosis by T1 mapping magnetic resonance imaging predicts incident cardiovascular events and all-cause mortality: the Multi-Ethnic Study of Atherosclerosis.

AIMS: To evaluate whether myocardial fibrosis predicts cardiovascular events (CVEs) and mortality in the Multi-Ethnic Study of Atherosclerosis. METHODS AND RESULTS: Cardiac magnetic resonance (CMR) T1 mapping with gadolinium administration for assessment of extracellular volume fraction (ECV) was performed in 1326 participants, in whom myocardial scar was assessed by late gadolinium enhancement (LGE). The clinical outcomes were defined as all-cause mortality, atherosclerotic CVEs, and incident heart failure (HF) during an average of 8 years of follow-up after the scan. Participants' mean native T1 time was 971 ms [standard deviation (SD) 45.5], ECV was 27 (SD 2.9), and 117 (8.8%) of them had LGE. At the time of the CMR exam, participant age was 68 years (SD 9) and 48% of them were women. Ideal cut-offs were identified using classification and regression trees accounting for time-to-event outcomes for ECV (30%) and native T1 time (954 ms). Over the follow-up period, 106 participants died, 78 developed CVE, and 23 developed HF. After adjustment for risk factors, ECV >30% was associated with death [hazard ratio (HR): 1.67, P < 0.05], incident CVE (HR: 2.02, P < 0.05), and incident HF (HR: 2.85, P < 0.05). After adjustments, native T1 >954 ms was associated with incident CVE (HR: 2.09, P < 0.05). Myocardial scar by LGE was not predictive of clinical outcomes after adjustments. CONCLUSION: ECV is an independent prognostic marker of incident HF, atherosclerotic CVEs, and all-cause mortality. ECV, with its ability to characterize both diffuse and focal fibrosis processes, better predicted incident events than regional myocardial abnormalities as visualized by LGE imaging in a large multi-ethnic population.

Association Between Inflammatory Markers and Myocardial Fibrosis.

Inflammation promotes adverse ventricular remodeling. T1 mapping has been used to noninvasively assess interstitial myocardial fibrosis. We examined the association of baseline markers of systemic inflammation with interstitial myocardial fibrosis measured by extracellular volume fraction (ECV) and native T1 mapping at 10-year follow-up in the MESA (Multi-Ethnic Study of Atherosclerosis). Seven hundred seventy-two participants had complete baseline data and underwent cardiac magnetic resonance imaging. All analyses were stratified by sex. Multivariable linear regression models were constructed to assess the associations of baseline CRP (C-reactive protein), IL (interleukin)-6, and fibrinogen with native T1 time and ECV. Longer native T1 times and higher percentages of ECV represent increasing myocardial fibrosis. A 1-SD increment of log-transformed IL-6 levels was associated with 0.4% higher ECV in men (ß=0.4; P=0.05). CRP and fibrinogen were not associated to ECV. A 1-SD increment in the log-transformed CRP levels was associated with 4.9 ms higher native T1 (ß=4.9; P=0.03). In women, the inflammatory markers did not demonstrate association with native T1 nor ECV. Higher IL-6 and CRP levels are associated with increased interstitial myocardial fibrosis assessed by cardiac magnetic resonance in men. However, no inflammatory markers were associated to myocardial fibrosis in women.

Relation between visceral fat and coronary artery disease evaluated by multidetector computed tomography.

Visceral abdominal fat has been associated to cardiovascular risk factors and coronary artery disease (CAD). Computed tomography (CT) coronary angiography is an emerging technology allowing detection of both obstructive and nonobstructive CAD adding information to clinical risk stratification. The aim of this study was to evaluate the association between CAD and adiposity measurements assessed clinically and by CT. We prospectively evaluated 125 consecutive subjects (57% men, age 56.0+/-12 years) referred to perform CT angiography. Clinical and laboratory variables were determined and CT angiography and abdominal CT were performed in a 64-slice scanner. CAD was defined as any plaque calcified or not detected by CT angiography. Visceral and subcutaneous adiposity areas were determined at different intervertebral levels. CT angiography detected CAD in 70 (56%) subjects, and no association was found with usual anthropometric adiposity measurements (waist and hip circumferences and body mass index). Otherwise, CT visceral fat areas (VFA) were significantly related to CAD. VFA T12-L1 values > or =145cm(2) had an odds ratio of 2.85 (95% CI 1.30-6.26) and VFA L4-L5 > or =150cm(2) had a 2.87-fold (95% CI 1.31-6.30) CAD risk. The multivariate analysis determined age and VFA T12-L1 as the only independent variables associated to CAD. Visceral fat assessed by CT is an independent marker of CAD determined by CT angiography.