Cardiovascular interactions of renin angiotensin aldosterone system assessed by cardiac magnetic resonance: The Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

The effects of the Renin Angiotensin Aldosterone System in cardiovascular system has been described based on small studies. The aim of this study was to evaluate the relationship between aldosterone and plasma renin activity and cardiovascular structure and function.

METHODS

We studied a random sample of Multi-Ethnic Study of Atherosclerosis participants who had aldosterone and plasma renin activity 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/m 2 higher left ventricle mass index (p=0.04) and 0.11 ml/m 2 higher left atrium minimal volume index (p < 0.01). Additionally, higher log-transformed aldosterone was associated with lower left atrium maximum strain and left atrium emptying fraction (βstandardized = -0.12, p < 0.01 and - 0.15, p < 0.01, respectively). Aldosterone levels were not significantly associated with aortic measures. Log-transformed plasma renin activity was associated with lower left ventricle end diastolic volume index (βstandardized = 0.08, p=0.05). Plasma renin activity levels were not significantly associated with left atrium and aortic structural or functional differences.

CONCLUSIONS

Higher levels of aldosterone and plasma renin activity are associated with concentric left ventricle remodeling changes. Moreover, aldosterone was related to deleterious left atrium remodeling changes.

RAS Genetic Variants in Interaction with ACE Inhibitors Drugs Influences Essential Hypertension Control

BACKGROUNDS AND AIMS

Essential Hypertension (EH) is a common disorder associated with increased cardiovascular morbidity and mortality in Malaysia. To investigate how genetic polymorphisms of the renin-angiotensin-aldosterone system (RAS) influence EH control with angiotensin-converting enzyme inhibitor drugs (ACEI).

METHODS

A case-control, cross-sectional population-based nested study (n = 142) included hypertensive subjects treated with ACEI drugs, either lisinopril or enalapril (20 mg, once daily) as monotherapy for 24 weeks. In total seven possible polymorphisms of RAS genes were genotyped. The association between those polymorphisms and the changes in blood pressure were observed in the 24 week treatment.

RESULTS

Statistically significant associations of I, G, T, M and G alleles of ACE (I/D, G2350A), AGT (M235T, T175M and G-6A) respectively were observed in essential hypertensive subjects. The decrease in systolic blood pressure and diastolic blood pressure after 24 weeks of treatment of the patients carrying II, GG, and TT genotypes were greater than the groups carrying DD, AA, MM, MM and GG of I/D, G2350A, M235T, T174M and G-6A genotypes respectively. In contrast, No significant difference was observed between renin gene polymorphisms (Bg/I and MboI) and hypertensives.

CONCLUSIONS

Although this study shows a possible association of polymorphisms of RAS genes with the risk of non-control of HT in ACEI-treated patients and indicates the importance of all this system's components in regulating HT, it needs to be replicated in other data sources.