Relation of the renin–angiotensin–aldosterone system with potential cardiac injury and remodelling: the SABPA study

Purpose: The renin-angiotensin-aldosterone system (RAAS) plays an important role in maintaining hemodynamic homeostasis. Ethnic disparities exist regarding RAAS activity due to sympathetic activity and sodium-water retention, however the implications thereof on cardiac damage is unknown. This study investigated the associations of cardiac troponin T (cTnT), N-terminal pro-brain natriuretic peptide (NTproBNP) and subclinical LVH with components of the RAAS (renin, aldosterone and aldosterone-to-renin ratio (ARR)) and copeptin in a black and white South African cohort.Materials and methods: The study population consisted of 305 participants (black = 139, white = 166) aged 20–62 years. Serum cTnT, NTproBNP, Cornell product, components of the RAAS (active renin, aldosterone and ARR) and copeptin were determined.Results: The black group had lower renin (p < 0.001) and higher ARR (p < 0.001), cTnT (p = 0.015) and Cornell product compared to whites (all p < 0.001). NTproBNP and copeptin were similar between the groups. After forward stepwise adjustments for multiple confounders, inverse associations of cTnT with renin (β = −0.17, p = 0.018) and aldosterone (β = −0.14, p = 0.048) as well as an inverse association between NTproBNP and aldosterone (β = −0.25, p < 0.001) were observed in the white population only. In the black group cTnT associated positively with renin (β = 0.16, p = 0.040) and copeptin (β = 0.21, p = 0.020) and inversely with ARR (β = −0.15, p = 0.047). Additionally, NTproBNP associated positively with copeptin (β = 0.18, p = 0.045). No correlations were observed between the RAAS and Cornell product in any of the groups.Conclusions: Our findings suggest that RAAS, together with cardiac stress may function differently in cardiac damage and remodelling in the two ethnic groups; which may influence treatment in clinical practice.