Cardiovascular Journal of Africa: Vol 31 No 3 (May/June 2020)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 31, No 3, May/June 2020 132 AFRICA
measurement was > 2.0 and > 14.0 pmol/l, respectively. The
angiotensin-based biomarkers AA2 ratio (aldosterone/eq Ang
II), PRA-S (eq Ang I + eq Ang II) and ACE-S (eq Ang II/eq
Ang I) were calculated from molar concentrations of respective
analytes.
Adrenocorticotrophic hormone (ACTH) was analysed with
electro-chemiluminescence immunoassay (ECLIA), e411 (Roche,
Basel, Switzerland). Inter- and intra-batch variability were 5.4 and
2.9%, respectively. Serum cortisol was analysed using an electro-
chemiluminescence immunoassay on the Elecsys 2010 apparatus
(Roche, Basel, Switzerland). Both the intra- and inter-assay
coefficients of variation for all the assays were less than 10%.
Serum and urinary sodium and potassium concentrations
were determined making use of the Konelab TM 20i sequential
multiple analyser computer (SMAC) (ThermoScientific, Vantaa,
Finland). Gamma-glutamyltransferase (GGT), cotinine and
high-sensitivity C-reactive protein (CRP) were analysed using
the sequential multiple analyser (Konelab 20i; Thermo Scientific,
Vantaa, Finland; Unicel DXC 800 – Beckman and Coulter®,
Germany). The intra- and inter-coefficients of variation for all
assays were below 10%.
The urinary creatinine from an eight-hour overnight fasting
urine sample was determined with a calorimetric method.
Albumin was determined with the turbidimetric method on a
Table 1. Characteristics of the black men with low and high serum aldosterone levels
Variables
Normotensive
(n = 7)
Hypertensive, aldosterone
≤ 133.2 pmol/l (n = 12)
Hypertensive, aldosterone
> 133.2 pmol/l (n = 15) p-valuea
Age (years) 45.0 (45.0–54.0) 50.0 (45.0–53.0) 47.0 (45.0–50.0) 0.373
BMI (kg/m2) 25.4 (23.5–27.3) 28.8 (23.3–34.4) 28.1 (24.8–30.4) 0.792
Cardiovascular variables
SBP (mmHg) 132.0 (120.0–138.0) 150.0 (140.0–156.5) 155.0 (130.0–180.0) 0.829
DBP (mmHg) 82.0 (80.0–88.0) 100.0 (95.0–106.5 110.0 (85.0–120.0) 0.548
SV (ml) 92.7 (87.0–142.1) 85.8 (75.8–105.4) 105.9 (83.8–113.5) 0.373
TPR (mmHg/ml/s) 0.96 (0.75–1.02) 1.12 (1.02–1.30) 0.97 (0.88–1.48) 0.516
Cwk (ml/mmHg) 1.81 (1.65–2.02) 1.59 (1.33–1.81) 1.84 (1.22–2.02) 0.399
c-pPWV (m/s) 10.2 (8.7–10.3) 9.6(9.4–11.6) 10.5 (9.5–11.0) 0.860
Biochemical variables
eq Ang I (pmol/l) 10.9 (3.1–23.3) 14.7 (3.5–21.4) 7.6 (3.1–33.4) 0.755
eq Ang II (pmol/l) 33.2 (12.7–58.4) 44.0 (19.0–76.9) 25.7 (10.3–55.2) 0.277
ACE-S (eq AngII/eq AngI) (pmol/l) 2.8 (2.1–4.7) 3.5 (2.4–5.4) 2.30 (0.5–4.9) 0.183
PRA-S (Ang I + Ang II) (pmol/l) 48.8 (15.8–81.7) 53.1 (25.3–102.6) 34.9 (13.4–83.7) 0.373
Aldosterone (pmol/l) 88.4 (71.7–146.0) 101.8 (88.0–126.5) 253.3 (163.9–341.2) < 0.001
AA2 ratio 2.7 (1.8–10.5) 3.0 (1.2–6.3) 10.2 (4.4–47.6) 0.003
Aldosterone/PRA-S 1.8 (1.3–7.0) 2.3 (0.9–4.4) 5.8 (3.1–22.0) 0.010
sACTH (pg/ml) 11.9 (9.3–33.6) 17.6 (11.8–29.4) 18.4 (12.4–25.9) 0.981
sCortisol (nmol/l 405.2 (255.2–438.0 371.3 (307.1–471.5) 347.3 (276.7–487.6) 0.943
Serum Na+ (mmol/l) 150.4 (127.3–173.5) 145.7 (125.9–177.2) 126.7 (124.4–132.6) 0.183
Serum K+ (mmol/l) 5.0 (4.4–5.2) 4.5 (4.0–5.7) 3.9 (3.6–4.4) 0.016
Serum Na+–K+ ratio 31.9 (29.4–32.8) 31.8 (29.2–33.0) 34.8 (31.5–35.5) 0.032
Urinary Na+ (mmol/l) 91.0 (62.0–112.0) 90.0 (66.0–139.0) 86.0 (44.0–107.0) 0.474
Urinary K+ (mmol/l) 14.0 (8.0–21.0) 18.0 (12.5–22.5) 14.0 (13.0–24.1) 0.867
Urinary Na+–K+ ratio 6.5 (5.3–7.8) 6.1 (4.6–7.6) 6.0 (2.5–6.6) 0.470
CRP (mg/l) 3.5 (2.9–4.9) 3.1 (1.7–5.2) 3.3 (2.1–9.3) 0.456
End-organ variables
Cornell product (> 244 mV/ms) 51.6 (30.2–80.6) 49.9 (40.0–111.9) 93.5 (59.2–141.1) 0.134
Silent 24-h ST events (n) 0.0 (0.0–3.0) 12.0 (0.0–25.0) 1.0 (0.0–7.0) 0.507
Est creatinine clearance 111.4 (102.8–127.9) 112.4 (97.3–139.3) 134.7 (113.2–154.1) 0.126
ACR 0.95 (0.72–1.87) 0.99 (0.62–2.77) 1.19 (0.78–1.84) 0.574
Lifestyle variables
Cotinine (ng/ml) 0.01 (0.01–30.00) 8.51 (0.01–28.01) 0.01 (0.01–61.01) 0.683
GGT (U/l) 53.9 (44.4–130.1) 77.0 (40.5–111.3) 57.4 (42.0–76.3) 0.548
TEE (kcal/day) 2339.9 (2228.7–2559.3) 2119.6 (1818.2–3198.2) 2627.2 (2436.5–3845.1) 0.126
Medication use, n (%)
SNS blocker – 0 (0) 1 (6.7) –
ACE inhibitor – 0 (0) 5 (33.3) –
Thiazide – 2 (16.7) 2 (13.3) –
Calcium antagonist – 0 (0) 6 (40) –
Beta-blocker – 0 (0) 2 (13.3) –
Data presented as median (lower; upper quartile). a2 × 1-sided exact p-value between high- and low-aldosterone hypertensives.
BMI: body mass index (kg/m2); SBP, DBP: systolic and diastolic blood pressure (mmHg), respectively; SV: stroke volume (ml); TPR: total peripheral resistance
(mmHg/s/ml); Cwk: Windkessel compliance (ml/mmHg); c-pPWV: carotid-pedalis pulse-wave velocity (m/s); eq Ang I and eq Ang II: angiotensin I and angiotensin II
(pmol/l); ACE-S: angiotensin-based ACE activity (eq AngII/eq AngI, pmol/l); PRA-S: angiotensin-based renin activity (eq Ang I + eq Ang II, pmol/l); AA2 ratio: aldo-
sterone–angiotensin II ratio; sACTH: serum adrenocorticotrophic hormone (pg/ml); CRP: C-reactive protein (mg/l); ACR: albumin–creatinine ratio; GGT: gamma-
glutamyltransferase (U/L); TEE: total energy expenditure (kcal/day); CNS blocker: central nervous system blocker; ACE inhibitor: angiotensin converting enzyme
inhibitor.