Fig. 1The flow diagram of the study subjects. All patients underwent both saline infusion test (SIT) and captopril challenge test (CCT). If positive result of SIT and CCT, adrenal venous sampling was conducted for distinguishing aldosterone producing adenoma (APA) and idiopathic hyperaldosteronism (IHA). ARR, aldosterone-to-renin ratio; PA, primary aldosteronism; EH, essential hypertension.
Fig. 2Receiver operating characteristic curve analysis for aldosterone-to-renin ratio (ARR), ARR post-captopril challenge test (CCT), and plasma aldosterone concentration (PAC) post-CCT for the diagnosis of primary aldosteronism. PAC post-CCT showed very accruable with large area under the curve (AUC). The black line represents the results equivalent to chance.
Fig. 3Plasma aldosterone concentration (PAC) post-captopril challenge test (CCT) at 90 minutes in patients with essential hypertension (EH) and primary aldosteronism (PA).
Table 1Clinical and Biochemical Characteristics of Study Subjects with Essential Hypertension or Primary Aldosteronism
Variable |
EH (n=13) |
APA (n=36) |
IHA (n=15) |
P value |
Age, yr |
56.3±12.3 |
48.8±10.1 |
51.2±10.0 |
0.096 |
Male |
4 (30.8) |
14 (38.9) |
9 (60.0) |
0.246 |
Body mass index, kg/m2
|
25.4±3.5 |
24.4±3.5 |
27.3±4.6 |
0.048 |
Hypertension |
10 (76.9) |
36 (100.0) |
14 (93.3) |
0.013 |
Diabetes |
5 (38.5) |
2 (5.6) |
2 (13.3) |
0.014 |
Duration of hypertension, yr |
4.6±4.7 |
5.2±4.8 |
7.4±7.5 |
0.332 |
No. of antihypertensive drugs |
1.08±0.64 |
1.72±0.88 |
1.87±1.00 |
0.040 |
SBP, mm Hg |
136±17.2 |
145±17.1 |
141.0±14.8 |
0.217 |
DBP, mm Hg |
83.6±14.1 |
91.3±14.4 |
91.7±11.3 |
0.192 |
PRA, ng/mL/hr |
0.44±0.41 |
0.31±0.41 |
0.24±0.19 |
0.326 |
PAC, ng/dL |
22.1±6.1 |
423±39.1 |
29.3±14.2 |
0.094 |
ARR, (ng/dL)/(ng/mL/hr) |
99.2±74.1 |
258±194 |
186.9±128.8 |
0.013 |
Serum potassium, mmol/L |
4.1±0.6 |
3.2±0.6 |
3.7±0.6 |
<0.001 |
Serum creatinine, mg/dL |
0.86±0.26 |
0.85±0.24 |
0.95±0.28 |
0.463 |
Estimated GFR, mL/min/1.73 m2
|
84.6±24.7 |
87.0±23.1 |
80.5±26.7 |
0.693 |
PAC post-SIT, ng/dL |
4.8±2.9 |
34.4±25.9 |
17.8±9.2 |
<0.001 |
ARR post-SIT, (ng/dL)/(ng/mL/hr) |
39.5±32.9 |
247±148 |
122.8±93.4 |
<0.001 |
PAC post-CCT at 60 min, ng/dL |
12.2±5.5 |
41.6±34.3 |
24.9±11.8 |
0.003 |
ARR post-CCT at 60 min, (ng/dL)/(ng/mL/hr) |
66.4±59.3 |
330±365 |
128.2±103.5 |
0.007 |
PAC post-CCT at 90 min, ng/dL |
9.9±4.5 |
41.1±31.7 |
23.3±10.6 |
0.001 |
ARR post-CCT at 90 min, (ng/dL)/(ng/mL/hr) |
54.6±48.5 |
322±314 |
141.7±147.8 |
0.003 |
PAC post-CCT, ng/dLa
|
9.8±4.4 |
37.6±28.1 |
22.3±9.9 |
0.001 |
ARR post-CCT, (ng/dL)/(ng/mL/hr)a
|
53.3±47.8 |
275±293 |
105.3±96.1 |
0.005 |
Table 2Comparison of Diagnostic Performance among Different Cut-off Values of PAC Post-Captopril Challenge Test
Cut-off value of PAC |
Sensitivity, % |
Sensitivity, % |
LR (+) |
LR (-) |
Odds ratio |
Combined, ng/dL |
|
|
|
|
|
8 |
100 |
46.2 |
1.86 |
0.00 |
- |
12 |
98 |
71.4 |
3.43 |
0.028 |
123 |
13 |
98 |
78.6 |
4.57 |
0.026 |
180 |
19 |
72 |
100 |
- |
0.28 |
- |
At 60 minutes, ng/dL |
|
|
|
|
|
9 |
100 |
46.2 |
1.86 |
0.00 |
- |
12 |
98 |
57.1 |
2.29 |
0.035 |
65.3 |
13 |
98 |
64.3 |
2.74 |
0.031 |
88.2 |
19 |
84 |
85.7 |
5.88 |
0.187 |
31.5 |
23 |
65 |
100 |
- |
0.350 |
- |
At 90 minutes, ng/dL |
|
|
|
|
|
8 |
100 |
46.2 |
1.86 |
0.00 |
- |
12 |
98 |
71.4 |
3.43 |
0.028 |
123 |
13 |
98 |
78.6 |
4.57 |
0.026 |
180 |
19 |
72 |
100 |
- |
0.28 |
- |