Pego M, Maldonado J, Demas P, Providencia LA
Renin and aldosterone measurements after captopril and supine
position in differential diagnosis of adenoma and hyperplasia in
primary aldosteronism
11th Scientific Meeting, American Society of Hypertension
Am J Hypert
(Apr) 9:91A 1996
The objective was to determine the changes in plasma renin activity (PRA)
and
aldosterone concentration (PAC) after captopril stimulation and the supine
test
in primary hyperaldosteronism.
Seventy-five patients with radiographically and histological confirmed
primary
hyperaldosteronism (54-adenoma; 21-hyperplasia) were compared with 50
normotensive subjects and 50 essential hypertensive patients. Medications
were
discontinued 2 weeks before the evaluation and subjects ingested a normal
sodium
diet. Blood samples were taken from patients submitted to captopril
stimulation
and the supine test. PRA and PAC were measured by radioimmunoassay.
PRA pre-captopril was higher in essential hypertension than in
primary hyperaldosteronism. PRA levels were lower in the adenoma than in
the
hyperplasia subgroup. Post-captopril stimulation, the primary
hyperaldosteronism group exhibited the most blunted renin secretory response
(Adenoma: 0.4 +/- 0.3 vs 0.6 +/- 0.4 ng/ml/h); Hyperplasia: 0.7 +/- 0.5 vs
1.0 +/-
0.4) in comparison with normotensive (2.6 +/- 0.2 vs 3.7 +/- 0.3 ng/ml/h)
and
essential hypertensive patients (3.9 +/- 0.5 vs 4.6 +/- 0.7 ng/ml/h). Blood
pressure also declined the least in primary hyperaldosteronism patients.
After
captopril stimulation the primary hyperaldosteronism group also exhibited
the
most blunted aldosterone secretory response (Adenoma: 475 +/- 129 vs 462 +/-
92
pg/ml/h; Hyperplasia: 295 +/- 93 vs 282 +/- 103) in comparison with
normotensive
(80.2 +/- 10.1 vs 83.0 +/- 12.0) and essential hypertensive patients (93.0 +/
- 5.9
vs 102 +/- 9.4). After the supine position test there was a decrease of PAC
levels in adenoma (475 +/- 129 vs 455 +/- 110 pg/ml/h) and a 71% increase in
the
hyperplasia (295 +/- 92 vs 506 +/- 115 pg/ml/h).
Captopril stimulation and the supine position test are important
in the diagnosis of primary aldosteronism. A blunted renin secretory
response
to captopril stimulation and a decrease in aldosterone level after supine
test
are suggestive of adenoma. A blunted renin secretory response to captopril
stimulation and a increase in aldosterone levels to supine test are
suggestive of hyperplasia.
Comment:
These data appear to confirm the known effect of posture on PAC in
adenoma vs. hyperplasia (PAC declines with upright position in adenoma but
increases in hyperplasia). The effects of captopril on PRA in both forms of
hyperaldosteronism are minimal.
(David J. Leehey, M.D., Loyola University at Chicago)
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11th Scientific Meeting, American Society of Hypertension
H: Special problems :
Endocrine hypertension