Gkw. Schwietzer et al., CHRONIC ANGIOTENSIN-CONVERTING ENZYME-INHIBITION MAY IMPROVE SODIUM-EXCRETION IN CARDIAC TRANSPLANT HYPERTENSION, Transplantation, 59(7), 1995, pp. 999-1004
Cyclosporine-associated hypertension (CAH) may be mediated in part by
sodium and volume retention, To investigate this issue, we studied the
effects of a calcium antagonist, nitrendipine (NIT, 10-20 mg b.i.d.),
and a converting enzyme inhibitor, lisinopril (LIS, 10-20 mg o.d.), o
n blood pressure (office BP, 24 hr ambulatory BP), excretion of an acu
te sodium load (200 mmol/2 hr i.v.), glomerular filtration rate (inuli
n clearance), cumulative dopamine excretion, plasma atrial natriuretic
peptide (ANP), and endothelin excretion in 8 patients with CAH after
cardiac transplantation in a double-blind, randomized, crossover trial
for 6 weeks. Five patients received a diuretic during the trial at a
constant dose. Office diastolic BP (DBP) decreased significantly with
LIS from 97+/-6 to 87+/- 9 mmHg and with MT from 96+/-7 to 92+/-12 mmH
g. Ambulatory 24 hr DBP decreased significantly from 96+/- 7 mmHg to 8
6+/-10 mmHg (LIS) and to 84+/-11 mmHg (NIT). Ambulatory DBP during the
day was lowered significantly from 98+/-11 mmHg to 87+/-10 mmHg (LIS)
and to 88+/-9 mmHg (MT) and during the night from 95+/-9 mmHg to 86+/
-8 mmHg (LIS) and to 79+/-7 mmHg (NIT). Cumulative sodium excretion 6
hr after an acute sodium load increased to 52+/-39 mmol (placebo), 96/-44 mmol (LIS, P<0.05 vs. placebo), and 71+/-34 mmol (NIT). Glomerula
r filtration rate, cumulative dopamine excretion, ANP, and endothelin
excretion did not differ between either treatment group. We conclude,
that: (1) both drugs were similar in lowering office BP and during the
day, but NIT tended to be more effective during the night; and (2) cu
mulative sodium excretion during LIS was significantly increased compa
red with placebo. There was a similar trend during NIT also. Therefore
, it is possible that chronic angiotensin-converting enzyme inhibition
and possibly calcium antagonists might improve the sodium-retaining s
tate in CAH independent of differences in blood pressure, ANP, dopamin
e, or renal function.