Left ventricular hypertrophy is considered to be a major cardiovascular risk factor in
hemodialysis patients. Not only
high blood pressure but also humoral factors such as
angiotensin II and
aldosterone are thought to contribute to the increase in left ventricular mass. We examined the effects of an
angiotensin converting enzyme (
ACE) inhibitor,
imidapril, on left ventricular mass in patients with end-stage renal diseases on maintenance
hemodialysis. Thirty patients on chronic
hemodialysis were randomly divided into 2 groups of 15 patients each and given placebo or 2.5 mg
imidapril once daily for 6 months. Before and after the 6-month period, left ventricular mass was evaluated by echocardiography, and circulating factors of the renin-angiotensin-aldosterone system were measured. Background characteristics such as age, gender ratio, causes of
renal failure, duration of
hemodialysis, body mass index and pre-dialysis blood pressure were comparable between the placebo and the
imidapril groups. Systolic and diastolic blood pressures were not significantly changed in either group during the study period. In the
imidapril group, serum ACE was reduced (12 +/- 1 to 5 +/- 2 U/l, p < 0.01) and plasma
renin activity was increased (3.3 +/- 0.8 to 8.1 +/- 3.2 ng/ml/h, p < 0.01), but plasma
angiotensin II and
aldosterone were not significantly changed after 6 months (13 +/- 3 to 17 +/- 3 pg/ml and 365 +/- 125 to 312 +/- 132 pg/ml, respectively). On the other hand, left ventricular mass index was significantly decreased in the
imidapril group (132 +/- 10 to 109 +/- 6 g/m2, p < 0.05) but was unchanged in the placebo group (129 +/- 6 to 126 +/- 5 g/m2). These results suggest that an
ACE inhibitor reduces left ventricular mass in
hemodialysis patients by a mechanism that is independent of changes in blood pressure.