The diuretic indapamide is significantly more effective than the ACE inhibitor
enalapril at reducing left ventricular mass index (LVMI) in hypertensive patients,
according to a European study.
The randomised, controlled LIVE (Left ventricular hypertrophy regression, Indapamide
Versus Enalapril) study was conducted in eight European countries. A total of
411 hypertensive patients with left ventricular hypertrophy (LVH) completed
the trial and received either indapamide SR 1.5mg or enalapril 20mg once daily.
The LIVE study showed that both antihypertensive agents achieved similar reductions
in blood pressure but that indapamide, unlike enalapril, progressively reduced
heart wall thicknesses throughout the one-year treatment period. The effect
of enalapril 20mg observed at six months was not maintained at 12 months, say
the researchers.
The researchers note that the results of the LIVE study differ from previously
published results from meta-analyses but comment that such techniques are prone
to bias.
In a press release issued on October 2, Professor Desmond Sheridan (professor
of cardiology, Imperial College school of medicine, and study co-author) said:
“LVH represents an important form of end organ damage in hypertensive patients
and these patients should be followed to ensure that LVH does not progress to
LV dysfunction and failure.” Professor Sheridan pointed out that, while
there was insufficient evidence to attribute the performance of indapamide to
diuretics as a class effect, he believed that the failure of enalapril to cause
significant LVH regression suggested that factors other than ACE inhibition
might be involved.
Commenting on the trial results, Dr John Pittard (founder member of the Primary
Care Cardiovascular Society) said in the same press release: “This is encouraging
data on a well-established, once-daily diuretic. The ACE inhibitor data is slightly
disappointing. It may reflect the choice of ACE or the dosing; however, enalapril
is quite commonly used on a once a day basis in hypertension, and these results
should give primary care prescribers pause for thought.” The study is published
in the Journal of Hypertension (2000;18:1465).
Another European study has found that, in patients with hypertensive heart disease,
the ACE inhibitor lisinopril regresses myo-
cardial fibrosis, irrespective of LVH regression, and results in improved LV
diastolic function (Circulation 2000;102:1388).
In the study, supported by a Zeneca research grant, 35 patients with primary
hypertension, LVH and LV diastolic dysfunction were treated with either lisinopril
or the thiazide diuretic, hydrochlorothiazide. After six months, a decrease
in myocardial fibrosis, as measured by collagen volume fraction and myocardial
hydroxy-proline concentration (a constituent of collagen), was seen in the lisinopril
group. Patients receiving lisinopril were also found to have improved LV diastolic
function evaluated by the ratio of LV peak flow velocities during early filling
and atrial contraction.