Irbesartan reduces common carotid artery intima-media thickness in hypertensive patients when compared with atenolol: the Swedish Irbesartan Left Ventricular Hypertrophy Investigation versus Atenolol (SILVHIA) study.
OBJECTIVE
Angiotensin II promotes cell growth and has been implicated in the development and maintenance of left ventricular (LV) hypertrophy and of structural vascular changes. We wished to examine whether an angiotensin receptor blocker (ARB) would influence structural vascular changes beyond the effects of blood pressure reduction.


METHODS
Hypertensive patients with LV hypertrophy (age 55 +/- 9 years, blood pressure 162 +/- 19/104 +/- 8 mmHg, LV mass index 148 +/- 31 g m(-2); mean +/- SD) were randomized double-blind to the ARB irbesartan (n=52) or the beta(1) receptor blocker atenolol (n=56) for 48 weeks. Ultrasonography of the left and right common carotid artery (CCA) and echocardiography were performed at week 0 and 48.


RESULTS
With similar reductions in blood pressure, CCA intima-media thickness (IMT) was reduced by irbesartan (from 0.92 +/- 0.14 by 0.01 +/- 0.10 mm, NS), whereas it was increased by atenolol (from 0.94 +/- 0.21 by 0.03 +/- 0.12 mm, P=0.018; P=0.002 between groups). CCA lumen diameter was less reduced by irbesartan than by atenolol. Thus, CCA intima-media area was reduced by irbesartan (from 21.3 +/- 5.0 by 0.90 +/- 2.45 mm(2), P=0.034) but not by atenolol (from 21.3 +/- 6.1 by 0.18 +/- 2.71 mm(2), NS; P=0.037 between groups). Changes in CCA IMT or area did not relate to changes in LV mass.


CONCLUSIONS
The favourable effects by irbesartan on CCA IMT with an outward vascular remodelling suggest that angiotensin II mediates structural vascular changes, beyond the effects of blood pressure. This may be important in the prevention of cerebrovascular events.
Mörtsell
D
D
Division of Cardiology, Department of Clinical Sciences, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden. davmor@ki.se
Malmqvist
K
K
Held
C
C
Kahan
T
T
D000328:Adult; D000368:Aged; D047228:Angiotensin II Type 1 Receptor Blockers / Q000009:adverse effects / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001262:Atenolol / Q000009:adverse effects / Q000627:therapeutic use*; D001713:Biphenyl Compounds / Q000009:adverse effects / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D017536:Carotid Artery, Common / Q000187:drug effects* / Q000473:pathology; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000473:pathology; D017379:Hypertrophy, Left Ventricular / Q000188:drug therapy / Q000473:pathology; D000077405:Irbesartan; D008297:Male; D008875:Middle Aged; D013777:Tetrazoles / Q000009:adverse effects / Q000627:therapeutic use*; D016896:Treatment Outcome; D017539:Tunica Intima / Q000187:drug effects / Q000473:pathology
D047228:Angiotensin II Type 1 Receptor Blockers; D000959:Antihypertensive Agents; D001713:Biphenyl Compounds; D013777:Tetrazoles; D001262:Atenolol; D000077405:Irbesartan