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

BACKGROUND AND PURPOSE: 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.