gms | German Medical Science

Background: In the LIFE trial treatment with an angiotensin receptor blocker (ARB) lead to greater reduction of cardiovascular mortality than betablocker treatment, even though brachial blood pressure was reduced similarly. We hypothesized as a pathogenetic mechanism that vascular stiffness and aortic blood pressure may be affected differently by ARBs and betablockers.

Methods: In the Cardiovascular Irbesartan Project subjects with essential hypertension were treated for 18 months with either irbesartan or atenolol. In 156 subjects aortic augmentation index (AI) and aortic blood pressure were determined by pulse wave analysis (SphygmocorÔ) at both the radial and carotid artery after 6 and 18 months of treatment.

Results: AI was reduced by irbesartan but not by atenolol (DAI derived from the carotid artery: -12.3±22.0 vs +6.0±23.0%; p<0.001 after 6 months and -8.7±24.1 vs +0.9±24.2% after 18 months; p=0.051). Aortic and brachial systolic blood pressure were reduced similarly by irbesartan (-12±17 vs -12±18 after 6 months and -13±19 vs -14±21 mmHg after 18 months; both n.s.) whereas atenolol lead to smaller reductions of aortic than brachial blood pressure (-9±17 vs -13±18 after 6 months and -11±18 vs -14±18 mmHg after 18 months, both p<0.001).

Conclusions: Vascular stiffness was reduced only with irbesartan. Furthermore, irbesartan reduced aortic and brachial blood pressure similarly, whereas atenolol reduced aortic blood pressure less than brachial blood pressure. These differences in central hemodynamics may contribute to the superior effect of ARBs compared to betablockers on cardiovascular mortality, despite similar brachial blood pressure reductions.