The effects of angiotensin II on pulse wave velocity in healthy humans

To examine the dose response relationship between Ang II and pulse wave velocity (an index of arterial stiffness) in healthy human volunteers.

We studied 9 healthy male volunteers (mean age 24.7 +/- 0.66 years) in a double-blind, randomized, cross-over, placebo-controlled design. We measured carotid-femoral PWV using a novel device complior. Subjects received placebo, 0.5, 1 and 5 ng/kg/min Ang II as infusions over 30 minutes under standardized conditions. Heart rate, blood pressure and PWV were recorded at baseline and then every 10 minutes during the infusion and twice after the end of the infusion.

Systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) in mmHg increased significantly with the 5 ng/kg/min dose compared to placebo (p = 0.004, p -0.007, p = 0.003, respectively). There was no significant difference in SBP, DBP and MAP between 1 and 0.5 ng/kg/min compared to placebo. There was a significant increase in PWV with 5 ng/kg/min dose only compared to placebo (p = 0.02). However, less than 30% of the total Ang II-induced rise in PWV was explained by the Ang II-induced rise in blood pressure (R2 = 0.257).

Ang II increases PWV in healthy human only when given in doses that significantly increase blood pressure. Not all the increase in Ang II-induced rise in PWV can be explained due to Ang II-induced rise in BP.