The mechanism underlying the stiffness of the aorta and iliofemoral artery that is required to maintain blood pressure (BP) is unclear. A new stiffness index of the aorta (aBeta) and iliac-femoral arteries (ifBeta) was defined by applying the cardio-ankle vascular index (CAVI). We compared changes in stiffness of the two arteries in response to reduced BP, due to the non-selective adrenergic blocker phentolamine and the 1 adrenergic blocker atenolol, in rabbits.Methods: Pressure waves at the origin (oA) and distal ends of the aorta (dA) and the distal end of the left femoral artery (fA) were recorded simultaneously using three pressure sensors in 25 anesthetized rabbits. Phentolamine (50 µg/kg/min) and atenolol (10 mg/kg/min) were infused for 2 min. The pulse wave velocity (PWV) in each artery was determined; aBeta, ifBeta, and whole Beta (aifBeta) were calculated by the following formula; Beta 2 /PP ln(SBP/DBP) PWV 2 ( : blood density; SBP, SBP, and PP: systolic, diastolic, and pulse pressures, respectively).Results: SBP and DBP at oA, dA, and fA decreased by the administration of phentolamine and atenolol, with and without decreased total peripheral vascular resistance. After phentramine infusion, cardiac output (CO), aBeta, and aifBeta increased, while ifBeta decreased. After infusion of atenolol, CO decreased, while aBeta, ifBeta, and aifBeta remained unchanged.
Conclusion:The contradictory reactions of aBeta and ifBeta to phentolamine suggest that the stiffness of the aorta and ilio-femoral artery is regulated separately during decreased BP induced by phentolamine, but not by atenolol.phase and sends it to peripheral tissue during the diastolic phase 3) , which plays a role as the afterload of the left ventricle. These functions are fulfilled by arterial stiffness, but there was no suitable arterial stiffness index to evaluate such vascular function, especially for clinical use. Pulse wave velocity (PWV) has been a widely-used index for reflecting arterial stiffness in clinical studies 1,[4][5][6][7] . However, PWV does not properly Copyright©2021 Japan Atherosclerosis Society This article is distributed under the terms of the latest version of CC BY-NC-SA defined by the Creative Commons Attribution License.