Purpose Valvuloarterial impedance (ZVA), estimating left ventricle (LV) afterload, has been proposed in transthoracic echocardiography (TTE) as a predictor of mortality in aortic valve stenosis (AVS). However, its calculation differs from arterial characteristic impedance (ZC). Our aim was to apply the concept of ZC calculation to estimate ZVA from MR with carotid tonometry and to evaluate these indices through their associations with symptoms, LV diastolic function and aortic stiffness. Materials and Methods In 40 patients with AVS (76 ± 13 years), ZVA-TI derived from velocity time integral and E/Ea were estimated by TTE. ZVA-INS, based on ZC formula, calculated as the instantaneous pressure gradient to peak flow ratio and aortic compliance were estimated by using MRI at 1.5 Tesla. Results Both ZVA estimates were higher in symptomatic than asymptomatic patients (707 ± 22 versus 579 ± 53 dyne.s/cm5, P = 0.031 for ZVA-INS and 4.35 ± 0.16 versus 3.33 ± 0.38 mmHg.m2/mL, P = 0.018 for ZVA-TI). Although they were both associated with aortic compliance (r = -0.45; P = 0.006 for ZVA-INS and r = -0.43; P = 0.008 for ZVA-TI) only ZVA-INS was associated with E/Ea (r = 0.50; P
