Background : A number of echo-doppler variables have been reported to predict adverse outcomes in patients with aortic stenosis (AS). However conventional parameters such as aortic valve area, peak velocity and mean pressure gradient have been known to have limitation in patients with paradoxical low flow and/or low gradient AS. The aim of this study was to evaluate the prognostic value of valvuloarterial impedance (Zva) in patients with AS. Methods : The clinical and echocardiographic data of 198 patients with AS were retrospectively reviewed. The Zva is calculated by dividing the estimated LV systolic pressure (systolic arterial pressure + mean transvalvular gradient) by the stroke volume indexed for the body surface area. The patients were subdivided into 3 groups according to the level of Zva (low group Zva <4.8, medium group 4.8���Zva<6.3, high group ���6.3 mmHg/ml/m²). Results : Twenty-eight deceased were older (75.6 vs 66.0 yr, p<0.001) and had lower left ventricular ejection fraction (LVEF, 51.3% vs 56.9%, p=0.016) and higher Zva (6.60 vs 5.70 mmHg/ml/m², p= 0.046). The risk of mortality was increased by 7.1-fold in moderate Zva group and by 11.5-fold in high Zva group assessed by Cox proportional hazards model after adjusting for age, systolic blood pressure, LVEF and aortic valve area. Kaplan-Meier event free survival curve stratified into 3 groups according to VAI showed significantly different event rates (p=0.002, Figure). Conclusion : Increased Zva is a useful marker of excessive LV hemodynamic load and poor prognosis. Zva may be useful to improve risk stratification and clinical decision making in patients with AS.