BACKGROUND The prognostic value of aortic valve calcification (AVC) measured by using multidetector computed tomography imaging has been well validated in native aortic stenosis, and sex-specific thresholds have been proposed. However, few data are available regarding the impact of leaflet calcification on outcomes after biological aortic valve replacement (AVR). OBJECTIVES The goal of this study was to analyze the association of quantitative bioprosthetic leaflet AVC with hemodynamic and clinical outcomes, as well as its possible interaction with sex. METHODS From 2008 to 2010, a total of 204 patients were prospectively enrolled with a median of 7.0 years (interquartile range: 5.1 to 9.2 years) after biological surgical AVR. AVC measured by using the Agatston method was indexed to the cross-sectional area of aortic annulus measured by echocardiography to calculate the AVC density (AVCd). Presence of hemodynamic valve deterioration (HVD; increase in mean gradient [MG] >= 10 mm Hg and/or increase in transprosthetic regurgitation >= 1) was assessed by echocardiography in 137 patients at the 3-year follow-up. The primary clinical endpoint was mortality or aortic valve re-intervention. RESULTS There was no significant sex-related difference in the relationship between bioprosthetic AVCd and the progression of MG. Baseline AVCd showed an independent association with HVD at 3 years. During follow-up, there were 134 (65.7%) deaths (n = 100) or valve re-interventions (n = 47). AVCd >= 58 AU/cm(2) was independently associated with an increased risk of mortality or aortic valve re-intervention (adjusted hazard ratio: 2.23; 95% confidence interval: 1.44 to 3.35; p < 0.001). The AVCd threshold combined with an MG progression threshold of 10 mm Hg amplified the stratification of patients at risk (log-rank, p < 0.001). The addition of AVCd threshold into the prediction model including traditional risk factors improved outcome prediction (net classification improvement: 0.25, p = 0.04; likelihood ratio test, p < 0.001). CONCLUSIONS Aortic bioprosthetic leaflet calcification is strongly and independently associated with HVD and the risk of death or aortic valve re-intervention. As opposed to native aortic stenosis, there is no sex-related differences in the relationship between AVCd and hemodynamic or clinical outcomes. (C) 2020 by the American College of Cardiology Foundation.