OBJECTIVES: We sought to define the clinical importance of an integrated classification of bicuspid aortic valve (BAV) phenotypes and aortopathy using multidetector computed tomography (MDCT). BACKGROUND: An association between BAV phenotypes and the pattern of valvular dysfunction or bicuspid aortopathy has yet to be definitely established. METHODS: The study cohort included 167 subjects (116 men, age 54.6 ± 14.4 years) who underwent both MDCT and transthoracic echocardiography from 2003 to 2010. Two BAV phenotypes-fusion of the right and left coronary cusps (BAV-AP) and fusion of the right or left coronary cusp and noncoronary cusp (BAV-RL)-were identified. Forty-five patients showed normal aortic dimensions and were classified as type 0. In the remaining patients, hierarchic cluster analysis showed 3 different types of bicuspid aortopathy according to the pattern of aortic dilation: type 1 (aortic enlargement confined to the sinus of Valsalva [n = 34]), type 2 (aortic enlargement involving the tubular portion of the ascending aorta [n = 49]), and type 3 (aortic enlargement extending to the transverse aortic arch [n = 39]). RESULTS: The prevalence of BAV-AP and BAV-RL was 55.7% and 44.3%, respectively. Comparing BAV-AP and BAV-RL, no differences in age or in the prevalence of male sex were determined. However, significant differences in the valvular dysfunction pattern were noted, with moderate-to-severe aortic stenosis predominating in patients with BAV-RL (66.2% vs. 46.2% in BAV-AP; p = 0.01), and moderate-to-severe aortic regurgitation in BAV-AP (32.3% vs. 6.8% in BAV-RL; p < 0.0001). A normal aorta was the most common phenotype in BAV-AP patients (33.3% vs. 18.9% in BAV-RL; p = 0.037), and type 3 aortopathy was the most common phenotype in BAV-RL patients (40.5% vs. 9.7% in BAV-AP; p < 0.0001). CONCLUSIONS: The patterns of valvular dysfunction and bicuspid aortopathy differed significantly between the 2 BAV phenotypes, suggesting the possibility of etiologically different entities.