Augmentation index and aortic stiffness in bicuspid aortic valve patients with non-dilated proximal aortas

BACKGROUND: We compared aortic stiffness, aortic impedance and pressure from wave reflections in the setting of bicuspid aortic valve (BAV) to the tricuspid aortic valve (TAV) in the absence of proximal aortic dilation. We hypothesized BAV is associated with abnormal arterial stiffness. METHODS: Ten BAV subjects (47 ± 4 years, 6 male) and 13 TAV subjects (46 ± 4 years, 10 male) without significant aortic valve disease were prospectively recruited. Characteristic impedance (Zc) was derived from echocardiographic images and pulse wave Doppler of the left ventricular outflow tract. Applanation tonometry was performed to obtain pulse wave velocity (PWV) at several sites as measures of arterial stiffness and augmentation index (AIx) as a measure of wave reflection. RESULTS: There were no significant differences between BAV and TAV subjects with regard to heart rate or blood pressure. Zc was similar between BAV and TAV subjects (p=0.25) as was carotid-femoral pulse wave velocity (cf-PWV) and carotid-radial PWV (cr-PWV) between BAV and TAV subjects (p=0.99). Carotid AIx was significantly higher in BAV patients compared with TAV patients (14.3 ± 4.18% versus -3.02 ± 3.96%, p=0.007). CONCLUSIONS: Aortic stiffness and impedance is similar between subjects with BAV and TAV with normal aortic dimensions. The significantly higher carotid AIx in BAV, a proxy of increased pressure from wave reflections, may reflect abnormal vascular function distal to the aorta.