Aortic elastic properties and left ventricular diastolic function in patients with isolated bicuspid aortic valve

Bicuspid aortic valve (BAV) is one of the most common congenital heart defects. BAV disease is not only a disorder of valvulogenesis, but also represents a genetic disorder of aorta and cardiac development. Recent studies have shown that BAV is associated with abnormal aortic elasticity, and that a reduced distensibility of the aortic root may have a negative impact on left ventricular function. Hence, the study aim was to investigate left ventricular diastolic function and its relationship to aortic elasticity in this patient group.

Thirty-nine patients with isolated BAV with a normal left ventricular ejection fraction, and 29 age- and gender-matched healthy (control) subjects, were studied prospectively. In none of the patients with BAV was the aortic velocity >2m/s, and no aortic regurgitation (other than mild) was present. Parameters of aortic elasticity (aortic strain, distensibility index, stiffness index and elastic modulus), left ventricular diastolic parameters (E, A, E/a, deceleration time, E', ratio of E/E', left atrial volume index) and valvulo-arterial impedance were calculated in all patients.

Aortic strain and distensibility were lower, and aortic stiffness index and aortic modulus higher, in patients with BAV than in controls. Compared to controls, the E/E' ratio and left atrial volume index were significantly higher in BAV patients (E/E' ratio 8.26 +/- 2.56 versus 6.85 +/- 1.45, p = 0.01; left atrium volume index 24.23 +/- 5.78 versus 21.68 +/- 4.11 ml/m2, p = 0.04). However, no significant correlations were identified between the aortic elasticity parameters, valvulo-arterial impedance, and left ventricular diastolic parameters.

These findings indicated that BAV is associated with an increased left atrial volume and a decreased E/E' ratio. In addition, these parameters did not correlate with any parameters of aortic elasticity, nor valvulo-arterial impedance. These data suggest that BAV disease might have subclinical cardiac dysfunction, and further studies are required to confirm these findings and any causal relationship.