Aortic Root Dilatation and Aortic Stiffness in Patients With Single Ventricular Circulation

BACKGROUND: This study tested the hypothesis that aortic stiffness is increased more in patients with single ventricular (SiV) circulation and dilated aorta than in those without aortic dilatation, and that aortic stiffness is an independent determinant of aortic dilatation in this type of patient. METHODS AND RESULTS: Pulse wave velocity (PWV) and aortic size were measured during catheterization in 56 consecutive patients with SiV circulation (aortic dilatation, n=31 [observed/expected aortic root diameter >1.5]; without aortic dilatation, n=25). PWV was found to be significantly higher in the dilatation group than in the non-dilatation group (483.6±10.3 vs. 394.0±8.9 cm/s, P<0.001) after controlling for age and aortic pressure, factors known to influence PWV (P<0.001, analysis of covariance). There was a strong positive correlation between aortic root diameter and PWV (P<0.001). Multivariate analysis adding aortic flow (index of aortic volume load) to independent variables in 25 pre-Glenn patients with directly calculated aortic flow volume showed that PWV was an independent determinant of aortic dilatation (P<0.001). CONCLUSIONS: In patients with SiV circulation and dilated aorta, aortic stiffness is increased and is an independent determinant of aortic dilatation. To improve prognosis of Fontan circulation, further studies on whether aortic stiffness modulation reduces the progression of aortic dilatation and resultant aortic regurgitation are warranted.