Abstract
Purpose
To assess pulmonary artery (PA) size, flow variables, and wall shear stress (WSS) in patients after Fontan operation at a young age.
Materials and Methods
Flow in the branch PA was obtained with phase contrast velocity‐encoded cardiovascular magnetic resonance imaging in 14 patients before and after low‐dose dobutamine stress (7.5 μg/kg/min) and in 17 healthy controls at rest.
Results
At rest, stroke index, total flow, average, and peak flow rate were all statistically significantly lower in patients than in controls (P < 0.001). With stress‐testing, all variables increased in patients (P < 0.001), apart from stroke index, which did not change. At rest, branch PA area did not differ between patients and controls. Distensibility was lower in patients than in controls (P < 0.001). With stress‐testing, area and distensibility did not change. At rest, WSS was lower in patients than in controls (P < 0.001). WSS increased with stress‐testing (P < 0.001), but not to the same levels as during resting conditions of the control group.
Conclusion
PA size is normal long‐term after Fontan operation at a young age. Flow variables, distensibility, and WSS are significantly lower compared to healthy controls, and do not show adequate reactions with stress‐testing, which is suggestive of pulmonary artery endothelial and/or vascular dysfunction. J. Magn. Reson. Imaging 2008;28:1101–1107. © 2008 Wiley‐Liss, Inc.