1057 Pulmonary artery size and function after Fontan operation at young age: assessment with phase contrast magnetic resonance imaging

Introduction

little is known about the effects of long-term non-pulsatile flow on pulmonary artery (PA) growth after Fontan operation. Furthermore, the effects on flow variables and shear stress have not been studied in a patient group operated on at young age.

Purpose

In this study, we assessed PA size, flow variables, and shear stress long-term after Fontan operation at young age and compared them with healthy controls, using cardiovascular magnetic resonance (CMR) imaging.

Methods

14 patients (9 males, aged 13.1 ± 4.0 years, follow-up after Fontan completion 9.7 (5.4–16.8) years) and 17 healthy controls (9 males, aged 13.3 ± 2.3 years) were included. Flow measurements in the branch PA were made during a CMR study, using phase contrast velocity-encoded imaging. In patients, flow measurements were repeated during low-dose dobutamine stress of 7.5 μg/kg/min. Shear stress was determined according to a previously published method [1].

Results

CMR scanning and dobutamine administration was well tolerated by all subjects without side effects. Results of the flow studies and shear stress determination are summarized in Table 1 (NS = not significant).

Table 1

Conclusion

PA diameter is normal in patients long-term after Fontan operation at young age. However, flow variables, distensibility and shear stress are significantly lower compared to healthy controls, implicating pulmonary endothelial and/or vascular dysfunction.