Four dimensional pulmonary flow evaluation in adolescent patients after surgical and percutaneous pulmonary valve implantation
Journal of Cardiovascular Magnetic Resonance volume 16, Article number: O45 (2014)
In patients with congenital heart defects, restoration of the connection between the right ventricle (RV) and the pulmonary artery (PA) by surgical or percutaneous valved conduit implantation is a common procedure. Flow characteristics in such conduits are complex, therefore the aim of this study was demonstrating the potential application of 4D MRI flow for the comprehensive assessment of pulmonary flow patterns after surgical and percutaneous RV-PA valved conduit implantation.
Fifteen patients after surgical RV-PA valved conduit implantation (15.8 ± 1.7 years), 15 patients after percutaneous implantation (17.2 ± 2.0 years), and 15 healthy volunteers (as a control group) (16.5 ± 1.5 years) were included. All subjects underwent a comprehensive cardiac MRI protocol. Analysis focused on evaluation of the RV systolic function and RV mass, the presence of vertical flow patterns, pulmonary flow eccentricity pulmonary artery diameters, and wall shear rate (WSR) assessment. (Figure 1)
Patients after surgical and percutaneous pulmonary valve implantation showed hypertrophied RV with a good systolic function. Patients with percutaneous implantation showed an eccentric pulmonary flow (deviation angle from the midline 31 ± 10 degree) with vortex appearance (vortex size 73 ± 18%), dilatation of mid RV-PA conduit and a significant asymmetric elevated WSR at focal regions of the conduit. The direction of the jet matched the regions with elevated WSR values. Pulmonary flow deviation angle was positively correlated with the conduit dilatation and with vortex size. In contrast, those after surgical implantation showed a laminar pulmonary flow with no visible vortex and had symmetric, although elevated WSR in the conduit regions. (Figure 2)
4D MRI flow revealed that pulmonary flow patterns after percutaneous pulmonary valve implantation are markedly different from those after the surgical implantation. Eccentric pulmonary flow is associated with vortex appearance, dilatation of RV-PA conduit, and asymmetrical elevated WSR, which is related to the direction of pulmonary flow jet. This could place this group at risk for future adverse events. Longer follow up studies are required to determine the implications of such knowledge for prognosis and therapy.
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Romeih, S., van der Geest, R.J., Roest, A. et al. Four dimensional pulmonary flow evaluation in adolescent patients after surgical and percutaneous pulmonary valve implantation. J Cardiovasc Magn Reson 16 (Suppl 1), O45 (2014). https://doi.org/10.1186/1532-429X-16-S1-O45