Background: The importance of cardiac magnetic resonance (CMR) in univentricular physiology lies in its ability to measure collateral flow using two-dimensional (2D) flow analysis. Our purpose is to determine the clinical use of flow studies in Fontan patients. Materials and Methods: All included patients underwent the Fontan protocol with 1.5 Tesla CMR, which included volumetric analysis, 2D phase-contrast flow, magnetic resonance angiography, noninvasive heavy T2 lymphatic imaging, and late gadolinium enhancement. Results: Twenty-two patients were included in the study. A significant negative correlation was observed between systemic–pulmonary collateral (SPC) flow and current blood oxygen saturation level, while a significant positive correlation was observed between SPC flow and post-Fontan hospital stay, single-ventricle end-diastolic volume index, single-ventricle end-systolic volume index, and aortic cardiac index. While there were no differences between New York Heart Association (NYHA) classes and SPC flow, the mean indexed superior vena cava (SVC) flow was significantly lower in NYHA Class 2 patients than in Class 1 patients. Conclusions: Measurement of collateral flow can provide physicians with information about their patients’ volume load status. The lower indexed SVC flow in NYHA Class 2, compared with Class 1, and the negative correlation between indexed SVC flow and hematocrit may have been caused by venovenous collateral flow.
Beyazal et al. (Thu,) studied this question.