Role of Cardiovascular Imaging in the Follow-Up of Patients with Fontan Circulation

Abstract

Since its first description in 1971, the Fontan procedure and its modifications have led to a substantial improvement in the survival rates of patients with a variety of types of complex Congenital Heart Disease (CHD) characterised by the presence of a single, dominant ventricle. However, despite the significant improvement of the prognosis over the years, Fontan patients are still exposed to several cardiovascular and systemic complications. It is, therefore, important to fully understand the pitfalls hidden behind a Fontan anatomy and the potential predictors of ventricular failure. Cardiovascular imaging plays a key role in this context, allowing for the early identification of complications with important prognostic implications. Echocardiography remains the first-line imaging modality for serial evaluation of Fontan patients. However, there is a growing role of cardiovascular magnetic resonance and cardiac computed tomography from pre-operative assessment to longitudinal follow-up. The aim of this paper will be to provide a comprehensive overview of the role, strengths, and weaknesses of each imaging modality in the assessment of congenital cardiac conditions palliated with the Fontan procedure.

Comparison of Echocardiographically-Calculated Fontan Fenestration Gradient and Catheter-Based Measurement

“…This holds clinical importance as many physicians monitor mFG serially as a marker of pulmonary vascular disease in Fontan patients. [13] A recent study suggests that elevated TPG > 6 mmHg is re ective of pulmonary hypertensive vascular disease in Fontan patients, even in the setting of a pulmonary artery pressure < 25 mmHg and PVR <3 woods units m 2 . [14] Given that ow to the lungs is passive via the cavo-pulmonary anastomosis and Fontan conduit in single ventricle patients, maintaining low PVR is crucial for the longevity of Fontan physiology.…”

“…[12] While cardiac catheterization remains the gold standard for the measurement of Fontan pressure and TPG, the mFG is often followed serially in the outpatient setting as a surrogate for TPG. [13] While this relationship is intuitive, it has never been rigorously evaluated. In this study, we aimed to evaluate the correlation between echocardiographically obtained mFG and catheter-based measurement of TPG.…”

The mechanics of congenital heart disease: from a morphological trait to the functional echocardiographic evaluation

“…In the presence of a univentricular heart with left morphology, the most common approach to estimate systolic function is the biplane Simpson's method. Even though this method is load-dependent and influenced by geometry, it has a moderate correlation with MRI measurements and reasonable reliability ( 86 ). Even more challenging can be the evaluation of a morphological right single ventricle.…”

The Role of Multimodality Imaging in Pediatric Cardiomyopathies

“…Dark-and bright-blood single-shot images are taken in the axial, coronal, and sagittal planes of the thorax, providing a foundation for planning further sequences and collecting information about structures outside the heart. Depending on the child's cooperation, these images can be obtained during a breath-hold or free-breathing [53,54]. These initial images are also extremely useful to screen for extracardiac findings.…”

“…These images permit the assessment of wall thickness as well as regional and global systolic function and are also used to calculate both the LV and RV end-diastolic and end-systolic volumes and determine the ejection fraction [53][54][55].…”