The Hemi-Fontan operation: A critical overview

Computed Tomography in the Evaluation of Fontan Circulation

The Fontan procedure is a well-established surgical technique to improve survival in patients with univentricular heart disease. The procedure reroutes the systemic venous flow to the lungs, bypassing the right ventricle. The originally proposed method involved direct anastomosis of the right atrium to the pulmonary artery. Since then, several modifications have been made in the original technique leading to the modern Fontan, or total cavopulmonary connection. The modern Fontan technique has shown improved surgical outcomes and increased life expectancy in patients with univentricular disease. Due to the increased survival of these patients, long-term complications are becoming more prevalent. Common complications of Fontan procedure include right atrial dilatation and thrombosis; conduit stenosis and thrombosis; right-to-left and left-to-right shunts; hepatic congestion and cirrhosis; and lymphovascular. Computed tomography (CT) can reliably depict the normal Fontan anatomy and various postoperative complications. A fundamental understanding of the techniques of CT, including imaging protocols and common interpretive pitfalls, allows targeted imaging and precise reporting of clinically significant findings. Radiologists should be familiar with the multiple stages of single-ventricle palliation, normal Fontan anatomy, pathophysiology, and imaging features of common Fontan-related complications.

A Comparison of Bidirectional Glenn vs. Hemi-Fontan Procedure: An Analysis of the Single Ventricle Reconstruction Trial Public Use Dataset

Patients with single ventricle (SV) heart defects have two primary surgical options for superior cavopulmonary connection (SCPC): bidirectional Glenn (BDG) and hemi-Fontan (HF). Outcomes based on type of SCPC have not been assessed in a multi-center cohort. This retrospective cohort study uses the Single Ventricle Reconstruction (SVR) Trial public use dataset. Infants who survived to SCPC were evaluated through 1 year of age, based on type of SCPC. The primary outcome was transplant-free survival at 1 year. The cohort included 343 patients undergoing SCPC across 15 centers in North America; 250 (73%) underwent the BDG. There was no difference between the groups in pre-SCPC clinical characteristics. Cardiopulmonary bypass times were longer [99 min (IQR 76, 126) vs 81 min (IQR 59, 116), p < 0.001] and use of deep hypothermic circulatory arrest (DHCA) more prevalent (51% vs 19%, p < 0.001) with HF. Patients who underwent HF had a higher likelihood of experiencing more than one post-operative complication (54% vs 41%, p = 0.05). There were no other differences including the rate of post-operative interventional cardiac catheterizations, length of stay, or survival at discharge, and there was no difference in transplant-free survival out to 1 year of age. Mortality after SCPC is low and there is no difference in mortality at 1 year of age based on type of SCPC. Differences in support time and post-operative complications support the preferential use of the BDG, but additional longitudinal follow-up is necessary to understand whether these differences have implications for long-term outcomes.

What have we learnt 50 years after the first Fontan procedure?

The Fontan procedure is often the only definitive palliative surgical option for patients with a variety of complex CHD sharing in common, a single, dominant ventricle. In recent decades, imaging and therapeutic improvement have played a crucial role in those patients in whom many complications can hamper their life. After 50 years from the first procedure, heart transplantation remains the only definitive treatment for those with a failing Fontan circulation.

The Adult with Post-operative Congenital Heart Disease: a Systematic Echocardiographic Approach

PURPOSE OF REVIEW

This article attempts to review some of the commonly seen repaired congenital heart defects in the adult population (ACHD), with a focus on important echocardiographic findings that may assist a practitioner in recognizing and managing this group of patients.

RECENT FINDINGS

The prevalence of ACHD population is increasing, and currently, there are over 1 million adults with congenital heart disease. At the current time, the total number of ACHD patients exceeds the total number of pediatric patients with CHD. The recently released 2018 American College of Cardiology/American Heart Association guidelines for the management of adults with congenital heart disease (ACHD) recommends transthoracic echocardiography for all ACHD patients for initial assessment and serial assessment as needed (class of recommendation: I) and echocardiography remains the mainstay for diagnosing and managing these patients in adjunct with other available imaging modalities. It is imperative for all cardiologists to be familiar with the echocardiographic features of the commonly seen repaired CHD in adult population.

Development of Tachyarrhythmias Late After the Fontan Procedure: The Role of Ablative Therapy

Patients with a Fontan circulation are at a high risk of developing a variety of cardiac dysrhythmias after cardiac surgery. These dysrhythmias are most often supraventricular tachyarrhythmias (SVT), but ventricular tachyarrhythmias (VT) may also occur. Mechanisms underlying SVT are variable, including both ectopic activity and reentry. Over time, successive SVT may be caused by different mechanisms. The acute success rate of ablative therapy of atrial tachyarrhythmias is considerably high yet during long-term follow-up 'recurrences' frequently occur. It is most likely that these 'recurrences' are caused by a progressive atrial cardiomyopathy instead of arrhythmogeneity of prior ablative lesions.