The mortality rate for transplantation in patients with prior Fontan surgery was double that reported by the International Society for Heart and Lung Transplantation (ISHLT) 20 years ago, reaching 30%. A multicenter study from a decade ago estimated this rate at 20-25%. More recently, outcomes have improved, with survival rates reaching 80% and even 90%. 

Why is transplantation mortality higher in Fontan patients? Perhaps comparisons should be made not with dilated cardiomyopathy in a virgin chest but with congenital heart disease (CHD) transplants in general. Single-ventricle physiology is inherently more precarious and may fail due to either dysfunction of the single (systemic) ventricle or venous congestion caused by the absence of a sub-pulmonary ventricle (hepatic fibrosis, protein-losing enteropathy). In this regard, circulatory support as a bridge to transplantation presents technical challenges and inferior outcomes compared with biventricular physiology. 

Several authors emphasize similarities with “conventional” transplantation, while highlighting strategy and technical differences in the anticipated anastomoses. Identifying the type of cavo-pulmonary connection (atrio-pulmonary, lateral tunnel, extracardiac conduit, etc.) is crucial due to their many variants. This necessitates the “deconstruction” of venous and arterial connections before graft implantation. Key considerations include: 

• Previous Interventions: These patients often face a fourth sternotomy following Norwood, Glenn, and Fontan procedures. The risk of antigenic sensitization is elevated. Adhesions and tissue fragility increase the likelihood of requiring cardiopulmonary bypass during dissection. However, peripheral cannulation (e.g., femoral) is frequently unfeasible due to vessel occlusion from repeated catheterizations, necessitating alternative cannulation strategies (axillary, carotid, jugular, etc.). 

• Collateral Circulation: The presence of abundant collateral circulation warrants low flows due to excessive return to the common atrium. Hypothermia, sometimes profound, with one or more periods of circulatory arrest, is often required. 

• Foreign Materials: External materials such as Dacron or PTFE patches, often adhered to tissues, are commonly encountered. Stents, predominantly in pulmonary branches and venae cavae, are increasingly prevalent. Their partial or complete removal depends on vessel fragility and suture line integrity. 

• Anatomical Variants: Situs abnormalities (solitus, inversus, ambiguus), apex orientation (levo-, meso-, dextrocardia), number and position of venae cavae (right or left-sided axis; one or two superior), and the relative position of the aorta and pulmonary artery (e.g., prior LeCompte) require preoperative planning. Sequential analysis of five suture lines in bi-caval procedures is imperative. Tissue harvesting from the donor (aorta, arch, superior vena cava with innominate vein, pericardial patch) is essential for anastomotic adaptations. 

Special attention is required for cases with initial Norwood surgery due to the need for aortic and pulmonary branch reconstructions. 

• Neo-aorta Challenges: The neo-aorta’s wide, short, and fragile structure complicates clamping and reconstruction. Extensive removal of prior material, hemi-arch anastomosis, or conduit interposition often necessitates alternative cannulation (e.g., innominate trunk) or brief circulatory arrest. 

• Pulmonary Branch Reconstruction: After Glenn disassembly, pulmonary branches (especially with left-sided stents) often require reconstruction. My preference is donor pericardial patch augmentation (or alternative materials) to expand these branches from hilum to hilum. Low flows or circulatory arrest in hypothermia are necessary. 

These complex surgeries often extend to 12 hours, with factors such as adhesions, hypothermia, extensive dissection, bleeding, and suspected pulmonary hypertension contributing to increased morbidity. Delayed chest closure and ECMO support during the first 48 hours are common. 

Our group published a series of 20 Fontan transplants in 2021 (including one heart-liver transplant), with 90% survival, comparable to 52 non-Fontan congenital transplants. From 2013 to 2023, we performed 112 congenital transplants, 32 of which were Fontan cases (13 adults). While demanding, preoperative strategies for cannulation, hypothermia, and reconstruction contribute to outcomes approaching those of other transplant cohorts. 

Significant challenges remain, such as combined heart-kidney and heart-liver transplants. For failed Fontan patients once deemed ineligible due to hepatopathy, heart-liver transplantation now offers a viable option, albeit with logistical and organ allocation complexities. Some authors advocate for a “special treatment” of Fontan patients, suggesting new risk stratification models and reconsideration of waitlist prioritization (e.g., young patients, poor candidates for mechanical support, right-sided support, prior sensitizations). 

REFERENCES: 

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