Advanced Cardiovascular and Lymphatic Imaging in an Adult With Long-Term Fontan Circulation Failure: A Case Report

Description of Clinical Presentation: A 30-year-old woman with pulmonary atresia and intact ventricular septum underwent a systemic-to-pulmonary shunt in infancy, followed by a fenestrated extracardiac Fontan at age 3. Postoperative complete atrioventricular block required epicardial DDD pacing, which was later discontinued at age 21 due to chronotropic independence. Over the following years, she developed plastic bronchitis, progressive cyanosis (baseline SpO₂ ~75%), and signs of systemic venous congestion. At age 29, she presented with abdominal pain, ascites, and pleural effusion, suggestive of Fontan pathway dysfunction.

Diagnostic Techniques and Their Most Important Findings: Transthoracic echocardiography revealed preserved left ventricular systolic function (EF 60%), with a patent fenestration and no significant valvular disease, but with pleural effusion and ascites. Contrast-enhanced cardiovascular magnetic resonance (CMR) with angiography and 4D flow (Figure 1) demonstrated:

• Pulmonary atresia with intact ventricular septum.


• Extracardiac Fontan conduit with concentric thickening, slow flow, and patent fenestration.


• Large secundum atrial septal defect (15 mm).


• Coronary fistula from the right coronary artery to the right ventricle.


• Mildly reduced left ventricular ejection fraction (47%).


• Congestive hepatopathy with splenomegaly and recanalized umbilical vein.


• Type 3 thoracic lymphatic perfusion pattern on T2-weighted sequences, indicating mediastinal and supraclavicular lymphatic involvement with extension into the mediastinum.

Cardiac catheterization confirmed unobstructed cavopulmonary and atriopulmonary connections (mean Fontan pressure 12 mmHg, elevated transpulmonary gradient, fenestration gradient 2.2 mmHg). A covered stent was placed in the fenestration without complications.

Learning Points from this Case: This case illustrates the complex, multisystem nature of late Fontan failure, where cardiac, hepatic, and lymphatic pathophysiology intersect. Advanced CMR protocols, including angiography, 4D flow, and dedicated lymphatic imaging, provided critical noninvasive characterization of conduit anatomy, systemic-to-pulmonary shunts, ventricular function, and lymphatic abnormalities. The type 3 lymphatic perfusion pattern correlated with clinical manifestations of protein-losing enteropathy risk and plastic bronchitis, supporting the role of pre-procedural lymphatic assessment in risk stratification. While routine surveillance in adult Fontan patients often focuses on ventricular and conduit assessment, incorporation of lymphatic imaging may identify patients at higher risk for decompensation and guide timing of interventions. This case reinforces the need for comprehensive, multimodality imaging—including CMR lymphatic protocols—in the longitudinal follow-up of adult Fontan survivors.

Figure 1. Fontan circulation assessed with 4D flow cardiovascular magnetic resonance.
Figure 2. T2-weighted SPACE magnetic resonance demonstrating type 3 lymphatic circulation pattern.