40%
Long-term Outcomes
Within 40 years of the initial surgery, a significant proportion of patients experience major complications including heart failure, arrhythmias, and the need for transplantation.
AdvancingFontan CareThrough Research
Exploring outcomes, challenges, and patient-centered solutions for single-ventricle heart disease.
70K+Patients Worldwide
50+Years of Research
8Partner Centers
About the Procedure
Understanding the Fontan Procedure
The Fontan procedure is a palliative surgical operation performed on children born with single-ventricle heart defects — conditions where only one of the heart's two pumping chambers is functional. First performed in 1971, the surgery redirects venous blood flow directly to the pulmonary arteries, bypassing the need for a ventricular pump.
While the Fontan circulation has dramatically improved survival for these patients, it creates a unique physiology that requires lifelong monitoring. The single ventricle must work harder to support the entire circulatory system, leading to a range of long-term complications that affect multiple organ systems.
The procedure typically follows a staged approach: initial neonatal palliation, superior cavopulmonary connection, and finally the total cavopulmonary connection. Each stage reshapes the heart and vessels to establish passive pulmonary blood flow while maintaining systemic output.
Because the pulmonary circuit is driven without a sub-pulmonary ventricle, Fontan patients experience elevated venous pressure, lower cardiac reserve, and higher risk for liver, kidney, and lymphatic sequelae. That makes monitoring, research, and patient-centered care essential for every life stage.
Staged surgical strategy
Norwood, Glenn, and Fontan operations gradually reconfigure circulation to optimize single-ventricle physiology.
Passive pulmonary flow
Blood reaches the lungs by pressure gradients rather than a pumping chamber, making low resistance and vessel health critical.
Lifelong surveillance
Regular imaging, biomarker testing, and exercise evaluation are key to detecting silent organ stress before it becomes a crisis.
Fontan Timeline
1971
First Fontan Procedure
Dr. Francis Fontan performs the first successful total cavopulmonary connection in a patient with tricuspid atresia.
1978
Glenn Shunt Introduced
Dr. William Glenn develops the superior cavopulmonary anastomosis, creating the staged approach to Fontan palliation.
1980s
Widespread Adoption
Fontan procedure becomes standard of care for single-ventricle defects, with survival rates improving dramatically.
1990s
Extracardiac Fontan
Introduction of extracardiac conduit technique reduces arrhythmia risk and improves long-term outcomes.
2000s
Adult Fontan Care
Growing recognition of adult Fontan patients' unique needs leads to specialized clinics and research programs.
2010s
Precision Medicine
Advanced imaging, biomarkers, and genetic testing enable personalized monitoring and intervention strategies.
2020s
Patient-Centered Research
Focus on quality of life, mental health, and long-term outcomes drives innovative care models and therapies.
70,000+Fontan patients worldwide
The Problem
Current Challenges in Fontan Management
Despite remarkable surgical advances, patients living with Fontan circulation face significant long-term challenges that demand innovative research, earlier intervention, and deeper patient-centered care.
2–3×
Ventricular Function
The single ventricle faces 2–3 times the normal workload, leading to progressive dysfunction. Current imaging and biomarker strategies often detect deterioration too late for effective intervention.
65%
Quality of Life
Up to 65% of adult Fontan patients report reduced exercise capacity, chronic fatigue, and psychosocial challenges that significantly impact their daily lives and mental health.
72%
Liver & Kidney Risk
Chronic venous hypertension in Fontan circulation places ongoing stress on the liver and kidneys, driving a need for earlier biomarker screening and organ-protective therapies.
Publications
Published Research
Peer-reviewed publications advancing our understanding of single-ventricle physiology and patient outcomes.
JACC: Advances2025
Association of Fontan Pathophysiology with Plasma Bile Acids
This study examined the relationship between Fontan circulation and plasma bile acid profiles, revealing systemic metabolic disruption as a key driver of multi-organ dysfunction in single-ventricle patients.
Read PaperJACC: Advances2025
Fontan-Associated Diastolic Dysfunction and Bile Acids: Mechanistic Parallels with Cirrhotic Cardiomyopathy
Drawing parallels between Fontan physiology and cirrhotic cardiomyopathy, this work explores how elevated bile acids contribute to diastolic dysfunction and impaired cardiac reserve in the Fontan population.
Read PaperMetabolites2025
Plasma Lipidomic Alterations in Fontan Circulation Reflect Cardiovascular Functional Reserve
A lipidomic analysis of Fontan patients demonstrating that plasma lipid profiles are altered in ways that correlate with cardiovascular functional reserve, offering novel biomarkers for monitoring disease progression.
Read PaperAmerican Heart Journal2025
MYSTIC Trial: Impact of Colesevelam Therapy Reducing Bile Acids in Fontan Circulation — Rationale and Study Design
Presents the design of the MYSTIC trial, a prospective study evaluating whether pharmacologic bile acid reduction with colesevelam can improve multi-system outcomes in patients with Fontan circulation.
Read PaperCanadian Journal of Cardiology2025
Fontan Circulation Beyond Preload: Metabolic Pathways and Mitochondrial Stress
This review reframes Fontan pathophysiology beyond hemodynamic preload dependency, highlighting metabolic dysfunction and mitochondrial stress as underappreciated contributors to exercise intolerance and organ injury.
Read PaperCurrent Cardiology Reports2025
Interplay Between Elevated Bile Acids and Reduced Vitamin D Levels in Fontan Circulation: A Double-Edged Sword
Examines how the combination of bile acid accumulation and vitamin D deficiency creates a compounding pathophysiologic burden in Fontan patients, with implications for hepatic, cardiac, and skeletal health.
Read PaperCurrent Cardiology Reports2022
Invasive Hemodynamic Evaluation of the Fontan Circulation: Current Day Practice and Limitations
A comprehensive review of hemodynamic catheterization in Fontan patients, critically evaluating current techniques, their interpretive limitations, and the need for standardized assessment protocols.
Read PaperHeart2021
Augmentation of Pulmonary Blood Flow and Cardiac Output by Non-Invasive External Ventilation Late After Fontan Palliation
A prospective study demonstrating that non-invasive external ventilation can acutely augment pulmonary blood flow and cardiac output in adult Fontan patients, with implications for rehabilitation and acute management.
Read PaperCJC Pediatric and Congenital Heart Disease2025
Fontan Circulation and High Cardiac Output State: A Forgotten Phenotype
Describes a clinically underrecognized high-output phenotype in Fontan patients, characterizing its hemodynamic features and distinguishing it from classical low-output Fontan failure.
Read PaperStem Cell Research2024
Establishment of a New Human iPSC Cell Line from a Patient with Congenital Heart Defect Who Has Undergone Fontan Procedure
Reports the successful derivation of an induced pluripotent stem cell line from a Fontan patient, providing a translational platform for modeling single-ventricle pathophysiology in vitro.
Read PaperCJC Pediatric and Congenital Heart Disease2025
Physician Perception of Fontan Failure, "Acceptable" Hemodynamics, Assessment, and Indications for Intervention — A Multinational Survey
A multinational survey revealing significant heterogeneity in how clinicians define Fontan failure and thresholds for intervention, underscoring the urgent need for consensus guidelines in Fontan management.
Read PaperCJC Pediatric and Congenital Heart Disease2025
Pan-Canadian Registry, Pan-System Disease: Rethinking Fontan Pathobiology
Advocates for a national registry framework and a multi-system perspective on Fontan disease, emphasizing that hepatic, renal, lymphatic, and cardiac pathology must be tracked longitudinally together.
Read PaperAnnals of Pediatric Cardiology2025
Fontan Circulation Versus Cirrhotic Cardiomyopathy: A Comparative Overview
A side-by-side comparison of Fontan-associated cardiac dysfunction and cirrhotic cardiomyopathy, identifying shared mechanisms of venous hypertension, bile acid signaling, and myocardial stiffness.
Read PaperCJC Pediatric and Congenital Heart Disease2026
The Fontan Conundrum: Rarity, Complexity, and the Research Gap
Examines the systemic barriers to Fontan research — including disease rarity, phenotypic heterogeneity, and funding gaps — and proposes collaborative and registry-based strategies to close the evidence deficit.
Read PaperEuropean Heart Journal2026
Excellent Early Outcomes, Elusive Long-Term Health: The Paradox of Fontan Success
Explores the central paradox of Fontan palliation: dramatically improved early survival paired with a growing burden of late multi-organ complications, calling for a shift toward proactive long-term surveillance.
Read PaperAmerican Heart Journal2026
From Hepatic Congestion to Ventricular Stiffness: Mechanistic Pathways of Diastolic Dysfunction After Fontan
Traces the pathophysiologic cascade from chronic venous hepatic congestion to progressive ventricular stiffness in Fontan patients, proposing mechanistic targets for intervention.
Read PaperInternational Journal of Cardiology Congenital Heart Disease2026
Safety, Feasibility, and Impact of a 12-Week Yoga Program in Adult Fontan Patients: A Pilot Study
A pilot clinical study assessing the safety and feasibility of structured yoga as a rehabilitation modality in adult Fontan patients, with preliminary data on exercise capacity and quality of life outcomes.
Read PaperJournal of Gastroenterology and Hepatology2026
Association of Fontan Circulation With Gut Microbiome-Derived Short and Branched Chain Fatty Acids
Investigates the gut-cardiac axis in Fontan patients by profiling microbiome-derived short and branched chain fatty acids, revealing dysbiotic patterns that may contribute to systemic inflammation and hepatic injury.
Read PaperJACC: Advances2026
Fibrosis Is Inevitable, But Heterogeneous: Time-Dependent and Biochemical Modifiers of Liver Injury After Fontan Completion
Characterizes the heterogeneous trajectory of hepatic fibrosis in Fontan patients, identifying time from surgery and biochemical markers as key modifiers of liver injury severity and progression.
Read PaperAmerican Journal of Physiology — Heart and Circulatory Physiology2026
Omega-6/Omega-3 Oxylipin Imbalance and Altered 15-LOX and sEH Pathways in Fontan Physiology
Profiles oxylipin metabolism in Fontan circulation, finding an omega-6/omega-3 imbalance and disruption of key lipid-resolving enzymes that may underlie chronic vascular inflammation and end-organ injury.
Read PaperTeam
Meet the Minds Behind the Research
Bridging the gap between medical research and digital accessibility.
Pioneering Fontan Research
Dr. Shah is one of Canada's leading interventional cardiologists with a specialized focus on adult congenital and structural heart disease, including patients living with Fontan circulation. Based at St. Boniface Hospital in Winnipeg, he holds the distinction of establishing Western Canada's first invasive hemodynamic evaluation program, a critical tool in understanding and managing the unique cardiovascular physiology of the Fontan patient.
His published research directly addresses the Fontan population. He has contributed to landmark work on augmenting pulmonary blood flow and cardiac output in late Fontan palliation, and has authored a publication on the complexities of permanent pacing in Fontan circulation, a notoriously difficult clinical challenge. He has also published on transcatheter valve implantation in the modified Björk-Fontan procedure, offering interventional solutions where surgery is high-risk or not feasible.
Trained across three countries: India, the United Kingdom (King's College London, MRCP), and Canada (Toronto General Hospital).
1st in WestInvasive Hemodynamic Program
3 ContinentsGlobal Clinical Training
LandmarkPulmonary Blood Flow Research
ExpertAdult Congenital Heart Disease
Architecting the Experience
Aman Shah is a computer science student at the University of Toronto, where his studies sit at the intersection of software engineering, artificial intelligence, and healthcare technology. A software engineer by trade and a hobbyist game developer by passion, he brings both rigour and creativity to every system he builds.
His work extends well beyond the classroom. With over 450,000 views and 6,500 subscribers on YouTube, Aman has built a reputation for making technically complex ideas genuinely accessible to a broad audience, a sensibility that shaped every design decision on this platform.
As co-author and developer, he worked alongside his father to transform years of peer-reviewed research into a clear, interactive, and performant digital experience. His focus on data visualization and structural clarity ensures that the research reaches and resonates with the Fontan community in a meaningful way.
U of TComputer Science & Medicine
Lead DevPlatform Architecture
Co-AuthorResearch Synthesis
ModernNext.js & Framer Motion Stack