Background: Transition from paediatric to adult care in congenital heart disease (CHD) represents a pivotal and vulnerable phase that critically influences long-term survival, morbidity, and quality of life. Advances in paediatric cardiology and surgery have generated a rapidly growing population of adults with congenital heart disease who exhibit complex, lifelong, and multidisciplinary needs. However, survival does not equate to cure, and discontinuity of care during adolescence remains a major predictor of adverse outcomes. Despite widespread recognition of their importance, transition programmes are heterogeneous worldwide, and standardised, evidence-based protocols are missing. Objective: This review calls for action acknowledging the urgent need for structured and standardised transition programmes in CHD care, integrating the key elements that should be addressed in any programme to optimise outcomes. Content: Transition should be understood as a multidisciplinary, longitudinal process integrating medical management, patient and family education, psychological preparation, and societal inclusion. Core domains include tailored physical activity, nutritional counselling, cardiovascular risk factor management, infective endocarditis prevention, reproductive health, psychosocial support, and engagement of primary care providers, educators, and employers. Evidence demonstrates that structured transition programmes enhance health literacy, adherence, and self-management, while reducing loss to follow-up. The active involvement of primary care providers, psychologists, educators, and employers is essential to sustain holistic and equitable care. Conclusions: Transition should be reframed as an essential, lifelong component of CHD care. The development and implementation of standardised, multidisciplinary, evidence-based transition protocols are urgently required to ensure continuity, empower patients, and optimise long-term clinical and psychosocial outcomes for adults with CHD.

The Fontan procedure has rewritten the natural history of many children with congenital heart disease and univentricular physiology. However, long-term survival is limited by the development of haemodynamic and multisystem failure, leading to high morbidity and mortality. Absence of a subpulmonary ventricular pump, chronically elevated central venous pressure, and reduced cardiac output, along with lymphatic dysfunction and progressive multiorgan involvement, define the clinical course of many patients with the Fontan procedure, resulting in the heterogeneous clinical entity of Fontan failure. This review provides a comprehensive overview of the pathophysiological mechanisms underlying Fontan failure and a critical analysis of the currently available advanced therapeutic options. Particular attention is paid to the current frontiers of mechanical circulatory support. Although the presence of a total cavopulmonary connection may represent an anatomical limitation, ventricular assist devices have gained attention both as a bridge to transplantation and, in selected cases, as a long-term strategy. Nonetheless, despite the high surgical complexity, heart transplantation currently represents the only definitive option for this patient population. Optimizing clinical outcomes in Fontan failure represents one of the most challenging frontiers in congenital heart disease. Achieving significant advances will require accurate risk stratification, timely transition to advanced therapies, and coordinated multidisciplinary collaboration.