Cardiorenal Syndrome in Adults with Congenital Heart Disease.

As the population of adults with congenital heart disease (ACHD) continues to grow, a significant and often underrecognized complication is the development of cardiorenal syndrome (CRS)-a complex, bidirectional interaction between cardiac and renal dysfunction. While CRS has been extensively studied in acquired heart failure, its manifestations and implications in ACHD remain insufficiently understood. Emerging data suggest that renal dysfunction is highly prevalent in ACHD, with significant associations to adverse outcomes regardless of cardiac lesion type or functional status. This review explores CRS within three key physiologic categories in ACHD: patients with a systemic right ventricle, those with a subpulmonary right ventricle, and those with Fontan circulation. Each subgroup presents unique hemodynamic challenges that affect renal perfusion, filtration pressure, and systemic congestion, contributing to both acute and chronic renal impairment. The utility of renal biomarkers such as albuminuria, cystatin C, and estimated glomerular filtration rate (eGFR) is emphasized, alongside the importance of early detection and multidisciplinary management. Heart failure therapy tailored to congenital anatomy, neurohormonal modulation, and careful volume control remain the cornerstones of treatment, while transplantation strategies must consider the potential for irreversible end-organ damage. Given the profound implications of CRS on quality of life and survival, a comprehensive understanding of its pathophysiology and management in ACHD is critical to optimizing long-term outcomes in this increasingly complex patient population.