The transition from pediatric to adult cardiology care is a pivotal moment in the healthcare journey of individuals with congenital heart conditions or childhood-onset heart diseases. This multifaceted process requires meticulous consideration of clinical, psychosocial, and logistical factors. This research aims to explore the critical criteria for transitioning pediatric patients to adult cardiology, delving into the challenges and opportunities inherent in this healthcare shift. The identified factors for successful transition, including age and developmental stage, medical complexity, cardiac function, psychosocial factors, insurance, and financial considerations, play integral roles in the transition process. Leveraging analytical methodologies, particularly the Fuzzy Decision-Making Trial and Evaluation Laboratory (DEMATEL), this study involves three experts who assess criteria linguistically, converted to Triangular Fuzzy Numbers, and averaged. Defuzzification, using the CFCS method, yields crisp values. Results reveal that Medical Complexity (U+V = 3.96, U-V = 0.233), Insurance (U+V = 3.931, U-V = 0.22), Psychosocial Factors (U+V = 3.839, U-V = 0.387), and Age and Developmental Stage (U+V = 3.802, U-V = 0.106) follow Cardiac Function (U+V = 4.312, U-V = 0.946) in ranking. Age and Developmental Stage, Medical Complexity, Psychosocial Factors, and Insurance are considered causal variables, with Cardiac Function as an effect. These numerical insights enhance our understanding of transition criteria interdependencies, informing tailored healthcare strategies.