Congenital heart disease is one of the most common congenital defects with high mortality and morbidity rates. The American Heart Association reports that at least eight out of every 1000 babies born are born with heart disease. In Turkey, an average of 11,000-17,000 babies are born with congenital heart disease each year. Congenital heart diseases are a very large group of diseases and the level and prognosis of defects in this group vary. While severe defects result in neonatal and infant mortality, almost all children with mild defects survive. With the adolescent period, children step from pediatric care to adult care. While the transition to adulthood causes psychological and social changes for a healthy adolescent and his/her family, the need for additional care for adolescents with chronic diseases and the change in access to health services make the transition period even more challenging. This situation has brought transition care, defined as "the purposeful and planned movement of adolescents and young adults with chronic physical and medical conditions from pediatric health systems to adult-oriented health systems" to the agenda. Since adolescents with congenital heart disease are at high risk for complications in adulthood, raising awareness of the need for regular medical follow-up and preparing them for changes in the health care environment are very important for a successful transition.

The aim of transitional care is to maintain the control and well-being of the disease in adulthood and maximize its potential by providing the quality care practices needed by the adolescent without interruption. Studies have shown that both adolescents with congenital heart disease and their caregivers need professional support, appropriate transition education and care before transition to adult care in order to increase their adaptation to adult care, gain self-management skills and reduce their concerns. The American Academy of Pediatrics (APA) recommends that the transition process should begin with transition planning between the ages of 12-14. However, since physiological and psychological development and needs are not related to the chronological age of the individual, the essence of timing in the transition process is flexibility. The timing of transition varies depending on many individual and environmental variables such as age, gender, physical and psychological maturation, current medical condition, compliance and adherence to treatment, readiness of the adolescent for transition, finding an appropriate adult care provider, and insurance policies. In studies in which adolescents with congenital heart disease were followed up after transition to adult care, when the transition process was not successfully completed, there was a gap between the last pediatric control and the first adult control. In conclusion, there is no intervention study in our country in which the developmental transition care model was applied to adolescents with congenital heart disease and the results were evaluated. In addition, based on clinical experiences and observations, it was determined that adolescents and their parents had difficulties in the transition from pediatric care to adult care and this negatively affected self-management related to the disease. The aim of this study was to evaluate the effect of the developmental transition care model applied to adolescents with congenital heart disease during the transition from pediatric care to adult care on the transition readiness level, self-management skills and care satisfaction of adolescents.