Discussion
CoA is a common congenital heart defect that is characterized by a narrowing distal to the aortic arch and the prenatal diagnosis is challenging and difficult.(9) Its coincidence with TTTS is rare and there have been only a few cases in the literature. (6) Assessment of ventricular size is helpful in prenatal diagnosis and the left ventricle is usually smaller than the right ventricle. Also, comparison of the width of the aorta, ductus arteriosus and coarctation shelf in color doppler studies may suggest that the defect will require an intervention after birth (10). TTTS is associated with an increased prevalence of congenital heart diseases (CHDs). In MC pregnancies with TTTS, the risk of at least one of the infants with CHD is threefold compared to uncomplicated MC twin pregnancies (11). The development of acquired CHDs in MC twins is associated with TTTS, indicating an influence of hemodynamic alterations on cardiac development. MC twins with TTTS are associated with increased risk of ventricular septal defect (VSD), RVOTO, atrial septal defect (ASD), CoA, and aortic stenosis (AS). Some of them are uncommon, such as CoA and AS (8). There are reports of a small number of CoA in recipient and donor twins in TTTS. After birth, due to ductal closure, a variety of hemodynamic changes may occur according to the severity of obstruction and critical coarctation increases the risk of heart failure and death in infants when the ductus arteriosus closes. So, prenatal diagnosis is important to reduce postnatal complications. After birth, prostaglandins type 1 is necessary to avoid closure of ductus arteriosus and definite treatment is end-to-end anastomosis, but transcatheter treatment is also an accepted alternative with comparable results (9). Balloon angioplasty is an acceptable technique, similar to what was done in our case. It is a safe procedure in infants between one and six months of age and also in critically ill patients regardless of age (12). The best time for CoA correction is in infancy or childhood in order to prevent persistence or late recurrence of systemic hypertension (13).