COIL ON THE LOOP AND SELECTIVELY ENHANCED STIFFNESS FOR IMPROVED CONTROL - FEASIBILITY STUDY IN THE NEONATAL OVINE MODEL OF THE LARGE PATENT DUCTUS-ARTERIOSUS

RATIONALE AND OBJECTIVES. Several devices have been suggested and test ed for interventional closure of the persistent ductus arteriosus, Coi ls were found effective only in small ducts due to their lack of maneu verability and physical limitation of grip forces leading to risk of e mbolization, The authors evaluated the feasibility to place single coi ls with selectively enhanced stiffness into high shunting ductus arter iosus, the coils being deployed and controlled through a veno-arterial loop in a bovine model, METHODS. ''Double-cone'' shaped, stainless st eel coils with enhanced stiffness of the outer rings were mounted on e ither end on a nitinol core wire. A snap-in mechanism attaches the coi l to this delivery wire and is freed by a pusher system of coiled stee l wire that is advanced over the core wire, Forming a veno-arterial lo op across the patent ductus allows for repositioning into the pulmonar y artery or aortic catheter, A chronic lamb model of large patent duct us arteriosus (PDAs) (greater than or equal to 9 mm) was used in which ductus patency was secured by a protocol of repetitive angioplasties, Different systems (n = 10) were placed having retrieved ed the previo us coil by a snare after definitive release, RESULTS. Placement of coi ls was possible in all 10 attempts, The coils were pulled back into th e catheters between five and eight times before definitive release. CO NCLUSIONS. The device allows controlled placement of single coils in o ur model of large PDAs and map lend the way to overcome previous limit ations of coils, Clinical trials are warranted.