DOUBLE-HELIX COIL FOR OCCLUSION OF LARGE PATENT DUCTUS-ARTERIOSUS - EVALUATION IN A CHRONIC LAMB MODEL

Objectives, We sought to evaluate the efficacy and tissue reaction of a new miniature interventional device for occlusion of large patent du ctus arteriosus (PDA) in a neonatal lamb model. Background. A variety of devices are used to close PDAs by interventional measures. Spring c oils found to have a high cumulative occlusion rate have thus far been limited to smaller PDAs because of the physical limitation of grip fo rces, Methods. Memory shaped double-cone stainless steel coils with en hanced stiffness of the outer rings by a double helix configuration we re mounted on a titanium/nickel core wire. A snap-in mechanism attache s the coil to the delivery wire, allowing intravascular coil retrieval and repositioning, The system was placed through a 4F or 5F Teflon ca theter. A chronic lamb model (n = 8) of PDA (>5 mm) was used in which ductus patency was secured by a protocol of repetitive angioplasty pro cedures. The animals were killed after 1 to 181 days, and the ductal r egion was examined by inspection as well as by light and electron micr oscopy, Results, Placement of the coils within the PDA was possible in all lambs. Before final detachment, the coils were retrieved or repos itioned, or both, up to 12 times. In all but one animal the ductus was closed within 6 days after the procedure. The coils caused no infecti ons or aortic and pulmonary artery obstruction, Histologic and electro n microscopic studies revealed endothelial coverage of the implants bu t no foreign body reaction or local or systemic inflammation or erosio n of the implant, Conclusions. The device effectively closed large PDA s in our model and may overcome the previous limitations of coils, Cli nical trials are indicated. (C) 1998 by the American College of Cardio logy.