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 ductus arteriosus (PDA) in a neonatal lamb model. BACKGROUND: A variety of devices are used to close PDAs by interventional measures. Spring coils found to have a high cumulative occlusion rate have thus far been limited to smaller PDAs because of the physical limitation of grip forces. METHODS: Memory-shaped double-cone stainless steel coils with enhanced stiffness of the outer rings by a double-helix configuration were mounted on a titanium/nickel core wire. A snap-in mechanism attaches the coil to the delivery wire, allowing intravascular coil retrieval and repositioning. The system was placed through a 4F or 5F Teflon catheter. A chronic lamb model (n = 8) of PDA (>5 mm) was used in which ductus patency was secured by a protocol of repetitive angioplasty procedures. The animals were killed after 1 to 181 days, and the ductal region was examined by inspection as well as by light and electron microscopy. RESULTS: Placement of the coils within the PDA was possible in all lambs. Before final detachment, the coils were retrieved or repositioned, 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 infections or aortic and pulmonary artery obstruction. Histologic and electron microscopic studies revealed endothelial coverage of the implants but no foreign body reaction or local or systemic inflammation or erosion of the implant. CONCLUSIONS: The device effectively closed large PDAs in our model and may overcome the previous limitations of coils. Clinical trials are indicated.

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 tested for interventional closure of the persistent ductus arteriosus. Coils were found effective only in small ducts due to their lack of maneuverability and physical limitation of grip forces leading to risk of embolization. The authors evaluated the feasibility to place single coils with selectively enhanced stiffness into high shunting ductus arteriosus, the coils being deployed and controlled through a veno-arterial loop in a bovine model. METHODS: "Double-cone" shaped, stainless steel coils with enhanced stiffness of the outer rings were mounted on either end on a nitinol core wire. A snap-in mechanism attaches the coil to this delivery wire and is freed by a pusher system of coiled steel wire that is advanced over the core wire. Forming a veno-arterial loop across the patent ductus allows for repositioning into the pulmonary artery or aortic catheter. A chronic lamb model of large patent ductus arteriosus (PDAs) (> or = 9 mm) was used in which ductus patency was secured by a protocol of repetitive angioplasties. Different systems (n = 10) were placed having retrieved the previous coil by a snare after definitive release. RESULTS: Placement of coils was possible in all 10 attempts. The coils were pulled back into the catheters between five and eight times before definitive release. CONCLUSIONS: The device allows controlled placement of single coils in our model of large PDAs and may lead the way to overcome previous limitations of coils. Clinical trials are warranted.

DuctOcclud--implant for transcatheter closure of patent ductus arteriosus.

The DuctOcclud implant is a metal coil device designed for transcatheter closure of small to moderate size patent ductus arteriosus, a Congenital Heart Disease in which a vessel-like communication between the aorta and the pulmonary artery persists after birth. The paper describes the design of the device, its delivery system, and the implant procedure. It also reviews and reports the experimental and the clinical experiences accumulated utilizing the device for occlusion of patent ductus arteriosus.

Endoscopic treatment of the "sump syndrome" after choledochoduodenostomy: a new technique using an amplatzer septal occluder.

A 58-year-old male patient had been suffering for 35 years from recurrent cholangitis, biliary sludge and infection-induced stone formation after open cholecystectomy because of empyema of the gallbladder and severe acute and delayed postoperative complications. The pathophysiological origin of this chronic "sump syndrome" was a choledochoduodenostomy which had been performed prophylactically at the time of the initial operation. The patient agreed to an experimental treatment option with use of an Amplatzer atrial-septal defect (ASD) occluder for closure of the symptomatic choledochoduodenal fistula. The double-disc occluder was introduced through a 9 French diameter and 90 cm long sheath side to side with a duodenoscope. Under endoscopic and fluoroscopic guidance the distal disc was opened in the common bile duct, then retracted against the fistula's orifice. Subsequently, the proximal disc was unfolded in the duodenum, while the 9 mm waist between the two discs filled and shut the fistula. No side effects or complications were detected. The day after the procedure, endoscopic evaluation demonstrated the correct position of the occluder and closure of the fistula. Over a period of 12 months, repeated assessments did not reveal any major problems. The patient felt a significant subjective improvement. The use of a self-expanding occluder system for closure of a choledochoduoenotomy complicated by chronic and symptomatic duodenocholedochal reflux might therefore represent an enrichment of the equipment of interventional endoscopists.

Partial malposition of PFO closure device: indication for elective surgical removal? Discussion of indications, procedural and anatomical aspects.

Partial malposition of a PFO closure device occurred, probably due to a right atrial ligamentous structure. Despite absence of residual shunt and uneventful postprocedural course, elective surgical removal was performed. Indications, procedural and anatomical aspects are discussed.