M Sigler

Double-helix coil for occlusion of large patent ductus arteriosus : Evaluation in a chronic lamb model

OBJECTIVESnWe 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.nnnBACKGROUNDnA 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.nnnMETHODSnMemory-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.nnnRESULTSnPlacement 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.nnnCONCLUSIONSnThe device effectively closed large PDAs in our model and may overcome the previous limitations of coils. Clinical trials are indicated.

Time course of cranial ultrasound abnormalities after arterial switch operation in neonates.

BACKGROUNDnThe object of this study was to investigate the time course and fate of abnormal findings in cranial ultrasound after performing an arterial switch operation in neonates with transposition of the great arteries, and to analyze the relationship to cerebral cell damage.nnnMETHODSnCranial ultrasound was performed prospectively in 35 neonates with transposition of the great arteries before the operation as well as 4 hours, 1, 2, and 3 days, and 1 and 2 weeks postoperatively. Blood levels of neuron-specific enolase, a marker of cerebral cell damage, were determined before, during, and 4 and 24 hours postoperatively.nnnRESULTSnIn 17 of 35 neonates (49%), early postoperative cranial ultrasound revealed abnormalities indistinguishable from intraventricular hemorrhage. In 11 neonates findings were transient and were normalized 2 weeks postoperatively, whereas in the remaining 6 neonates there was evidence of resolving hemorrhage. In all neonates there was a rise in neuron-specific enolase blood concentrations during and 4 hours after extracorporal circulation without correlation to sonographic findings.nnnCONCLUSIONSnEnhanced echogenicity of the choroid plexus or dilatation of the cerebral ventricular system is a frequent early postoperative finding that may be caused by transient plexus edema rather than intraventricular hemorrhage and is not related to cerebral cell damage.

Neurodevelopmental outcome related to cerebral risk factors in children after neonatal arterial switch operation

BACKGROUNDnNeurodevelopmental outcome after neonatal arterial switch operation for complete transposition of the great arteries is an important topic needing prospective assessment.nnnMETHODSnA group of 33 unselected children (3.0 to 4.6 years) operated on as neonates with combined deep hypothermic circulatory arrest and low flow cardiopulmonary bypass and a control group of 32 age-matched healthy children (3.0 to 4.8 years) underwent evaluation of socioeconomic and clinical neurological status and a standardized test comprising all areas of child development. Results of patients were related to those of the control group, to population norms, and to preoperative, perioperative, and postoperative cerebral risk factors.nnnRESULTSnClinical neurological status was normal in 26 patients (78.8%) and reduced in 7 (21.2%). Complete developmental score and the subscores for motor function, visual perception, learning and memory, cognitive function, language, and socioemotional functions were not different compared to population norms. Compared to the patients, the children of the control group scored higher on tests of complete development, cognition, and language, but also on socioeconomic status. Complete developmental score and the scores for motor, cognitive, and language functions were weakly inversely related to the duration of circulatory arrest, but not to the duration of bypass. Cerebral risk factors such as serum levels of the neuron-specific enolase, perinatal acidosis, perinatal asphyxia, peri- and postoperative cardiocirculatory insufficiency, or clinical seizures were not correlated to the test results.nnnCONCLUSIONSnNeonatal arterial switch operation with combined circulatory arrest and low flow bypass is associated with neurological impairment, but not with reduced development as assessed by formal testing of motor, cognitive, language, and behavioral functions. Perioperative serum level of the neuron-specific enolase is not a valid marker for later developmental impairment.

Endogenous production of nitric oxide in lambs |[dagger]| 1742

Objectives: To evaluate the course of nitrite and nitrate blood concentrations in lambs as indicator for endogenous nitric oxide (NO) production in relation to age and to the presence of a large left to right shunt through a patent ductus arteriosus which was maintained by repeated angioplasty.

Biocompatibility of different devices for interventional closure of the persistent ductus arteriosus in an animal model |[dagger]| 140

Objective. To evaluate and compare the tissue reaction of ductus arteriosus(DA) after implantation of three types of devices.