Management of anomalous circumflex coronary artery from the neo-pulmonary artery in an adolescent following neonatal arterial switch operation.

A 15-year-old male with transposition of the great arteries presented with exertional chest pain. He was found to have a circumflex coronary artery from the neo-pulmonary artery that had not been transferred during his arterial switch operation. The circumflex coronary artery, fed through collaterals from a re-implanted single coronary artery, resulted in coronary steal. This report describes a management pathway to treat this rare anomaly.

Unzipping of small diameter stents: an in vitro study.

OBJECTIVE: The purpose of this study was to determine if small-diameter stents can be unzipped in vitro. BACKGROUND: Small-diameter stents can relieve stenosis in infant blood vessels. As the child grows, refractory stenosis may result. If an implanted stent can be intentionally fractured along its length-"unzipped," it can be redilated to the eventual adult vessel diameter. METHODS: Stents of diameters ≤6 mm were dilated using angioplasty balloons until they fractured. The change in length-diameter (dL/dD ratio), and the yield-point-force (σy ) for each stent was calculated. RESULTS: Thirty-four coronary (CS), 11 biliary, and 10 nitinol peripheral stents (median diameter = 4, 5, and 6 mm; range = 2.75-4.5, 4-6, 6 mm, respectively) were tested. Stainless-steel (SS) CS unzipped predictably at twice their nominal diameter with minimal shortening (n = 24, median dL/dD = 0.4). Nitinol stents fractured in a disorganized fashion. The remaining stents unzipped, had disorganized fractures, and shortened significantly (dL/dD>1). A dL/dD ratio of<1 had a strong, positive correlation with the ability to unzip (Pearson rho = 0.94). By multivariate regression analysis, SS alloy, and closed-cell design were found to be significant predictors (P < 0.05) for unzipping. Optimal cut-off points for stents to unzip included, strut-thickness = 112 µm, alloy-density = 7.7 g/cm(3) , dL/dD ratio = 0.12 and σy = 108Mpa (Youden's index = 0.8, 0.4, 0.8, and 0.5, respectively). CONCLUSIONS: Stainless-steel, coronary stents of a closed-cell design unzip at twice their nominal diameter without significant shortening when serially dilated. This study may encourage the implantation of small stents in infant blood vessels and aid in selection of appropriate stent type.

Feasibility and Safety of Unzipping Small Diameter Stents in the Blood Vessels of Piglets.

OBJECTIVES: This study sought to determine the feasibility and safety of unzipping small-diameter stents (SDS) in a growing animal model. BACKGROUND: SDS implanted to relieve stenosis of blood vessels in infants may result in refractory stenosis as the child grows. If stents can be longitudinally fractured-unzipped-then the target vessel can potentially be redilated to the eventual adult vessel diameter. METHODS: Fifty stents (diameter 4 to 7 mm) were implanted in 5 neonatal piglets (mean age and weight = 1.5 weeks and 3.4 kg). Pre-mounted coronary (CS) (n = 24), biliary (BS) (n = 14), nitinol (NS) (n = 3), and renal stents (RS) (n = 9) were implanted in pulmonary arteries (n = 13), systemic arteries (n = 25), and systemic veins (n = 12). Three months later (median weight = 32 kg), unzipping was attempted by dilating the stents. RESULTS: All CS and RS unzipped at twice their nominal diameter with <20% shortening. None of the NS unzipped. The BS shortened the most (∼40%), with only 69% of the stents unzipping. Stainless steel CS and RS with an open cell design were significant predictors (p ≤ 0.01) for unzipping. On histopathology, unzipping of the BS caused the most medial dissection and vessel wall injury, while unzipping of the CS caused the least. CONCLUSIONS: Unzipping of small-diameter CS and RS implanted in systemic and pulmonary vessels is more feasible than the BS and NS. This study may encourage the implantation of small stents in infant blood vessels and aid in selection of appropriate stent type.

Current Trends in the Management of Neonates With Ebstein's Anomaly.

BACKGROUND: The optimal management strategy for neonates with Ebstein's anomaly is unknown. This analysis was undertaken to assess current trends in the management and prognosis of neonates born with Ebstein's anomaly in the United States, as reflected in an administrative database. METHODS: The Pediatric Health Information System database (40 children's hospitals) was used to review the reported incidence and available data on neonates with Ebstein's anomaly treated in the United States between 2003 and 2007. Primary outcome was hospital survival. Of the 415 patients identified, 257 (62%) did not undergo initial surgical intervention as neonates. Aortopulmonary shunt only was done on 63 patients (15%), single-ventricle palliation on 36 (9%), two-ventricle repair on 16 (4%), heart transplantation in 3 (1%), and a catheter-based intervention or a hybrid palliative approach was applied in 40 (10%). Intergroup comparisons were done using chi-square analyses. RESULTS: Mortality for the entire cohort was 24% (100 of 415). For medically treated patients, this was 22% (56 of 257). For surgically treated and hybrid patients, this was 30% and 23%, respectively (P = NS). CONCLUSIONS: The majority of patients born with Ebstein's anomaly currently do not undergo surgical intervention as neonates. Significant early mortality in this group suggests that certain subsets of patients may benefit from earlier surgical intervention. Among the severely symptomatic neonates who do undergo early surgical intervention, the mortality remains high, irrespective of the surgical approach taken. A multicenter trial may be appropriate to identify strategies to optimize care for these critically ill neonates. Further analysis of risk factors for early mortality is warranted.