Faculty Bibliography

Common atrioventricular canal (CAVC) is a common congenital heart lesion resulting from a defect in development of the endocardial cushions during early embryogenesis. Depending on the type of defect, CAVC can encompass a spectrum of lesions ranging from partial atrioventricular (AV) canal to complete AV canal. We describe a case of CAVC with unique anatomy in a 4-month-old male infant with Down syndrome.

Down syndrome is known to be an independent risk factor for mortality after surgical repair of congenital heart anomalies. It is also associated with neurodegenerative disease and accelerated aging. The mechanism of the latter features has been attributed to abnormal handling of oxygen-free radicals as well as mitochondrial dysfunction. These properties also place the child with Down syndrome at a risk of an exaggerated myocardial ischemia/reperfusion injury. A 6 month old child with Down syndrome is reported who suffered from obvious clinical ischemia/reperfusion injury following an uncomplicated repair of complete AV canal. Both intraoperative as well as postoperative echocardiography documented a satisfactory technical repair. After resting the heart on ECMO the child's myocardial function returned to normal. The mechanisms by which patients with Down syndrome are at risk of ischemia/reperfusion injury are reviewed. Future studies should focus on specific approaches for myocardial protection in the child with Down syndrome undergoing cardiac surgery.

BACKGROUND:The integrity of the blood brain barrier (BBB) after cardiopulmonary bypass (CPB) with hypothermic circulatory arrest (HCA) is controversial in children. We tested the hypothesis that the BBB is disrupted by HCA. METHODS:Forty-one piglets (mean weight 11 kg) were randomly allocated to acute and survival experiments. Five groups (25 piglets, 5 per group) underwent acute studies: anesthesia alone (control); CPB at 37°C with full-flow (FF); CPB at 25°C with very low flow (LF); HCA at 15°C, and HCA at 25°C. Two groups (16 piglets, 8 per group) underwent survival studies: CPB at 25°C with LF and HCA. In the acute studies, Evans blue dye (EBD) extravasation through the BBB into the brain was measured using two methods: EBD absorbance of homogenized brain, and immunohistochemical localization of EBD-linked albumin for cortex, caudate nucleus, thalamus, hippocampus, and cerebellum. In the survival studies, cerebral histology was assessed with hematoxylin-eosin stain after sacrifice at 4 days after surgery. RESULTS:The BBB disruption was clearly observed around watershed areas for 25°C HCA compared with other conditions. Microscopic data showed that leakage of EBD in 25°C HCA was more severe than control in all brain areas (p < 0.05), and EBD and albumin were colocalizing. Histologic damage scores were significantly higher in watershed areas with 25°C HCA. CONCLUSIONS:The BBB was impaired around watershed areas by 25°C HCA for 1 hour according to both macroscopic and microscopic data. An increase in permeability of the BBB may be both a sign and a mechanism of brain damage.

OBJECTIVE:Our objective was to assess the morbidity and mortality in children requiring extracorporeal membrane oxygenator support after cardiac surgery and to determine factors influencing outcome. METHODS:Between January 2003 and June 2008, 58 patients required extracorporeal membrane oxygenator support after cardiac surgery. A retrospective study was performed and factors influencing outcome were determined by logistic regression modeling with the probability of outcome based on a combination of multivariate predictors. RESULTS:Median age and weight were 12 days and 3.3 kg, respectively. Thirty-one patients had single ventricle repair and 27 had biventricular repair. Median duration of support with the oxygenator was 6 days. Thirty-nine (67%) patients were successfully weaned off the support, but only 24 (41%) survived to hospital discharge. Chief complications were renal failure (31%), neurologic complications (29%), and sepsis (16%). Multivariable logistic regression analysis identified 10 days or more of extracorporeal membrane oxygenation (odds ratio = 6.1), urine output less than 2 mL x kg(-1) x h(-1) in first 24 hours (odds ratio = 15), renal failure (odds ratio = 9.4), and pH less than 7.35 after 24 hours of extracorporeal membrane oxygenation (odds ratio = 82) as significant independent factors associated with failure to wean off extracorporeal membrane oxygenation. Factors associated with failure of hospital discharge despite successful decannulation were as follows: extracorporeal membrane oxygenator support time of 10 days or more, red blood cell transfusion of greater than 1000 mL/kg during the entire period of oxygenator support, and sepsis. Patients with single ventricle repair were at higher risk of hospital mortality. CONCLUSION/CONCLUSIONS:Longer duration of extracorporeal membrane oxygenator support, low pH and urine output in the first 24 hours, and renal failure are significant factors associated with mortality during extracorporeal membrane oxygenator support. Exposure to high amounts of blood transfusion during extracorporeal oxygenation, extended extracorporeal membrane oxygenator support, and sepsis increase risk of death after successful decannulation.

Extracorporeal membrane oxygenation is widely used to support and rest the heart before or following repair of congenital cardiac lesions in children. The beneficial effects of extracorporeal membrane oxygenation for the failing myocardium are undisputed. It is often an automatic choice whenever the heart seems incapable of supporting the circulation. However, its use may prove detrimental in patients with coronary anomalies, as illustrated by the case reports presented here.

A simple technique for reconstruction of the tricuspid valve in patients with congenital isolated tricuspid regurgitation is described. A single piece of autologous pericardium is used for en bloc reconstruction of the tricuspid valve and its chordae.

We report the case of a 41-year-old woman who presented with extensive papillary fibroelastomas of the heart after multiple previous surgical procedures for hypertrophic cardiomyopathy. This case is significant because of the locally aggressive nature of the cardiac papillary fibroelastoma.

We report a case of interrupted aortic arch and origin of the left pulmonary artery from the aorta with bilateral ductus arteriosus and discuss its possible embryological basis. To the best of our knowledge, this combination of anomalies has not been reported in the English medical literature.