Persistent risk of subsequent procedures and mortality in patients after interrupted aortic arch repair: A Congenital Heart Surgeons' Society study

ObjectiveMultiple subsequent procedures directed at the arch and/or the left ventricular outflow tract are frequently required after interrupted aortic arch repair. We the investigated patterns and factors associated with these subsequent procedures and mortality.MethodsWe reviewed the data from 447 patients with interrupted aortic arch at 33 institutions enrolled from 1987 to 1997. We classified the subsequent procedures by type (catheter-based or surgical) and focus (arch, left ventricular outflow tract, and “other” cardiovascular lesions). We used competing risks and modulated renewal analysis to explore subsequent procedures.ResultsThere were 158 subsequent arch and 100 left ventricular outflow tract procedures. Freedom from death at 21 years was 60% overall. The risk of additional subsequent arch procedures decreased after the first subsequent arch procedure in the acute phase, but did not significantly change in the chronic phase. The risk of additional subsequent left ventricular outflow tract procedures increased after the first subsequent left ventricular outflow tract procedure in the chronic phase. The risk factors for subsequent arch procedures and mortality, but not for subsequent outflow track procedures, were related in a complex way to previous procedures and their timing.ConclusionsInterrupted aortic arch is a chronic disease in which patients often undergo multiple subsequent procedures with persistent risk for additional intervention and mortality. The risk factors are related to the nature and timing of previous procedures and to the morphology and details of the index procedure. Interrupted aortic arch should be considered a chronic disorder

Gene expression in cardiac tissues from infants with idiopathic conotruncal defects

<p>Abstract</p> <p>Background</p> <p>Tetralogy of Fallot (TOF) is the most commonly observed conotruncal congenital heart defect. Treatment of these patients has evolved dramatically in the last few decades, yet a genetic explanation is lacking for the failure of cardiac development for the majority of children with TOF. Our goal was to perform genome wide analyses and characterize expression patterns in cardiovascular tissue (right ventricle, pulmonary valve and pulmonary artery) obtained at the time of reconstructive surgery from 19 children with tetralogy of Fallot.</p> <p>Methods</p> <p>We employed genome wide gene expression microarrays to characterize cardiovascular tissue (right ventricle, pulmonary valve and pulmonary artery) obtained at the time of reconstructive surgery from 19 children with TOF (16 idiopathic and three with 22q11.2 deletions) and compared gene expression patterns to normally developing subjects.</p> <p>Results</p> <p>We detected a signal from approximately 26,000 probes reflecting expression from about half of all genes, ranging from 35% to 49% of array probes in the three tissues. More than 1,000 genes had a 2-fold change in expression in the right ventricle (RV) of children with TOF as compared to the RV from matched control infants. Most of these genes were involved in compensatory functions (e.g., hypertrophy, cardiac fibrosis and cardiac dilation). However, two canonical pathways involved in spatial and temporal cell differentiation (WNT, <it>p </it>= 0.017 and Notch, <it>p </it>= 0.003) appeared to be generally suppressed.</p> <p>Conclusions</p> <p>The suppression of developmental networks may represent a remnant of a broad malfunction of regulatory pathways leading to inaccurate boundary formation and improper structural development in the embryonic heart. We suggest that small tissue specific genomic and/or epigenetic fluctuations could be cumulative, leading to regulatory network disruption and failure of proper cardiac development.</p

Pediatric Cardiopulmonary Bypass Adaptations for Long-Term Survival of Baboons Undergoing Pulmonary Artery Replacement

Cardiopulmonary bypass (CPB) protocols of the baboon (Papio cynocephalus anubis) are limited to obtaining experimental data without concern for long-term survival. In the evaluation of pulmonary artery tissue engineered heart valves (TEHVs), pediatric CPB methods are adapted to accommodate the animals’ unique physiology enabling survival up to 6 months until elective sacrifice. Aortic access was by a 14F arterial cannula and atrial access by a single 24F venous cannula. The CPB circuit includes a 3.3 L/min flow rated oxygenator, ¼″ × ⅜″ arterial-venous loop, ⅜″ raceway, and bubble trap. The prime contains 700 mL Plasma-Lyte, 700 units heparin, 5 mL of 50% dextrose, and 20 mg amiodarone. Heparinization (200 u/kg) targets an activated clotting time of 350 seconds. Normothermic CPB was initiated at a 2.5 L/m2/min cardiac index with a mean arterial pressure of 55–80 mmHg. Weaning was monitored with transesophageal echocardiogram. Post-CPB circuit blood was re-infused. Chest tubes were removed with cessation of bleeding. Extubation was performed upon spontaneous breathing. The animals were conscious and upright 3 hours post-CPB. Bioprosthetic valves or TEHVs were implanted as pulmonary replacements in 20 baboons: weight = 27.5 ± 5.6 kg, height = 73 ± 7 cm, body surface area = 0.77 m2 ± 0.08, mean blood flow = 1.973 ± .254 L/min, core temperature = 37.1 ± .1°C, and CPB time = 60 ± 40 minutes. No acidosis accompanied CPB. Sixteen animals survived, four expired. Three died of right ventricular failure and one of an anaphylactoid reaction. Surviving animals had normally functioning replacement valves and ventricles. Baboon CPB requires modifications to include high systemic blood pressure for adequate perfusion into small coronary arteries, careful CPB weaning to prevent ventricular distention, and drug and fluid interventions to abate variable venous return related to a muscularized spleno-splanchnic venous capacity