State of the art of cardiac surgery in patients with congenital heart disease

Transcriptome analysis defines myocardium gene signatures in children with ToF and ASD and reveals disease-specific molecular reprogramming in response to surgery with cardiopulmonary bypass

BACKGROUND

Tetralogy of Fallot (ToF) and Atrial Septal Defects (ASD) are the most common types of congenital heart diseases and a major cause of childhood morbidity and mortality. Cardiopulmonary bypass (CPB) is used during corrective cardiac surgery to support circulation and heart stabilization. However, this procedure triggers systemic inflammatory and stress response and consequent increased risk of postoperative complications. The aim of this study was to define the molecular bases of ToF and ASD pathogenesis and response to CPB and identify new potential biomarkers.

METHODS

Comparative transcriptome analysis of right atrium specimens collected from 10 ToF and 10 ASD patients was conducted before (Pre-CPB) and after (Post-CPB) corrective surgery. Total RNA isolated from each sample was individually hybridized on Affymetrix HG-U133 Plus Array Strips containing 38,500 unique human genes. Differences in the gene expression profiles and functional enrichment/network analyses were assessed using bioinformatic tools. qRT-PCR analysis was used to validate gene modulation.

RESULTS

Pre-CPB samples showed significant differential expression of a total of 72 genes, 28 of which were overexpressed in ToF and 44 in ASD. According to Gene Ontology annotation, the mostly enriched biological processes were represented by matrix organization and cell adhesion in ToF and by muscle development and contractility in ASD specimens. GSEA highlighted the specific enrichment of hypoxia gene sets in ToF samples, pointing to a role for hypoxia in disease pathogenesis. The post-CPB myocardium exhibited significant alterations in the expression profile of genes related to transcription regulation, growth/apoptosis, inflammation, adhesion/matrix organization, and oxidative stress. Among them, only 70 were common to the two disease groups, whereas 110 and 24 were unique in ToF and ASD, respectively. Multiple functional interactions among differentially expressed gene products were predicted by network analysis. Interestingly, gene expression changes in ASD samples followed a consensus hypoxia profile.

CONCLUSION

Our results provide a comprehensive view of gene reprogramming in right atrium tissues of ToF and ASD patients before and after CPB, defining specific molecular pathways underlying disease pathophysiology and myocardium response to CPB. These findings have potential translational value because they identify new candidate prognostic markers and targets for tailored cardioprotective post-surgical therapies.

Treatment of acute heart failure in the emergency department

Millions of patients are hospitalized for acute heart failure (AHF) every year throughout the world. Despite tremendous advances in cardiovascular care, morbidity and mortality for AHF remain high, consuming billions of health care dollars. With the aging of the population, the incidence and prevalence of HF is projected to increase. Yet, initial treatment of AHF today is similar to 40 years ago. Multiple studies have yielded new insights regarding initial management, with regards to both treatment and strategies of care. These advances will be reviewed in the context of initial or early AHF management. There remains, however, an unmet need to improve outcomes for AHF patients.

Ethical issues in cardiac surgery

While ethical behavior has always been part of cardiac surgical practice, ethical deliberation has only recently become an important component of cardiac surgical practice. Issues such as informed consent, conflict of interest and professional self-regulation, among many others, have increasingly attracted the attention of cardiac surgeons. This article covers several broad topics of interest to cardiac surgeons and cardiologists and discusses several other topics more briefly. There is much uncertainty regarding what the future holds for cardiac surgical practice, research and culture and we also discuss the background of ethical issues to serve as a platform for envisioning what is to come.

Adult congenital heart disease and pulmonary arterial hypertension: the Texas Adult Congenital Heart Program experience

Congenital heart disease (CHD) is a common structural defect of the heart or major blood vessels. Patients with adult congenital heart disease (ACHD) have medical needs that are distinct from those of pediatric patients with CHD, and the transition into adult health care is important for management of the patient with ACHD. A large proportion of patients with CHD develop diseases and complications associated with the long-term stress of intracardiac shunts. Pulmonary arterial hypertension (PAH) is a significant complication of some CHD lesions. The treatment of these patients remains challenging due to their combined heart and lung disease, and multidisciplinary care is ofen necessitated for a variety of secondary conditions. A number of treatment options are available for the management of PAH associated with CHD, including prostanoids, phosphodiesterase type-5 inhibitors, and endothelin receptor antagonists. This article discusses the diagnosis and management of such ACHD patients with PAH.

Application of nitric oxide in drug discovery and development

INTRODUCTION

It is becoming increasingly clear that many diseases are characterized or associated with perturbations in nitric oxide (NO) production/signaling. Therapeutics or strategies designed to restore normal NO homeostasis will likely have broad application and utility in human health. This highly complex and multi-step pathway for NO production and subsequent target activation provides many steps in the endogenous pathway that may be useful targets for drug development. Important therapeutic areas for NO-based therapies are inflammatory disorders, cardiovascular diseases, erectile dysfunction and metabolic disorders.

AREAS COVERED

The following review will discuss the endogenous NO pathway, highlight the current market and indications for NO-based therapeutics, as well as identify pathway targets currently under drug development. Each step along the NO pathway will be discussed including exogenous sources of NO, use of precursors to promote NO production and downstream pathways affected by NO production with advantages and disadvantages highlighted for each.

EXPERT OPINION

Development of NO-based therapeutics is and will continue to be a major focus of biotech and pharmaceutical companies. Understanding and utilizing dietary and nutritional strategies to restore NO homeostasis could allow for safer, quicker marketing of products that may be just as efficacious as drugs designed against specific targets.

Pediatric cardiac surgery in Northern Russia. Results from an international cooperative program

OBJECTIVES

In order to evaluate a Norwegian-Russian clinical cooperation, this study sought to compare the incidence, early mortality and morbidity of surgically treated patients with atrial septum defect (ASD), ventricular septum defect (VSD) and Tetralogy of Fallot (TOF) in Norway and Archangels region in Russia.

DESIGN

A retrospective analysis of patient records of all those surgically treated for ASD, VSD and TOF in Norway and from Archangels region from 1 January 2000 to 31 December 2005.

RESULTS

The Norwegian cohort consisted of 191 ASDs, 227 VSDs and 126 TOFs. The Russian cohort counted 128 ASDs, 77 VSDs and nine TOFs. Thirty-days mortality was 0.4% in the Norwegian VSD, 1.6% in the Norwegian TOF and 1.3% in the Russian VSD cohort. Postoperative complications in the Norwegian cohorts were 18.3% (ASDs), 15.9% (VSDs) and 34.1% (TOFs). The corresponding findings in Archangels were 4.7%, 11.7% and 0%.

CONCLUSION

Surgery for ASDs, VSDs and TOFs can be carried out with minimal early mortality in both countries. The discrepancy in early postoperative morbidity illustrates the challenges in comparative studies between different countries, cultures and health care systems. The establishment of a decentralized surgical facility has increased the access to cardiac surgery to the population in Archangels region.

Coagulation considerations for infants and children undergoing cardiopulmonary bypass

Cardiac surgery involving cardiopulmonary bypass imposes a significant pathophysiologic burden on patients. Pediatric patients are especially predisposed to the adverse effects of surgery and bypass on the coagulation system, with resultant bleeding, transfusion, and poor outcomes. These risks accrue to pediatric patients in inverse proportion to their weight and are attributable to hematologic immaturity, coagulation defects associated with congenital heart disease, bypass equipment, and the nature of congenital heart surgery. Standard anticoagulation does not completely inhibit thrombin generation, and continuous consumption of coagulation factor continues throughout bypass. Conventional measurements of anticoagulation during bypass poorly reflect this incomplete anticoagulation, and alternate methods may improve anticoagulant therapy. Emerging therapies for blocking the effects of bypass on the coagulation system hold promise for decreasing bleeding and related complications, and improving outcomes in congenital heart surgery.

Physical activity as a predictor of adolescent body fatness: a systematic review

Adolescent obesity has increased dramatically in several countries in recent decades; however, the contribution of physical activity level to adolescent adiposity requires clarification. This article investigates the effect of physical activity on subsequent levels of adiposity in adolescence. The methodological aspects of the studies included in this article, particularly in terms of measurement accuracy for both exposure (physical activity) and outcome (adiposity) variables, are also evaluated. Systematic searches of the literature were undertaken using online databases, including PubMed/MEDLINE, examination of citations and contacting of authors. The online databases were searched from their earliest records until 2007. Only longitudinal studies with 50 or more adolescents were included. Two independent reviewers assessed the quality of the studies using the Downs and Black checklist. Thirteen observational, five experimental and six quasi-experimental studies (without a control group) were identified. Almost all studies were carried out in high-income settings and showed protective effects of physical activity for both prevention and treatment of adolescent obesity. However, experimental studies undertaken with obese adolescents at baseline usually combined physical activity with dietary changes, making it difficult to assess the effect of physical activity itself on the treatment of obesity. Physical activity estimated from questionnaires and body mass index (BMI) were the most frequently used measures. Despite the feasibility of using these approaches in epidemiological studies, significant limitations are evident. Questionnaires are subjective and adolescents may not report physical activity level accurately. Furthermore, BMI is not an accurate measure of fatness for adolescents, as it is also associated with lean mass, hence bias may arise from its longitudinal association with physical activity level. Despite the majority of studies reviewed showing protective effects of physical activity on adiposity, particularly in individuals who are obese at baseline, the current literature on this issue is sparse and several methodological drawbacks are evident. The main limitations relate to a lack of validity in the measurements of both physical activity and body composition. Further studies are needed in order to generate evidence-based recommendations for the quantity and quality of adolescent physical activity required to prevent or treat adolescent obesity.

Congenital cardiac disease in the newborn infant: past, present, and future

Congenital heart defects are the most common of all congenital malformations, with a review of the literature reporting the incidence at 6 to 8 per 1000 live births. The Centers for Disease Control reports cyanotic heart defects occurred in 56.9 per 100,000 live births in the United States in 2005, with higher rates noted when maternal age exceeded 40 years. The incidence of congenital heart disease in premature infants is 12.5 per 1000 live births, excluding isolated patent ductus arteriosus and atrial septal defect. Despite advances in detection and treatment, congenital heart disease accounts for 3% of all infant deaths and 46% of death from congenital malformations. This article discusses the embryology, pathogenesis, clinical presentation, incidence, classifications, and management of congenital heart diseases.

Late complex biventricular repair after bidirectional cavopulmonary shunt

A child diagnosed with transposition of great arteries, multiple (Swiss cheese) ventricular septal defects, and a small right ventricle underwent pulmonary artery banding and patent ductus arteriosus ligation at the age of six months. At the age of three years bidirectional cavopulmonary shunt was performed as a first stage for univentricular repair. However, the patient was lost follow-up for four years, following which further evaluation showed that the right ventricle was reasonably adequate to support pulmonary circulation if the ventricular septal defects (VSDs) were closed using percutaneous techniques. Four VSDs were then closed using Amplatzer devices (AGA Medical Corporation, Plymouth, MN, USA). At the age of eight years she underwent complex biventricular repair in the form of arterial switch, closure of atrial septal defect, take down of Glenn shunt, and reanastomosis of the distal end of the superior vena cava to the distal superior vena cava stump on the right atrium. One year later the patient is alive and well. In conclusion; biventricular repair may be considered before completion of Fontan whenever cardiac anatomy allows.

The development of tissue-engineered grafts for reconstructive cardiothoracic surgical applications

Surgical correction of congenital heart defects often requires the use of valves, patches, or conduits to establish anatomic continuity. Homografts, xenografts, or mechanical prosthetic devices are frequently implanted during these surgical procedures. These grafts however lack growth potential, are associated with increased risk of thrombosis and infection and have limited durability, thus increasing the morbidity and mortality of their application in pediatric cardiac surgery. These limitations are being addressed through the development of living, biologic tissue-engineered valves, patches, and conduits. Pilot studies and phase 1 clinical trials are currently underway to evaluate their feasibility, safety, and efficacy. The optimal scaffold, cell source, and conditioning parameters, however, still remain to be determined and are areas of active research.