Last year saw a continuation of the trend to publish more articles on congenital heart diseases (CHD), a trend characterized by intensified interest in the epidemiological importance being acquired by this population.
One of the more notable studies on the consequences of modern interventions in CHD was the Finnish National Registry of late causes of death among patients younger than 15 years who underwent surgery between 1953 and 2009 (10 964 patients, 98% follow-up).1 This study compared causes of death with those in the general population, subdividing the results into 2 periods: 1953 to 1989 and 1990 to 2009. Total survival was higher in the second period, and the main cause of CHD-related death was heart failure (HF); however, the rate of HF-death declined significantly over the long-term among patients who underwent surgical correction of ventricular septal defects and transposition of the great arteries. An especially notable finding was the near complete absence of sudden death in the second period among patients with tetralogy of Fallot and transposition of the great arteries. Also of interest is the higher death rate from neurological diseases and infections among CHD patients and a higher incidence of neoplasms, especially in the second period.1
Although HF is the main cause of death among CHD patients, the indications and optimal timing for transplantation are less well defined than for other heart conditions. Patients with CHD are less likely than other heart disease patients to be fitted with a defibrillator or ventricular assist device or to be included on high-priority wait-lists, and their wait-list mortality is higher. These specific concerns prompted the American Heart Association to issue a scientific statement reviewing the particular characteristics of CHD patients that can affect transplant surgery, such as complex anatomies frequently requiring additional surgery, HLA antibody sensitization, and difficult vascular access.2 The review also examines evidence on the effectiveness of ventricular assist devices in the treatment of CHD and proposes therapeutic strategies to improve transplant outcome, including specific changes to the criteria used to assign urgency status to CHD patients on transplant wait-lists.2
Studies examining sudden death among CHD patients included a meta-analysis of the use of implantable cardioverter-defibrillators in a total of 2162 individuals followed up over 3.6±0.9 years.3 In this population, 1 or more appropriate shocks were recorded in 22% of patients in primary prevention and 35% of those in secondary prevention; inappropriate shocks were recorded in 25% of patients, and other defibrillator-related complications in 26%.3 These findings point to the need for continuing improvements in risk stratification and implantation programs.
There is also increasing awareness of the influence of CHD on psychosocial factors, reproductive function, and noncardiac conditions. A study published last year sought to characterize the effects of CHD on brain function, describing how neurodevelopment before birth and during infancy is influenced by a close interaction among genetic and epigenetic factors, direct disease consequences, such as severe cyanosis, and even therapeutic interventions; moreover, the cumulative burden of CHD continues into adulthood, when disease progression and the appearance of HF, arrhythmias, and comorbidities contribute to brain damage in the form of neurovascular disease.4 The article also suggests interesting future directions for translational research to improve prognosis and quality of life in this population. Several studies have explored the multiorgan consequences of univentricular circulation, examining post–Fontan-procedure hemodynamics and the prevalence of liver fibrosis; however, these studies have not yet been translated into a specific therapeutic program. It is nonetheless worth highlighting a small, single-center study that presented a new therapeutic option for plastic bronchitis, a serious complication after single-ventricle palliation; the authors used a percutaneous embolization technique to reduce lymphatic flow to the pulmonary parenchyma, reporting significant symptomatic improvement in 15 of the 17 patients treated.5 Plastic bronchitis is associated with high morbidity and mortality, and this new treatment could therefore represent an important advance if confirmed in a larger population over a longer follow-up.
Cardiac magnetic resonance is undoubtedly one of the most important imaging tools for diagnosis, risk stratification, and treatment planning. A recent review summarized advances applied to CHD such as 3D flow imaging, which helps to elucidate underlying pathophysiology, and tissue characterization techniques such as T1 mapping, which can detect clinical features of tetralogy of Fallot and systemic right ventricle.6 The article also emphasizes the need to carefully manage gadolinium contrast agent administration to patients who will require repeat examinations throughout life from an early age.
On a final note, the past year saw a continued dearth of randomized studies in large CHD cohorts; moreover, a high proportion of published articles reported retrospective single-center studies, demonstrating the enormous potential for future research in this area.