Congenital heart disease (CHD) is an abnormal formation that occurs during the development of a baby’s heart, heart valves and/or large vessels such as the aorta artery. CHD is the most common cause of major congenital defects accounting for almost 30% of all defects (Van der Linde D, JACC 2011). While the statistics vary among studies, the best birth prevalence estimate is 8 per 1000 live births (Bernier PL 2010). In the USA, CHD affects 1% of all births per year (Krasuki & Bashore 2016), with an estimated 40,000 babies born with any type of heart defect every year (Benjamin Emelia 2018). Twenty-five percentof these are affected by a severe congenital heart defect (https://www.cdc.gov/ncbddd/heartdefects/data.html#References). Children with CHD who survive after the surgical procedures can develop heart failure and require a heart transplant at any time in their lives. Infants born with CHD need immediate medical attention and multiple follow-ups throughout their lives. Besides the social and economic impact of CHD on the individual and family lives, CHD treatment places a significant financial burden on the healthcare system. Simeone et al, (2014) reported that the cost of CHD hospitalization in the US was approximately $5.6 billion in 2019, accounting for 15.1% of the total cost for all pediatric hospitalizations in that year.
The important improvements in CHD diagnosis and surgical treatment in the last decades has led to an increased survival of newborns affected with heart defects. A large number of CHD can be diagnosed during pregnancy, and the patients can present a broad range of symptoms. Forms of CHD are usually classified based on their severity, from mild to severe. One of the mildest forms of CHD is atrial septal defect, which can be undetectable until adulthood (Hoffman & Kaplan, 2002) and VSD (Penny DJ, 2011). On the other hand, severe CHD that requires multiple palliative surgeries includes single ventricle defects, such as hypoplastic left heart syndrome (HLHS) and tricuspid atresia.
The survival of infants with CHD will depend on the severity of the defect and the time of diagnosis and treatment received. The one-year survival of newborns with severe or critical CHD (generally any type of surgery/procedures in their first year of life) is estimated to be 75%.
Stem cell therapy has emerged as a new paradigm of treatment in the field of CHD with promising results. Cardiac regeneration has been the focus of acquired, adult heart disease for many years. However, congenital heart disease with structural abnormalities may also be a good target for other research studies. In fact, the pediatric heart is naturally growing and may be amendable to regenerative strategies. Furthermore, the initial pre-clinical and clinical studies have demonstrated that the delivery of stem cells into the heart of patients with CHD is feasible and safe. Moreover, the cell therapy approach, along with the standard surgical palliation, seems to offer benefits over surgical treatment alone. Even though the number of cell therapy clinical trials for CHD has increased in the last decade, more long-term follow-up studies are needed in this population setting in order to define the role of stem cell therapy in the clinical practice. Therefore, confirming our ability to produce autologous cells (cells from the patient's own body) from patients with severe CHD is an important step towards the long-term goal of being able to discover innovative cell-based protocols.