The global prevalence of CHDs shows an increase of 10% every 5 years, which is due to the expansion of the use of echocardiography and the improvement of technologies, according to a meta-analysis on the epidemiological situation of congenital heart diseases [9].
In the study hospital, 502 patients were referred by the cardiopaediatrics group, most often coming to us for elective surgery, but many also were transferred from other hospitals or were born in the obstetric centre of our hospital. In Brazil, a study on the local epidemiological situation estimated 25,757 new cases of CHD/year, without considering the large amount of underreporting, serving as a warning about the growing number of new cases and the need to direct investments to the care of this local population [10].
We saw no predominance of one sex over another, in line with several other studies [11, 12]; however, there are studies that report significant sex-related differences in specific heart diseases [13].
Some 19.3% of our sample were born prematurely. This high number is in line with the finding that 16% of children born with cardiovascular malformations are premature, according to a large English study [14]. In addition, an important issue in this population is the high mortality rate [14]. Premature infants who have CHD have a worse performance than those born at term because they are more vulnerable, and this condition remains a clinical and surgical challenge [15].
The most frequent CHDs found in the present study were acyanogenic, which is in agreement with the epidemiological data from national publications [4–10, 16]. In international data, there is also a predominance of acyanogenic heart diseases [9, 17]. The prevalence of mild injuries is due to the greater use of echocardiography worldwide, which has increased the diagnosis rate. In addition, abortion in complex heart diseases is an option in many countries, which also influences the reduction of the incidence of these specific CHDs [9, 17].
Total atrioventricular septal defect (10.56%), interventricular communication (9.96%), and aortic coarctation (9.56%) are the most prevalent acyanogenic CHDs. Of the congenital cyanogenic heart diseases, the most commonly found were tetralogy of Fallot (10.56%), transposition of the great arteries (6.38), and left heart hypoplasia syndrome (5.98%). Other studies have found that tetralogy of Fallot was the most frequent cyanogenic CHD [9, 11]. Total atrioventricular septal defect was the most common acyanogenic CHD, but it is not the most prevalent in the world literature, which can be explained by the significant number of patients with Down syndrome (n = 91) in our study population [16].
In CHDs, the anatomy determines the cardiac physiology, and patients with univentricular physiology have a more complex clinical management and undergo numerous invasive interventions throughout life [18]. In this study, the classification of patients according to physiology showed a prevalence of 81.1% with biventricular physiology, whereas univentricular patients represented 18.9% of the sample. This significant proportion presents a challenge for the entire multidisciplinary intensive care team. The physiology of a single ventricle may result from a series of anatomical lesions that are associated with a variety of physiological manifestations, requiring great expertise from the professionals involved in conducting treatment and surgical correction [18].
Syndromes were diagnosed in 31.2% of our sample, which is in agreement with the range found in the literature of 25 to 30% 19,20. Chromosomal diseases stood out, especially Down syndrome, representing 58% of the syndromes found. The high prevalence of chromosomal diseases corroborates the recommendation of the need to perform chromosomal studies in new-borns with multiple anomalies [4].
A total of 34.7% of our sample had associated comorbidities. The abnormal circulatory physiology in children with CHD influences the development and functioning of other systems, with a significant impact on the clinical management and outcome of cases [21]. Seizures, protein-calorie malnutrition, and encephalopathies were the main comorbidities found in this study.
Syndromes, extracardiac anomalies, prematurity, low birth weight, and other associated comorbidities aggravate the challenges associated with the treatment of CHD and are significant risk factors that affect the survival of these patients [21, 22]. The vast majority of patients included in the study (88.65%) underwent invasive intervention. In total, 530 procedures were performed, of which 77% were surgeries, 18.5% were haemodynamic procedures, and 4.5% were hybrid procedures. A risk score called RACHS-1 was used to categorize the surgeries. Despite some shortcomings, such as the low individual predictive power and the inability to classify all cardiac procedures, RACHS-1 is a well-used and widespread tool that categorizes CHD according to the expected mortality in six categories. Each of them is used as a predictor of postoperative mortality [23, 24]. In the present study, there was a predominance of category 3 (38.4%), followed by category 2 (28.6%), category 1 (18.2%), category 4 (9.6%), and category 6 (5, 2%). According to a Brazilian study of mortality in CHD using RACHS-1 in a single centre, the mortality rate of category 3, the main one in this study, was 8.5%, though it ranged from 10.4–60% in international reports [23]. On top of the high risk scores for the surgeries themselves, surgical complexity and treatment outcome are also strongly influenced by comorbidities and associated syndromes, both present in one-third of our sample [24]. This information reflects the need for highly specialized care, presenting a challenge for clinical and surgical teams.
This study’s main limitation was its retrospective nature. Because of this and the changes in the hospital evolution system, the data were limited.