Current Pediatric Research

Table 4. Distribution of single and multiple CHD in children with Down syndrome

At presentation, among all 70 children with DS, 42 (60.0%) were undernourished, 36 of whom had CHD and the remaining six were among the 17 children with DS but without CHD. Thus, this higher proportion (67.9%) of children with DS with CHD being undernourished relative to 35.3% among those without CHD was statistically significant (χ² _{Yate’s correction applied}=4.432 and p=0.035). From among the 53 DS children with CHD, 14 (26.4%) had developed pulmonary arterial hypertension, 10 (18.9%) had left ventricular dysfunction and 10 (18.9%) had varying degrees of pericardial effusions.

Only 4 (7.5%) of the children with DS in contrast with 21 (14.1%) of the non-syndromic children have had definitive corrective interventions of their CHD. 25 (47.2%) have been unable to have definitive treatments because of costs of surgery, 2 (3.8%) declined open heart surgery on religious grounds and 10 (18.9%) opted for faith-based interventions. Ten (18.9%) of the children with DS and CHD have died and another 4 (7.5%) lost to follow-up. The remainder are undergoing palliative care.

Discussion

In this study, 75.7% of children with Down syndrome had congenital heart disease. This is higher than the 40- 60% documented in some literature [7-9]. But similar to the findings in Kano, Northern Nigeria by Asani et al. [12] who reported 77.1% and Shrestha and Shakya [16] who reported 80% from Nepal. In addition to plausible racial and geographic influences, another reason for this discrepancy may be that most of our subjects were referred because they had clinical features suggestive of cardiac defects and not just dysmorphism.

We found solitary cardiac lesions in 45.3% of our subjects with DS with AVCD being the most common lesion similar to the findings of Ekure et al. [13] in Lagos and Asani et al. [12] There are varied reports as to the most prevalent cardiac lesions seen in children with DS with AVCD being the most common [8,17-19]. Mourato et al. [20] and Vilas et al. [21] in Brazil reported ASD while Shrestha and Shakya [16] and Laursen [22] reported VSD. Otaigbe et al. [14] reported PDA to be the most common lesion in Port Harcourt, Nigeria similar to a study in Guatemala [23]. In our study, 54.7% of DS patients with CHD had multiple lesions with the combination of VSD and ASD being the most common. Shrestha and Shakya reported PDA as the most frequently associated lesion followed by ASD among patients with multiple lesions [16]. Granzotti et al. [24] found a significant number of children with Tetralogy of Fallot while other studies have shown low incidence of this lesion [25]. In this study, 16.9% of children with DS had TOF. Presence of multiple defects in these children may worsen their prognosis and predispose them to the development of complications earlier than other non-syndromic children with CHD. This buttresses the need to refer all DS children for routine echocardiographic examination as soon as the diagnosis of DS has been made in them.

The mean age of about 12 months of the children with DS at presentation in the present study illustrates the delay in clinical suspicion of associated congenital heart diseases in these children. In contrast, diagnosis of CHD would have been made earlier in children with DS in developed countries [7]. Absence of foetal diagnosis and early neonatal echocardiographic screening of children with DS in developing countries caused delay in making a definitive diagnosis of CHD in such children. None of the children from this series was diagnosed with CHD in the neonatal period. Other contributors to delay in making the diagnosis of CHD in children with DS may include delivery outside of a health facility, wrong cultural beliefs and poor health seeking behaviour.

More than half of the children with DS in the present study were the first or second born children of their parents. Otaigbe et al. [14] also reported 60% of the children as second born different from previous studies of patients in which they were mainly first born [16,26]. Also a slight majority of the mothers of the children with Down syndrome were younger than 30 years. Similarly, Figueroa et al reported a high proportion of 34% of young mothers of children with DS [26]. The high proportion of young mothers with DS may be explained by greater number of pregnancies occurring in this age group. Contribution of environmental factors, such as abnormalities of folate metabolism, to the aetiopathogenesis of Down syndrome may also partly explain why a significant majority of mothers of patients with DS are in the younger age category in the present study [27]. This has great social implication on the people of Ile-Ife and possibly by inference on Nigerians. There is a need to increase awareness of congenital malformation, especially DS among the population. Foetal screening and early neonatal echocardiographic evaluation of children with congenital malformation should be encouraged and advocated. The mean ages of both mothers and fathers were also significantly lower among children with CHD than those without. An old study by Rowe and Uchida found no apparent difference in the maternal age distribution in cases with and without congenital heart diseases [28]. A more recent study by Khoury and Erickson also did not find a significant difference when he compared the proportion of DS with CHD between women <35 years and those ≥ 35 years [29]. Freeman et al. [8] also reported no relationship between maternal age and congenital heart diseases. Vilas et al. [21] reported that half of the mothers and 89% of the fathers were older than 35 years during pregnancy. However, parental age did not have an influence on the occurrence of congenital heart diseases in other studies [21,30,31].

Figure 1: Types and frequencies of individual CHD seen in children with Down syndrome.

Our study also showed that DS patients with CHD had lower birth weights and presented earlier than those without. Malnutrition is common in children with DS. Those with congenital heart disease are smaller and lighter than those without or with mild disease [32].

Pulmonary arterial hypertension (PAH) was recorded in 26.4% of the children with DS. Shrestha reported 52.5% having PAH and Mourato recorded 37.5% developing PAH [16,20]. It has been reported that patients with DS develop pulmonary hypertension early when they have left to right shunt lesions. Individuals with DS may have pulmonary arterial hypertension for various reasons such as chronic airway obstruction, abnormal growth of the pulmonary vasculature, alveolar hypoventilation, decreased number of alveoli and thinner pulmonary arterioles [33,34].

21 (14.1%) of the non-syndromic children had corrective surgery compared with only 4 (7.5%) of the children with DS. This is mainly because many parents could not afford the cost of treatment particularly for those patients with complex lesions. Also, many of them had developed complications such as severe PAH. The presence of other health challenges in some of the patients, which the parents had to constantly address, probably also limited the chances of the parents of being financially buoyant enough to pay for the cost of correction of heart defects. Thus, there is need for the establishment of Foundations and Trusts to support the care of the children with DS and their families in this community to brighten their chances of earlier surgical correction of CHD with the likelihood of improved quality of life.

Conclusion

The occurrence of CHD among children with Down syndrome seen in our setting is higher than previously documented in other regions of Nigeria. Majority of these children have multiple lesions with atrial septal and atrioventricular canal defects being the most common. These children present late and the level of definitive care they currently receive is minimal. We advocate for routine and early cardiologic evaluation of all children suspected with Down syndrome.

Acknowledgement

We acknowledge with thanks, the efforts of Prof. Oluwagbemiga Adeodu (MBBS, FWACP) of the Department of Paediatrics and Child Health, Obafemi Awolowo University, Ile-Ife in the review of the manuscript.

Declarations

Availability of Data and Materials

The data will not be shared to respect the privacy of participants.

Authors’ Contributions

Study design: JO.1; Data collection and interpretation: JO1, IS, OA, JO; Manuscript preparation: JO1, UO; Literature search: UO, OA, IS, JO; Final approval: All authors.

Consent for Publication

Consent to publish was obtained from all patients’ parents.

Ethics Approval and Consent to Participate

Sort and obtained from the Department of Paediatrics, OAUTHC, Ile-Ife.

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