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ORIGINAL ARTICLE
Year : 2020  |  Volume : 22  |  Issue : 1  |  Page : 46-50

Congenital heart disease and associated comorbidities among children with Down syndrome in the Niger Delta region of Nigeria


1 Department of Paediatrics and Child Health, Niger Delta University, Amassoma, Bayelsa State, Nigeria
2 Department of Paediatrics, University of Jos, Jos, Plateau State, Nigeria
3 Department of Paediatrics, University of Uyo Teaching Hospital, Uyo, Akwa Ibom State, Nigeria
4 Department of Paediatrics, Federal Medical Centre, Keffi, Nasarawa State, Nigeria
5 University of Texas Medical School, San Antonio, Texas, USA

Date of Submission19-Nov-2019
Date of Decision05-Feb-2020
Date of Acceptance25-Feb-2020
Date of Web Publication20-May-2020

Correspondence Address:
Chika O Duru
Department of Paediatrics and Child Health, Niger Delta University, Amassoma, Bayelsa State
Nigeria
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jomt.jomt_39_19

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  Abstract 


Introduction and Objectives: Congenital heart disease (CHD) in children with Down syndrome is a common association. This study aims to describe the pattern of CHD and associated co-morbidities seen in children with Down syndrome in the Niger Delta Region of Nigeria. Materials and Methods: This was a descriptive cross-sectional study conducted in Uyo, Akwa Ibom State, during a cardiac mission. Children with phenotypic features suggestive of Down syndrome and a prior diagnosis of CHD had trans-thoracic echocardiogram performed by a team of paediatric cardiologists. The data were analyzed with STATA 14.0 Statistical package. Results: Thirty-five children with physical features suggestive of Down syndrome were seen, all of whom had CHD. They had a mean age of 5.8 months at diagnosis and 25.8 months at presentation. The most common heart defects detected were Atrioventricular septal defects in 28.6% of cases. The most common co-morbidity noted was heart failure in 17 (48.6%) of them followed by wasting in 15 (42.9%). Though 14 (40.0%) children were on a pulmonary vasodilator (sildenafil), only 5 (14.3%) children had features suggestive of pulmonary hypertension on echocardiography, all with atrioventricular septal defects (AVSD). Conclusion: AVSD is the most common CHD seen among children with Down syndrome in our study and is frequently associated with pulmonary hypertension.

Keywords: Congenital heart disease, Down syndrome, Niger Delta


How to cite this article:
Duru CO, Ige OO, Okpokowuruk FS, Daniels QO, Udo PA, Megbelayin F, Edem KB, Olabiyi O, Yilgwan CS. Congenital heart disease and associated comorbidities among children with Down syndrome in the Niger Delta region of Nigeria. J Med Trop 2020;22:46-50

How to cite this URL:
Duru CO, Ige OO, Okpokowuruk FS, Daniels QO, Udo PA, Megbelayin F, Edem KB, Olabiyi O, Yilgwan CS. Congenital heart disease and associated comorbidities among children with Down syndrome in the Niger Delta region of Nigeria. J Med Trop [serial online] 2020 [cited 2020 May 31];22:46-50. Available from: http://www.jmedtropics.org/text.asp?2020/22/1/46/284640




  Introduction Top


Down syndrome (DS) also known as Trisomy 21 is the most common chromosomal disorder with a worldwide incidence that varies from 1 in 600 to 1 in 800.[1],[2] In Nigeria, DS is estimated to occur in 1 in 865 live births.[3] It is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21.[4] The presence of this unique genetic material is responsible for their characteristic phenotypic features as well as other associated medical conditions such as congenital heart disease (CHD), gastrointestinal malformations, visual and hearing impairments, thyroid disorders, leukaemia and varying degrees of cognitive impairment.[4]

CHD is the most common abnormality seen in about 40–60% of infants born with DS.[5],[6] Atrioventricular septal defect (AVSD), Ventricular septal defect (VSD) and Atrial septal defect (ASD) are the most common lesions seen in DS.[5],[6] These left to right shunt lesions frequently lead to heart failure because of volume overload of the pulmonary circulation.[7] Prolonged pulmonary overcirculation leads to pulmonary hypertension which typically occurs earlier in those with DS compared with their non-DS counterparts because of concomitant abnormalities in pulmonary vessel growth, obstructive sleep apnea, gastro-esophageal reflux, recurrent aspiration, chronic upper airway obstruction and recurrent pulmonary infections to which they are prone.[8] The early detection and prompt management of CHD in children with DS is thus important to prevent the development of complications.[7],[8]

Echocardiography is currently the best non-invasive method to detect CHD. Early diagnosis of CHD and associated co-morbidities is an important step for effective management of these children so as to optimize their overall quality of life. We thus set out to describe the prevalence of CHD and associated co-morbidities in DS patients seen in the Niger Delta region of Nigeria during a cardiac screening mission using trans-thoracic echocardiography.


  Materials and methods Top


Study setting

This study was conducted in Uyo, Akwa Ibom State during a cardiac mission in May 2019. General paediatricians and Paediatric Cardiologists in Private and Government hospitals in five states (Akwa Ibom, Rivers, Delta, Bayelsa and Cross River) in the Niger Delta region of Nigeria were informed via telephone, Whatsapp and email communications to refer known patients with congenital or acquired heart diseases for the free cardiac screening. The study was approved by the Research and Ethics committee of the University of Uyo Teaching Hospital, Uyo, Akwa Ibom State.

Study population

We selected 35 patients with phenotypic features suggestive of DS[9] to participate in the study during the cardiac screening, program. We excluded any patient who had phenotypic features suggestive of other chromosomal anomalies. Written informed consent was obtained from the parents of the children before including them in the study. An interviewer administered semi-structured questionnaire was then used to obtain demographic data such as the age, sex, parental ages, age of mother at delivery and contact details. The socioeconomic class was determined using the methods described by Oyedeji et al [10]. The patients’ weights were measured using a bassinet weighing scale for infants and a calibrated weighing scale for older children, using standard methods. The heights of the children were taken using a stadiometer to the nearest 0.1 cm while those less than 2 years old had their lengths taken with a non-elastic tape rule. Wasting was assessed using weight for length/height. The CDC charts for children with DS was used in assessing and evaluating wasting in these children.[11]

Study design

This study was a cross sectional study that evaluated the spectrum of congenital heart disease (CHD) in children with DS living in five states of the Niger Delta region of Nigeria

Study procedure

Each child had a transthoracic echocardiography with 2D, M-mode and Doppler measurements done using GE vivid IQ and GE vivid E by two trained paediatric cardiologists. All echocardiograms were thereafter evaluated by the entire cardiology team before a conclusive diagnosis was confirmed. The diagnosis, severity and classification of cardiac malformation were determined according to the recommendations of the American Society of Echocardiography. [12]

Children with only one anatomical heart defect, such as Ventricular septal defect (VSD), Atrial septal defect (ASD), Patent ductus arteriosus (PDA), or with a well-known combination, such as Tetralogy of Fallot (TOF) were classified to have isolated CHD. The presence of two or more anatomical defects with the combination of VSD, ASD, and PDA were categorized as mixed left to Right shunt defects. Co-morbidities documented in this study included the presence of pulmonary hypertension which was determined using the tricuspid regurgitation velocity and right atrial pressures, right ventricular hypertrophy and dilated main pulmonary artery.[13] Other co-morbidities documented included the presence of congestive cardiac failure (CCF), recurrent respiratory tract infections, wasting and delayed milestones.

Statistical analysis

The data was analyzed using the STATA 14.0 Statistical Package (Texas 77845, USA). Means of the children and parental ages were calculated using t-test while proportions and percentages were used to display distribution across the three strata of socioeconomic classification. Bar chart was used to depict frequency of occurrence of co-morbidities in the children. Spectrum and frequency of occurrence of CHD was depicted in percentages using frequency tables.


  Results Top


Out of the 154 children who participated in the cardiac screening exercise, 35(22.7%) had physical features suggestive of DS. Out of the 35 children with DS, there were 17 males and 18 females with a male to female ratio of 0.9:1. The ages of the children ranged from11 days to 114 months; mean age of 25.8 months (95% CI 16.7–34.9 months). All the 35 children with DS seen at the mission had CHD with a mean time from diagnosis of 20.0 months, 95% CI, 11.5–28.5. The age at diagnosis ranged from 11 days to 18 months; mean age of 5.8 months (95% CI 3.6–8.1 months) [see [Table 1].
Table 1: Demographic parameters of children and their parents

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Majority (40.0%) of the children with DS ranked second among the children in the family followed by the third (22.9%) and then the first (17.1%) ranking. The ages of the fathers ranged from 32 to 62 years with a mean age of 40.4 years (95% CI 36.3–44.5 years) while the mothers ages ranged from 30 to 46 years; mean age of 37.8 years (95% CI 36.4–39.2 years). At delivery, the maternal age ranged from 24 to 43 years with a mean age of 35.6 years (95% CI 34.1–37.0 years) [Table 1] majority; 26 (74.3%) of the parents were from the upper socioeconomic class, while 7 (20.0%) and 2 (5.7%) parents were from the middle and lower socioeconomic class respectively [Table 1]]. Seventeen (48.6%) children were on anti-failure medication while 14 (40.0%) were on a pulmonary vasodilator (sildenafil). The most common co-morbidity was congestive heart failure (CHF) noted in 17 (48.6%) of them. This was followed by wasting seen in 15 (42.8%), pulmonary hypertension in 5 (14.3%), respiratory tract infections (RTI) in 4(11.4%) and delayed milestones in 3 (8.6%) [see Figure 1]. All five children with pulmonary hypertension had atrioventricular septal defects (AVSD).
Figure 1: Comorbidities seen in 35 children with Down syndrome and CHD

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Thirty four (97.1%) of the children had acyanotic CHD while only one (2.9%) child had a cyanotic CHD. Of all the cases of CHD, 28 (80.0%) had isolated defects, 5 (14.3%) had mixed defects, 1 (2.85%) had a coexisting rheumatic heart disease (RHD) to his CHD, while 1 (2.85%) child with cyanotic CHD had Tetralogy of Fallot [Table 2]. AVSD was the most common CHD detected in 10 (28.6%) children followed by isolated ventricular septal defects (VSD) in 8 (22.9%) and isolated patent ductus arteriosus in 5(14.3%).
Table 2: Pattern of heart disease seen in the 35 children with Down syndrome

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  Discussion Top


The association of CHD with DS has been widely described in literature and remains the most important contribution to morbidity and mortality in these patients. [14],[15] In our study, all the 35 children with DS had CHD which was not surprising as they were referred after being reviewed by Paediatricians. Echocardiography in all children with phenotypic characteristics of DS at birth has been recommended by the American Academy of Paediatricians for the early detection of CHD.[16]

The mean age of diagnosis of these patients was six months which is late considering that the first 6 months of life of a child with DS and CHD has been reported as the optimal time for surgical repair.[15],[17] Early detection of CHD and prompt surgical intervention is paramount in children with DS who have an increased tendency to develop irreversible pulmonary arterial hypertension (PAH) as early as 6 months of age.[15]

None of the children in this study had received definitive management at the time of review even though some children were as old as 9 years of age. The main barrier to surgical correction is the lack of resources for open heart surgery.[17],[18] Although about two-thirds of the parents belonged to the upper socioeconomic class, it is evident that out of pocket expenditure for health care services offered in Nigeria cannot sustain the high cost of open heart surgery.[17] A viable health insurance scheme will help in decreasing the financial burden on parents by providing prompt and definitive treatment to these children.

We found AVSD to be the most common cardiac defect in this study which is similar to reports from the Western [9],[20] and Northern parts of our country, Nigeria.[21],[22] Our findings also mirror what has been reported in parts of Asia, Europe and Africa.[23],[24],[25] Our findings however contrasts with reports by Otaigbe et al.[26] in Port Harcourt, an urban cosmopolitan city in the Niger Delta who reported patent ductus arteriosus (PDA) as the most common lesion observed in children with DS. The reason for this disparity between our study and that of Otaigbe et al.[26] is not immediately clear. However, considering the fact that the patients in our study were referred from several cities within the region, self-selection bias might have occurred and thus preclude significant generalization of our findings. A large-scale community-based study to screen all babies with DS at birth is thus needed to accurately map out the pattern of cardiac anomalies in this sub-region.

There were more isolated cardiac defects than multiple ones in our study, similar to what has been reported in many parts of Nigeria and the rest of the world.[19],[21],[22],[26] Isolated VSD and AVSD were the main lesions seen in our report, similar to what has been reported globally.[20],[21],[22],[23],[24],[25] The occurrence of these lesions with DS predispose to pulmonary over circulation and hence the early occurrence of co-morbidities such as heart failure and irreversible PAH when surgical closure is not performed early. In Nigeria, cardiac surgical services are not widely available making many of the children to present with PAH even at first appointment with the cardiologist as seen in our report.

Heart failure was a major co-morbidity noted in our study and nearly 50% of the children seen were already on anti-failure medications. This report is similar to findings by other authors.[20] Heart failure is a common complication in children with CHDs especially those lesions associated with large intracardiac shunts.[8],[9] These shunt lesions result in increases in pulmonary blood flow leading to recurrent episodes of respiratory tract infections, PAH and subsequently, failure to thrive.[27] Early initiation of diuretics and other medications to control heart failure is thus advisable in order to prevent early onset PAH.PAH was another co-morbidity which noted only in the children with AVSD. The association of PAH with AVSD in children with DS has been similarly reported in other studies as a common co-morbidity.[27] The large intracardiac lesions lead to increased pulmonary blood flow through left to right shunting of blood. Prolonged exposure of the pulmonary vascular bed to high pulmonary blood flow leads to rapid development of PAH.[27] Although it is not clear if sildenafil was given to prevent or treat pulmonary hypertension in these children, it is important to study the effect of early commencement of sildenafil on the development of pulmonary hypertension in children with DS and left to right shunt lesions.[28] This is important in an environment where open heart surgery is not readily accessible and affordable presently.


  Conclusion Top


AVSD is the most common CHD seen among children with DS in our study. Most of these children also present late in our sub-region thus leading to an increased incidence of co-morbidities especially in those with large left to right shunt lesions. Routine echocardiographic screening of all babies with features suggestive of DS at birth or as soon as possible after birth in order to identify CHD early and institute management promptly is advocated.

Acknowledgement

The authors gratefully acknowledge the Hospitals for Humanity Non-Governmental Organization and Delta Afrik Charitable Organization for sponsoring the cardiac screening exercise and the University of Uyo Teaching Hospital Uyo for hosting the cardiac mission.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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